add HistogramExt method with custom quantiles

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

.gitea/workflows/lint.yml

@@ -1,24 +0,0 @@
-name: lint
-on:
-  pull_request:
-    branches:
-    - master
-    - v3
-jobs:
-  lint:
-    name: lint
-    runs-on: ubuntu-latest
-    steps:
-    - name: setup-go
-      uses: https://gitea.com/actions/setup-go@v3
-      with:
-        go-version: 1.18
-    - name: checkout
-      uses: https://gitea.com/actions/checkout@v3
-    - name: deps
-      run: go get -v -d ./...
-    - name: lint
-      uses: https://github.com/golangci/golangci-lint-action@v3.4.0
-      continue-on-error: true
-      with:
-        version: v1.52

.gitea/workflows/pr.yml

@@ -1,23 +0,0 @@
-name: pr
-on:
-  pull_request:
-    branches:
-    - master
-    - v3
-jobs:
-  test:
-    name: test
-    runs-on: ubuntu-latest
-    steps:
-    - name: checkout
-      uses: https://gitea.com/actions/checkout@v3
-    - name: setup-go
-      uses: https://gitea.com/actions/setup-go@v3
-      with:
-        go-version: 1.18
-    - name: deps
-      run: go get -v -t -d ./...
-    - name: test
-      env:
-        INTEGRATION_TESTS: yes
-      run: go test -mod readonly -v ./...

.github/workflows/job_coverage.yml

@@ -0,0 +1,53 @@
+name: coverage
+
+on:
+  push:
+    branches: [ main, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+  pull_request:
+    branches: [ main, v3, v4 ]
+
+jobs:
+
+  build:
+    if: github.server_url != 'https://github.com'
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+
+    - name: test coverage
+      run: |
+        go test -v -cover ./... -covermode=count -coverprofile coverage.out -coverpkg ./...
+        go tool cover -func coverage.out -o coverage.out
+
+    - name: coverage badge
+      uses: tj-actions/coverage-badge-go@v2
+      with:
+        green: 80
+        filename: coverage.out
+
+    - uses: stefanzweifel/git-auto-commit-action@v4
+      name: autocommit
+      with:
+        commit_message: Apply Code Coverage Badge
+        skip_fetch: false
+        skip_checkout: false
+        file_pattern: ./README.md
+
+    - name: push
+      if: steps.auto-commit-action.outputs.changes_detected == 'true'
+      uses: ad-m/github-push-action@master
+      with:
+        github_token: ${{ github.token }}
+        branch: ${{ github.ref }}

.github/workflows/job_lint.yml

@@ -0,0 +1,29 @@
+name: lint
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches: [ master, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+    - name: setup deps
+      run: go get -v ./...
+    - name: run lint
+      uses: golangci/golangci-lint-action@v6
+      with:
+        version: 'latest'

.github/workflows/job_sync.yml

@@ -0,0 +1,94 @@
+name: sync
+
+on:
+  schedule:
+    - cron: '*/5 * * * *'
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+  sync:
+    if: github.server_url != 'https://github.com'
+    runs-on: ubuntu-latest
+    steps:
+    - name: init
+      run: |
+        git config --global user.email "vtolstov <vtolstov@users.noreply.github.com>"
+        git config --global user.name "github-actions[bot]"
+        echo "machine git.unistack.org login vtolstov password ${{ secrets.TOKEN_GITEA }}" >> /root/.netrc
+        echo "machine github.com login vtolstov password ${{ secrets.TOKEN_GITHUB }}" >> /root/.netrc
+
+    - name: check master
+      id: check_master
+      run: |
+        src_hash=$(git ls-remote https://github.com/${GITHUB_REPOSITORY} refs/heads/master | cut -f1)
+        dst_hash=$(git ls-remote ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} refs/heads/master | cut -f1)
+        echo "src_hash=$src_hash"
+        echo "dst_hash=$dst_hash"
+        if [ "$src_hash" != "$dst_hash" ]; then
+          echo "sync_needed=true" >> $GITHUB_OUTPUT
+        else
+          echo "sync_needed=false" >> $GITHUB_OUTPUT
+        fi
+
+    - name: sync master
+      if: steps.check_master.outputs.sync_needed == 'true'
+      run: |
+        git clone --filter=blob:none --filter=tree:0 --branch master --single-branch ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} repo
+        cd repo
+        git remote add --no-tags --fetch --track master upstream https://github.com/${GITHUB_REPOSITORY}
+        git pull --rebase upstream master
+        git push upstream master --progress
+        git push origin master --progress
+        cd ../
+        rm -rf repo
+
+    - name: check v3
+      id: check_v3
+      run: |
+        src_hash=$(git ls-remote https://github.com/${GITHUB_REPOSITORY} refs/heads/v3 | cut -f1)
+        dst_hash=$(git ls-remote ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} refs/heads/v3 | cut -f1)
+        echo "src_hash=$src_hash"
+        echo "dst_hash=$dst_hash"
+        if [ "$src_hash" != "$dst_hash" ]; then
+          echo "sync_needed=true" >> $GITHUB_OUTPUT
+        else
+          echo "sync_needed=false" >> $GITHUB_OUTPUT
+        fi
+
+    - name: sync v3
+      if: steps.check_v3.outputs.sync_needed == 'true'
+      run: |
+        git clone --filter=blob:none --filter=tree:0 --branch v3 --single-branch ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} repo
+        cd repo
+        git remote add --no-tags --fetch --track v3 upstream https://github.com/${GITHUB_REPOSITORY}
+        git pull --rebase upstream v3
+        git push upstream v3 --progress
+        git push origin v3 --progress
+        cd ../
+        rm -rf repo
+
+    - name: check v4
+      id: check_v4
+      run: |
+        src_hash=$(git ls-remote https://github.com/${GITHUB_REPOSITORY} refs/heads/v4 | cut -f1)
+        dst_hash=$(git ls-remote ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} refs/heads/v4 | cut -f1)
+        echo "src_hash=$src_hash"
+        echo "dst_hash=$dst_hash"
+        if [ "$src_hash" != "$dst_hash" ]; then
+          echo "sync_needed=true" >> $GITHUB_OUTPUT
+        else
+          echo "sync_needed=false" >> $GITHUB_OUTPUT
+        fi
+
+    - name: sync v4
+      if: steps.check_v4.outputs.sync_needed == 'true'
+      run: |
+        git clone --filter=blob:none --filter=tree:0 --branch v4 --single-branch ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} repo
+        cd repo
+        git remote add --no-tags --fetch --track v4 upstream https://github.com/${GITHUB_REPOSITORY}
+        git pull --rebase upstream v4
+        git push upstream v4 --progress
+        git push origin v4 --progress
+        cd ../
+        rm -rf repo

.github/workflows/job_test.yml

@@ -0,0 +1,31 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches: [ master, v3, v4 ]
+  push:
+    branches: [ master, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+    - name: setup deps
+      run: go get -v ./...
+    - name: run test
+      env:
+        INTEGRATION_TESTS: yes
+      run: go test -mod readonly -v ./...

.github/workflows/job_tests.yml

@@ -0,0 +1,50 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches: [ master, v3, v4 ]
+  push:
+    branches: [ master, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: checkout tests
+      uses: actions/checkout@v4
+      with:
+        ref: master
+        filter: 'blob:none'
+        repository: unistack-org/micro-tests
+        path: micro-tests
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+    - name: setup go work
+      env:
+        GOWORK: ${{ github.workspace }}/go.work
+      run: |
+        go work init
+        go work use .
+        go work use micro-tests
+    - name: setup deps
+      env:
+        GOWORK: ${{ github.workspace }}/go.work
+      run: go get -v ./...
+    - name: run tests
+      env:
+        INTEGRATION_TESTS: yes
+        GOWORK: ${{ github.workspace }}/go.work
+      run: |
+        cd micro-tests
+        go test -mod readonly -v ./... || true

.gitignore

@@ -1,6 +1,8 @@
 # Develop tools
 /.vscode/
 /.idea/
+.idea
+.vscode
 
 # Binaries for programs and plugins
 *.exe
@@ -13,6 +15,7 @@
 _obj
 _test
 _build
+.DS_Store
 
 # Architecture specific extensions/prefixes
 *.[568vq]

.golangci.yml

@@ -1,44 +1,5 @@
 run:
-  concurrency: 4
+  concurrency: 8
-  deadline: 5m
+  timeout: 5m
   issues-exit-code: 1
   tests: true
-
-linters-settings:
-  govet:
-    check-shadowing: true
-    enable:
-      - fieldalignment
-
-linters:
-  enable:
-    - govet
-    - deadcode
-    - errcheck
-    - govet
-    - ineffassign
-    - staticcheck
-    - structcheck
-    - typecheck
-    - unused
-    - varcheck
-    - bodyclose
-    - gci
-    - goconst
-    - gocritic
-    - gosimple
-    - gofmt
-    - gofumpt
-    - goimports
-    - revive
-    - gosec
-    - makezero
-    - misspell
-    - nakedret
-    - nestif
-    - nilerr
-    - noctx
-    - prealloc
-    - unconvert
-    - unparam
-  disable-all: false

README.md

@@ -1,4 +1,9 @@
-# Micro [![License](https://img.shields.io/:license-apache-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![Doc](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/github.com/unistack-org/micro/v3?tab=overview) [![Status](https://github.com/unistack-org/micro/workflows/build/badge.svg?branch=master)](https://github.com/unistack-org/micro/actions?query=workflow%3Abuild+branch%3Amaster+event%3Apush) [![Lint](https://goreportcard.com/badge/go.unistack.org/micro/v3)](https://goreportcard.com/report/go.unistack.org/micro/v3) [![Coverage](https://codecov.io/gh/unistack-org/micro/branch/v3/graph/badge.svg?token=OZPO2LP7VS)](https://codecov.io/gh/unistack-org/micro)
+# Micro
+![Coverage](https://img.shields.io/badge/Coverage-33.6%25-yellow)
+[![License](https://img.shields.io/:license-apache-blue.svg)](https://opensource.org/licenses/Apache-2.0)
+[![Doc](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/go.unistack.org/micro/v4?tab=overview)
+[![Status](https://git.unistack.org/unistack-org/micro/actions/workflows/job_tests.yml/badge.svg?branch=v4)](https://git.unistack.org/unistack-org/micro/actions?query=workflow%3Abuild+branch%3Av4+event%3Apush)
+[![Lint](https://goreportcard.com/badge/go.unistack.org/micro/v4)](https://goreportcard.com/report/go.unistack.org/micro/v4)
 
 Micro is a standard library for microservices.
 
@@ -10,30 +15,20 @@ Micro provides the core requirements for distributed systems development includi
 
 Micro abstracts away the details of distributed systems. Here are the main features.
 
-- **Authentication** - Auth is built in as a first class citizen. Authentication and authorization enable secure 
-zero trust networking by providing every service an identity and certificates. This additionally includes rule 
-based access control.
-
 - **Dynamic Config** - Load and hot reload dynamic config from anywhere. The config interface provides a way to load application 
-level config from any source such as env vars, file, etcd. You can merge the sources and even define fallbacks.
+level config from any source such as env vars, cmdline, file, consul, vault... You can merge the sources and even define fallbacks.
 
 - **Data Storage** - A simple data store interface to read, write and delete records. It includes support for memory, file and 
-CockroachDB by default. State and persistence becomes a core requirement beyond prototyping and Micro looks to build that into the framework.
+s3. State and persistence becomes a core requirement beyond prototyping and Micro looks to build that into the framework.
 
 - **Service Discovery** - Automatic service registration and name resolution. Service discovery is at the core of micro service 
 development. When service A needs to speak to service B it needs the location of that service.
 
-- **Load Balancing** - Client side load balancing built on service discovery. Once we have the addresses of any number of instances 
-of a service we now need a way to decide which node to route to. We use random hashed load balancing to provide even distribution 
-across the services and retry a different node if there's a problem. 
-
 - **Message Encoding** - Dynamic message encoding based on content-type. The client and server will use codecs along with content-type 
 to seamlessly encode and decode Go types for you. Any variety of messages could be encoded and sent from different clients. The client 
 and server handle this by default.
 
-- **Transport** - gRPC or http based request/response with support for bidirectional streaming. We provide an abstraction for synchronous communication. A request made to a service will be automatically resolved, load balanced, dialled and streamed.
+- **Async Messaging** - Pub/Sub is built in as a first class citizen for asynchronous communication and event driven architectures.
-
-- **Async Messaging** - PubSub is built in as a first class citizen for asynchronous communication and event driven architectures.
 Event notifications are a core pattern in micro service development.
 
 - **Synchronization** - Distributed systems are often built in an eventually consistent manner. Support for distributed locking and 
@@ -42,10 +37,6 @@ leadership are built in as a Sync interface. When using an eventually consistent
 - **Pluggable Interfaces** - Micro makes use of Go interfaces for each system abstraction. Because of this these interfaces 
 are pluggable and allows Micro to be runtime agnostic.
 
-## Getting Started
-
-To be created.
-
 ## License
 
 Micro is Apache 2.0 licensed.

SECURITY.md

@@ -1,15 +0,0 @@
-# Security Policy
-
-## Supported Versions
-
-Use this section to tell people about which versions of your project are
-currently being supported with security updates.
-
-| Version | Supported          |
-| ------- | ------------------ |
-| 3.7.x   | :white_check_mark: |
-| < 3.7.0 | :x:                |
-
-## Reporting a Vulnerability
-
-If you find any issue, please create github issue in this repo

broker/broker.go

@@ -1,22 +1,29 @@
 // Package broker is an interface used for asynchronous messaging
-package broker // import "go.unistack.org/micro/v3/broker"
+package broker
 
 import (
 	"context"
 	"errors"
+	"time"
 
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 // DefaultBroker default memory broker
-var DefaultBroker = NewBroker()
+var DefaultBroker Broker = NewBroker()
 
 var (
 	// ErrNotConnected returns when broker used but not connected yet
 	ErrNotConnected = errors.New("broker not connected")
 	// ErrDisconnected returns when broker disconnected
 	ErrDisconnected = errors.New("broker disconnected")
+	// ErrInvalidMessage returns when invalid Message passed
+	ErrInvalidMessage = errors.New("invalid message")
+	// ErrInvalidHandler returns when subscriber passed to Subscribe
+	ErrInvalidHandler = errors.New("invalid handler, ony func(Message) error and func([]Message) error supported")
+	// DefaultGracefulTimeout
+	DefaultGracefulTimeout = 5 * time.Second
 )
 
 // Broker is an interface used for asynchronous messaging.
@@ -33,72 +40,44 @@ type Broker interface {
 	Connect(ctx context.Context) error
 	// Disconnect disconnect from broker
 	Disconnect(ctx context.Context) error
+	// NewMessage create new broker message to publish.
+	NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...MessageOption) (Message, error)
 	// Publish message to broker topic
-	Publish(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error
+	Publish(ctx context.Context, topic string, messages ...Message) error
 	// Subscribe subscribes to topic message via handler
-	Subscribe(ctx context.Context, topic string, h Handler, opts ...SubscribeOption) (Subscriber, error)
+	Subscribe(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error)
-	// BatchPublish messages to broker with multiple topics
-	BatchPublish(ctx context.Context, msgs []*Message, opts ...PublishOption) error
-	// BatchSubscribe subscribes to topic messages via handler
-	BatchSubscribe(ctx context.Context, topic string, h BatchHandler, opts ...SubscribeOption) (Subscriber, error)
 	// String type of broker
 	String() string
+	// Live returns broker liveness
+	Live() bool
+	// Ready returns broker readiness
+	Ready() bool
+	// Health returns broker health
+	Health() bool
 }
 
-// Handler is used to process messages via a subscription of a topic.
+type (
-type Handler func(Event) error
+	FuncPublish   func(ctx context.Context, topic string, messages ...Message) error
+	HookPublish   func(next FuncPublish) FuncPublish
+	FuncSubscribe func(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error)
+	HookSubscribe func(next FuncSubscribe) FuncSubscribe
+)
 
-// Events contains multiple events
+// Message is given to a subscription handler for processing
-type Events []Event
+type Message interface {
-
+	// Context for the message.
-// Ack try to ack all events and return
+	Context() context.Context
-func (evs Events) Ack() error {
+	// Topic returns message destination topic.
-	var err error
-	for _, ev := range evs {
-		if err = ev.Ack(); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// SetError sets error on event
-func (evs Events) SetError(err error) {
-	for _, ev := range evs {
-		ev.SetError(err)
-	}
-}
-
-// BatchHandler is used to process messages in batches via a subscription of a topic.
-type BatchHandler func(Events) error
-
-// Event is given to a subscription handler for processing
-type Event interface {
-	// Topic returns event topic
 	Topic() string
-	// Message returns broker message
+	// Header returns message headers.
-	Message() *Message
+	Header() metadata.Metadata
-	// Ack acknowledge message
+	// Body returns broker message []byte slice
+	Body() []byte
+	// Unmarshal try to decode message body to dst.
+	// This is helper method that uses codec.Unmarshal.
+	Unmarshal(dst interface{}, opts ...codec.Option) error
+	// Ack acknowledge message if supported.
 	Ack() error
-	// Error returns message error (like decoding errors or some other)
-	Error() error
-	// SetError set event processing error
-	SetError(err error)
-}
-
-// Message is used to transfer data
-type Message struct {
-	// Header contains message metadata
-	Header metadata.Metadata
-	// Body contains message body
-	Body codec.RawMessage
-}
-
-// NewMessage create broker message with topic filled
-func NewMessage(topic string) *Message {
-	m := &Message{Header: metadata.New(2)}
-	m.Header.Set(metadata.HeaderTopic, topic)
-	return m
 }
 
 // Subscriber is a convenience return type for the Subscribe method

broker/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Broker, bool) {
 	return c, ok
 }
 
+// MustContext returns broker from passed context
+func MustContext(ctx context.Context) Broker {
+	b, ok := FromContext(ctx)
+	if !ok {
+		panic("missing broker")
+	}
+	return b
+}
+
 // NewContext savess broker in context
 func NewContext(ctx context.Context, s Broker) context.Context {
 	if ctx == nil {
@@ -33,6 +42,16 @@ func SetSubscribeOption(k, v interface{}) SubscribeOption {
 	}
 }
 
+// SetMessageOption returns a function to setup a context with given value
+func SetMessageOption(k, v interface{}) MessageOption {
+	return func(o *MessageOptions) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}
+
 // SetOption returns a function to setup a context with given value
 func SetOption(k, v interface{}) Option {
 	return func(o *Options) {
@@ -42,13 +61,3 @@ func SetOption(k, v interface{}) Option {
 		o.Context = context.WithValue(o.Context, k, v)
 	}
 }
-
-// SetPublishOption returns a function to setup a context with given value
-func SetPublishOption(k, v interface{}) PublishOption {
-	return func(o *PublishOptions) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, k, v)
-	}
-}

broker/context_test.go

@@ -49,17 +49,6 @@ func TestSetSubscribeOption(t *testing.T) {
 	}
 }
 
-func TestSetPublishOption(t *testing.T) {
-	type key struct{}
-	o := SetPublishOption(key{}, "test")
-	opts := &PublishOptions{}
-	o(opts)
-
-	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
-		t.Fatal("SetPublishOption not works")
-	}
-}
-
 func TestSetOption(t *testing.T) {
 	type key struct{}
 	o := SetOption(key{}, "test")

broker/memory.go

@@ -1,342 +0,0 @@
-package broker
-
-import (
-	"context"
-	"sync"
-
-	"go.unistack.org/micro/v3/logger"
-	"go.unistack.org/micro/v3/metadata"
-	maddr "go.unistack.org/micro/v3/util/addr"
-	"go.unistack.org/micro/v3/util/id"
-	mnet "go.unistack.org/micro/v3/util/net"
-	"go.unistack.org/micro/v3/util/rand"
-)
-
-type memoryBroker struct {
-	subscribers map[string][]*memorySubscriber
-	addr        string
-	opts        Options
-	sync.RWMutex
-	connected bool
-}
-
-type memoryEvent struct {
-	err     error
-	message interface{}
-	topic   string
-	opts    Options
-}
-
-type memorySubscriber struct {
-	ctx          context.Context
-	exit         chan bool
-	handler      Handler
-	batchhandler BatchHandler
-	id           string
-	topic        string
-	opts         SubscribeOptions
-}
-
-func (m *memoryBroker) Options() Options {
-	return m.opts
-}
-
-func (m *memoryBroker) Address() string {
-	return m.addr
-}
-
-func (m *memoryBroker) Connect(ctx context.Context) error {
-	m.Lock()
-	defer m.Unlock()
-
-	if m.connected {
-		return nil
-	}
-
-	// use 127.0.0.1 to avoid scan of all network interfaces
-	addr, err := maddr.Extract("127.0.0.1")
-	if err != nil {
-		return err
-	}
-	var rng rand.Rand
-	i := rng.Intn(20000)
-	// set addr with port
-	addr = mnet.HostPort(addr, 10000+i)
-
-	m.addr = addr
-	m.connected = true
-
-	return nil
-}
-
-func (m *memoryBroker) Disconnect(ctx context.Context) error {
-	m.Lock()
-	defer m.Unlock()
-
-	if !m.connected {
-		return nil
-	}
-
-	m.connected = false
-	return nil
-}
-
-func (m *memoryBroker) Init(opts ...Option) error {
-	for _, o := range opts {
-		o(&m.opts)
-	}
-	return nil
-}
-
-func (m *memoryBroker) Publish(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error {
-	msg.Header.Set(metadata.HeaderTopic, topic)
-	return m.publish(ctx, []*Message{msg}, opts...)
-}
-
-func (m *memoryBroker) BatchPublish(ctx context.Context, msgs []*Message, opts ...PublishOption) error {
-	return m.publish(ctx, msgs, opts...)
-}
-
-func (m *memoryBroker) publish(ctx context.Context, msgs []*Message, opts ...PublishOption) error {
-	m.RLock()
-	if !m.connected {
-		m.RUnlock()
-		return ErrNotConnected
-	}
-	m.RUnlock()
-
-	var err error
-
-	select {
-	case <-ctx.Done():
-		return ctx.Err()
-	default:
-		options := NewPublishOptions(opts...)
-
-		msgTopicMap := make(map[string]Events)
-		for _, v := range msgs {
-			p := &memoryEvent{opts: m.opts}
-
-			if m.opts.Codec == nil || options.BodyOnly {
-				p.topic, _ = v.Header.Get(metadata.HeaderTopic)
-				p.message = v.Body
-			} else {
-				p.topic, _ = v.Header.Get(metadata.HeaderTopic)
-				p.message, err = m.opts.Codec.Marshal(v)
-				if err != nil {
-					return err
-				}
-			}
-			msgTopicMap[p.topic] = append(msgTopicMap[p.topic], p)
-		}
-
-		beh := m.opts.BatchErrorHandler
-		eh := m.opts.ErrorHandler
-
-		for t, ms := range msgTopicMap {
-			m.RLock()
-			subs, ok := m.subscribers[t]
-			m.RUnlock()
-			if !ok {
-				continue
-			}
-
-			for _, sub := range subs {
-				if sub.opts.BatchErrorHandler != nil {
-					beh = sub.opts.BatchErrorHandler
-				}
-				if sub.opts.ErrorHandler != nil {
-					eh = sub.opts.ErrorHandler
-				}
-
-				switch {
-				// batch processing
-				case sub.batchhandler != nil:
-					if err = sub.batchhandler(ms); err != nil {
-						ms.SetError(err)
-						if beh != nil {
-							_ = beh(ms)
-						} else if m.opts.Logger.V(logger.ErrorLevel) {
-							m.opts.Logger.Error(m.opts.Context, err.Error())
-						}
-					} else if sub.opts.AutoAck {
-						if err = ms.Ack(); err != nil {
-							m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
-						}
-					}
-					// single processing
-				case sub.handler != nil:
-					for _, p := range ms {
-						if err = sub.handler(p); err != nil {
-							p.SetError(err)
-							if eh != nil {
-								_ = eh(p)
-							} else if m.opts.Logger.V(logger.ErrorLevel) {
-								m.opts.Logger.Error(m.opts.Context, err.Error())
-							}
-						} else if sub.opts.AutoAck {
-							if err = p.Ack(); err != nil {
-								m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
-							}
-						}
-					}
-				}
-			}
-		}
-	}
-
-	return nil
-}
-
-func (m *memoryBroker) BatchSubscribe(ctx context.Context, topic string, handler BatchHandler, opts ...SubscribeOption) (Subscriber, error) {
-	m.RLock()
-	if !m.connected {
-		m.RUnlock()
-		return nil, ErrNotConnected
-	}
-	m.RUnlock()
-
-	sid, err := id.New()
-	if err != nil {
-		return nil, err
-	}
-
-	options := NewSubscribeOptions(opts...)
-
-	sub := &memorySubscriber{
-		exit:         make(chan bool, 1),
-		id:           sid,
-		topic:        topic,
-		batchhandler: handler,
-		opts:         options,
-		ctx:          ctx,
-	}
-
-	m.Lock()
-	m.subscribers[topic] = append(m.subscribers[topic], sub)
-	m.Unlock()
-
-	go func() {
-		<-sub.exit
-		m.Lock()
-		newSubscribers := make([]*memorySubscriber, 0, len(m.subscribers)-1)
-		for _, sb := range m.subscribers[topic] {
-			if sb.id == sub.id {
-				continue
-			}
-			newSubscribers = append(newSubscribers, sb)
-		}
-		m.subscribers[topic] = newSubscribers
-		m.Unlock()
-	}()
-
-	return sub, nil
-}
-
-func (m *memoryBroker) Subscribe(ctx context.Context, topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
-	m.RLock()
-	if !m.connected {
-		m.RUnlock()
-		return nil, ErrNotConnected
-	}
-	m.RUnlock()
-
-	sid, err := id.New()
-	if err != nil {
-		return nil, err
-	}
-
-	options := NewSubscribeOptions(opts...)
-
-	sub := &memorySubscriber{
-		exit:    make(chan bool, 1),
-		id:      sid,
-		topic:   topic,
-		handler: handler,
-		opts:    options,
-		ctx:     ctx,
-	}
-
-	m.Lock()
-	m.subscribers[topic] = append(m.subscribers[topic], sub)
-	m.Unlock()
-
-	go func() {
-		<-sub.exit
-		m.Lock()
-		newSubscribers := make([]*memorySubscriber, 0, len(m.subscribers)-1)
-		for _, sb := range m.subscribers[topic] {
-			if sb.id == sub.id {
-				continue
-			}
-			newSubscribers = append(newSubscribers, sb)
-		}
-		m.subscribers[topic] = newSubscribers
-		m.Unlock()
-	}()
-
-	return sub, nil
-}
-
-func (m *memoryBroker) String() string {
-	return "memory"
-}
-
-func (m *memoryBroker) Name() string {
-	return m.opts.Name
-}
-
-func (m *memoryEvent) Topic() string {
-	return m.topic
-}
-
-func (m *memoryEvent) Message() *Message {
-	switch v := m.message.(type) {
-	case *Message:
-		return v
-	case []byte:
-		msg := &Message{}
-		if err := m.opts.Codec.Unmarshal(v, msg); err != nil {
-			if m.opts.Logger.V(logger.ErrorLevel) {
-				m.opts.Logger.Error(m.opts.Context, "[memory]: failed to unmarshal: %v", err)
-			}
-			return nil
-		}
-		return msg
-	}
-
-	return nil
-}
-
-func (m *memoryEvent) Ack() error {
-	return nil
-}
-
-func (m *memoryEvent) Error() error {
-	return m.err
-}
-
-func (m *memoryEvent) SetError(err error) {
-	m.err = err
-}
-
-func (m *memorySubscriber) Options() SubscribeOptions {
-	return m.opts
-}
-
-func (m *memorySubscriber) Topic() string {
-	return m.topic
-}
-
-func (m *memorySubscriber) Unsubscribe(ctx context.Context) error {
-	m.exit <- true
-	return nil
-}
-
-// NewBroker return new memory broker
-func NewBroker(opts ...Option) Broker {
-	return &memoryBroker{
-		opts:        NewOptions(opts...),
-		subscribers: make(map[string][]*memorySubscriber),
-	}
-}

broker/memory/memory.go

@@ -0,0 +1,341 @@
+package broker
+
+import (
+	"context"
+	"strings"
+	"sync"
+
+	"go.unistack.org/micro/v4/broker"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/options"
+	maddr "go.unistack.org/micro/v4/util/addr"
+	"go.unistack.org/micro/v4/util/id"
+	mnet "go.unistack.org/micro/v4/util/net"
+	"go.unistack.org/micro/v4/util/rand"
+)
+
+type Broker struct {
+	funcPublish   broker.FuncPublish
+	funcSubscribe broker.FuncSubscribe
+	subscribers   map[string][]*Subscriber
+	addr          string
+	opts          broker.Options
+	mu            sync.RWMutex
+	connected     bool
+}
+
+type memoryMessage struct {
+	c     codec.Codec
+	topic string
+	ctx   context.Context
+	body  []byte
+	hdr   metadata.Metadata
+	opts  broker.MessageOptions
+}
+
+func (m *memoryMessage) Ack() error {
+	return nil
+}
+
+func (m *memoryMessage) Body() []byte {
+	return m.body
+}
+
+func (m *memoryMessage) Header() metadata.Metadata {
+	return m.hdr
+}
+
+func (m *memoryMessage) Context() context.Context {
+	return m.ctx
+}
+
+func (m *memoryMessage) Topic() string {
+	return ""
+}
+
+func (m *memoryMessage) Unmarshal(dst interface{}, opts ...codec.Option) error {
+	return m.c.Unmarshal(m.body, dst)
+}
+
+type Subscriber struct {
+	ctx     context.Context
+	exit    chan bool
+	handler interface{}
+	id      string
+	topic   string
+	opts    broker.SubscribeOptions
+}
+
+func (b *Broker) newCodec(ct string) (codec.Codec, error) {
+	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
+		ct = ct[:idx]
+	}
+	b.mu.RLock()
+	c, ok := b.opts.Codecs[ct]
+	b.mu.RUnlock()
+	if ok {
+		return c, nil
+	}
+	return nil, codec.ErrUnknownContentType
+}
+
+func (b *Broker) Options() broker.Options {
+	return b.opts
+}
+
+func (b *Broker) Address() string {
+	return b.addr
+}
+
+func (b *Broker) Connect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if b.connected {
+		return nil
+	}
+
+	// use 127.0.0.1 to avoid scan of all network interfaces
+	addr, err := maddr.Extract("127.0.0.1")
+	if err != nil {
+		return err
+	}
+	var rng rand.Rand
+	i := rng.Intn(20000)
+	// set addr with port
+	addr = mnet.HostPort(addr, 10000+i)
+
+	b.addr = addr
+	b.connected = true
+
+	return nil
+}
+
+func (b *Broker) Disconnect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if !b.connected {
+		return nil
+	}
+
+	b.connected = false
+	return nil
+}
+
+func (b *Broker) Init(opts ...broker.Option) error {
+	for _, o := range opts {
+		o(&b.opts)
+	}
+
+	b.funcPublish = b.fnPublish
+	b.funcSubscribe = b.fnSubscribe
+
+	b.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case broker.HookPublish:
+			b.funcPublish = h(b.funcPublish)
+		case broker.HookSubscribe:
+			b.funcSubscribe = h(b.funcSubscribe)
+		}
+	})
+
+	return nil
+}
+
+func (b *Broker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...broker.MessageOption) (broker.Message, error) {
+	options := broker.NewMessageOptions(opts...)
+	if options.ContentType == "" {
+		options.ContentType = b.opts.ContentType
+	}
+	m := &memoryMessage{ctx: ctx, hdr: hdr, opts: options}
+	c, err := b.newCodec(m.opts.ContentType)
+	if err == nil {
+		m.body, err = c.Marshal(body)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}
+
+func (b *Broker) Publish(ctx context.Context, topic string, messages ...broker.Message) error {
+	return b.funcPublish(ctx, topic, messages...)
+}
+
+func (b *Broker) fnPublish(ctx context.Context, topic string, messages ...broker.Message) error {
+	return b.publish(ctx, topic, messages...)
+}
+
+func (b *Broker) publish(ctx context.Context, topic string, messages ...broker.Message) error {
+	b.mu.RLock()
+	if !b.connected {
+		b.mu.RUnlock()
+		return broker.ErrNotConnected
+	}
+	b.mu.RUnlock()
+
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	b.mu.RLock()
+	subs, ok := b.subscribers[topic]
+	b.mu.RUnlock()
+	if !ok {
+		return nil
+	}
+
+	var err error
+
+	for _, sub := range subs {
+		switch s := sub.handler.(type) {
+		default:
+			if b.opts.Logger.V(logger.ErrorLevel) {
+				b.opts.Logger.Error(ctx, "broker  handler error", broker.ErrInvalidHandler)
+			}
+		case func(broker.Message) error:
+			for _, message := range messages {
+				msg, ok := message.(*memoryMessage)
+				if !ok {
+					if b.opts.Logger.V(logger.ErrorLevel) {
+						b.opts.Logger.Error(ctx, "broker handler error", broker.ErrInvalidMessage)
+					}
+				}
+				msg.topic = topic
+				if err = s(msg); err == nil && sub.opts.AutoAck {
+					err = msg.Ack()
+				}
+				if err != nil {
+					if b.opts.Logger.V(logger.ErrorLevel) {
+						b.opts.Logger.Error(ctx, "broker handler error", err)
+					}
+				}
+			}
+		case func([]broker.Message) error:
+			if err = s(messages); err == nil && sub.opts.AutoAck {
+				for _, message := range messages {
+					err = message.Ack()
+					if err != nil {
+						if b.opts.Logger.V(logger.ErrorLevel) {
+							b.opts.Logger.Error(ctx, "broker handler error", err)
+						}
+					}
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+func (b *Broker) Subscribe(ctx context.Context, topic string, handler interface{}, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	return b.funcSubscribe(ctx, topic, handler, opts...)
+}
+
+func (b *Broker) fnSubscribe(ctx context.Context, topic string, handler interface{}, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	if err := broker.IsValidHandler(handler); err != nil {
+		return nil, err
+	}
+
+	b.mu.RLock()
+	if !b.connected {
+		b.mu.RUnlock()
+		return nil, broker.ErrNotConnected
+	}
+	b.mu.RUnlock()
+
+	sid, err := id.New()
+	if err != nil {
+		return nil, err
+	}
+
+	options := broker.NewSubscribeOptions(opts...)
+
+	sub := &Subscriber{
+		exit:    make(chan bool, 1),
+		id:      sid,
+		topic:   topic,
+		handler: handler,
+		opts:    options,
+		ctx:     ctx,
+	}
+
+	b.mu.Lock()
+	b.subscribers[topic] = append(b.subscribers[topic], sub)
+	b.mu.Unlock()
+
+	go func() {
+		<-sub.exit
+		b.mu.Lock()
+		newSubscribers := make([]*Subscriber, 0, len(b.subscribers)-1)
+		for _, sb := range b.subscribers[topic] {
+			if sb.id == sub.id {
+				continue
+			}
+			newSubscribers = append(newSubscribers, sb)
+		}
+		b.subscribers[topic] = newSubscribers
+		b.mu.Unlock()
+	}()
+
+	return sub, nil
+}
+
+func (b *Broker) String() string {
+	return "memory"
+}
+
+func (b *Broker) Name() string {
+	return b.opts.Name
+}
+
+func (b *Broker) Live() bool {
+	return true
+}
+
+func (b *Broker) Ready() bool {
+	return true
+}
+
+func (b *Broker) Health() bool {
+	return true
+}
+
+func (m *Subscriber) Options() broker.SubscribeOptions {
+	return m.opts
+}
+
+func (m *Subscriber) Topic() string {
+	return m.topic
+}
+
+func (m *Subscriber) Unsubscribe(ctx context.Context) error {
+	m.exit <- true
+	return nil
+}
+
+// NewBroker return new memory broker
+func NewBroker(opts ...broker.Option) broker.Broker {
+	return &Broker{
+		opts:        broker.NewOptions(opts...),
+		subscribers: make(map[string][]*Subscriber),
+	}
+}

broker/memory/memory_test.go

@@ -0,0 +1,74 @@
+package broker
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"go.uber.org/atomic"
+	"go.unistack.org/micro/v4/broker"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
+)
+
+type hldr struct {
+	c atomic.Int64
+}
+
+func (h *hldr) Handler(m broker.Message) error {
+	h.c.Add(1)
+	return nil
+}
+
+func TestMemoryBroker(t *testing.T) {
+	b := NewBroker(broker.Codec("application/octet-stream", codec.NewCodec()))
+	ctx := context.Background()
+
+	if err := b.Init(); err != nil {
+		t.Fatalf("Unexpected init error %v", err)
+	}
+
+	if err := b.Connect(ctx); err != nil {
+		t.Fatalf("Unexpected connect error %v", err)
+	}
+
+	topic := "test"
+	count := int64(10)
+
+	h := &hldr{}
+
+	sub, err := b.Subscribe(ctx, topic, h.Handler)
+	if err != nil {
+		t.Fatalf("Unexpected error subscribing %v", err)
+	}
+
+	for i := int64(0); i < count; i++ {
+		message, err := b.NewMessage(ctx,
+			metadata.Pairs(
+				"foo", "bar",
+				"id", fmt.Sprintf("%d", i),
+			),
+			[]byte(`"hello world"`),
+			broker.MessageContentType("application/octet-stream"),
+		)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if err := b.Publish(ctx, topic, message); err != nil {
+			t.Fatalf("Unexpected error publishing %d err: %v", i, err)
+		}
+	}
+
+	if err := sub.Unsubscribe(ctx); err != nil {
+		t.Fatalf("Unexpected error unsubscribing from %s: %v", topic, err)
+	}
+
+	if err := b.Disconnect(ctx); err != nil {
+		t.Fatalf("Unexpected connect error %v", err)
+	}
+
+	if h.c.Load() != count {
+		t.Fatal("invalid messages count received")
+	}
+}

broker/memory_test.go

@@ -1,105 +0,0 @@
-package broker
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	"go.unistack.org/micro/v3/metadata"
-)
-
-func TestMemoryBatchBroker(t *testing.T) {
-	b := NewBroker()
-	ctx := context.Background()
-
-	if err := b.Connect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-
-	topic := "test"
-	count := 10
-
-	fn := func(evts Events) error {
-		return evts.Ack()
-	}
-
-	sub, err := b.BatchSubscribe(ctx, topic, fn)
-	if err != nil {
-		t.Fatalf("Unexpected error subscribing %v", err)
-	}
-
-	msgs := make([]*Message, 0, count)
-	for i := 0; i < count; i++ {
-		message := &Message{
-			Header: map[string]string{
-				metadata.HeaderTopic: topic,
-				"foo":                "bar",
-				"id":                 fmt.Sprintf("%d", i),
-			},
-			Body: []byte(`"hello world"`),
-		}
-		msgs = append(msgs, message)
-	}
-
-	if err := b.BatchPublish(ctx, msgs); err != nil {
-		t.Fatalf("Unexpected error publishing %v", err)
-	}
-
-	if err := sub.Unsubscribe(ctx); err != nil {
-		t.Fatalf("Unexpected error unsubscribing from %s: %v", topic, err)
-	}
-
-	if err := b.Disconnect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-}
-
-func TestMemoryBroker(t *testing.T) {
-	b := NewBroker()
-	ctx := context.Background()
-
-	if err := b.Connect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-
-	topic := "test"
-	count := 10
-
-	fn := func(p Event) error {
-		return nil
-	}
-
-	sub, err := b.Subscribe(ctx, topic, fn)
-	if err != nil {
-		t.Fatalf("Unexpected error subscribing %v", err)
-	}
-
-	msgs := make([]*Message, 0, count)
-	for i := 0; i < count; i++ {
-		message := &Message{
-			Header: map[string]string{
-				metadata.HeaderTopic: topic,
-				"foo":                "bar",
-				"id":                 fmt.Sprintf("%d", i),
-			},
-			Body: []byte(`"hello world"`),
-		}
-		msgs = append(msgs, message)
-
-		if err := b.Publish(ctx, topic, message); err != nil {
-			t.Fatalf("Unexpected error publishing %d err: %v", i, err)
-		}
-	}
-
-	if err := b.BatchPublish(ctx, msgs); err != nil {
-		t.Fatalf("Unexpected error publishing %v", err)
-	}
-
-	if err := sub.Unsubscribe(ctx); err != nil {
-		t.Fatalf("Unexpected error unsubscribing from %s: %v", topic, err)
-	}
-
-	if err := b.Disconnect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-}

broker/noop.go

@@ -0,0 +1,179 @@
+package broker
+
+import (
+	"context"
+	"strings"
+	"sync"
+
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/options"
+)
+
+type NoopBroker struct {
+	funcPublish   FuncPublish
+	funcSubscribe FuncSubscribe
+	opts          Options
+	mu            sync.RWMutex
+}
+
+func (b *NoopBroker) newCodec(ct string) (codec.Codec, error) {
+	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
+		ct = ct[:idx]
+	}
+	b.mu.RLock()
+	c, ok := b.opts.Codecs[ct]
+	b.mu.RUnlock()
+	if ok {
+		return c, nil
+	}
+	return nil, codec.ErrUnknownContentType
+}
+
+func NewBroker(opts ...Option) *NoopBroker {
+	b := &NoopBroker{opts: NewOptions(opts...)}
+	b.funcPublish = b.fnPublish
+	b.funcSubscribe = b.fnSubscribe
+
+	return b
+}
+
+func (b *NoopBroker) Health() bool {
+	return true
+}
+
+func (b *NoopBroker) Live() bool {
+	return true
+}
+
+func (b *NoopBroker) Ready() bool {
+	return true
+}
+
+func (b *NoopBroker) Name() string {
+	return b.opts.Name
+}
+
+func (b *NoopBroker) String() string {
+	return "noop"
+}
+
+func (b *NoopBroker) Options() Options {
+	return b.opts
+}
+
+func (b *NoopBroker) Init(opts ...Option) error {
+	for _, opt := range opts {
+		opt(&b.opts)
+	}
+
+	b.funcPublish = b.fnPublish
+	b.funcSubscribe = b.fnSubscribe
+
+	b.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookPublish:
+			b.funcPublish = h(b.funcPublish)
+		case HookSubscribe:
+			b.funcSubscribe = h(b.funcSubscribe)
+		}
+	})
+
+	return nil
+}
+
+func (b *NoopBroker) Connect(_ context.Context) error {
+	return nil
+}
+
+func (b *NoopBroker) Disconnect(_ context.Context) error {
+	return nil
+}
+
+func (b *NoopBroker) Address() string {
+	return strings.Join(b.opts.Addrs, ",")
+}
+
+type noopMessage struct {
+	c    codec.Codec
+	ctx  context.Context
+	body []byte
+	hdr  metadata.Metadata
+	opts MessageOptions
+}
+
+func (m *noopMessage) Ack() error {
+	return nil
+}
+
+func (m *noopMessage) Body() []byte {
+	return m.body
+}
+
+func (m *noopMessage) Header() metadata.Metadata {
+	return m.hdr
+}
+
+func (m *noopMessage) Context() context.Context {
+	return m.ctx
+}
+
+func (m *noopMessage) Topic() string {
+	return ""
+}
+
+func (m *noopMessage) Unmarshal(dst interface{}, opts ...codec.Option) error {
+	return m.c.Unmarshal(m.body, dst)
+}
+
+func (b *NoopBroker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...MessageOption) (Message, error) {
+	options := NewMessageOptions(opts...)
+	if options.ContentType == "" {
+		options.ContentType = b.opts.ContentType
+	}
+	m := &noopMessage{ctx: ctx, hdr: hdr, opts: options}
+	c, err := b.newCodec(m.opts.ContentType)
+	if err == nil {
+		m.body, err = c.Marshal(body)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}
+
+func (b *NoopBroker) fnPublish(_ context.Context, _ string, _ ...Message) error {
+	return nil
+}
+
+func (b *NoopBroker) Publish(ctx context.Context, topic string, msg ...Message) error {
+	return b.funcPublish(ctx, topic, msg...)
+}
+
+type NoopSubscriber struct {
+	ctx     context.Context
+	topic   string
+	handler interface{}
+	opts    SubscribeOptions
+}
+
+func (b *NoopBroker) fnSubscribe(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error) {
+	return &NoopSubscriber{ctx: ctx, topic: topic, opts: NewSubscribeOptions(opts...), handler: handler}, nil
+}
+
+func (b *NoopBroker) Subscribe(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error) {
+	return b.funcSubscribe(ctx, topic, handler, opts...)
+}
+
+func (s *NoopSubscriber) Options() SubscribeOptions {
+	return s.opts
+}
+
+func (s *NoopSubscriber) Topic() string {
+	return s.topic
+}
+
+func (s *NoopSubscriber) Unsubscribe(_ context.Context) error {
+	return nil
+}

broker/noop_test.go

@@ -0,0 +1,35 @@
+package broker
+
+import (
+	"context"
+	"testing"
+)
+
+type testHook struct {
+	f bool
+}
+
+func (t *testHook) Publish1(fn FuncPublish) FuncPublish {
+	return func(ctx context.Context, topic string, messages ...Message) error {
+		t.f = true
+		return fn(ctx, topic, messages...)
+	}
+}
+
+func TestNoopHook(t *testing.T) {
+	h := &testHook{}
+
+	b := NewBroker(Hooks(HookPublish(h.Publish1)))
+
+	if err := b.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := b.Publish(context.TODO(), "", nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if !h.f {
+		t.Fatal("hook not works")
+	}
+}

broker/options.go

@@ -5,55 +5,74 @@ import (
 	"crypto/tls"
 	"time"
 
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v4/options"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/register"
+	"go.unistack.org/micro/v4/sync"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Options struct
 type Options struct {
+	// Name holds the broker name
+	Name string
+
 	// Tracer used for tracing
 	Tracer tracer.Tracer
 	// Register can be used for clustering
 	Register register.Register
-	// Codec holds the codec for marshal/unmarshal
+	// Codecs holds the codecs for marshal/unmarshal based on content-type
-	Codec codec.Codec
+	Codecs map[string]codec.Codec
 	// Logger used for logging
 	Logger logger.Logger
 	// Meter used for metrics
 	Meter meter.Meter
 	// Context holds external options
 	Context context.Context
+
+	// Wait waits for a collection of goroutines to finish
+	Wait *sync.WaitGroup
 	// TLSConfig holds tls.TLSConfig options
 	TLSConfig *tls.Config
-	// ErrorHandler used when broker can't unmarshal incoming message
+
-	ErrorHandler Handler
-	// BatchErrorHandler used when broker can't unmashal incoming messages
-	BatchErrorHandler BatchHandler
-	// Name holds the broker name
-	Name string
 	// Addrs holds the broker address
 	Addrs []string
+	// Hooks can be run before broker Publish/BatchPublish and
+	// Subscribe/BatchSubscribe methods
+	Hooks options.Hooks
+
+	// GracefulTimeout contains time to wait to finish in flight requests
+	GracefulTimeout time.Duration
+
+	// ContentType will be used if no content-type set when creating message
+	ContentType string
 }
 
 // NewOptions create new Options
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Register: register.DefaultRegister,
+		Register:        register.DefaultRegister,
-		Logger:   logger.DefaultLogger,
+		Logger:          logger.DefaultLogger,
-		Context:  context.Background(),
+		Context:         context.Background(),
-		Meter:    meter.DefaultMeter,
+		Meter:           meter.DefaultMeter,
-		Codec:    codec.DefaultCodec,
+		Codecs:          make(map[string]codec.Codec),
-		Tracer:   tracer.DefaultTracer,
+		Tracer:          tracer.DefaultTracer,
+		GracefulTimeout: DefaultGracefulTimeout,
+		ContentType:     DefaultContentType,
 	}
+
 	for _, o := range opts {
 		o(&options)
 	}
+
 	return options
 }
 
+// DefaultContentType is the default content-type if not specified
+var DefaultContentType = ""
+
 // Context sets the context option
 func Context(ctx context.Context) Option {
 	return func(o *Options) {
@@ -61,17 +80,27 @@ func Context(ctx context.Context) Option {
 	}
 }
 
-// PublishOptions struct
+// ContentType used by default if not specified
-type PublishOptions struct {
+func ContentType(ct string) Option {
-	// Context holds external options
+	return func(o *Options) {
-	Context context.Context
+		o.ContentType = ct
-	// BodyOnly flag says the message contains raw body bytes
+	}
-	BodyOnly bool
 }
 
-// NewPublishOptions creates PublishOptions struct
+// MessageOptions struct
-func NewPublishOptions(opts ...PublishOption) PublishOptions {
+type MessageOptions struct {
-	options := PublishOptions{
+	// ContentType for message body
+	ContentType string
+	// BodyOnly flag says the message contains raw body bytes and don't need
+	// codec Marshal method
+	BodyOnly bool
+	// Context holds custom options
+	Context context.Context
+}
+
+// NewMessageOptions creates MessageOptions struct
+func NewMessageOptions(opts ...MessageOption) MessageOptions {
+	options := MessageOptions{
 		Context: context.Background(),
 	}
 	for _, o := range opts {
@@ -84,10 +113,6 @@ func NewPublishOptions(opts ...PublishOption) PublishOptions {
 type SubscribeOptions struct {
 	// Context holds external options
 	Context context.Context
-	// ErrorHandler used when broker can't unmarshal incoming message
-	ErrorHandler Handler
-	// BatchErrorHandler used when broker can't unmashal incoming messages
-	BatchErrorHandler BatchHandler
 	// Group holds consumer group
 	Group string
 	// AutoAck flag specifies auto ack of incoming message when no error happens
@@ -103,20 +128,20 @@ type SubscribeOptions struct {
 // Option func
 type Option func(*Options)
 
-// PublishOption func
+// MessageOption func
-type PublishOption func(*PublishOptions)
+type MessageOption func(*MessageOptions)
 
-// PublishBodyOnly publish only body of the message
+// MessageContentType sets message content-type that used to Marshal
-func PublishBodyOnly(b bool) PublishOption {
+func MessageContentType(ct string) MessageOption {
-	return func(o *PublishOptions) {
+	return func(o *MessageOptions) {
-		o.BodyOnly = b
+		o.ContentType = ct
 	}
 }
 
-// PublishContext sets the context
+// MessageBodyOnly publish only body of the message
-func PublishContext(ctx context.Context) PublishOption {
+func MessageBodyOnly(b bool) MessageOption {
-	return func(o *PublishOptions) {
+	return func(o *MessageOptions) {
-		o.Context = ctx
+		o.BodyOnly = b
 	}
 }
 
@@ -127,51 +152,10 @@ func Addrs(addrs ...string) Option {
 	}
 }
 
-// Codec sets the codec used for encoding/decoding used where
+// Codec sets the codec used for encoding/decoding messages
-// a broker does not support headers
+func Codec(ct string, c codec.Codec) Option {
-func Codec(c codec.Codec) Option {
 	return func(o *Options) {
-		o.Codec = c
+		o.Codecs[ct] = c
-	}
-}
-
-// ErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func ErrorHandler(h Handler) Option {
-	return func(o *Options) {
-		o.ErrorHandler = h
-	}
-}
-
-// BatchErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func BatchErrorHandler(h BatchHandler) Option {
-	return func(o *Options) {
-		o.BatchErrorHandler = h
-	}
-}
-
-// SubscribeErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func SubscribeErrorHandler(h Handler) SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.ErrorHandler = h
-	}
-}
-
-// SubscribeBatchErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func SubscribeBatchErrorHandler(h BatchHandler) SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.BatchErrorHandler = h
-	}
-}
-
-// Queue sets the subscribers queue
-// Deprecated
-func Queue(name string) SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.Group = name
 	}
 }
 
@@ -224,6 +208,13 @@ func Name(n string) Option {
 	}
 }
 
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}
+
 // SubscribeContext set context
 func SubscribeContext(ctx context.Context) SubscribeOption {
 	return func(o *SubscribeOptions) {
@@ -231,14 +222,6 @@ func SubscribeContext(ctx context.Context) SubscribeOption {
 	}
 }
 
-// DisableAutoAck disables auto ack
-// Deprecated
-func DisableAutoAck() SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.AutoAck = false
-	}
-}
-
 // SubscribeAutoAck contol auto acking of messages
 // after they have been handled.
 func SubscribeAutoAck(b bool) SubscribeOption {

broker/subscriber.go

@@ -0,0 +1,14 @@
+package broker
+
+// IsValidHandler func signature
+func IsValidHandler(sub interface{}) error {
+	switch sub.(type) {
+	default:
+		return ErrInvalidHandler
+	case func(Message) error:
+		break
+	case func([]Message) error:
+		break
+	}
+	return nil
+}

client/backoff.go

@@ -5,7 +5,7 @@ import (
 	"math"
 	"time"
 
-	"go.unistack.org/micro/v3/util/backoff"
+	"go.unistack.org/micro/v4/util/backoff"
 )
 
 // BackoffFunc is the backoff call func
@@ -17,13 +17,13 @@ func BackoffExp(_ context.Context, _ Request, attempts int) (time.Duration, erro
 }
 
 // BackoffInterval specifies randomization interval for backoff func
-func BackoffInterval(min time.Duration, max time.Duration) BackoffFunc {
+func BackoffInterval(minTime time.Duration, maxTime time.Duration) BackoffFunc {
 	return func(_ context.Context, _ Request, attempts int) (time.Duration, error) {
 		td := time.Duration(math.Pow(float64(attempts), math.E)) * time.Millisecond * 100
-		if td < min {
+		if td < minTime {
-			return min, nil
+			return minTime, nil
-		} else if td > max {
+		} else if td > maxTime {
-			return max, nil
+			return maxTime, nil
 		}
 		return td, nil
 	}

client/backoff_test.go

@@ -34,23 +34,23 @@ func TestBackoffExp(t *testing.T) {
 }
 
 func TestBackoffInterval(t *testing.T) {
-	min := 100 * time.Millisecond
+	minTime := 100 * time.Millisecond
-	max := 300 * time.Millisecond
+	maxTime := 300 * time.Millisecond
 
 	r := &testRequest{
 		service: "test",
 		method:  "test",
 	}
 
-	fn := BackoffInterval(min, max)
+	fn := BackoffInterval(minTime, maxTime)
 	for i := 0; i < 5; i++ {
 		d, err := fn(context.TODO(), r, i)
 		if err != nil {
 			t.Fatal(err)
 		}
 
-		if d < min || d > max {
+		if d < minTime || d > maxTime {
-			t.Fatalf("Expected %v < %v < %v", min, d, max)
+			t.Fatalf("Expected %v < %v < %v", minTime, d, maxTime)
 		}
 	}
 }

client/client.go

@@ -1,12 +1,12 @@
 // Package client is an interface for an RPC client
-package client // import "go.unistack.org/micro/v3/client"
+package client
 
 import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 var (
@@ -29,28 +29,23 @@ var (
 )
 
 // Client is the interface used to make requests to services.
-// It supports Request/Response via Transport and Publishing via the Broker.
 // It also supports bidirectional streaming of requests.
 type Client interface {
 	Name() string
 	Init(opts ...Option) error
 	Options() Options
-	NewMessage(topic string, msg interface{}, opts ...MessageOption) Message
 	NewRequest(service string, endpoint string, req interface{}, opts ...RequestOption) Request
 	Call(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error
 	Stream(ctx context.Context, req Request, opts ...CallOption) (Stream, error)
-	Publish(ctx context.Context, msg Message, opts ...PublishOption) error
-	BatchPublish(ctx context.Context, msg []Message, opts ...PublishOption) error
 	String() string
 }
 
-// Message is the interface for publishing asynchronously
+type (
-type Message interface {
+	FuncCall   func(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error
-	Topic() string
+	HookCall   func(next FuncCall) FuncCall
-	Payload() interface{}
+	FuncStream func(ctx context.Context, req Request, opts ...CallOption) (Stream, error)
-	ContentType() string
+	HookStream func(next FuncStream) FuncStream
-	Metadata() metadata.Metadata
+)
-}
 
 // Request is the interface for a synchronous request used by Call or Stream
 type Request interface {
@@ -110,11 +105,5 @@ type Option func(*Options)
 // CallOption used by Call or Stream
 type CallOption func(*CallOptions)
 
-// PublishOption used by Publish
-type PublishOption func(*PublishOptions)
-
-// MessageOption used by NewMessage
-type MessageOption func(*MessageOptions)
-
 // RequestOption used by NewRequest
 type RequestOption func(*RequestOptions)

client/client_call_options_test.go

@@ -1,26 +0,0 @@
-package client
-
-import (
-	"context"
-	"testing"
-	"time"
-)
-
-func TestNewClientCallOptions(t *testing.T) {
-	var flag bool
-	w := func(fn CallFunc) CallFunc {
-		flag = true
-		return fn
-	}
-	c := NewClientCallOptions(NewClient(),
-		WithAddress("127.0.0.1"),
-		WithCallWrapper(w),
-		WithRequestTimeout(1*time.Millisecond),
-		WithRetries(0),
-		WithBackoff(BackoffInterval(10*time.Millisecond, 100*time.Millisecond)),
-	)
-	_ = c.Call(context.TODO(), c.NewRequest("service", "endpoint", nil), nil)
-	if !flag {
-		t.Fatalf("NewClientCallOptions not works")
-	}
-}

client/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Client, bool) {
 	return c, ok
 }
 
+// MustContext get client from context
+func MustContext(ctx context.Context) Client {
+	c, ok := FromContext(ctx)
+	if !ok {
+		panic("missing client")
+	}
+	return c
+}
+
 // NewContext put client in context
 func NewContext(ctx context.Context, c Client) context.Context {
 	if ctx == nil {
@@ -23,16 +32,6 @@ func NewContext(ctx context.Context, c Client) context.Context {
 	return context.WithValue(ctx, clientKey{}, c)
 }
 
-// SetPublishOption returns a function to setup a context with given value
-func SetPublishOption(k, v interface{}) PublishOption {
-	return func(o *PublishOptions) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, k, v)
-	}
-}
-
 // SetCallOption returns a function to setup a context with given value
 func SetCallOption(k, v interface{}) CallOption {
 	return func(o *CallOptions) {

client/context_test.go

@@ -39,17 +39,6 @@ func TestNewNilContext(t *testing.T) {
 	}
 }
 
-func TestSetPublishOption(t *testing.T) {
-	type key struct{}
-	o := SetPublishOption(key{}, "test")
-	opts := &PublishOptions{}
-	o(opts)
-
-	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
-		t.Fatal("SetPublishOption not works")
-	}
-}
-
 func TestSetCallOption(t *testing.T) {
 	type key struct{}
 	o := SetCallOption(key{}, "test")

client/lookup.go

@@ -4,8 +4,8 @@ import (
 	"context"
 	"sort"
 
-	"go.unistack.org/micro/v3/errors"
+	"go.unistack.org/micro/v4/errors"
-	"go.unistack.org/micro/v3/router"
+	"go.unistack.org/micro/v4/router"
 )
 
 // LookupFunc is used to lookup routes for a service

client/noop.go

@@ -3,13 +3,16 @@ package client
 import (
 	"context"
 	"fmt"
+	"strconv"
 	"time"
 
-	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/errors"
-	"go.unistack.org/micro/v3/errors"
+	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/options"
-	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v4/selector"
+	"go.unistack.org/micro/v4/semconv"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // DefaultCodecs will be used to encode/decode data
@@ -18,13 +21,9 @@ var DefaultCodecs = map[string]codec.Codec{
 }
 
 type noopClient struct {
-	opts Options
+	funcCall   FuncCall
-}
+	funcStream FuncStream
-
+	opts       Options
-type noopMessage struct {
-	topic   string
-	payload interface{}
-	opts    MessageOptions
 }
 
 type noopRequest struct {
@@ -39,16 +38,12 @@ type noopRequest struct {
 
 // NewClient returns new noop client
 func NewClient(opts ...Option) Client {
-	nc := &noopClient{opts: NewOptions(opts...)}
+	n := &noopClient{opts: NewOptions(opts...)}
-	// wrap in reverse
 
-	c := Client(nc)
+	n.funcCall = n.fnCall
+	n.funcStream = n.fnStream
 
-	for i := len(nc.opts.Wrappers); i > 0; i-- {
+	return n
-		c = nc.opts.Wrappers[i-1](c)
-	}
-
-	return c
 }
 
 func (n *noopClient) Name() string {
@@ -100,10 +95,13 @@ func (n *noopResponse) Read() ([]byte, error) {
 	return nil, nil
 }
 
-type noopStream struct{}
+type noopStream struct {
+	err error
+	ctx context.Context
+}
 
 func (n *noopStream) Context() context.Context {
-	return context.Background()
+	return n.ctx
 }
 
 func (n *noopStream) Request() Request {
@@ -131,47 +129,40 @@ func (n *noopStream) RecvMsg(interface{}) error {
 }
 
 func (n *noopStream) Error() error {
-	return nil
+	return n.err
 }
 
 func (n *noopStream) Close() error {
-	return nil
+	if sp, ok := tracer.SpanFromContext(n.ctx); ok && sp != nil {
+		if n.err != nil {
+			sp.SetStatus(tracer.SpanStatusError, n.err.Error())
+		}
+		sp.Finish()
+	}
+	return n.err
 }
 
 func (n *noopStream) CloseSend() error {
-	return nil
+	return n.err
-}
-
-func (n *noopMessage) Topic() string {
-	return n.topic
-}
-
-func (n *noopMessage) Payload() interface{} {
-	return n.payload
-}
-
-func (n *noopMessage) ContentType() string {
-	return n.opts.ContentType
-}
-
-func (n *noopMessage) Metadata() metadata.Metadata {
-	return n.opts.Metadata
-}
-
-func (n *noopClient) newCodec(contentType string) (codec.Codec, error) {
-	if cf, ok := n.opts.Codecs[contentType]; ok {
-		return cf, nil
-	}
-	if cf, ok := DefaultCodecs[contentType]; ok {
-		return cf, nil
-	}
-	return nil, codec.ErrUnknownContentType
 }
 
 func (n *noopClient) Init(opts ...Option) error {
 	for _, o := range opts {
 		o(&n.opts)
 	}
+
+	n.funcCall = n.fnCall
+	n.funcStream = n.fnStream
+
+	n.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookCall:
+			n.funcCall = h(n.funcCall)
+		case HookStream:
+			n.funcStream = h(n.funcStream)
+		}
+	})
+
 	return nil
 }
 
@@ -184,6 +175,31 @@ func (n *noopClient) String() string {
 }
 
 func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error {
+	ts := time.Now()
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
+	var sp tracer.Span
+	ctx, sp = n.opts.Tracer.Start(ctx, "rpc-client",
+		tracer.WithSpanKind(tracer.SpanKindClient),
+		tracer.WithSpanLabels("endpoint", req.Endpoint()),
+	)
+	err := n.funcCall(ctx, req, rsp, opts...)
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Dec()
+	te := time.Since(ts)
+	n.opts.Meter.Summary(semconv.ClientRequestLatencyMicroseconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+	n.opts.Meter.Histogram(semconv.ClientRequestDurationSeconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+
+	if me := errors.FromError(err); me == nil {
+		sp.Finish()
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "success", "code", strconv.Itoa(int(200))).Inc()
+	} else {
+		sp.SetStatus(tracer.SpanStatusError, err.Error())
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "failure", "code", strconv.Itoa(int(me.Code))).Inc()
+	}
+
+	return err
+}
+
+func (n *noopClient) fnCall(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error {
 	// make a copy of call opts
 	callOpts := n.opts.CallOptions
 	for _, opt := range opts {
@@ -212,11 +228,8 @@ func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opt
 	}
 
 	// make copy of call method
-	hcall := n.call
+	hcall := func(ctx context.Context, addr string, req Request, rsp interface{}, opts CallOptions) error {
-
+		return nil
-	// wrap the call in reverse
-	for i := len(callOpts.CallWrappers); i > 0; i-- {
-		hcall = callOpts.CallWrappers[i-1](hcall)
 	}
 
 	// use the router passed as a call option, or fallback to the rpc clients router
@@ -241,7 +254,7 @@ func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opt
 		// call backoff first. Someone may want an initial start delay
 		t, err := callOpts.Backoff(ctx, req, i)
 		if err != nil {
-			return errors.InternalServerError("go.micro.client", err.Error())
+			return errors.InternalServerError("go.micro.client", "%s", err)
 		}
 
 		// only sleep if greater than 0
@@ -255,7 +268,7 @@ func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opt
 			// TODO apply any filtering here
 			routes, err = n.opts.Lookup(ctx, req, callOpts)
 			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
+				return errors.InternalServerError("go.micro.client", "%s", err)
 			}
 
 			// balance the list of nodes
@@ -315,20 +328,36 @@ func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opt
 	return gerr
 }
 
-func (n *noopClient) call(ctx context.Context, addr string, req Request, rsp interface{}, opts CallOptions) error {
+func (n *noopClient) NewRequest(service, endpoint string, _ interface{}, _ ...RequestOption) Request {
-	return nil
-}
-
-func (n *noopClient) NewRequest(service, endpoint string, req interface{}, opts ...RequestOption) Request {
 	return &noopRequest{service: service, endpoint: endpoint}
 }
 
-func (n *noopClient) NewMessage(topic string, msg interface{}, opts ...MessageOption) Message {
+func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption) (Stream, error) {
-	options := NewMessageOptions(append([]MessageOption{MessageContentType(n.opts.ContentType)}, opts...)...)
+	ts := time.Now()
-	return &noopMessage{topic: topic, payload: msg, opts: options}
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
+	var sp tracer.Span
+	ctx, sp = n.opts.Tracer.Start(ctx, "rpc-client",
+		tracer.WithSpanKind(tracer.SpanKindClient),
+		tracer.WithSpanLabels("endpoint", req.Endpoint()),
+	)
+	stream, err := n.funcStream(ctx, req, opts...)
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Dec()
+	te := time.Since(ts)
+	n.opts.Meter.Summary(semconv.ClientRequestLatencyMicroseconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+	n.opts.Meter.Histogram(semconv.ClientRequestDurationSeconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+
+	if me := errors.FromError(err); me == nil {
+		sp.Finish()
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "success", "code", strconv.Itoa(int(200))).Inc()
+	} else {
+		sp.SetStatus(tracer.SpanStatusError, err.Error())
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "failure", "code", strconv.Itoa(int(me.Code))).Inc()
+	}
+
+	return stream, err
 }
 
-func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption) (Stream, error) {
+func (n *noopClient) fnStream(ctx context.Context, req Request, opts ...CallOption) (Stream, error) {
 	var err error
 
 	// make a copy of call opts
@@ -388,7 +417,7 @@ func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption
 		// call backoff first. Someone may want an initial start delay
 		t, cerr := callOpts.Backoff(ctx, req, i)
 		if cerr != nil {
-			return nil, errors.InternalServerError("go.micro.client", cerr.Error())
+			return nil, errors.InternalServerError("go.micro.client", "%s", cerr)
 		}
 
 		// only sleep if greater than 0
@@ -402,7 +431,7 @@ func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption
 			// TODO apply any filtering here
 			routes, err = n.opts.Lookup(ctx, req, callOpts)
 			if err != nil {
-				return nil, errors.InternalServerError("go.micro.client", err.Error())
+				return nil, errors.InternalServerError("go.micro.client", "%s", err)
 			}
 
 			// balance the list of nodes
@@ -468,71 +497,6 @@ func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption
 	return nil, grr
 }
 
-func (n *noopClient) stream(ctx context.Context, addr string, req Request, opts CallOptions) (Stream, error) {
+func (n *noopClient) stream(ctx context.Context, _ string, _ Request, _ CallOptions) (Stream, error) {
-	return &noopStream{}, nil
+	return &noopStream{ctx: ctx}, nil
-}
-
-func (n *noopClient) BatchPublish(ctx context.Context, ps []Message, opts ...PublishOption) error {
-	return n.publish(ctx, ps, opts...)
-}
-
-func (n *noopClient) Publish(ctx context.Context, p Message, opts ...PublishOption) error {
-	return n.publish(ctx, []Message{p}, opts...)
-}
-
-func (n *noopClient) publish(ctx context.Context, ps []Message, opts ...PublishOption) error {
-	options := NewPublishOptions(opts...)
-
-	msgs := make([]*broker.Message, 0, len(ps))
-
-	for _, p := range ps {
-		md, ok := metadata.FromOutgoingContext(ctx)
-		if !ok {
-			md = metadata.New(0)
-		}
-
-		iter := p.Metadata().Iterator()
-		var k, v string
-		for iter.Next(&k, &v) {
-			md.Set(k, v)
-		}
-
-		md[metadata.HeaderContentType] = p.ContentType()
-
-		topic := p.Topic()
-
-		// get the exchange
-		if len(options.Exchange) > 0 {
-			topic = options.Exchange
-		}
-
-		md[metadata.HeaderTopic] = topic
-
-		var body []byte
-
-		// passed in raw data
-		if d, ok := p.Payload().(*codec.Frame); ok {
-			body = d.Data
-		} else {
-			// use codec for payload
-			cf, err := n.newCodec(p.ContentType())
-			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
-			}
-
-			// set the body
-			b, err := cf.Marshal(p.Payload())
-			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
-			}
-			body = b
-		}
-
-		msgs = append(msgs, &broker.Message{Header: md, Body: body})
-	}
-
-	return n.opts.Broker.BatchPublish(ctx, msgs,
-		broker.PublishContext(options.Context),
-		broker.PublishBodyOnly(options.BodyOnly),
-	)
 }

client/options.go

@@ -6,23 +6,31 @@ import (
 	"net"
 	"time"
 
-	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v3/network/transport"
+	"go.unistack.org/micro/v4/options"
-	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v4/register"
-	"go.unistack.org/micro/v3/router"
+	"go.unistack.org/micro/v4/router"
-	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v4/selector"
-	"go.unistack.org/micro/v3/selector/random"
+	"go.unistack.org/micro/v4/selector/random"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Options holds client options
 type Options struct {
-	// Transport used for transfer messages
+	// Codecs map
-	Transport transport.Transport
+	Codecs map[string]codec.Codec
+
+	// Proxy is used for proxy requests
+	Proxy string
+	// ContentType is used to select codec
+	ContentType string
+	// Name is the client name
+	Name string
+
 	// Selector used to select needed address
 	Selector selector.Selector
 	// Logger used to log messages
@@ -37,28 +45,28 @@ type Options struct {
 	Context context.Context
 	// Router used to get route
 	Router router.Router
+
 	// TLSConfig specifies tls.Config for secure connection
 	TLSConfig *tls.Config
-	// Codecs map
+
-	Codecs map[string]codec.Codec
 	// Lookup func used to get destination addr
 	Lookup LookupFunc
-	// Proxy is used for proxy requests
+	// ContextDialer used to connect
-	Proxy string
+	ContextDialer func(context.Context, string) (net.Conn, error)
-	// ContentType is used to select codec
+
-	ContentType string
-	// Name is the client name
-	Name string
 	// Wrappers contains wrappers
 	Wrappers []Wrapper
+	// Hooks can be run before broker Publish/BatchPublish and
+	// Subscribe/BatchSubscribe methods
+	Hooks options.Hooks
+
 	// CallOptions contains default CallOptions
 	CallOptions CallOptions
+
 	// PoolSize connection pool size
 	PoolSize int
 	// PoolTTL connection pool ttl
 	PoolTTL time.Duration
-	// ContextDialer used to connect
-	ContextDialer func(context.Context, string) (net.Conn, error)
 }
 
 // NewCallOptions creates new call options struct
@@ -72,6 +80,16 @@ func NewCallOptions(opts ...CallOption) CallOptions {
 
 // CallOptions holds client call options
 type CallOptions struct {
+	// RequestMetadata holds additional metadata for call
+	RequestMetadata metadata.Metadata
+
+	// Network name
+	Network string
+	// Content-Type
+	ContentType string
+	// AuthToken string
+	AuthToken string
+
 	// Selector selects addr
 	Selector selector.Selector
 	// Context used for deadline
@@ -79,35 +97,30 @@ type CallOptions struct {
 	// Router used for route
 	Router router.Router
 	// Retry func used for retries
+
+	// ResponseMetadata holds additional metadata from call
+	ResponseMetadata *metadata.Metadata
+
 	Retry RetryFunc
 	// Backoff func used for backoff when retry
 	Backoff BackoffFunc
-	// Network name
+	// ContextDialer used to connect
-	Network string
+	ContextDialer func(context.Context, string) (net.Conn, error)
-	// Content-Type
+
-	ContentType string
-	// AuthToken string
-	AuthToken string
 	// Address specifies static addr list
 	Address []string
 	// SelectOptions selector options
 	SelectOptions []selector.SelectOption
-	// CallWrappers call wrappers
+
-	CallWrappers []CallWrapper
 	// StreamTimeout stream timeout
 	StreamTimeout time.Duration
 	// RequestTimeout request timeout
 	RequestTimeout time.Duration
-	// RequestMetadata holds additional metadata for call
+
-	RequestMetadata metadata.Metadata
-	// ResponseMetadata holds additional metadata from call
-	ResponseMetadata *metadata.Metadata
 	// DialTimeout dial timeout
 	DialTimeout time.Duration
 	// Retries specifies retries num
 	Retries int
-	// ContextDialer used to connect
-	ContextDialer func(context.Context, string) (net.Conn, error)
 }
 
 // ContextDialer pass ContextDialer to client
@@ -124,43 +137,6 @@ func Context(ctx context.Context) Option {
 	}
 }
 
-// NewPublishOptions create new PublishOptions struct from option
-func NewPublishOptions(opts ...PublishOption) PublishOptions {
-	options := PublishOptions{}
-	for _, o := range opts {
-		o(&options)
-	}
-	return options
-}
-
-// PublishOptions holds publish options
-type PublishOptions struct {
-	// Context used for external options
-	Context context.Context
-	// Exchange topic exchange name
-	Exchange string
-	// BodyOnly will publish only message body
-	BodyOnly bool
-}
-
-// NewMessageOptions creates message options struct
-func NewMessageOptions(opts ...MessageOption) MessageOptions {
-	options := MessageOptions{Metadata: metadata.New(1)}
-	for _, o := range opts {
-		o(&options)
-	}
-	return options
-}
-
-// MessageOptions holds client message options
-type MessageOptions struct {
-	// Metadata additional metadata
-	Metadata metadata.Metadata
-	// ContentType specify content-type of message
-	// deprecated
-	ContentType string
-}
-
 // NewRequestOptions creates new RequestOptions struct
 func NewRequestOptions(opts ...RequestOption) RequestOptions {
 	options := RequestOptions{}
@@ -185,25 +161,23 @@ func NewOptions(opts ...Option) Options {
 	options := Options{
 		Context:     context.Background(),
 		ContentType: DefaultContentType,
-		Codecs:      make(map[string]codec.Codec),
+		Codecs:      DefaultCodecs,
 		CallOptions: CallOptions{
 			Context:        context.Background(),
 			Backoff:        DefaultBackoff,
 			Retry:          DefaultRetry,
 			Retries:        DefaultRetries,
 			RequestTimeout: DefaultRequestTimeout,
-			DialTimeout:    transport.DefaultDialTimeout,
 		},
-		Lookup:    LookupRoute,
+		Lookup:   LookupRoute,
-		PoolSize:  DefaultPoolSize,
+		PoolSize: DefaultPoolSize,
-		PoolTTL:   DefaultPoolTTL,
+		PoolTTL:  DefaultPoolTTL,
-		Selector:  random.NewSelector(),
+		Selector: random.NewSelector(),
-		Logger:    logger.DefaultLogger,
+		Logger:   logger.DefaultLogger,
-		Broker:    broker.DefaultBroker,
+		Broker:   broker.DefaultBroker,
-		Meter:     meter.DefaultMeter,
+		Meter:    meter.DefaultMeter,
-		Tracer:    tracer.DefaultTracer,
+		Tracer:   tracer.DefaultTracer,
-		Router:    router.DefaultRouter,
+		Router:   router.DefaultRouter,
-		Transport: transport.DefaultTransport,
 	}
 
 	for _, o := range opts {
@@ -276,13 +250,6 @@ func PoolTTL(d time.Duration) Option {
 	}
 }
 
-// Transport to use for communication e.g http, rabbitmq, etc
-func Transport(t transport.Transport) Option {
-	return func(o *Options) {
-		o.Transport = t
-	}
-}
-
 // Register sets the routers register
 func Register(r register.Register) Option {
 	return func(o *Options) {
@@ -306,20 +273,6 @@ func Selector(s selector.Selector) Option {
 	}
 }
 
-// Wrap adds a wrapper to the list of options passed into the client
-func Wrap(w Wrapper) Option {
-	return func(o *Options) {
-		o.Wrappers = append(o.Wrappers, w)
-	}
-}
-
-// WrapCall adds a wrapper to the list of CallFunc wrappers
-func WrapCall(cw ...CallWrapper) Option {
-	return func(o *Options) {
-		o.CallOptions.CallWrappers = append(o.CallOptions.CallWrappers, cw...)
-	}
-}
-
 // Backoff is used to set the backoff function used when retrying Calls
 func Backoff(fn BackoffFunc) Option {
 	return func(o *Options) {
@@ -346,14 +299,6 @@ func TLSConfig(t *tls.Config) Option {
 	return func(o *Options) {
 		// set the internal tls
 		o.TLSConfig = t
-
-		// set the default transport if one is not
-		// already set. Required for Init call below.
-
-		// set the transport tls
-		_ = o.Transport.Init(
-			transport.TLSConfig(t),
-		)
 	}
 }
 
@@ -392,43 +337,6 @@ func DialTimeout(d time.Duration) Option {
 	}
 }
 
-// WithExchange sets the exchange to route a message through
-// Deprecated
-func WithExchange(e string) PublishOption {
-	return func(o *PublishOptions) {
-		o.Exchange = e
-	}
-}
-
-// PublishExchange sets the exchange to route a message through
-func PublishExchange(e string) PublishOption {
-	return func(o *PublishOptions) {
-		o.Exchange = e
-	}
-}
-
-// WithBodyOnly publish only message body
-// DERECATED
-func WithBodyOnly(b bool) PublishOption {
-	return func(o *PublishOptions) {
-		o.BodyOnly = b
-	}
-}
-
-// PublishBodyOnly publish only message body
-func PublishBodyOnly(b bool) PublishOption {
-	return func(o *PublishOptions) {
-		o.BodyOnly = b
-	}
-}
-
-// PublishContext sets the context in publish options
-func PublishContext(ctx context.Context) PublishOption {
-	return func(o *PublishOptions) {
-		o.Context = ctx
-	}
-}
-
 // WithContextDialer pass ContextDialer to client call
 func WithContextDialer(fn func(context.Context, string) (net.Conn, error)) CallOption {
 	return func(o *CallOptions) {
@@ -450,13 +358,6 @@ func WithAddress(a ...string) CallOption {
 	}
 }
 
-// WithCallWrapper is a CallOption which adds to the existing CallFunc wrappers
-func WithCallWrapper(cw ...CallWrapper) CallOption {
-	return func(o *CallOptions) {
-		o.CallWrappers = append(o.CallWrappers, cw...)
-	}
-}
-
 // WithBackoff is a CallOption which overrides that which
 // set in Options.CallOptions
 func WithBackoff(fn BackoffFunc) CallOption {
@@ -526,13 +427,6 @@ func WithAuthToken(t string) CallOption {
 	}
 }
 
-// WithNetwork is a CallOption which sets the network attribute
-func WithNetwork(n string) CallOption {
-	return func(o *CallOptions) {
-		o.Network = n
-	}
-}
-
 // WithRouter sets the router to use for this call
 func WithRouter(r router.Router) CallOption {
 	return func(o *CallOptions) {
@@ -554,30 +448,6 @@ func WithSelectOptions(sops ...selector.SelectOption) CallOption {
 	}
 }
 
-// WithMessageContentType sets the message content type
-// Deprecated
-func WithMessageContentType(ct string) MessageOption {
-	return func(o *MessageOptions) {
-		o.Metadata.Set(metadata.HeaderContentType, ct)
-		o.ContentType = ct
-	}
-}
-
-// MessageContentType sets the message content type
-func MessageContentType(ct string) MessageOption {
-	return func(o *MessageOptions) {
-		o.Metadata.Set(metadata.HeaderContentType, ct)
-		o.ContentType = ct
-	}
-}
-
-// MessageMetadata sets the message metadata
-func MessageMetadata(k, v string) MessageOption {
-	return func(o *MessageOptions) {
-		o.Metadata.Set(k, v)
-	}
-}
-
 // StreamingRequest specifies that request is streaming
 func StreamingRequest(b bool) RequestOption {
 	return func(o *RequestOptions) {
@@ -591,3 +461,10 @@ func RequestContentType(ct string) RequestOption {
 		o.ContentType = ct
 	}
 }
+
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}

client/retry.go

@@ -3,7 +3,7 @@ package client
 import (
 	"context"
 
-	"go.unistack.org/micro/v3/errors"
+	"go.unistack.org/micro/v4/errors"
 )
 
 // RetryFunc that returning either false or a non-nil error will result in the call not being retried

client/retry_test.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"testing"
 
-	"go.unistack.org/micro/v3/errors"
+	"go.unistack.org/micro/v4/errors"
 )
 
 func TestRetryAlways(t *testing.T) {

client/test_request.go

@@ -1,7 +1,7 @@
 package client
 
 import (
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
 )
 
 type testRequest struct {

cluster/cluster.go

@@ -0,0 +1,47 @@
+package cluster
+
+import (
+	"context"
+
+	"go.unistack.org/micro/v4/metadata"
+)
+
+// Message sent to member in cluster
+type Message interface {
+	// Header returns message headers
+	Header() metadata.Metadata
+	// Body returns broker message may be []byte slice or some go struct or interface
+	Body() interface{}
+}
+
+type Node interface {
+	// Name returns node name
+	Name() string
+	// Address returns node address
+	Address() string
+	// Metadata returns node metadata
+	Metadata() metadata.Metadata
+}
+
+// Cluster interface used for cluster communication across nodes
+type Cluster interface {
+	// Join is used to take an existing members and performing state sync
+	Join(ctx context.Context, addr ...string) error
+	// Leave broadcast a leave message and stop listeners
+	Leave(ctx context.Context) error
+	// Ping is used to probe live status of the node
+	Ping(ctx context.Context, node Node, payload []byte) error
+	// Members returns the cluster members
+	Members() ([]Node, error)
+	// Broadcast send message for all members in cluster, if filter is not nil, nodes may be filtered
+	// by key/value pairs
+	Broadcast(ctx context.Context, msg Message, filter ...string) error
+	// Unicast send message to single member in cluster
+	Unicast(ctx context.Context, node Node, msg Message) error
+	// Live returns cluster liveness
+	Live() bool
+	// Ready returns cluster readiness
+	Ready() bool
+	// Health returns cluster health
+	Health() bool
+}

cluster/hasql/cluster.go

@@ -0,0 +1,235 @@
+package sql
+
+import (
+	"context"
+	"database/sql"
+	"reflect"
+	"unsafe"
+
+	"golang.yandex/hasql/v2"
+)
+
+func newSQLRowError() *sql.Row {
+	row := &sql.Row{}
+	t := reflect.TypeOf(row).Elem()
+	field, _ := t.FieldByName("err")
+	rowPtr := unsafe.Pointer(row)
+	errFieldPtr := unsafe.Pointer(uintptr(rowPtr) + field.Offset)
+	errPtr := (*error)(errFieldPtr)
+	*errPtr = ErrorNoAliveNodes
+	return row
+}
+
+type ClusterQuerier interface {
+	Querier
+	WaitForNodes(ctx context.Context, criterion ...hasql.NodeStateCriterion) error
+}
+
+type Cluster struct {
+	hasql   *hasql.Cluster[Querier]
+	options ClusterOptions
+}
+
+// NewCluster returns [Querier] that provides cluster of nodes
+func NewCluster[T Querier](opts ...ClusterOption) (ClusterQuerier, error) {
+	options := ClusterOptions{Context: context.Background()}
+	for _, opt := range opts {
+		opt(&options)
+	}
+	if options.NodeChecker == nil {
+		return nil, ErrClusterChecker
+	}
+	if options.NodeDiscoverer == nil {
+		return nil, ErrClusterDiscoverer
+	}
+	if options.NodePicker == nil {
+		return nil, ErrClusterPicker
+	}
+
+	if options.Retries < 1 {
+		options.Retries = 1
+	}
+
+	if options.NodeStateCriterion == 0 {
+		options.NodeStateCriterion = hasql.Primary
+	}
+
+	options.Options = append(options.Options, hasql.WithNodePicker(options.NodePicker))
+	if p, ok := options.NodePicker.(*CustomPicker[Querier]); ok {
+		p.opts.Priority = options.NodePriority
+	}
+
+	c, err := hasql.NewCluster(
+		options.NodeDiscoverer,
+		options.NodeChecker,
+		options.Options...,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Cluster{hasql: c, options: options}, nil
+}
+
+func (c *Cluster) BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error) {
+	var tx *sql.Tx
+	var err error
+
+	retries := 0
+	c.hasql.NodesIter(c.getNodeStateCriterion(ctx))(func(n *hasql.Node[Querier]) bool {
+		for ; retries < c.options.Retries; retries++ {
+			if tx, err = n.DB().BeginTx(ctx, opts); err != nil && retries >= c.options.Retries {
+				return true
+			}
+		}
+		return false
+	})
+
+	if tx == nil && err == nil {
+		err = ErrorNoAliveNodes
+	}
+
+	return tx, err
+}
+
+func (c *Cluster) Close() error {
+	return c.hasql.Close()
+}
+
+func (c *Cluster) Conn(ctx context.Context) (*sql.Conn, error) {
+	var conn *sql.Conn
+	var err error
+
+	retries := 0
+	c.hasql.NodesIter(c.getNodeStateCriterion(ctx))(func(n *hasql.Node[Querier]) bool {
+		for ; retries < c.options.Retries; retries++ {
+			if conn, err = n.DB().Conn(ctx); err != nil && retries >= c.options.Retries {
+				return true
+			}
+		}
+		return false
+	})
+
+	if conn == nil && err == nil {
+		err = ErrorNoAliveNodes
+	}
+
+	return conn, err
+}
+
+func (c *Cluster) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
+	var res sql.Result
+	var err error
+
+	retries := 0
+	c.hasql.NodesIter(c.getNodeStateCriterion(ctx))(func(n *hasql.Node[Querier]) bool {
+		for ; retries < c.options.Retries; retries++ {
+			if res, err = n.DB().ExecContext(ctx, query, args...); err != nil && retries >= c.options.Retries {
+				return true
+			}
+		}
+		return false
+	})
+
+	if res == nil && err == nil {
+		err = ErrorNoAliveNodes
+	}
+
+	return res, err
+}
+
+func (c *Cluster) PrepareContext(ctx context.Context, query string) (*sql.Stmt, error) {
+	var res *sql.Stmt
+	var err error
+
+	retries := 0
+	c.hasql.NodesIter(c.getNodeStateCriterion(ctx))(func(n *hasql.Node[Querier]) bool {
+		for ; retries < c.options.Retries; retries++ {
+			if res, err = n.DB().PrepareContext(ctx, query); err != nil && retries >= c.options.Retries {
+				return true
+			}
+		}
+		return false
+	})
+
+	if res == nil && err == nil {
+		err = ErrorNoAliveNodes
+	}
+
+	return res, err
+}
+
+func (c *Cluster) QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error) {
+	var res *sql.Rows
+	var err error
+
+	retries := 0
+	c.hasql.NodesIter(c.getNodeStateCriterion(ctx))(func(n *hasql.Node[Querier]) bool {
+		for ; retries < c.options.Retries; retries++ {
+			if res, err = n.DB().QueryContext(ctx, query); err != nil && err != sql.ErrNoRows && retries >= c.options.Retries {
+				return true
+			}
+		}
+		return false
+	})
+
+	if res == nil && err == nil {
+		err = ErrorNoAliveNodes
+	}
+
+	return res, err
+}
+
+func (c *Cluster) QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row {
+	var res *sql.Row
+
+	retries := 0
+	c.hasql.NodesIter(c.getNodeStateCriterion(ctx))(func(n *hasql.Node[Querier]) bool {
+		for ; retries < c.options.Retries; retries++ {
+			res = n.DB().QueryRowContext(ctx, query, args...)
+			if res.Err() == nil {
+				return false
+			} else if res.Err() != nil && retries >= c.options.Retries {
+				return false
+			}
+		}
+		return true
+	})
+
+	if res == nil {
+		res = newSQLRowError()
+	}
+
+	return res
+}
+
+func (c *Cluster) PingContext(ctx context.Context) error {
+	var err error
+	var ok bool
+
+	retries := 0
+	c.hasql.NodesIter(c.getNodeStateCriterion(ctx))(func(n *hasql.Node[Querier]) bool {
+		ok = true
+		for ; retries < c.options.Retries; retries++ {
+			if err = n.DB().PingContext(ctx); err != nil && retries >= c.options.Retries {
+				return true
+			}
+		}
+		return false
+	})
+
+	if !ok {
+		err = ErrorNoAliveNodes
+	}
+
+	return err
+}
+
+func (c *Cluster) WaitForNodes(ctx context.Context, criterions ...hasql.NodeStateCriterion) error {
+	for _, criterion := range criterions {
+		if _, err := c.hasql.WaitForNode(ctx, criterion); err != nil {
+			return err
+		}
+	}
+	return nil
+}

cluster/hasql/cluster_test.go

@@ -0,0 +1,171 @@
+package sql
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"golang.yandex/hasql/v2"
+)
+
+func TestNewCluster(t *testing.T) {
+	dbMaster, dbMasterMock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbMaster.Close()
+	dbMasterMock.MatchExpectationsInOrder(false)
+
+	dbMasterMock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(1, 0)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbMasterMock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("master-dc1"))
+
+	dbDRMaster, dbDRMasterMock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbDRMaster.Close()
+	dbDRMasterMock.MatchExpectationsInOrder(false)
+
+	dbDRMasterMock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(2, 40)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbDRMasterMock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("drmaster1-dc2"))
+
+	dbDRMasterMock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("drmaster"))
+
+	dbSlaveDC1, dbSlaveDC1Mock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbSlaveDC1.Close()
+	dbSlaveDC1Mock.MatchExpectationsInOrder(false)
+
+	dbSlaveDC1Mock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(2, 50)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbSlaveDC1Mock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("slave-dc1"))
+
+	dbSlaveDC2, dbSlaveDC2Mock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbSlaveDC2.Close()
+	dbSlaveDC1Mock.MatchExpectationsInOrder(false)
+
+	dbSlaveDC2Mock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(2, 50)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbSlaveDC2Mock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("slave-dc1"))
+
+	tctx, cancel := context.WithTimeout(t.Context(), 10*time.Second)
+	defer cancel()
+
+	c, err := NewCluster[Querier](
+		WithClusterContext(tctx),
+		WithClusterNodeChecker(hasql.PostgreSQLChecker),
+		WithClusterNodePicker(NewCustomPicker[Querier](
+			CustomPickerMaxLag(100),
+		)),
+		WithClusterNodes(
+			ClusterNode{"slave-dc1", dbSlaveDC1, 1},
+			ClusterNode{"master-dc1", dbMaster, 1},
+			ClusterNode{"slave-dc2", dbSlaveDC2, 2},
+			ClusterNode{"drmaster1-dc2", dbDRMaster, 0},
+		),
+		WithClusterOptions(
+			hasql.WithUpdateInterval[Querier](2*time.Second),
+			hasql.WithUpdateTimeout[Querier](1*time.Second),
+		),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	if err = c.WaitForNodes(tctx, hasql.Primary, hasql.Standby); err != nil {
+		t.Fatal(err)
+	}
+
+	time.Sleep(500 * time.Millisecond)
+
+	node1Name := ""
+	fmt.Printf("check for Standby\n")
+	if row := c.QueryRowContext(NodeStateCriterion(tctx, hasql.Standby), "SELECT node_name as name"); row.Err() != nil {
+		t.Fatal(row.Err())
+	} else if err = row.Scan(&node1Name); err != nil {
+		t.Fatal(err)
+	} else if "slave-dc1" != node1Name {
+		t.Fatalf("invalid node name %s != %s", "slave-dc1", node1Name)
+	}
+
+	dbSlaveDC1Mock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("slave-dc1"))
+
+	node2Name := ""
+	fmt.Printf("check for PreferStandby\n")
+	if row := c.QueryRowContext(NodeStateCriterion(tctx, hasql.PreferStandby), "SELECT node_name as name"); row.Err() != nil {
+		t.Fatal(row.Err())
+	} else if err = row.Scan(&node2Name); err != nil {
+		t.Fatal(err)
+	} else if "slave-dc1" != node2Name {
+		t.Fatalf("invalid node name %s != %s", "slave-dc1", node2Name)
+	}
+
+	node3Name := ""
+	fmt.Printf("check for PreferPrimary\n")
+	if row := c.QueryRowContext(NodeStateCriterion(tctx, hasql.PreferPrimary), "SELECT node_name as name"); row.Err() != nil {
+		t.Fatal(row.Err())
+	} else if err = row.Scan(&node3Name); err != nil {
+		t.Fatal(err)
+	} else if "master-dc1" != node3Name {
+		t.Fatalf("invalid node name %s != %s", "master-dc1", node3Name)
+	}
+
+	dbSlaveDC1Mock.ExpectQuery(`.*`).WillReturnRows(sqlmock.NewRows([]string{"role"}).RowError(1, fmt.Errorf("row error")))
+
+	time.Sleep(2 * time.Second)
+
+	fmt.Printf("check for PreferStandby\n")
+	if row := c.QueryRowContext(NodeStateCriterion(tctx, hasql.PreferStandby), "SELECT node_name as name"); row.Err() == nil {
+		t.Fatal("must return error")
+	}
+
+	if dbMasterErr := dbMasterMock.ExpectationsWereMet(); dbMasterErr != nil {
+		t.Error(dbMasterErr)
+	}
+}

cluster/hasql/db.go

@@ -0,0 +1,25 @@
+package sql
+
+import (
+	"context"
+	"database/sql"
+)
+
+type Querier interface {
+	// Basic connection methods
+	PingContext(ctx context.Context) error
+	Close() error
+
+	// Query methods with context
+	ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)
+	QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error)
+	QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row
+
+	// Prepared statements with context
+	PrepareContext(ctx context.Context, query string) (*sql.Stmt, error)
+
+	// Transaction management with context
+	BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error)
+
+	Conn(ctx context.Context) (*sql.Conn, error)
+}

cluster/hasql/driver.go

@@ -0,0 +1,295 @@
+package sql
+
+import (
+	"context"
+	"database/sql"
+	"database/sql/driver"
+	"io"
+	"sync"
+	"time"
+)
+
+// OpenDBWithCluster creates a [*sql.DB] that uses the [ClusterQuerier]
+func OpenDBWithCluster(db ClusterQuerier) (*sql.DB, error) {
+	driver := NewClusterDriver(db)
+	connector, err := driver.OpenConnector("")
+	if err != nil {
+		return nil, err
+	}
+	return sql.OpenDB(connector), nil
+}
+
+// ClusterDriver implements [driver.Driver] and driver.Connector for an existing [Querier]
+type ClusterDriver struct {
+	db ClusterQuerier
+}
+
+// NewClusterDriver creates a new [driver.Driver] that uses an existing [ClusterQuerier]
+func NewClusterDriver(db ClusterQuerier) *ClusterDriver {
+	return &ClusterDriver{db: db}
+}
+
+// Open implements [driver.Driver.Open]
+func (d *ClusterDriver) Open(name string) (driver.Conn, error) {
+	return d.Connect(context.Background())
+}
+
+// OpenConnector implements [driver.DriverContext.OpenConnector]
+func (d *ClusterDriver) OpenConnector(name string) (driver.Connector, error) {
+	return d, nil
+}
+
+// Connect implements [driver.Connector.Connect]
+func (d *ClusterDriver) Connect(ctx context.Context) (driver.Conn, error) {
+	conn, err := d.db.Conn(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return &dbConn{conn: conn}, nil
+}
+
+// Driver implements [driver.Connector.Driver]
+func (d *ClusterDriver) Driver() driver.Driver {
+	return d
+}
+
+// dbConn implements driver.Conn with both context and legacy methods
+type dbConn struct {
+	conn *sql.Conn
+	mu   sync.Mutex
+}
+
+// Prepare implements [driver.Conn.Prepare] (legacy method)
+func (c *dbConn) Prepare(query string) (driver.Stmt, error) {
+	return c.PrepareContext(context.Background(), query)
+}
+
+// PrepareContext implements [driver.ConnPrepareContext.PrepareContext]
+func (c *dbConn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	stmt, err := c.conn.PrepareContext(ctx, query)
+	if err != nil {
+		return nil, err
+	}
+
+	return &dbStmt{stmt: stmt}, nil
+}
+
+// Exec implements [driver.Execer.Exec] (legacy method)
+func (c *dbConn) Exec(query string, args []driver.Value) (driver.Result, error) {
+	namedArgs := make([]driver.NamedValue, len(args))
+	for i, value := range args {
+		namedArgs[i] = driver.NamedValue{Value: value}
+	}
+	return c.ExecContext(context.Background(), query, namedArgs)
+}
+
+// ExecContext implements [driver.ExecerContext.ExecContext]
+func (c *dbConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	// Convert driver.NamedValue to any
+	interfaceArgs := make([]any, len(args))
+	for i, arg := range args {
+		interfaceArgs[i] = arg.Value
+	}
+
+	return c.conn.ExecContext(ctx, query, interfaceArgs...)
+}
+
+// Query implements [driver.Queryer.Query] (legacy method)
+func (c *dbConn) Query(query string, args []driver.Value) (driver.Rows, error) {
+	namedArgs := make([]driver.NamedValue, len(args))
+	for i, value := range args {
+		namedArgs[i] = driver.NamedValue{Value: value}
+	}
+	return c.QueryContext(context.Background(), query, namedArgs)
+}
+
+// QueryContext implements [driver.QueryerContext.QueryContext]
+func (c *dbConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	// Convert driver.NamedValue to any
+	interfaceArgs := make([]any, len(args))
+	for i, arg := range args {
+		interfaceArgs[i] = arg.Value
+	}
+
+	rows, err := c.conn.QueryContext(ctx, query, interfaceArgs...)
+	if err != nil {
+		return nil, err
+	}
+
+	return &dbRows{rows: rows}, nil
+}
+
+// Begin implements [driver.Conn.Begin] (legacy method)
+func (c *dbConn) Begin() (driver.Tx, error) {
+	return c.BeginTx(context.Background(), driver.TxOptions{})
+}
+
+// BeginTx implements [driver.ConnBeginTx.BeginTx]
+func (c *dbConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	sqlOpts := &sql.TxOptions{
+		Isolation: sql.IsolationLevel(opts.Isolation),
+		ReadOnly:  opts.ReadOnly,
+	}
+
+	tx, err := c.conn.BeginTx(ctx, sqlOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	return &dbTx{tx: tx}, nil
+}
+
+// Ping implements [driver.Pinger.Ping]
+func (c *dbConn) Ping(ctx context.Context) error {
+	return c.conn.PingContext(ctx)
+}
+
+// Close implements [driver.Conn.Close]
+func (c *dbConn) Close() error {
+	return c.conn.Close()
+}
+
+// IsValid implements [driver.Validator.IsValid]
+func (c *dbConn) IsValid() bool {
+	// Ping with a short timeout to check if the connection is still valid
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	defer cancel()
+
+	return c.conn.PingContext(ctx) == nil
+}
+
+// dbStmt implements [driver.Stmt] with both context and legacy methods
+type dbStmt struct {
+	stmt *sql.Stmt
+	mu   sync.Mutex
+}
+
+// Close implements [driver.Stmt.Close]
+func (s *dbStmt) Close() error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.stmt.Close()
+}
+
+// Close implements [driver.Stmt.NumInput]
+func (s *dbStmt) NumInput() int {
+	return -1 // Number of parameters is unknown
+}
+
+// Exec implements [driver.Stmt.Exec] (legacy method)
+func (s *dbStmt) Exec(args []driver.Value) (driver.Result, error) {
+	namedArgs := make([]driver.NamedValue, len(args))
+	for i, value := range args {
+		namedArgs[i] = driver.NamedValue{Value: value}
+	}
+	return s.ExecContext(context.Background(), namedArgs)
+}
+
+// ExecContext implements [driver.StmtExecContext.ExecContext]
+func (s *dbStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	interfaceArgs := make([]any, len(args))
+	for i, arg := range args {
+		interfaceArgs[i] = arg.Value
+	}
+	return s.stmt.ExecContext(ctx, interfaceArgs...)
+}
+
+// Query implements [driver.Stmt.Query] (legacy method)
+func (s *dbStmt) Query(args []driver.Value) (driver.Rows, error) {
+	namedArgs := make([]driver.NamedValue, len(args))
+	for i, value := range args {
+		namedArgs[i] = driver.NamedValue{Value: value}
+	}
+	return s.QueryContext(context.Background(), namedArgs)
+}
+
+// QueryContext implements [driver.StmtQueryContext.QueryContext]
+func (s *dbStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	interfaceArgs := make([]any, len(args))
+	for i, arg := range args {
+		interfaceArgs[i] = arg.Value
+	}
+
+	rows, err := s.stmt.QueryContext(ctx, interfaceArgs...)
+	if err != nil {
+		return nil, err
+	}
+
+	return &dbRows{rows: rows}, nil
+}
+
+// dbRows implements [driver.Rows]
+type dbRows struct {
+	rows *sql.Rows
+}
+
+// Columns implements [driver.Rows.Columns]
+func (r *dbRows) Columns() []string {
+	cols, err := r.rows.Columns()
+	if err != nil {
+		// This shouldn't happen if the query was successful
+		return []string{}
+	}
+	return cols
+}
+
+// Close implements [driver.Rows.Close]
+func (r *dbRows) Close() error {
+	return r.rows.Close()
+}
+
+// Next implements [driver.Rows.Next]
+func (r *dbRows) Next(dest []driver.Value) error {
+	if !r.rows.Next() {
+		if err := r.rows.Err(); err != nil {
+			return err
+		}
+		return io.EOF
+	}
+
+	// Create a slice of interfaces to scan into
+	scanArgs := make([]any, len(dest))
+	for i := range scanArgs {
+		scanArgs[i] = &dest[i]
+	}
+
+	return r.rows.Scan(scanArgs...)
+}
+
+// dbTx implements [driver.Tx]
+type dbTx struct {
+	tx *sql.Tx
+	mu sync.Mutex
+}
+
+// Commit implements [driver.Tx.Commit]
+func (t *dbTx) Commit() error {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	return t.tx.Commit()
+}
+
+// Rollback implements [driver.Tx.Rollback]
+func (t *dbTx) Rollback() error {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	return t.tx.Rollback()
+}

cluster/hasql/driver_test.go

@@ -0,0 +1,141 @@
+package sql
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"golang.yandex/hasql/v2"
+)
+
+func TestDriver(t *testing.T) {
+	dbMaster, dbMasterMock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbMaster.Close()
+	dbMasterMock.MatchExpectationsInOrder(false)
+
+	dbMasterMock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(1, 0)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbMasterMock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("master-dc1"))
+
+	dbDRMaster, dbDRMasterMock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbDRMaster.Close()
+	dbDRMasterMock.MatchExpectationsInOrder(false)
+
+	dbDRMasterMock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(2, 40)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbDRMasterMock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("drmaster1-dc2"))
+
+	dbDRMasterMock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("drmaster"))
+
+	dbSlaveDC1, dbSlaveDC1Mock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbSlaveDC1.Close()
+	dbSlaveDC1Mock.MatchExpectationsInOrder(false)
+
+	dbSlaveDC1Mock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(2, 50)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbSlaveDC1Mock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("slave-dc1"))
+
+	dbSlaveDC2, dbSlaveDC2Mock, err := sqlmock.New(sqlmock.MonitorPingsOption(true))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer dbSlaveDC2.Close()
+	dbSlaveDC1Mock.MatchExpectationsInOrder(false)
+
+	dbSlaveDC2Mock.ExpectQuery(`.*pg_is_in_recovery.*`).WillReturnRows(
+		sqlmock.NewRowsWithColumnDefinition(
+			sqlmock.NewColumn("role").OfType("int8", 0),
+			sqlmock.NewColumn("replication_lag").OfType("int8", 0)).
+			AddRow(2, 50)).
+		RowsWillBeClosed().
+		WithoutArgs()
+
+	dbSlaveDC2Mock.ExpectQuery(`SELECT node_name as name`).WillReturnRows(
+		sqlmock.NewRows([]string{"name"}).
+			AddRow("slave-dc1"))
+
+	tctx, cancel := context.WithTimeout(t.Context(), 10*time.Second)
+	defer cancel()
+
+	c, err := NewCluster[Querier](
+		WithClusterContext(tctx),
+		WithClusterNodeChecker(hasql.PostgreSQLChecker),
+		WithClusterNodePicker(NewCustomPicker[Querier](
+			CustomPickerMaxLag(100),
+		)),
+		WithClusterNodes(
+			ClusterNode{"slave-dc1", dbSlaveDC1, 1},
+			ClusterNode{"master-dc1", dbMaster, 1},
+			ClusterNode{"slave-dc2", dbSlaveDC2, 2},
+			ClusterNode{"drmaster1-dc2", dbDRMaster, 0},
+		),
+		WithClusterOptions(
+			hasql.WithUpdateInterval[Querier](2*time.Second),
+			hasql.WithUpdateTimeout[Querier](1*time.Second),
+		),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	if err = c.WaitForNodes(tctx, hasql.Primary, hasql.Standby); err != nil {
+		t.Fatal(err)
+	}
+
+	db, err := OpenDBWithCluster(c)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Use context methods
+	row := db.QueryRowContext(NodeStateCriterion(t.Context(), hasql.Primary), "SELECT node_name as name")
+	if err = row.Err(); err != nil {
+		t.Fatal(err)
+	}
+
+	nodeName := ""
+	if err = row.Scan(&nodeName); err != nil {
+		t.Fatal(err)
+	}
+
+	if nodeName != "master-dc1" {
+		t.Fatalf("invalid node_name %s != %s", "master-dc1", nodeName)
+	}
+}

cluster/hasql/error.go

@@ -0,0 +1,10 @@
+package sql
+
+import "errors"
+
+var (
+	ErrClusterChecker    = errors.New("cluster node checker required")
+	ErrClusterDiscoverer = errors.New("cluster node discoverer required")
+	ErrClusterPicker     = errors.New("cluster node picker required")
+	ErrorNoAliveNodes    = errors.New("cluster no alive nodes")
+)

cluster/hasql/options.go

@@ -0,0 +1,110 @@
+package sql
+
+import (
+	"context"
+	"math"
+
+	"golang.yandex/hasql/v2"
+)
+
+// ClusterOptions contains cluster specific options
+type ClusterOptions struct {
+	NodeChecker        hasql.NodeChecker
+	NodePicker         hasql.NodePicker[Querier]
+	NodeDiscoverer     hasql.NodeDiscoverer[Querier]
+	Options            []hasql.ClusterOpt[Querier]
+	Context            context.Context
+	Retries            int
+	NodePriority       map[string]int32
+	NodeStateCriterion hasql.NodeStateCriterion
+}
+
+// ClusterOption apply cluster options to ClusterOptions
+type ClusterOption func(*ClusterOptions)
+
+// WithClusterNodeChecker pass hasql.NodeChecker to cluster options
+func WithClusterNodeChecker(c hasql.NodeChecker) ClusterOption {
+	return func(o *ClusterOptions) {
+		o.NodeChecker = c
+	}
+}
+
+// WithClusterNodePicker pass hasql.NodePicker to cluster options
+func WithClusterNodePicker(p hasql.NodePicker[Querier]) ClusterOption {
+	return func(o *ClusterOptions) {
+		o.NodePicker = p
+	}
+}
+
+// WithClusterNodeDiscoverer pass hasql.NodeDiscoverer to cluster options
+func WithClusterNodeDiscoverer(d hasql.NodeDiscoverer[Querier]) ClusterOption {
+	return func(o *ClusterOptions) {
+		o.NodeDiscoverer = d
+	}
+}
+
+// WithRetries retry count on other nodes in case of error
+func WithRetries(n int) ClusterOption {
+	return func(o *ClusterOptions) {
+		o.Retries = n
+	}
+}
+
+// WithClusterContext pass context.Context to cluster options and used for checks
+func WithClusterContext(ctx context.Context) ClusterOption {
+	return func(o *ClusterOptions) {
+		o.Context = ctx
+	}
+}
+
+// WithClusterOptions pass hasql.ClusterOpt
+func WithClusterOptions(opts ...hasql.ClusterOpt[Querier]) ClusterOption {
+	return func(o *ClusterOptions) {
+		o.Options = append(o.Options, opts...)
+	}
+}
+
+// WithClusterNodeStateCriterion pass default hasql.NodeStateCriterion
+func WithClusterNodeStateCriterion(c hasql.NodeStateCriterion) ClusterOption {
+	return func(o *ClusterOptions) {
+		o.NodeStateCriterion = c
+	}
+}
+
+type ClusterNode struct {
+	Name     string
+	DB       Querier
+	Priority int32
+}
+
+// WithClusterNodes create cluster with static NodeDiscoverer
+func WithClusterNodes(cns ...ClusterNode) ClusterOption {
+	return func(o *ClusterOptions) {
+		nodes := make([]*hasql.Node[Querier], 0, len(cns))
+		if o.NodePriority == nil {
+			o.NodePriority = make(map[string]int32, len(cns))
+		}
+		for _, cn := range cns {
+			nodes = append(nodes, hasql.NewNode(cn.Name, cn.DB))
+			if cn.Priority == 0 {
+				cn.Priority = math.MaxInt32
+			}
+			o.NodePriority[cn.Name] = cn.Priority
+		}
+		o.NodeDiscoverer = hasql.NewStaticNodeDiscoverer(nodes...)
+	}
+}
+
+type nodeStateCriterionKey struct{}
+
+// NodeStateCriterion inject hasql.NodeStateCriterion to context
+func NodeStateCriterion(ctx context.Context, c hasql.NodeStateCriterion) context.Context {
+	return context.WithValue(ctx, nodeStateCriterionKey{}, c)
+}
+
+func (c *Cluster) getNodeStateCriterion(ctx context.Context) hasql.NodeStateCriterion {
+	if v, ok := ctx.Value(nodeStateCriterionKey{}).(hasql.NodeStateCriterion); ok {
+		return v
+	}
+	return c.options.NodeStateCriterion
+}

cluster/hasql/picker.go

@@ -0,0 +1,113 @@
+package sql
+
+import (
+	"fmt"
+	"math"
+	"time"
+
+	"golang.yandex/hasql/v2"
+)
+
+// compile time guard
+var _ hasql.NodePicker[Querier] = (*CustomPicker[Querier])(nil)
+
+// CustomPickerOptions holds options to pick nodes
+type CustomPickerOptions struct {
+	MaxLag   int
+	Priority map[string]int32
+	Retries  int
+}
+
+// CustomPickerOption func apply option to CustomPickerOptions
+type CustomPickerOption func(*CustomPickerOptions)
+
+// CustomPickerMaxLag specifies max lag for which node can be used
+func CustomPickerMaxLag(n int) CustomPickerOption {
+	return func(o *CustomPickerOptions) {
+		o.MaxLag = n
+	}
+}
+
+// NewCustomPicker creates new node picker
+func NewCustomPicker[T Querier](opts ...CustomPickerOption) *CustomPicker[Querier] {
+	options := CustomPickerOptions{}
+	for _, o := range opts {
+		o(&options)
+	}
+	return &CustomPicker[Querier]{opts: options}
+}
+
+// CustomPicker holds node picker options
+type CustomPicker[T Querier] struct {
+	opts CustomPickerOptions
+}
+
+// PickNode used to return specific node
+func (p *CustomPicker[T]) PickNode(cnodes []hasql.CheckedNode[T]) hasql.CheckedNode[T] {
+	for _, n := range cnodes {
+		fmt.Printf("node %s\n", n.Node.String())
+	}
+	return cnodes[0]
+}
+
+func (p *CustomPicker[T]) getPriority(nodeName string) int32 {
+	if prio, ok := p.opts.Priority[nodeName]; ok {
+		return prio
+	}
+	return math.MaxInt32 // Default to lowest priority
+}
+
+// CompareNodes used to sort nodes
+func (p *CustomPicker[T]) CompareNodes(a, b hasql.CheckedNode[T]) int {
+	// Get replication lag values
+	aLag := a.Info.(interface{ ReplicationLag() int }).ReplicationLag()
+	bLag := b.Info.(interface{ ReplicationLag() int }).ReplicationLag()
+
+	// First check that lag lower then MaxLag
+	if aLag > p.opts.MaxLag && bLag > p.opts.MaxLag {
+		return 0 // both are equal
+	}
+
+	// If one node exceeds MaxLag and the other doesn't, prefer the one that doesn't
+	if aLag > p.opts.MaxLag {
+		return 1 // b is better
+	}
+	if bLag > p.opts.MaxLag {
+		return -1 // a is better
+	}
+
+	// Get node priorities
+	aPrio := p.getPriority(a.Node.String())
+	bPrio := p.getPriority(b.Node.String())
+
+	// if both priority equals
+	if aPrio == bPrio {
+		// First compare by replication lag
+		if aLag < bLag {
+			return -1
+		}
+		if aLag > bLag {
+			return 1
+		}
+		// If replication lag is equal, compare by latency
+		aLatency := a.Info.(interface{ Latency() time.Duration }).Latency()
+		bLatency := b.Info.(interface{ Latency() time.Duration }).Latency()
+
+		if aLatency < bLatency {
+			return -1
+		}
+		if aLatency > bLatency {
+			return 1
+		}
+
+		// If lag and latency is equal
+		return 0
+	}
+
+	// If priorities are different, prefer the node with lower priority value
+	if aPrio < bPrio {
+		return -1
+	}
+
+	return 1
+}

codec/codec.go

@@ -1,19 +1,8 @@
 // Package codec is an interface for encoding messages
-package codec // import "go.unistack.org/micro/v3/codec"
+package codec
 
 import (
 	"errors"
-	"io"
-
-	"go.unistack.org/micro/v3/metadata"
-)
-
-// Message types
-const (
-	Error MessageType = iota
-	Request
-	Response
-	Event
 )
 
 var (
@@ -24,65 +13,23 @@ var (
 )
 
 var (
-	// DefaultMaxMsgSize specifies how much data codec can handle
-	DefaultMaxMsgSize = 1024 * 1024 * 4 // 4Mb
 	// DefaultCodec is the global default codec
 	DefaultCodec = NewCodec()
 	// DefaultTagName specifies struct tag name to control codec Marshal/Unmarshal
 	DefaultTagName = "codec"
 )
 
-// MessageType specifies message type for codec
+// Codec encodes/decodes various types of messages.
-type MessageType int
-
-// Codec encodes/decodes various types of messages used within micro.
-// ReadHeader and ReadBody are called in pairs to read requests/responses
-// from the connection. Close is called when finished with the
-// connection. ReadBody may be called with a nil argument to force the
-// body to be read and discarded.
 type Codec interface {
-	ReadHeader(r io.Reader, m *Message, mt MessageType) error
-	ReadBody(r io.Reader, v interface{}) error
-	Write(w io.Writer, m *Message, v interface{}) error
 	Marshal(v interface{}, opts ...Option) ([]byte, error)
 	Unmarshal(b []byte, v interface{}, opts ...Option) error
 	String() string
 }
 
-// Message represents detailed information about
+type CodecV2 interface {
-// the communication, likely followed by the body.
+	Marshal(buf []byte, v interface{}, opts ...Option) ([]byte, error)
-// In the case of an error, body may be nil.
+	Unmarshal(buf []byte, v interface{}, opts ...Option) error
-type Message struct {
+	String() string
-	Header   metadata.Metadata
-	Target   string
-	Method   string
-	Endpoint string
-	Error    string
-	ID       string
-	Body     []byte
-	Type     MessageType
-}
-
-// NewMessage creates new codec message
-func NewMessage(t MessageType) *Message {
-	return &Message{Type: t, Header: metadata.New(0)}
-}
-
-// MarshalAppend calls codec.Marshal(v) and returns the data appended to buf.
-// If codec implements MarshalAppend, that is called instead.
-func MarshalAppend(buf []byte, c Codec, v interface{}, opts ...Option) ([]byte, error) {
-	if nc, ok := c.(interface {
-		MarshalAppend([]byte, interface{}, ...Option) ([]byte, error)
-	}); ok {
-		return nc.MarshalAppend(buf, v, opts...)
-	}
-
-	mbuf, err := c.Marshal(v, opts...)
-	if err != nil {
-		return nil, err
-	}
-
-	return append(buf, mbuf...), nil
 }
 
 // RawMessage is a raw encoded JSON value.
@@ -93,6 +40,8 @@ type RawMessage []byte
 func (m *RawMessage) MarshalJSON() ([]byte, error) {
 	if m == nil {
 		return []byte("null"), nil
+	} else if len(*m) == 0 {
+		return []byte("null"), nil
 	}
 	return *m, nil
 }
@@ -105,3 +54,22 @@ func (m *RawMessage) UnmarshalJSON(data []byte) error {
 	*m = append((*m)[0:0], data...)
 	return nil
 }
+
+// MarshalYAML returns m as the JSON encoding of m.
+func (m *RawMessage) MarshalYAML() ([]byte, error) {
+	if m == nil {
+		return []byte("null"), nil
+	} else if len(*m) == 0 {
+		return []byte("null"), nil
+	}
+	return *m, nil
+}
+
+// UnmarshalYAML sets *m to a copy of data.
+func (m *RawMessage) UnmarshalYAML(data []byte) error {
+	if m == nil {
+		return errors.New("RawMessage UnmarshalYAML on nil pointer")
+	}
+	*m = append((*m)[0:0], data...)
+	return nil
+}

codec/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Codec, bool) {
 	return c, ok
 }
 
+// MustContext returns codec from context
+func MustContext(ctx context.Context) Codec {
+	c, ok := FromContext(ctx)
+	if !ok {
+		panic("missing codec")
+	}
+	return c
+}
+
 // NewContext put codec in context
 func NewContext(ctx context.Context, c Codec) context.Context {
 	if ctx == nil {

codec/frame.go

@@ -20,6 +20,17 @@ func (m *Frame) UnmarshalJSON(data []byte) error {
 	return m.Unmarshal(data)
 }
 
+// MarshalYAML returns frame data
+func (m *Frame) MarshalYAML() ([]byte, error) {
+	return m.Marshal()
+}
+
+// UnmarshalYAML set frame data
+func (m *Frame) UnmarshalYAML(data []byte) error {
+	m.Data = append((m.Data)[0:0], data...)
+	return nil
+}
+
 // ProtoMessage noop func
 func (m *Frame) ProtoMessage() {}
 

codec/frame.proto

@@ -17,7 +17,7 @@ syntax = "proto3";
 package micro.codec;
 
 option cc_enable_arenas = true;
-option go_package = "go.unistack.org/micro/v3/codec;codec";
+option go_package = "go.unistack.org/micro/v4/codec;codec";
 option java_multiple_files = true;
 option java_outer_classname = "MicroCodec";
 option java_package = "micro.codec";

codec/noop.go

@@ -2,70 +2,14 @@ package codec
 
 import (
 	"encoding/json"
-	"io"
+
+	codecpb "go.unistack.org/micro-proto/v4/codec"
 )
 
 type noopCodec struct {
 	opts Options
 }
 
-func (c *noopCodec) ReadHeader(conn io.Reader, m *Message, t MessageType) error {
-	return nil
-}
-
-func (c *noopCodec) ReadBody(conn io.Reader, b interface{}) error {
-	// read bytes
-	buf, err := io.ReadAll(conn)
-	if err != nil {
-		return err
-	}
-
-	if b == nil {
-		return nil
-	}
-
-	switch v := b.(type) {
-	case *string:
-		*v = string(buf)
-	case *[]byte:
-		*v = buf
-	case *Frame:
-		v.Data = buf
-	default:
-		return json.Unmarshal(buf, v)
-	}
-
-	return nil
-}
-
-func (c *noopCodec) Write(conn io.Writer, m *Message, b interface{}) error {
-	if b == nil {
-		return nil
-	}
-
-	var v []byte
-	switch vb := b.(type) {
-	case *Frame:
-		v = vb.Data
-	case string:
-		v = []byte(vb)
-	case *string:
-		v = []byte(*vb)
-	case *[]byte:
-		v = *vb
-	case []byte:
-		v = vb
-	default:
-		var err error
-		v, err = json.Marshal(vb)
-		if err != nil {
-			return err
-		}
-	}
-	_, err := conn.Write(v)
-	return err
-}
-
 func (c *noopCodec) String() string {
 	return "noop"
 }
@@ -91,8 +35,8 @@ func (c *noopCodec) Marshal(v interface{}, opts ...Option) ([]byte, error) {
 		return ve, nil
 	case *Frame:
 		return ve.Data, nil
-	case *Message:
+	case *codecpb.Frame:
-		return ve.Body, nil
+		return ve.Data, nil
 	}
 
 	return json.Marshal(v)
@@ -115,8 +59,8 @@ func (c *noopCodec) Unmarshal(d []byte, v interface{}, opts ...Option) error {
 	case *Frame:
 		ve.Data = d
 		return nil
-	case *Message:
+	case *codecpb.Frame:
-		ve.Body = d
+		ve.Data = d
 		return nil
 	}
 

codec/options.go

@@ -3,9 +3,9 @@ package codec
 import (
 	"context"
 
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Option func
@@ -23,15 +23,8 @@ type Options struct {
 	Context context.Context
 	// TagName specifies tag name in struct to control codec
 	TagName string
-	// MaxMsgSize specifies max messages size that reads by codec
+	// Flatten specifies that struct must be analyzed for flatten tag
-	MaxMsgSize int
+	Flatten bool
-}
-
-// MaxMsgSize sets the max message size
-func MaxMsgSize(n int) Option {
-	return func(o *Options) {
-		o.MaxMsgSize = n
-	}
 }
 
 // TagName sets the codec tag name in struct
@@ -41,6 +34,13 @@ func TagName(n string) Option {
 	}
 }
 
+// Flatten enables checking for flatten tag name
+func Flatten(b bool) Option {
+	return func(o *Options) {
+		o.Flatten = b
+	}
+}
+
 // Logger sets the logger
 func Logger(l logger.Logger) Option {
 	return func(o *Options) {
@@ -65,12 +65,12 @@ func Meter(m meter.Meter) Option {
 // NewOptions returns new options
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Context:    context.Background(),
+		Context: context.Background(),
-		Logger:     logger.DefaultLogger,
+		Logger:  logger.DefaultLogger,
-		Meter:      meter.DefaultMeter,
+		Meter:   meter.DefaultMeter,
-		Tracer:     tracer.DefaultTracer,
+		Tracer:  tracer.DefaultTracer,
-		MaxMsgSize: DefaultMaxMsgSize,
+		TagName: DefaultTagName,
-		TagName:    DefaultTagName,
+		Flatten: false,
 	}
 
 	for _, o := range opts {

config/config.go

@@ -1,5 +1,5 @@
 // Package config is an interface for dynamic configuration.
-package config // import "go.unistack.org/micro/v3/config"
+package config
 
 import (
 	"context"
@@ -50,6 +50,13 @@ type Config interface {
 	String() string
 }
 
+type (
+	FuncLoad func(ctx context.Context, opts ...LoadOption) error
+	HookLoad func(next FuncLoad) FuncLoad
+	FuncSave func(ctx context.Context, opts ...SaveOption) error
+	HookSave func(next FuncSave) FuncSave
+)
+
 // Watcher is the config watcher
 type Watcher interface {
 	// Next blocks until update happens or error returned
@@ -131,7 +138,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Errorf(ctx, "%s BeforeLoad err: %v", c.String(), err)
+				c.Options().Logger.Error(ctx, c.String()+" BeforeLoad error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -146,7 +153,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Errorf(ctx, "%s AfterLoad err: %v", c.String(), err)
+				c.Options().Logger.Error(ctx, c.String()+" AfterLoad error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -161,7 +168,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Errorf(ctx, "%s BeforeSave err: %v", c.String(), err)
+				c.Options().Logger.Error(ctx, c.String()+" BeforeSave error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -176,7 +183,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Errorf(ctx, "%s AfterSave err: %v", c.String(), err)
+				c.Options().Logger.Error(ctx, c.String()+" AfterSave error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -191,7 +198,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Errorf(ctx, "%s BeforeInit err: %v", c.String(), err)
+				c.Options().Logger.Error(ctx, c.String()+" BeforeInit error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -206,7 +213,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Errorf(ctx, "%s AfterInit err: %v", c.String(), err)
+				c.Options().Logger.Error(ctx, c.String()+" AfterInit error", err)
 				if !c.Options().AllowFail {
 					return err
 				}

config/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Config, bool) {
 	return c, ok
 }
 
+// MustContext returns store from context
+func MustContext(ctx context.Context) Config {
+	c, ok := FromContext(ctx)
+	if !ok {
+		panic("missing config")
+	}
+	return c
+}
+
 // NewContext put store in context
 func NewContext(ctx context.Context, c Config) context.Context {
 	if ctx == nil {

config/default.go

@@ -7,15 +7,18 @@ import (
 	"strings"
 	"time"
 
+	"dario.cat/mergo"
 	"github.com/google/uuid"
-	"github.com/imdario/mergo"
+	"go.unistack.org/micro/v4/options"
-	mid "go.unistack.org/micro/v3/util/id"
+	mid "go.unistack.org/micro/v4/util/id"
-	rutil "go.unistack.org/micro/v3/util/reflect"
+	rutil "go.unistack.org/micro/v4/util/reflect"
-	mtime "go.unistack.org/micro/v3/util/time"
+	mtime "go.unistack.org/micro/v4/util/time"
 )
 
 type defaultConfig struct {
-	opts Options
+	funcLoad FuncLoad
+	funcSave FuncSave
+	opts     Options
 }
 
 func (c *defaultConfig) Options() Options {
@@ -31,6 +34,18 @@ func (c *defaultConfig) Init(opts ...Option) error {
 		return err
 	}
 
+	c.funcLoad = c.fnLoad
+	c.funcSave = c.fnSave
+
+	c.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookLoad:
+			c.funcLoad = h(c.funcLoad)
+		case HookSave:
+			c.funcSave = h(c.funcSave)
+		}
+	})
+
 	if err := DefaultAfterInit(c.opts.Context, c); err != nil && !c.opts.AllowFail {
 		return err
 	}
@@ -39,7 +54,17 @@ func (c *defaultConfig) Init(opts ...Option) error {
 }
 
 func (c *defaultConfig) Load(ctx context.Context, opts ...LoadOption) error {
-	if err := DefaultBeforeLoad(ctx, c); err != nil && !c.opts.AllowFail {
+	return c.funcLoad(ctx, opts...)
+}
+
+func (c *defaultConfig) fnLoad(ctx context.Context, opts ...LoadOption) error {
+	var err error
+
+	if c.opts.SkipLoad != nil && c.opts.SkipLoad(ctx, c) {
+		return nil
+	}
+
+	if err = DefaultBeforeLoad(ctx, c); err != nil && !c.opts.AllowFail {
 		return err
 	}
 
@@ -185,7 +210,7 @@ func fillValue(value reflect.Value, val string) error {
 				return err
 			}
 			value.Set(reflect.ValueOf(v))
-		case value.Type().String() == "time.Duration" && value.Type().PkgPath() == "go.unistack.org/micro/v3/util/time":
+		case value.Type().String() == "time.Duration" && value.Type().PkgPath() == "go.unistack.org/micro/v4/util/time":
 			v, err := mtime.ParseDuration(val)
 			if err != nil {
 				return err
@@ -229,6 +254,7 @@ func fillValue(value reflect.Value, val string) error {
 		}
 		value.Set(reflect.ValueOf(v))
 	}
+
 	return nil
 }
 
@@ -292,6 +318,14 @@ func fillValues(valueOf reflect.Value, tname string) error {
 }
 
 func (c *defaultConfig) Save(ctx context.Context, opts ...SaveOption) error {
+	return c.funcSave(ctx, opts...)
+}
+
+func (c *defaultConfig) fnSave(ctx context.Context, opts ...SaveOption) error {
+	if c.opts.SkipSave != nil && c.opts.SkipSave(ctx, c) {
+		return nil
+	}
+
 	if err := DefaultBeforeSave(ctx, c); err != nil {
 		return err
 	}
@@ -311,7 +345,7 @@ func (c *defaultConfig) Name() string {
 	return c.opts.Name
 }
 
-func (c *defaultConfig) Watch(ctx context.Context, opts ...WatchOption) (Watcher, error) {
+func (c *defaultConfig) Watch(_ context.Context, _ ...WatchOption) (Watcher, error) {
 	return nil, ErrWatcherNotImplemented
 }
 
@@ -321,5 +355,9 @@ func NewConfig(opts ...Option) Config {
 	if len(options.StructTag) == 0 {
 		options.StructTag = "default"
 	}
-	return &defaultConfig{opts: options}
+	c := &defaultConfig{opts: options}
+	c.funcLoad = c.fnLoad
+	c.funcSave = c.fnSave
+
+	return c
 }

config/default_test.go

@@ -3,24 +3,26 @@ package config_test
 import (
 	"context"
 	"fmt"
+	"reflect"
 	"testing"
 	"time"
 
-	"go.unistack.org/micro/v3/config"
+	"go.unistack.org/micro/v4/config"
-	mid "go.unistack.org/micro/v3/util/id"
+	mtime "go.unistack.org/micro/v4/util/time"
-	mtime "go.unistack.org/micro/v3/util/time"
 )
 
 type cfg struct {
-	StringValue    string `default:"string_value"`
+	MapValue    map[string]bool `default:"key1=true,key2=false"`
-	IgnoreValue    string `json:"-"`
+	StructValue *cfgStructValue
-	StructValue    *cfgStructValue
+
-	IntValue       int             `default:"99"`
+	StringValue string `default:"string_value"`
-	DurationValue  time.Duration   `default:"10s"`
+	IgnoreValue string `json:"-"`
-	MDurationValue mtime.Duration  `default:"10s"`
+	UUIDValue   string `default:"micro:generate uuid"`
-	MapValue       map[string]bool `default:"key1=true,key2=false"`
+	IDValue     string `default:"micro:generate id"`
-	UUIDValue      string          `default:"micro:generate uuid"`
+
-	IDValue        string          `default:"micro:generate id"`
+	DurationValue  time.Duration  `default:"10s"`
+	MDurationValue mtime.Duration `default:"10s"`
+	IntValue       int            `default:"99"`
 }
 
 type cfgStructValue struct {
@@ -41,6 +43,35 @@ func (c *cfgStructValue) Validate() error {
 	return nil
 }
 
+type testHook struct {
+	f bool
+}
+
+func (t *testHook) Load(fn config.FuncLoad) config.FuncLoad {
+	return func(ctx context.Context, opts ...config.LoadOption) error {
+		t.f = true
+		return fn(ctx, opts...)
+	}
+}
+
+func TestHook(t *testing.T) {
+	h := &testHook{}
+
+	c := config.NewConfig(config.Struct(h), config.Hooks(config.HookLoad(h.Load)))
+
+	if err := c.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := c.Load(context.TODO()); err != nil {
+		t.Fatal(err)
+	}
+
+	if !h.f {
+		t.Fatal("hook not works")
+	}
+}
+
 func TestDefault(t *testing.T) {
 	ctx := context.Background()
 	conf := &cfg{IntValue: 10}
@@ -83,8 +114,6 @@ func TestDefault(t *testing.T) {
 
 	if conf.IDValue == "" {
 		t.Fatalf("id value empty")
-	} else if len(conf.IDValue) != mid.DefaultSize {
-		t.Fatalf("id value invalid: %s", conf.IDValue)
 	}
 	_ = conf
 	// t.Logf("%#+v\n", conf)
@@ -105,3 +134,13 @@ func TestValidate(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func Test_SizeOf(t *testing.T) {
+	st := cfg{}
+
+	tVal := reflect.TypeOf(st)
+	for i := 0; i < tVal.NumField(); i++ {
+		field := tVal.Field(i)
+		fmt.Printf("Field: %s, Offset: %d, Size: %d\n", field.Name, field.Offset, field.Type.Size())
+	}
+}

config/options.go

@@ -4,10 +4,11 @@ import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Options hold the config options
@@ -40,6 +41,14 @@ type Options struct {
 	BeforeInit []func(context.Context, Config) error
 	// AfterInit contains slice of funcs that runs after Init
 	AfterInit []func(context.Context, Config) error
+
+	// SkipLoad runs only if condition returns true
+	SkipLoad func(context.Context, Config) bool
+	// SkipSave runs only if condition returns true
+	SkipSave func(context.Context, Config) bool
+	// Hooks can be run before/after config Save/Load
+	Hooks options.Hooks
+
 	// AllowFail flag to allow fail in config source
 	AllowFail bool
 }
@@ -68,9 +77,9 @@ type LoadOption func(o *LoadOptions)
 // LoadOptions struct
 type LoadOptions struct {
 	Struct   interface{}
+	Context  context.Context
 	Override bool
 	Append   bool
-	Context  context.Context
 }
 
 // NewLoadOptions create LoadOptions struct with provided opts
@@ -271,10 +280,10 @@ func WatchCoalesce(b bool) WatchOption {
 }
 
 // WatchInterval specifies min and max time.Duration for pulling changes
-func WatchInterval(min, max time.Duration) WatchOption {
+func WatchInterval(minTime, maxTime time.Duration) WatchOption {
 	return func(o *WatchOptions) {
-		o.MinInterval = min
+		o.MinInterval = minTime
-		o.MaxInterval = max
+		o.MaxInterval = maxTime
 	}
 }
 
@@ -284,3 +293,10 @@ func WatchStruct(src interface{}) WatchOption {
 		o.Struct = src
 	}
 }
+
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}

errors/errors.go

@@ -1,6 +1,6 @@
 // Package errors provides a way to return detailed information
 // for an RPC request error. The error is normally JSON encoded.
-package errors // import "go.unistack.org/micro/v3/errors"
+package errors
 
 import (
 	"bytes"
@@ -44,6 +44,20 @@ var (
 	ErrGatewayTimeout = &Error{Code: 504}
 )
 
+const ProblemContentType = "application/problem+json"
+
+type Problem struct {
+	Type     string `json:"type,omitempty"`
+	Title    string `json:"title,omitempty"`
+	Detail   string `json:"detail,omitempty"`
+	Instance string `json:"instance,omitempty"`
+	Errors   []struct {
+		Title  string `json:"title,omitempty"`
+		Detail string `json:"detail,omitempty"`
+	} `json:"errors,omitempty"`
+	Status int `json:"status,omitempty"`
+}
+
 // Error type
 type Error struct {
 	// ID holds error id or service, usually someting like my_service or id
@@ -262,6 +276,10 @@ func CodeIn(err interface{}, codes ...int32) bool {
 
 // FromError try to convert go error to *Error
 func FromError(err error) *Error {
+	if err == nil {
+		return nil
+	}
+
 	if verr, ok := err.(*Error); ok && verr != nil {
 		return verr
 	}

errors/errors.proto

@@ -17,7 +17,7 @@ syntax = "proto3";
 package micro.errors;
 
 option cc_enable_arenas = true;
-option go_package = "go.unistack.org/micro/v3/errors;errors";
+option go_package = "go.unistack.org/micro/v4/errors;errors";
 option java_multiple_files = true;
 option java_outer_classname = "MicroErrors";
 option java_package = "micro.errors";

errors/errors_test.go

@@ -2,7 +2,7 @@ package errors
 
 import (
 	"encoding/json"
-	er "errors"
+	"errors"
 	"fmt"
 	"net/http"
 	"testing"
@@ -26,7 +26,7 @@ func TestMarshalJSON(t *testing.T) {
 func TestEmpty(t *testing.T) {
 	msg := "test"
 	var err *Error
-	err = FromError(fmt.Errorf(msg))
+	err = FromError(errors.New(msg))
 	if err.Detail != msg {
 		t.Fatalf("invalid error %v", err)
 	}
@@ -42,7 +42,7 @@ func TestFromError(t *testing.T) {
 	if merr.ID != "go.micro.test" || merr.Code != 404 {
 		t.Fatalf("invalid conversation %v != %v", err, merr)
 	}
-	err = er.New(err.Error())
+	err = errors.New(err.Error())
 	merr = FromError(err)
 	if merr.ID != "go.micro.test" || merr.Code != 404 {
 		t.Fatalf("invalid conversation %v != %v", err, merr)
@@ -57,7 +57,7 @@ func TestEqual(t *testing.T) {
 		t.Fatal("errors must be equal")
 	}
 
-	err3 := er.New("my test err")
+	err3 := errors.New("my test err")
 	if Equal(err1, err3) {
 		t.Fatal("errors must be not equal")
 	}

event.go

@@ -1,27 +0,0 @@
-package micro
-
-import (
-	"context"
-
-	"go.unistack.org/micro/v3/client"
-)
-
-// Event is used to publish messages to a topic
-type Event interface {
-	// Publish publishes a message to the event topic
-	Publish(ctx context.Context, msg interface{}, opts ...client.PublishOption) error
-}
-
-type event struct {
-	c     client.Client
-	topic string
-}
-
-// NewEvent creates a new event publisher
-func NewEvent(topic string, c client.Client) Event {
-	return &event{c, topic}
-}
-
-func (e *event) Publish(ctx context.Context, msg interface{}, opts ...client.PublishOption) error {
-	return e.c.Publish(ctx, e.c.NewMessage(e.topic, msg), opts...)
-}

flow/context_test.go

@@ -1,3 +1,5 @@
+//go:build ignore
+
 package flow
 
 import (

flow/default.go

@@ -1,17 +1,19 @@
+//go:build ignore
+
 package flow
 
 import (
 	"context"
 	"fmt"
+	"path/filepath"
 	"sync"
 
-	"github.com/silas/dag"
+	"github.com/heimdalr/dag"
-	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/store"
-	"go.unistack.org/micro/v3/store"
+	"go.unistack.org/micro/v4/util/id"
-	"go.unistack.org/micro/v3/util/id"
 )
 
 type microFlow struct {
@@ -20,7 +22,7 @@ type microFlow struct {
 
 type microWorkflow struct {
 	opts   Options
-	g      *dag.AcyclicGraph
+	g      *dag.DAG
 	steps  map[string]Step
 	id     string
 	status Status
@@ -32,20 +34,20 @@ func (w *microWorkflow) ID() string {
 	return w.id
 }
 
-func (w *microWorkflow) Steps() ([][]Step, error) {
-	return w.getSteps("", false)
-}
-
 func (w *microWorkflow) Status() Status {
 	return w.status
 }
 
 func (w *microWorkflow) AppendSteps(steps ...Step) error {
+	var err error
 	w.Lock()
+	defer w.Unlock()
 
 	for _, s := range steps {
 		w.steps[s.String()] = s
-		w.g.Add(s)
+		if _, err = w.g.AddVertex(s); err != nil {
+			return err
+		}
 	}
 
 	for _, dst := range steps {
@@ -54,18 +56,13 @@ func (w *microWorkflow) AppendSteps(steps ...Step) error {
 			if !ok {
 				return ErrStepNotExists
 			}
-			w.g.Connect(dag.BasicEdge(src, dst))
+			if err = w.g.AddEdge(src.String(), dst.String()); err != nil {
+				return err
+			}
 		}
 	}
 
-	if err := w.g.Validate(); err != nil {
+	w.g.ReduceTransitively()
-		w.Unlock()
-		return err
-	}
-
-	w.g.TransitiveReduction()
-
-	w.Unlock()
 
 	return nil
 }
@@ -74,10 +71,11 @@ func (w *microWorkflow) RemoveSteps(steps ...Step) error {
 	// TODO: handle case when some step requires or required by removed step
 
 	w.Lock()
+	defer w.Unlock()
 
 	for _, s := range steps {
 		delete(w.steps, s.String())
-		w.g.Remove(s)
+		w.g.DeleteVertex(s.String())
 	}
 
 	for _, dst := range steps {
@@ -86,91 +84,34 @@ func (w *microWorkflow) RemoveSteps(steps ...Step) error {
 			if !ok {
 				return ErrStepNotExists
 			}
-			w.g.Connect(dag.BasicEdge(src, dst))
+			w.g.AddEdge(src.String(), dst.String())
 		}
 	}
 
-	if err := w.g.Validate(); err != nil {
+	w.g.ReduceTransitively()
-		w.Unlock()
-		return err
-	}
-
-	w.g.TransitiveReduction()
-
-	w.Unlock()
 
 	return nil
 }
 
-func (w *microWorkflow) getSteps(start string, reverse bool) ([][]Step, error) {
-	var steps [][]Step
-	var root dag.Vertex
-	var err error
-
-	fn := func(n dag.Vertex, idx int) error {
-		if idx == 0 {
-			steps = make([][]Step, 1)
-			steps[0] = make([]Step, 0, 1)
-		} else if idx >= len(steps) {
-			tsteps := make([][]Step, idx+1)
-			copy(tsteps, steps)
-			steps = tsteps
-			steps[idx] = make([]Step, 0, 1)
-		}
-		steps[idx] = append(steps[idx], n.(Step))
-		return nil
-	}
-
-	if start != "" {
-		var ok bool
-		w.RLock()
-		root, ok = w.steps[start]
-		w.RUnlock()
-		if !ok {
-			return nil, ErrStepNotExists
-		}
-	} else {
-		root, err = w.g.Root()
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	if reverse {
-		err = w.g.SortedReverseDepthFirstWalk([]dag.Vertex{root}, fn)
-	} else {
-		err = w.g.SortedDepthFirstWalk([]dag.Vertex{root}, fn)
-	}
-	if err != nil {
-		return nil, err
-	}
-
-	return steps, nil
-}
-
 func (w *microWorkflow) Abort(ctx context.Context, id string) error {
-	workflowStore := store.NewNamespaceStore(w.opts.Store, "workflows"+w.opts.Store.Options().Separator+id)
+	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", id))
 	return workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusAborted.String())})
 }
 
 func (w *microWorkflow) Suspend(ctx context.Context, id string) error {
-	workflowStore := store.NewNamespaceStore(w.opts.Store, "workflows"+w.opts.Store.Options().Separator+id)
+	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", id))
 	return workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusSuspend.String())})
 }
 
 func (w *microWorkflow) Resume(ctx context.Context, id string) error {
-	workflowStore := store.NewNamespaceStore(w.opts.Store, "workflows"+w.opts.Store.Options().Separator+id)
+	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", id))
 	return workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusRunning.String())})
 }
 
 func (w *microWorkflow) Execute(ctx context.Context, req *Message, opts ...ExecuteOption) (string, error) {
 	w.Lock()
 	if !w.init {
-		if err := w.g.Validate(); err != nil {
+		w.g.ReduceTransitively()
-			w.Unlock()
-			return "", err
-		}
-		w.g.TransitiveReduction()
 		w.init = true
 	}
 	w.Unlock()
@@ -180,26 +121,11 @@ func (w *microWorkflow) Execute(ctx context.Context, req *Message, opts ...Execu
 		return "", err
 	}
 
-	stepStore := store.NewNamespaceStore(w.opts.Store, "steps"+w.opts.Store.Options().Separator+eid)
+	//	stepStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("steps", eid))
-	workflowStore := store.NewNamespaceStore(w.opts.Store, "workflows"+w.opts.Store.Options().Separator+eid)
+	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", eid))
 
 	options := NewExecuteOptions(opts...)
 
-	steps, err := w.getSteps(options.Start, options.Reverse)
-	if err != nil {
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusPending.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
-		}
-		return "", err
-	}
-
-	var wg sync.WaitGroup
-	cherr := make(chan error, 1)
-	chstatus := make(chan Status, 1)
-
-	nctx, cancel := context.WithCancel(ctx)
-	defer cancel()
-
 	nopts := make([]ExecuteOption, 0, len(opts)+5)
 
 	nopts = append(nopts,
@@ -209,143 +135,274 @@ func (w *microWorkflow) Execute(ctx context.Context, req *Message, opts ...Execu
 		ExecuteMeter(w.opts.Meter),
 	)
 	nopts = append(nopts, opts...)
-	done := make(chan struct{})
 
-	if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
+	if werr := workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
-		w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+		w.opts.Logger.Error(ctx, "store error: %v", werr)
 		return eid, werr
 	}
-	for idx := range steps {
+
-		for nidx := range steps[idx] {
+	var startID string
-			cstep := steps[idx][nidx]
+	if options.Start == "" {
-			if werr := stepStore.Write(ctx, cstep.ID()+w.opts.Store.Options().Separator+"status", &codec.Frame{Data: []byte(StatusPending.String())}); werr != nil {
+		mp := w.g.GetRoots()
-				return eid, werr
+		if len(mp) != 1 {
+			return eid, ErrStepNotExists
+		}
+		for k := range mp {
+			startID = k
+		}
+	} else {
+		for k, v := range w.g.GetVertices() {
+			if v == options.Start {
+				startID = k
 			}
 		}
 	}
 
-	go func() {
+	if startID == "" {
-		for idx := range steps {
+		return eid, ErrStepNotExists
-			for nidx := range steps[idx] {
+	}
-				wStatus := &codec.Frame{}
+
-				if werr := workflowStore.Read(w.opts.Context, "status", wStatus); werr != nil {
+	if options.Async {
-					cherr <- werr
+		go w.handleWorkflow(startID, nopts...)
-					return
+		return eid, nil
+	}
+
+	return eid, w.handleWorkflow(startID, nopts...)
+}
+
+func (w *microWorkflow) handleWorkflow(startID string, opts ...ExecuteOption) error {
+	w.RLock()
+	defer w.RUnlock()
+
+	//	stepStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("steps", eid))
+	// workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", eid))
+
+	// Get IDs of all descendant vertices.
+	flowIDs, errDes := w.g.GetDescendants(startID)
+	if errDes != nil {
+		return errDes
+	}
+
+	// inputChannels provides for input channels for each of the descendant vertices (+ the start-vertex).
+	inputChannels := make(map[string]chan FlowResult, len(flowIDs)+1)
+
+	// Iterate vertex IDs and create an input channel for each of them and a single
+	// output channel for leaves. Note, this "pre-flight" is needed to ensure we
+	// really have an input channel regardless of how we traverse the tree and spawn
+	// workers.
+	leafCount := 0
+
+	for id := range flowIDs {
+
+		// Get all parents of this vertex.
+		parents, errPar := w.g.GetParents(id)
+		if errPar != nil {
+			return errPar
+		}
+
+		// Create a buffered input channel that has capacity for all parent results.
+		inputChannels[id] = make(chan FlowResult, len(parents))
+
+		if ok, err := w.g.IsLeaf(id); ok && err == nil {
+			leafCount += 1
+		}
+	}
+
+	// outputChannel caries the results of leaf vertices.
+	outputChannel := make(chan FlowResult, leafCount)
+
+	// To also process the start vertex and to have its results being passed to its
+	// children, add it to the vertex IDs. Also add an input channel for the start
+	// vertex and feed the inputs to this channel.
+	flowIDs[startID] = struct{}{}
+	inputChannels[startID] = make(chan FlowResult, len(inputs))
+	for _, i := range inputs {
+		inputChannels[startID] <- i
+	}
+
+	wg := sync.WaitGroup{}
+
+	// Iterate all vertex IDs (now incl. start vertex) and handle each worker (incl.
+	// inputs and outputs) in a separate goroutine.
+	for id := range flowIDs {
+
+		// Get all children of this vertex that later need to be notified. Note, we
+		// collect all children before the goroutine to be able to release the read
+		// lock as early as possible.
+		children, errChildren := w.g.GetChildren(id)
+		if errChildren != nil {
+			return errChildren
+		}
+
+		// Remember to wait for this goroutine.
+		wg.Add(1)
+
+		go func(id string) {
+			// Get this vertex's input channel.
+			// Note, only concurrent read here, which is fine.
+			c := inputChannels[id]
+
+			// Await all parent inputs and stuff them into a slice.
+			parentCount := cap(c)
+			parentResults := make([]FlowResult, parentCount)
+			for i := 0; i < parentCount; i++ {
+				parentResults[i] = <-c
+			}
+
+			// Execute the worker.
+			errWorker := callback(w.g, id, parentResults)
+			if errWorker != nil {
+				return errWorker
+			}
+
+			// Send this worker's FlowResult onto all children's input channels or, if it is
+			// a leaf (i.e. no children), send the result onto the output channel.
+			if len(children) > 0 {
+				for child := range children {
+					inputChannels[child] <- flowResult
 				}
-				if status := StringStatus[string(wStatus.Data)]; status != StatusRunning {
+			} else {
-					chstatus <- status
+				outputChannel <- flowResult
-					return
+			}
-				}
+
-				if w.opts.Logger.V(logger.TraceLevel) {
+			// "Sign off".
-					w.opts.Logger.Tracef(nctx, "will be executed %v", steps[idx][nidx])
+			wg.Done()
-				}
+		}(id)
-				cstep := steps[idx][nidx]
+	}
-				// nolint: nestif
+
-				if len(cstep.Requires()) == 0 {
+	// Wait for all go routines to finish.
-					wg.Add(1)
+	wg.Wait()
-					go func(step Step) {
+
-						defer wg.Done()
+	// Await all leaf vertex results and stuff them into a slice.
-						if werr := stepStore.Write(ctx, step.ID()+w.opts.Store.Options().Separator+"req", req); werr != nil {
+	resultCount := cap(outputChannel)
+	results := make([]FlowResult, resultCount)
+	for i := 0; i < resultCount; i++ {
+		results[i] = <-outputChannel
+	}
+
+	/*
+		go func() {
+			for idx := range steps {
+				for nidx := range steps[idx] {
+					wStatus := &codec.Frame{}
+					if werr := workflowStore.Read(w.opts.Context, "status", wStatus); werr != nil {
+						cherr <- werr
+						return
+					}
+					if status := StringStatus[string(wStatus.Data)]; status != StatusRunning {
+						chstatus <- status
+						return
+					}
+					if w.opts.Logger.V(logger.TraceLevel) {
+						w.opts.Logger.Tracef(nctx, "will be executed %v", steps[idx][nidx])
+					}
+					cstep := steps[idx][nidx]
+					// nolint: nestif
+					if len(cstep.Requires()) == 0 {
+						wg.Add(1)
+						go func(step Step) {
+							defer wg.Done()
+							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "req"), req); werr != nil {
+								cherr <- werr
+								return
+							}
+							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "status"), &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
+								cherr <- werr
+								return
+							}
+							rsp, serr := step.Execute(nctx, req, nopts...)
+							if serr != nil {
+								step.SetStatus(StatusFailure)
+								if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "rsp"), serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+									w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+								}
+								if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "status"), &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+									w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+								}
+								cherr <- serr
+								return
+							}
+							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "rsp"), rsp); werr != nil {
+								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+								cherr <- werr
+								return
+							}
+							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "status"), &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
+								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+								cherr <- werr
+								return
+							}
+						}(cstep)
+						wg.Wait()
+					} else {
+						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "req"), req); werr != nil {
 							cherr <- werr
 							return
 						}
-						if werr := stepStore.Write(ctx, step.ID()+w.opts.Store.Options().Separator+"status", &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
+						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
 							cherr <- werr
 							return
 						}
-						rsp, serr := step.Execute(nctx, req, nopts...)
+						rsp, serr := cstep.Execute(nctx, req, nopts...)
 						if serr != nil {
-							step.SetStatus(StatusFailure)
+							cstep.SetStatus(StatusFailure)
-							if werr := stepStore.Write(ctx, step.ID()+w.opts.Store.Options().Separator+"rsp", serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+							if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "rsp"), serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
 								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
 							}
-							if werr := stepStore.Write(ctx, step.ID()+w.opts.Store.Options().Separator+"status", &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+							if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
 								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
 							}
 							cherr <- serr
 							return
 						}
-						if werr := stepStore.Write(ctx, step.ID()+w.opts.Store.Options().Separator+"rsp", rsp); werr != nil {
+						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "rsp"), rsp); werr != nil {
 							w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
 							cherr <- werr
 							return
 						}
-						if werr := stepStore.Write(ctx, step.ID()+w.opts.Store.Options().Separator+"status", &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
+						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
-							w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
 							cherr <- werr
 							return
 						}
-					}(cstep)
-					wg.Wait()
-				} else {
-					if werr := stepStore.Write(ctx, cstep.ID()+w.opts.Store.Options().Separator+"req", req); werr != nil {
-						cherr <- werr
-						return
-					}
-					if werr := stepStore.Write(ctx, cstep.ID()+w.opts.Store.Options().Separator+"status", &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
-						cherr <- werr
-						return
-					}
-					rsp, serr := cstep.Execute(nctx, req, nopts...)
-					if serr != nil {
-						cstep.SetStatus(StatusFailure)
-						if werr := stepStore.Write(ctx, cstep.ID()+w.opts.Store.Options().Separator+"rsp", serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
-							w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
-						}
-						if werr := stepStore.Write(ctx, cstep.ID()+w.opts.Store.Options().Separator+"status", &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
-							w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
-						}
-						cherr <- serr
-						return
-					}
-					if werr := stepStore.Write(ctx, cstep.ID()+w.opts.Store.Options().Separator+"rsp", rsp); werr != nil {
-						w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
-						cherr <- werr
-						return
-					}
-					if werr := stepStore.Write(ctx, cstep.ID()+w.opts.Store.Options().Separator+"status", &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
-						cherr <- werr
-						return
 					}
 				}
 			}
-		}
+			close(done)
-		close(done)
+		}()
-	}()
 
-	if options.Async {
+		if options.Async {
-		return eid, nil
+			return eid, nil
-	}
-
-	logger.Tracef(ctx, "wait for finish or error")
-	select {
-	case <-nctx.Done():
-		err = nctx.Err()
-	case cerr := <-cherr:
-		err = cerr
-	case <-done:
-		close(cherr)
-	case <-chstatus:
-		close(chstatus)
-		return eid, nil
-	}
-
-	switch {
-	case nctx.Err() != nil:
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusAborted.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
 		}
-	case err == nil:
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
-		}
-	case err != nil:
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
-		}
-	}
 
-	return eid, err
+		logger.Tracef(ctx, "wait for finish or error")
+		select {
+		case <-nctx.Done():
+			err = nctx.Err()
+		case cerr := <-cherr:
+			err = cerr
+		case <-done:
+			close(cherr)
+		case <-chstatus:
+			close(chstatus)
+			return eid, nil
+		}
+
+		switch {
+		case nctx.Err() != nil:
+			if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusAborted.String())}); werr != nil {
+				w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+			}
+		case err == nil:
+			if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
+				w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+			}
+		case err != nil:
+			if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil {
+				w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+			}
+		}
+	*/
+	return err
 }
 
 // NewFlow create new flow
@@ -385,11 +442,11 @@ func (f *microFlow) WorkflowList(ctx context.Context) ([]Workflow, error) {
 }
 
 func (f *microFlow) WorkflowCreate(ctx context.Context, id string, steps ...Step) (Workflow, error) {
-	w := &microWorkflow{opts: f.opts, id: id, g: &dag.AcyclicGraph{}, steps: make(map[string]Step, len(steps))}
+	w := &microWorkflow{opts: f.opts, id: id, g: &dag.DAG{}, steps: make(map[string]Step, len(steps))}
 
 	for _, s := range steps {
 		w.steps[s.String()] = s
-		w.g.Add(s)
+		w.g.AddVertex(s)
 	}
 
 	for _, dst := range steps {
@@ -398,14 +455,11 @@ func (f *microFlow) WorkflowCreate(ctx context.Context, id string, steps ...Step
 			if !ok {
 				return nil, ErrStepNotExists
 			}
-			w.g.Connect(dag.BasicEdge(src, dst))
+			w.g.AddEdge(src.String(), dst.String())
 		}
 	}
 
-	if err := w.g.Validate(); err != nil {
+	w.g.ReduceTransitively()
-		return nil, err
-	}
-	w.g.TransitiveReduction()
 
 	w.init = true
 

flow/flow.go

@@ -1,5 +1,5 @@
 // Package flow is an interface used for saga pattern microservice workflow
-package flow // import "go.unistack.org/micro/v3/flow"
+package flow // import "go.unistack.org/micro/v4/flow"
 
 import (
 	"context"
@@ -7,7 +7,7 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 var (
@@ -125,8 +125,6 @@ type Workflow interface {
 	AppendSteps(steps ...Step) error
 	// Status returns workflow status
 	Status() Status
-	// Steps returns steps slice where parallel steps returned on the same level
-	Steps() ([][]Step, error)
 	// Suspend suspends execution
 	Suspend(ctx context.Context, id string) error
 	// Resume resumes execution

flow/options.go

@@ -4,11 +4,11 @@ import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v3/store"
+	"go.unistack.org/micro/v4/store"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Option func
@@ -123,8 +123,6 @@ type ExecuteOptions struct {
 	Start string
 	// Timeout for execution
 	Timeout time.Duration
-	// Reverse execution
-	Reverse bool
 	// Async enables async execution
 	Async bool
 }
@@ -167,13 +165,6 @@ func ExecuteContext(ctx context.Context) ExecuteOption {
 	}
 }
 
-// ExecuteReverse says that dag must be run in reverse order
-func ExecuteReverse(b bool) ExecuteOption {
-	return func(o *ExecuteOptions) {
-		o.Reverse = b
-	}
-}
-
 // ExecuteTimeout pass timeout time.Duration for execution
 func ExecuteTimeout(td time.Duration) ExecuteOption {
 	return func(o *ExecuteOptions) {

fsm/default.go

@@ -32,7 +32,7 @@ type fsm struct {
 
 // NewFSM creates a new finite state machine having the specified initial state
 // with specified options
-func NewFSM(opts ...Option) *fsm {
+func NewFSM(opts ...Option) FSM {
 	return &fsm{
 		statesMap: map[string]StateFunc{},
 		opts:      NewOptions(opts...),

fsm/fsm.go

@@ -1,4 +1,4 @@
-package fsm // import "go.unistack.org/micro/v3/fsm"
+package fsm
 
 import (
 	"context"

fsm/fsm_test.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"testing"
 
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
 )
 
 func TestFSMStart(t *testing.T) {
@@ -17,7 +17,7 @@ func TestFSMStart(t *testing.T) {
 
 	wrapper := func(next StateFunc) StateFunc {
 		return func(sctx context.Context, s State, opts ...StateOption) (State, error) {
-			sctx = logger.NewContext(sctx, logger.Fields("state", s.Name()))
+			sctx = logger.NewContext(sctx, logger.DefaultLogger.Fields("state", s.Name()))
 			return next(sctx, s, opts...)
 		}
 	}

go.mod

@@ -1,20 +1,35 @@
-module go.unistack.org/micro/v3
+module go.unistack.org/micro/v4
 
-go 1.19
+go 1.24
 
 require (
-	github.com/DATA-DOG/go-sqlmock v1.5.0
+	dario.cat/mergo v1.0.1
-	github.com/google/uuid v1.3.0
+	github.com/DATA-DOG/go-sqlmock v1.5.2
-	github.com/imdario/mergo v0.3.15
+	github.com/KimMachineGun/automemlimit v0.7.0
+	github.com/goccy/go-yaml v1.17.1
+	github.com/google/uuid v1.6.0
+	github.com/matoous/go-nanoid v1.5.1
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5
-	golang.org/x/sync v0.3.0
+	github.com/spf13/cast v1.7.1
-	google.golang.org/grpc v1.57.0
+	github.com/stretchr/testify v1.10.0
-	google.golang.org/protobuf v1.31.0
+	go.uber.org/atomic v1.11.0
+	go.uber.org/automaxprocs v1.6.0
+	go.unistack.org/micro-proto/v4 v4.1.0
+	golang.org/x/sync v0.10.0
+	golang.yandex/hasql/v2 v2.1.0
+	google.golang.org/grpc v1.69.4
+	google.golang.org/protobuf v1.36.3
 )
 
 require (
-	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	golang.org/x/net v0.14.0 // indirect
+	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20230526203410-71b5a4ffd15e // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/rogpeppe/go-internal v1.13.1 // indirect
+	golang.org/x/net v0.34.0 // indirect
+	golang.org/x/sys v0.29.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20241216192217-9240e9c98484 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,33 +1,71 @@
-github.com/DATA-DOG/go-sqlmock v1.5.0 h1:Shsta01QNfFxHCfpW6YH2STWB0MudeXXEWMr20OEh60=
+dario.cat/mergo v1.0.1 h1:Ra4+bf83h2ztPIQYNP99R6m+Y7KfnARDfID+a+vLl4s=
-github.com/DATA-DOG/go-sqlmock v1.5.0/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
+dario.cat/mergo v1.0.1/go.mod h1:uNxQE+84aUszobStD9th8a29P2fMDhsBdgRYvZOxGmk=
-github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
+github.com/DATA-DOG/go-sqlmock v1.5.2 h1:OcvFkGmslmlZibjAjaHm3L//6LiuBgolP7OputlJIzU=
-github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
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hooks/metadata/metadata.go

@@ -0,0 +1,117 @@
+package metadata
+
+import (
+	"context"
+
+	"go.unistack.org/micro/v4/client"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/server"
+)
+
+type wrapper struct {
+	keys []string
+
+	client.Client
+}
+
+func NewClientWrapper(keys ...string) client.Wrapper {
+	return func(c client.Client) client.Client {
+		handler := &wrapper{
+			Client: c,
+			keys:   keys,
+		}
+		return handler
+	}
+}
+
+func NewClientCallWrapper(keys ...string) client.CallWrapper {
+	return func(fn client.CallFunc) client.CallFunc {
+		return func(ctx context.Context, addr string, req client.Request, rsp interface{}, opts client.CallOptions) error {
+			if keys == nil {
+				return fn(ctx, addr, req, rsp, opts)
+			}
+			if imd, iok := metadata.FromIncomingContext(ctx); iok && imd != nil {
+				omd, ook := metadata.FromOutgoingContext(ctx)
+				if !ook || omd == nil {
+					omd = metadata.New(len(imd))
+				}
+				for _, k := range keys {
+					if v := imd.Get(k); v != nil {
+						omd.Set(k, v...)
+					}
+				}
+				if !ook {
+					ctx = metadata.NewOutgoingContext(ctx, omd)
+				}
+			}
+			return fn(ctx, addr, req, rsp, opts)
+		}
+	}
+}
+
+func (w *wrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
+	if w.keys == nil {
+		return w.Client.Call(ctx, req, rsp, opts...)
+	}
+	if imd, iok := metadata.FromIncomingContext(ctx); iok && imd != nil {
+		omd, ook := metadata.FromOutgoingContext(ctx)
+		if !ook || omd == nil {
+			omd = metadata.New(len(imd))
+		}
+		for _, k := range w.keys {
+			if v := imd.Get(k); v != nil {
+				omd.Set(k, v...)
+			}
+		}
+		if !ook {
+			ctx = metadata.NewOutgoingContext(ctx, omd)
+		}
+	}
+	return w.Client.Call(ctx, req, rsp, opts...)
+}
+
+func (w *wrapper) Stream(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) {
+	if w.keys == nil {
+		return w.Client.Stream(ctx, req, opts...)
+	}
+	if imd, iok := metadata.FromIncomingContext(ctx); iok && imd != nil {
+		omd, ook := metadata.FromOutgoingContext(ctx)
+		if !ook || omd == nil {
+			omd = metadata.New(len(imd))
+		}
+		for _, k := range w.keys {
+			if v := imd.Get(k); v != nil {
+				omd.Set(k, v...)
+			}
+		}
+		if !ook {
+			ctx = metadata.NewOutgoingContext(ctx, omd)
+		}
+	}
+	return w.Client.Stream(ctx, req, opts...)
+}
+
+func NewServerHandlerWrapper(keys ...string) server.HandlerWrapper {
+	return func(fn server.HandlerFunc) server.HandlerFunc {
+		return func(ctx context.Context, req server.Request, rsp interface{}) error {
+			if keys == nil {
+				return fn(ctx, req, rsp)
+			}
+			if imd, iok := metadata.FromIncomingContext(ctx); iok && imd != nil {
+				omd, ook := metadata.FromOutgoingContext(ctx)
+				if !ook || omd == nil {
+					omd = metadata.New(len(imd))
+				}
+				for _, k := range keys {
+					if v := imd.Get(k); v != nil {
+						omd.Set(k, v...)
+					}
+				}
+				if !ook {
+					ctx = metadata.NewOutgoingContext(ctx, omd)
+				}
+			}
+			return fn(ctx, req, rsp)
+		}
+	}
+}

hooks/recovery/recovery.go

@@ -0,0 +1,63 @@
+package recovery
+
+import (
+	"context"
+	"fmt"
+
+	"go.unistack.org/micro/v4/errors"
+	"go.unistack.org/micro/v4/server"
+)
+
+func NewOptions(opts ...Option) Options {
+	options := Options{
+		ServerHandlerFn: DefaultServerHandlerFn,
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+	return options
+}
+
+type Options struct {
+	ServerHandlerFn func(context.Context, server.Request, interface{}, error) error
+}
+
+type Option func(*Options)
+
+func ServerHandlerFunc(fn func(context.Context, server.Request, interface{}, error) error) Option {
+	return func(o *Options) {
+		o.ServerHandlerFn = fn
+	}
+}
+
+var DefaultServerHandlerFn = func(ctx context.Context, req server.Request, rsp interface{}, err error) error {
+	return errors.BadRequest("", "%v", err)
+}
+
+var Hook = NewHook()
+
+type hook struct {
+	opts Options
+}
+
+func NewHook(opts ...Option) *hook {
+	return &hook{opts: NewOptions(opts...)}
+}
+
+func (w *hook) ServerHandler(next server.FuncHandler) server.FuncHandler {
+	return func(ctx context.Context, req server.Request, rsp interface{}) (err error) {
+		defer func() {
+			r := recover()
+			switch verr := r.(type) {
+			case nil:
+				return
+			case error:
+				err = w.opts.ServerHandlerFn(ctx, req, rsp, verr)
+			default:
+				err = w.opts.ServerHandlerFn(ctx, req, rsp, fmt.Errorf("%v", r))
+			}
+		}()
+		err = next(ctx, req, rsp)
+		return err
+	}
+}

hooks/requestid/requestid.go

@@ -0,0 +1,103 @@
+package requestid
+
+import (
+	"context"
+	"net/textproto"
+
+	"go.unistack.org/micro/v4/client"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/server"
+	"go.unistack.org/micro/v4/util/id"
+)
+
+type XRequestIDKey struct{}
+
+// DefaultMetadataKey contains metadata key
+var DefaultMetadataKey = textproto.CanonicalMIMEHeaderKey("x-request-id")
+
+// DefaultMetadataFunc wil be used if user not provide own func to fill metadata
+var DefaultMetadataFunc = func(ctx context.Context) (context.Context, error) {
+	var xid string
+
+	cid, cok := ctx.Value(XRequestIDKey{}).(string)
+	if cok && cid != "" {
+		xid = cid
+	}
+
+	imd, iok := metadata.FromIncomingContext(ctx)
+	if !iok || imd == nil {
+		imd = metadata.New(1)
+		ctx = metadata.NewIncomingContext(ctx, imd)
+	}
+
+	omd, ook := metadata.FromOutgoingContext(ctx)
+	if !ook || omd == nil {
+		omd = metadata.New(1)
+		ctx = metadata.NewOutgoingContext(ctx, omd)
+	}
+
+	if xid == "" {
+		xid = imd.GetJoined(DefaultMetadataKey)
+		if xid == "" {
+			xid = omd.GetJoined(DefaultMetadataKey)
+		}
+	}
+
+	if xid == "" {
+		var err error
+		xid, err = id.New()
+		if err != nil {
+			return ctx, err
+		}
+	}
+
+	if !cok {
+		ctx = context.WithValue(ctx, XRequestIDKey{}, xid)
+	}
+
+	if !iok {
+		imd.Set(DefaultMetadataKey, xid)
+	}
+
+	if !ook {
+		omd.Set(DefaultMetadataKey, xid)
+	}
+
+	return ctx, nil
+}
+
+type hook struct{}
+
+func NewHook() *hook {
+	return &hook{}
+}
+
+func (w *hook) ServerHandler(next server.FuncHandler) server.FuncHandler {
+	return func(ctx context.Context, req server.Request, rsp interface{}) error {
+		var err error
+		if ctx, err = DefaultMetadataFunc(ctx); err != nil {
+			return err
+		}
+		return next(ctx, req, rsp)
+	}
+}
+
+func (w *hook) ClientCall(next client.FuncCall) client.FuncCall {
+	return func(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
+		var err error
+		if ctx, err = DefaultMetadataFunc(ctx); err != nil {
+			return err
+		}
+		return next(ctx, req, rsp, opts...)
+	}
+}
+
+func (w *hook) ClientStream(next client.FuncStream) client.FuncStream {
+	return func(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) {
+		var err error
+		if ctx, err = DefaultMetadataFunc(ctx); err != nil {
+			return nil, err
+		}
+		return next(ctx, req, opts...)
+	}
+}

hooks/requestid/requestid_test.go

@@ -0,0 +1,34 @@
+package requestid
+
+import (
+	"context"
+	"slices"
+	"testing"
+
+	"go.unistack.org/micro/v4/metadata"
+)
+
+func TestDefaultMetadataFunc(t *testing.T) {
+	ctx := context.TODO()
+
+	nctx, err := DefaultMetadataFunc(ctx)
+	if err != nil {
+		t.Fatalf("%v", err)
+	}
+
+	imd, ok := metadata.FromIncomingContext(nctx)
+	if !ok {
+		t.Fatalf("md missing in incoming context")
+	}
+	omd, ok := metadata.FromOutgoingContext(nctx)
+	if !ok {
+		t.Fatalf("md missing in outgoing context")
+	}
+
+	iv := imd.Get(DefaultMetadataKey)
+	ov := omd.Get(DefaultMetadataKey)
+
+	if !slices.Equal(iv, ov) {
+		t.Fatalf("missing metadata key value %v != %v", iv, ov)
+	}
+}

hooks/sql/common.go

@@ -0,0 +1,51 @@
+package sql
+
+import (
+	"database/sql/driver"
+	"errors"
+	"fmt"
+	"runtime"
+)
+
+//go:generate sh -c "go run gen.go > wrap_gen.go"
+
+// namedValueToValue converts driver arguments of NamedValue format to Value format. Implemented in the same way as in
+// database/sql ctxutil.go.
+func namedValueToValue(named []driver.NamedValue) ([]driver.Value, error) {
+	dargs := make([]driver.Value, len(named))
+	for n, param := range named {
+		if len(param.Name) > 0 {
+			return nil, errors.New("sql: driver does not support the use of Named Parameters")
+		}
+		dargs[n] = param.Value
+	}
+	return dargs, nil
+}
+
+// namedValueToLabels convert driver arguments to interface{} slice
+func namedValueToLabels(named []driver.NamedValue) []interface{} {
+	largs := make([]interface{}, 0, len(named)*2)
+	var name string
+	for _, param := range named {
+		if param.Name != "" {
+			name = param.Name
+		} else {
+			name = fmt.Sprintf("$%d", param.Ordinal)
+		}
+		largs = append(largs, fmt.Sprintf("%s=%v", name, param.Value))
+	}
+	return largs
+}
+
+// getCallerName get the name of the function A where A() -> B() -> GetFunctionCallerName()
+func getCallerName() string {
+	pc, _, _, ok := runtime.Caller(3)
+	details := runtime.FuncForPC(pc)
+	var callerName string
+	if ok && details != nil {
+		callerName = details.Name()
+	} else {
+		callerName = labelUnknown
+	}
+	return callerName
+}

hooks/sql/conn.go

@@ -0,0 +1,467 @@
+package sql
+
+import (
+	"context"
+	"database/sql/driver"
+	"fmt"
+	"time"
+
+	"go.unistack.org/micro/v4/hooks/requestid"
+	"go.unistack.org/micro/v4/tracer"
+)
+
+var (
+	_ driver.Conn               = (*wrapperConn)(nil)
+	_ driver.ConnBeginTx        = (*wrapperConn)(nil)
+	_ driver.ConnPrepareContext = (*wrapperConn)(nil)
+	_ driver.Pinger             = (*wrapperConn)(nil)
+	_ driver.Validator          = (*wrapperConn)(nil)
+	_ driver.Queryer            = (*wrapperConn)(nil) // nolint:staticcheck
+	_ driver.QueryerContext     = (*wrapperConn)(nil)
+	_ driver.Execer             = (*wrapperConn)(nil) // nolint:staticcheck
+	_ driver.ExecerContext      = (*wrapperConn)(nil)
+	//	_ driver.Connector
+	//	_ driver.Driver
+	//	_ driver.DriverContext
+)
+
+// wrapperConn defines a wrapper for driver.Conn
+type wrapperConn struct {
+	d     *wrapperDriver
+	dname string
+	conn  driver.Conn
+	opts  Options
+	ctx   context.Context
+	//span  tracer.Span
+}
+
+// Close implements driver.Conn Close
+func (w *wrapperConn) Close() error {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+	_ = ctx
+	labels := []string{labelMethod, "Close"}
+	ts := time.Now()
+	err := w.conn.Close()
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Close", getCallerName(), td, err)...)
+		}
+	*/
+	return err
+}
+
+// Begin implements driver.Conn Begin
+func (w *wrapperConn) Begin() (driver.Tx, error) {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+
+	labels := []string{labelMethod, "Begin"}
+	ts := time.Now()
+	tx, err := w.conn.Begin() // nolint:staticcheck
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+		w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Begin", getCallerName(), td, err)...)
+			}
+		*/
+		return nil, err
+	}
+	w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Begin", getCallerName(), td, err)...)
+		}
+	*/
+	return &wrapperTx{tx: tx, opts: w.opts, ctx: ctx}, nil
+}
+
+// BeginTx implements driver.ConnBeginTx BeginTx
+func (w *wrapperConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	name := getQueryName(ctx)
+	nctx, span := w.opts.Tracer.Start(ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	span.AddLabels("db.method", "BeginTx")
+	span.AddLabels("db.statement", name)
+	if id, ok := ctx.Value(requestid.XRequestIDKey{}).(string); ok {
+		span.AddLabels("x-request-id", id)
+	}
+	labels := []string{labelMethod, "BeginTx", labelQuery, name}
+
+	connBeginTx, ok := w.conn.(driver.ConnBeginTx)
+	if !ok {
+		return w.Begin()
+	}
+
+	ts := time.Now()
+	tx, err := connBeginTx.BeginTx(nctx, opts)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+		w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "BeginTx", getCallerName(), td, err)...)
+			}
+		*/
+		return nil, err
+	}
+	w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "BeginTx", getCallerName(), td, err)...)
+		}
+	*/
+	return &wrapperTx{tx: tx, opts: w.opts, ctx: ctx, span: span}, nil
+}
+
+// Prepare implements driver.Conn Prepare
+func (w *wrapperConn) Prepare(query string) (driver.Stmt, error) {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+	_ = ctx
+	labels := []string{labelMethod, "Prepare", labelQuery, getCallerName()}
+	ts := time.Now()
+	stmt, err := w.conn.Prepare(query)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+		w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Prepare", getCallerName(), td, err)...)
+			}
+		*/
+		return nil, err
+	}
+	w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Prepare", getCallerName(), td, err)...)
+		}
+	*/
+	return wrapStmt(stmt, query, w.opts), nil
+}
+
+// PrepareContext implements driver.ConnPrepareContext PrepareContext
+func (w *wrapperConn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
+	var nctx context.Context
+	var span tracer.Span
+
+	name := getQueryName(ctx)
+	if w.ctx != nil {
+		nctx, span = w.opts.Tracer.Start(w.ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	} else {
+		nctx, span = w.opts.Tracer.Start(ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	}
+	span.AddLabels("db.method", "PrepareContext")
+	span.AddLabels("db.statement", name)
+	if id, ok := ctx.Value(requestid.XRequestIDKey{}).(string); ok {
+		span.AddLabels("x-request-id", id)
+	}
+	labels := []string{labelMethod, "PrepareContext", labelQuery, name}
+	conn, ok := w.conn.(driver.ConnPrepareContext)
+	if !ok {
+		return w.Prepare(query)
+	}
+
+	ts := time.Now()
+	stmt, err := conn.PrepareContext(nctx, query)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+		w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "PrepareContext", getCallerName(), td, err)...)
+			}
+		*/
+		return nil, err
+	}
+	w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "PrepareContext", getCallerName(), td, err)...)
+		}
+	*/
+	return wrapStmt(stmt, query, w.opts), nil
+}
+
+// Exec implements driver.Execer Exec
+func (w *wrapperConn) Exec(query string, args []driver.Value) (driver.Result, error) {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+	_ = ctx
+	labels := []string{labelMethod, "Exec", labelQuery, getCallerName()}
+
+	// nolint:staticcheck
+	conn, ok := w.conn.(driver.Execer)
+	if !ok {
+		return nil, driver.ErrSkip
+	}
+
+	ts := time.Now()
+	res, err := conn.Exec(query, args)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Exec", getCallerName(), td, err)...)
+		}
+	*/
+	return res, err
+}
+
+// Exec implements driver.StmtExecContext ExecContext
+func (w *wrapperConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	var nctx context.Context
+	var span tracer.Span
+
+	name := getQueryName(ctx)
+	if w.ctx != nil {
+		nctx, span = w.opts.Tracer.Start(w.ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	} else {
+		nctx, span = w.opts.Tracer.Start(ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	}
+	span.AddLabels("db.method", "ExecContext")
+	span.AddLabels("db.statement", name)
+	if id, ok := ctx.Value(requestid.XRequestIDKey{}).(string); ok {
+		span.AddLabels("x-request-id", id)
+	}
+	defer span.Finish()
+	if len(args) > 0 {
+		span.AddLabels("db.args", fmt.Sprintf("%v", namedValueToLabels(args)))
+	}
+	labels := []string{labelMethod, "ExecContext", labelQuery, name}
+
+	conn, ok := w.conn.(driver.ExecerContext)
+	if !ok {
+		// nolint:staticcheck
+		return nil, driver.ErrSkip
+	}
+
+	ts := time.Now()
+	res, err := conn.ExecContext(nctx, query, args)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "ExecContext", getCallerName(), td, err)...)
+		}
+	*/
+	return res, err
+}
+
+// Ping implements driver.Pinger Ping
+func (w *wrapperConn) Ping(ctx context.Context) error {
+	conn, ok := w.conn.(driver.Pinger)
+
+	if !ok {
+		// fallback path to check db alive
+		pc, err := w.d.Open(w.dname)
+		if err != nil {
+			return err
+		}
+		return pc.Close()
+	}
+
+	var nctx context.Context //nolint:gosimple
+	nctx = ctx
+	/*
+		var span tracer.Span
+		if w.ctx != nil {
+			nctx, span = w.opts.Tracer.Start(w.ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+		} else {
+			nctx, span = w.opts.Tracer.Start(ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+		}
+		span.AddLabels("db.method", "Ping")
+		defer span.Finish()
+	*/
+	labels := []string{labelMethod, "Ping"}
+	ts := time.Now()
+	err := conn.Ping(nctx)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		// span.SetStatus(tracer.SpanStatusError, err.Error())
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Ping", getCallerName(), td, err)...)
+			}
+		*/
+		return err
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+
+	return nil
+}
+
+// Query implements driver.Queryer Query
+func (w *wrapperConn) Query(query string, args []driver.Value) (driver.Rows, error) {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+	_ = ctx
+	// nolint:staticcheck
+	conn, ok := w.conn.(driver.Queryer)
+	if !ok {
+		return nil, driver.ErrSkip
+	}
+
+	labels := []string{labelMethod, "Query", labelQuery, getCallerName()}
+	ts := time.Now()
+	rows, err := conn.Query(query, args)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Query", getCallerName(), td, err)...)
+		}
+	*/
+	return rows, err
+}
+
+// QueryContext implements Driver.QueryerContext QueryContext
+func (w *wrapperConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	var nctx context.Context
+	var span tracer.Span
+
+	name := getQueryName(ctx)
+	if w.ctx != nil {
+		nctx, span = w.opts.Tracer.Start(w.ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	} else {
+		nctx, span = w.opts.Tracer.Start(ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	}
+	span.AddLabels("db.method", "QueryContext")
+	span.AddLabels("db.statement", name)
+	if id, ok := ctx.Value(requestid.XRequestIDKey{}).(string); ok {
+		span.AddLabels("x-request-id", id)
+	}
+	defer span.Finish()
+	if len(args) > 0 {
+		span.AddLabels("db.args", fmt.Sprintf("%v", namedValueToLabels(args)))
+	}
+	labels := []string{labelMethod, "QueryContext", labelQuery, name}
+	conn, ok := w.conn.(driver.QueryerContext)
+	if !ok {
+		return nil, driver.ErrSkip
+	}
+
+	ts := time.Now()
+	rows, err := conn.QueryContext(nctx, query, args)
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "QueryContext", getCallerName(), td, err)...)
+		}
+	*/
+	return rows, err
+}
+
+// CheckNamedValue implements driver.NamedValueChecker
+func (w *wrapperConn) CheckNamedValue(v *driver.NamedValue) error {
+	s, ok := w.conn.(driver.NamedValueChecker)
+	if !ok {
+		return driver.ErrSkip
+	}
+	return s.CheckNamedValue(v)
+}
+
+// IsValid implements driver.Validator
+func (w *wrapperConn) IsValid() bool {
+	v, ok := w.conn.(driver.Validator)
+	if !ok {
+		return w.conn != nil
+	}
+	return v.IsValid()
+}
+
+func (w *wrapperConn) ResetSession(ctx context.Context) error {
+	s, ok := w.conn.(driver.SessionResetter)
+	if !ok {
+		return driver.ErrSkip
+	}
+	return s.ResetSession(ctx)
+}

hooks/sql/driver.go

@@ -0,0 +1,94 @@
+package sql
+
+import (
+	"context"
+	"database/sql/driver"
+	"time"
+)
+
+var (
+// _ driver.DriverContext = (*wrapperDriver)(nil)
+// _ driver.Connector     = (*wrapperDriver)(nil)
+)
+
+/*
+type conn interface {
+	driver.Pinger
+	driver.Execer
+	driver.ExecerContext
+	driver.Queryer
+	driver.QueryerContext
+	driver.Conn
+	driver.ConnPrepareContext
+	driver.ConnBeginTx
+}
+*/
+
+// wrapperDriver defines a wrapper for driver.Driver
+type wrapperDriver struct {
+	driver driver.Driver
+	opts   Options
+	ctx    context.Context
+}
+
+// NewWrapper creates and returns a new SQL driver with passed capabilities
+func NewWrapper(d driver.Driver, opts ...Option) driver.Driver {
+	return &wrapperDriver{driver: d, opts: NewOptions(opts...), ctx: context.Background()}
+}
+
+type wrappedConnector struct {
+	connector driver.Connector
+//	name      string
+	opts      Options
+	ctx       context.Context
+}
+
+func NewWrapperConnector(c driver.Connector, opts ...Option) driver.Connector {
+	return &wrappedConnector{connector: c, opts: NewOptions(opts...), ctx: context.Background()}
+}
+
+// Connect implements driver.Driver Connect
+func (w *wrappedConnector) Connect(ctx context.Context) (driver.Conn, error) {
+	return w.connector.Connect(ctx)
+}
+
+// Driver implements driver.Driver Driver
+func (w *wrappedConnector) Driver() driver.Driver {
+	return w.connector.Driver()
+}
+
+/*
+// Connect implements driver.Driver OpenConnector
+func (w *wrapperDriver) OpenConnector(name string) (driver.Conn, error) {
+	return &wrapperConnector{driver: w.driver, name: name, opts: w.opts}, nil
+}
+*/
+
+// Open implements driver.Driver Open
+func (w *wrapperDriver) Open(name string) (driver.Conn, error) {
+	// ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second) // Ensure eventual timeout
+	// defer cancel()
+
+	/*
+		connector, err := w.OpenConnector(name)
+		if err != nil {
+			return nil, err
+		}
+		return connector.Connect(ctx)
+	*/
+
+	ts := time.Now()
+	c, err := w.driver.Open(name)
+	td := time.Since(ts)
+	/*
+		if w.opts.LoggerEnabled {
+			w.opts.Logger.Log(w.ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(w.ctx, "Open", getCallerName(), td, err)...)
+		}
+	*/
+	_ = td
+	if err != nil {
+		return nil, err
+	}
+
+	return wrapConn(c, w.opts), nil
+}

hooks/sql/gen.go

@@ -0,0 +1,167 @@
+//go:build ignore
+
+package main
+
+import (
+	"bytes"
+	"crypto/md5"
+	"fmt"
+	"io"
+	"sort"
+	"strings"
+)
+
+var connIfaces = []string{
+	"driver.ConnBeginTx",
+	"driver.ConnPrepareContext",
+	"driver.Execer",
+	"driver.ExecerContext",
+	"driver.NamedValueChecker",
+	"driver.Pinger",
+	"driver.Queryer",
+	"driver.QueryerContext",
+	"driver.SessionResetter",
+	"driver.Validator",
+}
+
+var stmtIfaces = []string{
+	"driver.StmtExecContext",
+	"driver.StmtQueryContext",
+	"driver.ColumnConverter",
+	"driver.NamedValueChecker",
+}
+
+func getHash(s []string) string {
+	h := md5.New()
+	io.WriteString(h, strings.Join(s, "|"))
+	return fmt.Sprintf("%x", h.Sum(nil))
+}
+
+func main() {
+	comboConn := all(connIfaces)
+
+	sort.Slice(comboConn, func(i, j int) bool {
+		return len(comboConn[i]) < len(comboConn[j])
+	})
+
+	comboStmt := all(stmtIfaces)
+
+	sort.Slice(comboStmt, func(i, j int) bool {
+		return len(comboStmt[i]) < len(comboStmt[j])
+	})
+
+	b := bytes.NewBuffer(nil)
+	b.WriteString("// Code generated. DO NOT EDIT.\n\n")
+	b.WriteString("package sql\n\n")
+	b.WriteString(`import "database/sql/driver"`)
+	b.WriteString("\n\n")
+
+	b.WriteString("func wrapConn(dc driver.Conn, opts Options) driver.Conn {\n")
+	b.WriteString("\tc := &wrapperConn{conn: dc, opts: opts}\n")
+
+	for idx := len(comboConn) - 1; idx >= 0; idx-- {
+		ifaces := comboConn[idx]
+		n := len(ifaces)
+		if n == 0 {
+			continue
+		}
+		h := getHash(ifaces)
+		b.WriteString(fmt.Sprintf("\tif _, ok := dc.(wrapConn%04d_%s); ok {\n", n, h))
+		b.WriteString("\treturn struct {\n")
+		b.WriteString("\t\tdriver.Conn\n")
+		b.WriteString(fmt.Sprintf("\t\t\t%s", strings.Join(ifaces, "\n\t\t\t")))
+		b.WriteString("\t\t\n}{")
+		for idx := range ifaces {
+			if idx > 0 {
+				b.WriteString(", ")
+				b.WriteString("c")
+			} else if idx == 0 {
+				b.WriteString("c")
+			} else {
+				b.WriteString("c")
+			}
+		}
+		b.WriteString(", c}\n")
+		b.WriteString("}\n\n")
+	}
+	b.WriteString("return c\n")
+	b.WriteString("}\n")
+
+	for idx := len(comboConn) - 1; idx >= 0; idx-- {
+		ifaces := comboConn[idx]
+		n := len(ifaces)
+		if n == 0 {
+			continue
+		}
+		h := getHash(ifaces)
+		b.WriteString(fmt.Sprintf("// %s\n", strings.Join(ifaces, "|")))
+		b.WriteString(fmt.Sprintf("type wrapConn%04d_%s interface {\n", n, h))
+		for _, iface := range ifaces {
+			b.WriteString(fmt.Sprintf("\t%s\n", iface))
+		}
+		b.WriteString("}\n\n")
+	}
+
+	b.WriteString("func wrapStmt(stmt driver.Stmt, query string, opts Options) driver.Stmt {\n")
+	b.WriteString("\tc := &wrapperStmt{stmt: stmt, query: query, opts: opts}\n")
+
+	for idx := len(comboStmt) - 1; idx >= 0; idx-- {
+		ifaces := comboStmt[idx]
+		n := len(ifaces)
+		if n == 0 {
+			continue
+		}
+		h := getHash(ifaces)
+		b.WriteString(fmt.Sprintf("\tif _, ok := stmt.(wrapStmt%04d_%s); ok {\n", n, h))
+		b.WriteString("\treturn struct {\n")
+		b.WriteString("\t\tdriver.Stmt\n")
+		b.WriteString(fmt.Sprintf("\t\t\t%s", strings.Join(ifaces, "\n\t\t\t")))
+		b.WriteString("\t\t\n}{")
+		for idx := range ifaces {
+			if idx > 0 {
+				b.WriteString(", ")
+				b.WriteString("c")
+			} else if idx == 0 {
+				b.WriteString("c")
+			} else {
+				b.WriteString("c")
+			}
+		}
+		b.WriteString(", c}\n")
+		b.WriteString("}\n\n")
+	}
+	b.WriteString("return c\n")
+	b.WriteString("}\n")
+
+	for idx := len(comboStmt) - 1; idx >= 0; idx-- {
+		ifaces := comboStmt[idx]
+		n := len(ifaces)
+		if n == 0 {
+			continue
+		}
+		h := getHash(ifaces)
+		b.WriteString(fmt.Sprintf("// %s\n", strings.Join(ifaces, "|")))
+		b.WriteString(fmt.Sprintf("type wrapStmt%04d_%s interface {\n", n, h))
+		for _, iface := range ifaces {
+			b.WriteString(fmt.Sprintf("\t%s\n", iface))
+		}
+		b.WriteString("}\n\n")
+	}
+
+	fmt.Printf("%s\n", b.String())
+}
+
+// all returns all combinations for a given string array.
+func all[T any](set []T) (subsets [][]T) {
+	length := uint(len(set))
+	for subsetBits := 1; subsetBits < (1 << length); subsetBits++ {
+		var subset []T
+		for object := uint(0); object < length; object++ {
+			if (subsetBits>>object)&1 == 1 {
+				subset = append(subset, set[object])
+			}
+		}
+		subsets = append(subsets, subset)
+	}
+	return subsets
+}

hooks/sql/options.go

@@ -0,0 +1,172 @@
+package sql
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/meter"
+	"go.unistack.org/micro/v4/tracer"
+)
+
+var (
+	// DefaultMeterStatsInterval holds default stats interval
+	DefaultMeterStatsInterval = 5 * time.Second
+	// DefaultLoggerObserver used to prepare labels for logger
+	DefaultLoggerObserver = func(ctx context.Context, method string, query string, td time.Duration, err error) []interface{} {
+		labels := []interface{}{"db.method", method, "took", fmt.Sprintf("%v", td)}
+		if err != nil {
+			labels = append(labels, "error", err.Error())
+		}
+		if query != labelUnknown {
+			labels = append(labels, "query", query)
+		}
+		return labels
+	}
+)
+
+var (
+	MaxOpenConnections = "micro_sql_max_open_conn"
+	OpenConnections    = "micro_sql_open_conn"
+	InuseConnections   = "micro_sql_inuse_conn"
+	IdleConnections    = "micro_sql_idle_conn"
+	WaitConnections    = "micro_sql_waited_conn"
+	BlockedSeconds     = "micro_sql_blocked_seconds"
+	MaxIdleClosed      = "micro_sql_max_idle_closed"
+	MaxIdletimeClosed  = "micro_sql_closed_max_idle"
+	MaxLifetimeClosed  = "micro_sql_closed_max_lifetime"
+
+	meterRequestTotal               = "micro_sql_request_total"
+	meterRequestLatencyMicroseconds = "micro_sql_latency_microseconds"
+	meterRequestDurationSeconds     = "micro_sql_request_duration_seconds"
+
+	labelUnknown  = "unknown"
+	labelQuery    = "db_statement"
+	labelMethod   = "db_method"
+	labelStatus   = "status"
+	labelSuccess  = "success"
+	labelFailure  = "failure"
+	labelHost     = "db_host"
+	labelDatabase = "db_name"
+)
+
+// Options struct holds wrapper options
+type Options struct {
+	Logger             logger.Logger
+	Meter              meter.Meter
+	Tracer             tracer.Tracer
+	DatabaseHost       string
+	DatabaseName       string
+	MeterStatsInterval time.Duration
+	LoggerLevel        logger.Level
+	LoggerEnabled      bool
+	LoggerObserver     func(ctx context.Context, method string, name string, td time.Duration, err error) []interface{}
+}
+
+// Option func signature
+type Option func(*Options)
+
+// NewOptions create new Options struct from provided option slice
+func NewOptions(opts ...Option) Options {
+	options := Options{
+		Logger:             logger.DefaultLogger,
+		Meter:              meter.DefaultMeter,
+		Tracer:             tracer.DefaultTracer,
+		MeterStatsInterval: DefaultMeterStatsInterval,
+		LoggerLevel:        logger.ErrorLevel,
+		LoggerObserver:     DefaultLoggerObserver,
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+
+	options.Meter = options.Meter.Clone(
+		meter.Labels(
+			labelHost, options.DatabaseHost,
+			labelDatabase, options.DatabaseName,
+		),
+	)
+
+	options.Logger = options.Logger.Clone(logger.WithAddCallerSkipCount(1))
+
+	return options
+}
+
+// MetricInterval specifies stats interval for *sql.DB
+func MetricInterval(td time.Duration) Option {
+	return func(o *Options) {
+		o.MeterStatsInterval = td
+	}
+}
+
+func DatabaseHost(host string) Option {
+	return func(o *Options) {
+		o.DatabaseHost = host
+	}
+}
+
+func DatabaseName(name string) Option {
+	return func(o *Options) {
+		o.DatabaseName = name
+	}
+}
+
+// Meter passes meter.Meter to wrapper
+func Meter(m meter.Meter) Option {
+	return func(o *Options) {
+		o.Meter = m
+	}
+}
+
+// Logger passes logger.Logger to wrapper
+func Logger(l logger.Logger) Option {
+	return func(o *Options) {
+		o.Logger = l
+	}
+}
+
+// LoggerEnabled enable sql logging
+func LoggerEnabled(b bool) Option {
+	return func(o *Options) {
+		o.LoggerEnabled = b
+	}
+}
+
+// LoggerLevel passes logger.Level option
+func LoggerLevel(lvl logger.Level) Option {
+	return func(o *Options) {
+		o.LoggerLevel = lvl
+	}
+}
+
+// LoggerObserver passes observer to fill logger fields
+func LoggerObserver(obs func(context.Context, string, string, time.Duration, error) []interface{}) Option {
+	return func(o *Options) {
+		o.LoggerObserver = obs
+	}
+}
+
+// Tracer passes tracer.Tracer to wrapper
+func Tracer(t tracer.Tracer) Option {
+	return func(o *Options) {
+		o.Tracer = t
+	}
+}
+
+type queryNameKey struct{}
+
+// QueryName passes query name to wrapper func
+func QueryName(ctx context.Context, name string) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, queryNameKey{}, name)
+}
+
+func getQueryName(ctx context.Context) string {
+	if v, ok := ctx.Value(queryNameKey{}).(string); ok && v != labelUnknown {
+		return v
+	}
+	return getCallerName()
+}

hooks/sql/stats.go

@@ -0,0 +1,95 @@
+package sql
+
+import (
+	"context"
+	"database/sql"
+	"sync"
+	"time"
+)
+
+type Statser interface {
+	Stats() sql.DBStats
+}
+
+func NewStatsMeter(ctx context.Context, db Statser, opts ...Option) {
+	if db == nil {
+		return
+	}
+
+	options := NewOptions(opts...)
+
+	var (
+		statsMu                                                     sync.Mutex
+		lastUpdated                                                 time.Time
+		maxOpenConnections, openConnections, inUse, idle, waitCount float64
+		maxIdleClosed, maxIdleTimeClosed, maxLifetimeClosed         float64
+		waitDuration                                                float64
+	)
+
+	updateFn := func() {
+		statsMu.Lock()
+		defer statsMu.Unlock()
+
+		if time.Since(lastUpdated) < options.MeterStatsInterval {
+			return
+		}
+
+		stats := db.Stats()
+		maxOpenConnections = float64(stats.MaxOpenConnections)
+		openConnections = float64(stats.OpenConnections)
+		inUse = float64(stats.InUse)
+		idle = float64(stats.Idle)
+		waitCount = float64(stats.WaitCount)
+		maxIdleClosed = float64(stats.MaxIdleClosed)
+		maxIdleTimeClosed = float64(stats.MaxIdleTimeClosed)
+		maxLifetimeClosed = float64(stats.MaxLifetimeClosed)
+		waitDuration = float64(stats.WaitDuration.Seconds())
+
+		lastUpdated = time.Now()
+	}
+
+	options.Meter.Gauge(MaxOpenConnections, func() float64 {
+		updateFn()
+		return maxOpenConnections
+	})
+
+	options.Meter.Gauge(OpenConnections, func() float64 {
+		updateFn()
+		return openConnections
+	})
+
+	options.Meter.Gauge(InuseConnections, func() float64 {
+		updateFn()
+		return inUse
+	})
+
+	options.Meter.Gauge(IdleConnections, func() float64 {
+		updateFn()
+		return idle
+	})
+
+	options.Meter.Gauge(WaitConnections, func() float64 {
+		updateFn()
+		return waitCount
+	})
+
+	options.Meter.Gauge(BlockedSeconds, func() float64 {
+		updateFn()
+		return waitDuration
+	})
+
+	options.Meter.Gauge(MaxIdleClosed, func() float64 {
+		updateFn()
+		return maxIdleClosed
+	})
+
+	options.Meter.Gauge(MaxIdletimeClosed, func() float64 {
+		updateFn()
+		return maxIdleTimeClosed
+	})
+
+	options.Meter.Gauge(MaxLifetimeClosed, func() float64 {
+		updateFn()
+		return maxLifetimeClosed
+	})
+}

hooks/sql/stmt.go

@@ -0,0 +1,287 @@
+package sql
+
+import (
+	"context"
+	"database/sql/driver"
+	"fmt"
+	"time"
+
+	requestid "go.unistack.org/micro/v4/hooks/requestid"
+	"go.unistack.org/micro/v4/tracer"
+)
+
+var (
+	_ driver.Stmt              = (*wrapperStmt)(nil)
+	_ driver.StmtQueryContext  = (*wrapperStmt)(nil)
+	_ driver.StmtExecContext   = (*wrapperStmt)(nil)
+	_ driver.NamedValueChecker = (*wrapperStmt)(nil)
+)
+
+// wrapperStmt defines a wrapper for driver.Stmt
+type wrapperStmt struct {
+	stmt  driver.Stmt
+	opts  Options
+	query string
+	ctx   context.Context
+}
+
+// Close implements driver.Stmt Close
+func (w *wrapperStmt) Close() error {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+	_ = ctx
+	labels := []string{labelMethod, "Close"}
+	ts := time.Now()
+	err := w.stmt.Close()
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Close", getCallerName(), td, err)...)
+		}
+	*/
+	return err
+}
+
+// NumInput implements driver.Stmt NumInput
+func (w *wrapperStmt) NumInput() int {
+	return w.stmt.NumInput()
+}
+
+// CheckNamedValue implements driver.NamedValueChecker
+func (w *wrapperStmt) CheckNamedValue(v *driver.NamedValue) error {
+	s, ok := w.stmt.(driver.NamedValueChecker)
+	if !ok {
+		return driver.ErrSkip
+	}
+	return s.CheckNamedValue(v)
+}
+
+// Exec implements driver.Stmt Exec
+func (w *wrapperStmt) Exec(args []driver.Value) (driver.Result, error) {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+	_ = ctx
+	labels := []string{labelMethod, "Exec"}
+	ts := time.Now()
+	res, err := w.stmt.Exec(args) // nolint:staticcheck
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Exec", getCallerName(), td, err)...)
+		}
+	*/
+	return res, err
+}
+
+// Query implements driver.Stmt Query
+func (w *wrapperStmt) Query(args []driver.Value) (driver.Rows, error) {
+	var ctx context.Context
+	if w.ctx != nil {
+		ctx = w.ctx
+	} else {
+		ctx = context.Background()
+	}
+	_ = ctx
+	labels := []string{labelMethod, "Query"}
+	ts := time.Now()
+	rows, err := w.stmt.Query(args) // nolint:staticcheck
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "Query", getCallerName(), td, err)...)
+		}
+	*/
+	return rows, err
+}
+
+// ColumnConverter implements driver.ColumnConverter
+func (w *wrapperStmt) ColumnConverter(idx int) driver.ValueConverter {
+	s, ok := w.stmt.(driver.ColumnConverter) // nolint:staticcheck
+	if !ok {
+		return nil
+	}
+	return s.ColumnConverter(idx)
+}
+
+// ExecContext implements driver.StmtExecContext ExecContext
+func (w *wrapperStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	var nctx context.Context
+	var span tracer.Span
+
+	name := getQueryName(ctx)
+	if w.ctx != nil {
+		nctx, span = w.opts.Tracer.Start(w.ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	} else {
+		nctx, span = w.opts.Tracer.Start(ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	}
+	span.AddLabels("db.method", "ExecContext")
+	span.AddLabels("db.statement", name)
+	defer span.Finish()
+	if len(args) > 0 {
+		span.AddLabels("db.args", fmt.Sprintf("%v", namedValueToLabels(args)))
+	}
+	if id, ok := ctx.Value(requestid.XRequestIDKey{}).(string); ok {
+		span.AddLabels("x-request-id", id)
+	}
+	labels := []string{labelMethod, "ExecContext", labelQuery, name}
+
+	if conn, ok := w.stmt.(driver.StmtExecContext); ok {
+		ts := time.Now()
+		res, err := conn.ExecContext(nctx, args)
+		td := time.Since(ts)
+		te := td.Seconds()
+		if err != nil {
+			w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+			span.SetStatus(tracer.SpanStatusError, err.Error())
+		} else {
+			w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+		}
+		w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+		w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "ExecContext", name, td, err)...)
+			}
+		*/
+		return res, err
+	}
+
+	values, err := namedValueToValue(args)
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "ExecContext", name, 0, err)...)
+			}
+		*/
+		return nil, err
+	}
+	ts := time.Now()
+	res, err := w.Exec(values) // nolint:staticcheck
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "ExecContext", name, td, err)...)
+		}
+	*/
+	return res, err
+}
+
+// QueryContext implements driver.StmtQueryContext StmtQueryContext
+func (w *wrapperStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	var nctx context.Context
+	var span tracer.Span
+
+	name := getQueryName(ctx)
+	if w.ctx != nil {
+		nctx, span = w.opts.Tracer.Start(w.ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	} else {
+		nctx, span = w.opts.Tracer.Start(ctx, "sdk.database", tracer.WithSpanKind(tracer.SpanKindClient))
+	}
+	span.AddLabels("db.method", "QueryContext")
+	span.AddLabels("db.statement", name)
+	defer span.Finish()
+	if len(args) > 0 {
+		span.AddLabels("db.args", fmt.Sprintf("%v", namedValueToLabels(args)))
+	}
+	if id, ok := ctx.Value(requestid.XRequestIDKey{}).(string); ok {
+		span.AddLabels("x-request-id", id)
+	}
+	labels := []string{labelMethod, "QueryContext", labelQuery, name}
+	if conn, ok := w.stmt.(driver.StmtQueryContext); ok {
+		ts := time.Now()
+		rows, err := conn.QueryContext(nctx, args)
+		td := time.Since(ts)
+		te := td.Seconds()
+		if err != nil {
+			w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+			span.SetStatus(tracer.SpanStatusError, err.Error())
+		} else {
+			w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+		}
+
+		w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+		w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "QueryContext", name, td, err)...)
+			}
+		*/
+		return rows, err
+	}
+
+	values, err := namedValueToValue(args)
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+		/*
+			if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+				w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "QueryContext", name, 0, err)...)
+			}
+		*/
+		return nil, err
+	}
+	ts := time.Now()
+	rows, err := w.Query(values) // nolint:staticcheck
+	td := time.Since(ts)
+	te := td.Seconds()
+	if err != nil {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelFailure)...).Inc()
+		span.SetStatus(tracer.SpanStatusError, err.Error())
+	} else {
+		w.opts.Meter.Counter(meterRequestTotal, append(labels, labelStatus, labelSuccess)...).Inc()
+	}
+
+	w.opts.Meter.Summary(meterRequestLatencyMicroseconds, labels...).Update(te)
+	w.opts.Meter.Histogram(meterRequestDurationSeconds, labels...).Update(te)
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(ctx, "QueryContext", name, td, err)...)
+		}
+	*/
+	return rows, err
+}

hooks/sql/tx.go

@@ -0,0 +1,63 @@
+package sql
+
+import (
+	"context"
+	"database/sql/driver"
+	"time"
+
+	"go.unistack.org/micro/v4/tracer"
+)
+
+var _ driver.Tx = (*wrapperTx)(nil)
+
+// wrapperTx defines a wrapper for driver.Tx
+type wrapperTx struct {
+	tx   driver.Tx
+	span tracer.Span
+	opts Options
+	ctx  context.Context
+}
+
+// Commit implements driver.Tx Commit
+func (w *wrapperTx) Commit() error {
+	ts := time.Now()
+	err := w.tx.Commit()
+	td := time.Since(ts)
+	_ = td
+	if w.span != nil {
+		if err != nil {
+			w.span.SetStatus(tracer.SpanStatusError, err.Error())
+		}
+		w.span.Finish()
+	}
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(w.ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(w.ctx, "Commit", getCallerName(), td, err)...)
+		}
+	*/
+	w.ctx = nil
+
+	return err
+}
+
+// Rollback implements driver.Tx Rollback
+func (w *wrapperTx) Rollback() error {
+	ts := time.Now()
+	err := w.tx.Rollback()
+	td := time.Since(ts)
+	_ = td
+	if w.span != nil {
+		if err != nil {
+			w.span.SetStatus(tracer.SpanStatusError, err.Error())
+		}
+		w.span.Finish()
+	}
+	/*
+		if w.opts.LoggerEnabled && w.opts.Logger.V(w.opts.LoggerLevel) {
+			w.opts.Logger.Log(w.ctx, w.opts.LoggerLevel, w.opts.LoggerObserver(w.ctx, "Rollback", getCallerName(), td, err)...)
+		}
+	*/
+	w.ctx = nil
+
+	return err
+}

hooks/sql/wrap.go

@@ -0,0 +1,19 @@
+package sql
+
+import (
+	"database/sql/driver"
+)
+
+/*
+func wrapDriver(d driver.Driver, opts Options) driver.Driver {
+	if _, ok := d.(driver.DriverContext); ok {
+		return &wrapperDriver{driver: d, opts: opts}
+	}
+	return struct{ driver.Driver }{&wrapperDriver{driver: d, opts: opts}}
+}
+*/
+
+// WrapConn allows an existing driver.Conn to be wrapped.
+func WrapConn(c driver.Conn, opts ...Option) driver.Conn {
+	return wrapConn(c, NewOptions(opts...))
+}

hooks/validator/validator.go

@@ -0,0 +1,133 @@
+package validator
+
+import (
+	"context"
+
+	"go.unistack.org/micro/v4/client"
+	"go.unistack.org/micro/v4/errors"
+	"go.unistack.org/micro/v4/server"
+)
+
+var (
+	DefaultClientErrorFunc = func(req client.Request, rsp interface{}, err error) error {
+		if rsp != nil {
+			return errors.BadGateway(req.Service(), "%v", err)
+		}
+		return errors.BadRequest(req.Service(), "%v", err)
+	}
+
+	DefaultServerErrorFunc = func(req server.Request, rsp interface{}, err error) error {
+		if rsp != nil {
+			return errors.BadGateway(req.Service(), "%v", err)
+		}
+		return errors.BadRequest(req.Service(), "%v", err)
+	}
+)
+
+type (
+	ClientErrorFunc func(client.Request, interface{}, error) error
+	ServerErrorFunc func(server.Request, interface{}, error) error
+)
+
+// Options struct holds wrapper options
+type Options struct {
+	ClientErrorFn          ClientErrorFunc
+	ServerErrorFn          ServerErrorFunc
+	ClientValidateResponse bool
+	ServerValidateResponse bool
+}
+
+// Option func signature
+type Option func(*Options)
+
+func ClientValidateResponse(b bool) Option {
+	return func(o *Options) {
+		o.ClientValidateResponse = b
+	}
+}
+
+func ServerValidateResponse(b bool) Option {
+	return func(o *Options) {
+		o.ClientValidateResponse = b
+	}
+}
+
+func ClientReqErrorFn(fn ClientErrorFunc) Option {
+	return func(o *Options) {
+		o.ClientErrorFn = fn
+	}
+}
+
+func ServerErrorFn(fn ServerErrorFunc) Option {
+	return func(o *Options) {
+		o.ServerErrorFn = fn
+	}
+}
+
+func NewOptions(opts ...Option) Options {
+	options := Options{
+		ClientErrorFn: DefaultClientErrorFunc,
+		ServerErrorFn: DefaultServerErrorFunc,
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+	return options
+}
+
+func NewHook(opts ...Option) *hook {
+	return &hook{opts: NewOptions(opts...)}
+}
+
+type validator interface {
+	Validate() error
+}
+
+type hook struct {
+	opts Options
+}
+
+func (w *hook) ClientCall(next client.FuncCall) client.FuncCall {
+	return func(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
+		if v, ok := req.Body().(validator); ok {
+			if err := v.Validate(); err != nil {
+				return w.opts.ClientErrorFn(req, nil, err)
+			}
+		}
+		err := next(ctx, req, rsp, opts...)
+		if v, ok := rsp.(validator); ok && w.opts.ClientValidateResponse {
+			if verr := v.Validate(); verr != nil {
+				return w.opts.ClientErrorFn(req, rsp, verr)
+			}
+		}
+		return err
+	}
+}
+
+func (w *hook) ClientStream(next client.FuncStream) client.FuncStream {
+	return func(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) {
+		if v, ok := req.Body().(validator); ok {
+			if err := v.Validate(); err != nil {
+				return nil, w.opts.ClientErrorFn(req, nil, err)
+			}
+		}
+		return next(ctx, req, opts...)
+	}
+}
+
+func (w *hook) ServerHandler(next server.FuncHandler) server.FuncHandler {
+	return func(ctx context.Context, req server.Request, rsp interface{}) error {
+		if v, ok := req.Body().(validator); ok {
+			if err := v.Validate(); err != nil {
+				return w.opts.ServerErrorFn(req, nil, err)
+			}
+		}
+		err := next(ctx, req, rsp)
+		if v, ok := rsp.(validator); ok && w.opts.ServerValidateResponse {
+			if verr := v.Validate(); verr != nil {
+				return w.opts.ServerErrorFn(req, rsp, verr)
+			}
+		}
+		return err
+	}
+}

logger/context.go

@@ -13,6 +13,15 @@ func FromContext(ctx context.Context) (Logger, bool) {
 	return l, ok
 }
 
+// MustContext returns logger from passed context or DefaultLogger if empty
+func MustContext(ctx context.Context) Logger {
+	l, ok := FromContext(ctx)
+	if !ok {
+		panic("missing logger")
+	}
+	return l
+}
+
 // NewContext stores logger into passed context
 func NewContext(ctx context.Context, l Logger) context.Context {
 	if ctx == nil {

logger/default.go

@@ -1,230 +0,0 @@
-package logger
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"os"
-	"runtime"
-	"strings"
-	"sync"
-	"time"
-)
-
-type defaultLogger struct {
-	enc  *json.Encoder
-	opts Options
-	sync.RWMutex
-}
-
-// Init(opts...) should only overwrite provided options
-func (l *defaultLogger) Init(opts ...Option) error {
-	l.Lock()
-	for _, o := range opts {
-		o(&l.opts)
-	}
-	l.enc = json.NewEncoder(l.opts.Out)
-	// wrap the Log func
-	l.Unlock()
-	return nil
-}
-
-func (l *defaultLogger) String() string {
-	return "micro"
-}
-
-func (l *defaultLogger) Clone(opts ...Option) Logger {
-	newopts := NewOptions(opts...)
-	oldopts := l.opts
-	for _, o := range opts {
-		o(&newopts)
-		o(&oldopts)
-	}
-
-	l.Lock()
-	cl := &defaultLogger{opts: oldopts, enc: json.NewEncoder(l.opts.Out)}
-	l.Unlock()
-
-	return cl
-}
-
-func (l *defaultLogger) V(level Level) bool {
-	l.RLock()
-	ok := l.opts.Level.Enabled(level)
-	l.RUnlock()
-	return ok
-}
-
-func (l *defaultLogger) Level(level Level) {
-	l.Lock()
-	l.opts.Level = level
-	l.Unlock()
-}
-
-func (l *defaultLogger) Fields(fields ...interface{}) Logger {
-	l.RLock()
-	nl := &defaultLogger{opts: l.opts, enc: l.enc}
-	if len(fields) == 0 {
-		l.RUnlock()
-		return nl
-	} else if len(fields)%2 != 0 {
-		fields = fields[:len(fields)-1]
-	}
-	nl.opts.Fields = copyFields(l.opts.Fields)
-	nl.opts.Fields = append(nl.opts.Fields, fields...)
-	l.RUnlock()
-	return nl
-}
-
-func copyFields(src []interface{}) []interface{} {
-	dst := make([]interface{}, len(src))
-	copy(dst, src)
-	return dst
-}
-
-// logCallerfilePath returns a package/file:line description of the caller,
-// preserving only the leaf directory name and file name.
-func logCallerfilePath(loggingFilePath string) string {
-	// To make sure we trim the path correctly on Windows too, we
-	// counter-intuitively need to use '/' and *not* os.PathSeparator here,
-	// because the path given originates from Go stdlib, specifically
-	// runtime.Caller() which (as of Mar/17) returns forward slashes even on
-	// Windows.
-	//
-	// See https://github.com/golang/go/issues/3335
-	// and https://github.com/golang/go/issues/18151
-	//
-	// for discussion on the issue on Go side.
-	idx := strings.LastIndexByte(loggingFilePath, '/')
-	if idx == -1 {
-		return loggingFilePath
-	}
-	idx = strings.LastIndexByte(loggingFilePath[:idx], '/')
-	if idx == -1 {
-		return loggingFilePath
-	}
-	return loggingFilePath[idx+1:]
-}
-
-func (l *defaultLogger) Info(ctx context.Context, args ...interface{}) {
-	l.Log(ctx, InfoLevel, args...)
-}
-
-func (l *defaultLogger) Error(ctx context.Context, args ...interface{}) {
-	l.Log(ctx, ErrorLevel, args...)
-}
-
-func (l *defaultLogger) Debug(ctx context.Context, args ...interface{}) {
-	l.Log(ctx, DebugLevel, args...)
-}
-
-func (l *defaultLogger) Warn(ctx context.Context, args ...interface{}) {
-	l.Log(ctx, WarnLevel, args...)
-}
-
-func (l *defaultLogger) Trace(ctx context.Context, args ...interface{}) {
-	l.Log(ctx, TraceLevel, args...)
-}
-
-func (l *defaultLogger) Fatal(ctx context.Context, args ...interface{}) {
-	l.Log(ctx, FatalLevel, args...)
-	os.Exit(1)
-}
-
-func (l *defaultLogger) Infof(ctx context.Context, msg string, args ...interface{}) {
-	l.Logf(ctx, InfoLevel, msg, args...)
-}
-
-func (l *defaultLogger) Errorf(ctx context.Context, msg string, args ...interface{}) {
-	l.Logf(ctx, ErrorLevel, msg, args...)
-}
-
-func (l *defaultLogger) Debugf(ctx context.Context, msg string, args ...interface{}) {
-	l.Logf(ctx, DebugLevel, msg, args...)
-}
-
-func (l *defaultLogger) Warnf(ctx context.Context, msg string, args ...interface{}) {
-	l.Logf(ctx, WarnLevel, msg, args...)
-}
-
-func (l *defaultLogger) Tracef(ctx context.Context, msg string, args ...interface{}) {
-	l.Logf(ctx, TraceLevel, msg, args...)
-}
-
-func (l *defaultLogger) Fatalf(ctx context.Context, msg string, args ...interface{}) {
-	l.Logf(ctx, FatalLevel, msg, args...)
-	os.Exit(1)
-}
-
-func (l *defaultLogger) Log(ctx context.Context, level Level, args ...interface{}) {
-	if !l.V(level) {
-		return
-	}
-
-	l.RLock()
-	fields := copyFields(l.opts.Fields)
-	l.RUnlock()
-
-	fields = append(fields, "level", level.String())
-
-	if _, file, line, ok := runtime.Caller(l.opts.CallerSkipCount); ok {
-		fields = append(fields, "caller", fmt.Sprintf("%s:%d", logCallerfilePath(file), line))
-	}
-	fields = append(fields, "timestamp", time.Now().Format("2006-01-02 15:04:05"))
-
-	if len(args) > 0 {
-		fields = append(fields, "msg", fmt.Sprint(args...))
-	}
-
-	out := make(map[string]interface{}, len(fields)/2)
-	for i := 0; i < len(fields); i += 2 {
-		out[fields[i].(string)] = fields[i+1]
-	}
-	l.RLock()
-	_ = l.enc.Encode(out)
-	l.RUnlock()
-}
-
-func (l *defaultLogger) Logf(ctx context.Context, level Level, msg string, args ...interface{}) {
-	if !l.V(level) {
-		return
-	}
-
-	l.RLock()
-	fields := copyFields(l.opts.Fields)
-	l.RUnlock()
-
-	fields = append(fields, "level", level.String())
-
-	if _, file, line, ok := runtime.Caller(l.opts.CallerSkipCount); ok {
-		fields = append(fields, "caller", fmt.Sprintf("%s:%d", logCallerfilePath(file), line))
-	}
-
-	fields = append(fields, "timestamp", time.Now().Format("2006-01-02 15:04:05"))
-	if len(args) > 0 {
-		fields = append(fields, "msg", fmt.Sprintf(msg, args...))
-	} else if msg != "" {
-		fields = append(fields, "msg", msg)
-	}
-
-	out := make(map[string]interface{}, len(fields)/2)
-	for i := 0; i < len(fields); i += 2 {
-		out[fields[i].(string)] = fields[i+1]
-	}
-	l.RLock()
-	_ = l.enc.Encode(out)
-	l.RUnlock()
-}
-
-func (l *defaultLogger) Options() Options {
-	return l.opts
-}
-
-// NewLogger builds a new logger based on options
-func NewLogger(opts ...Option) Logger {
-	l := &defaultLogger{
-		opts: NewOptions(opts...),
-	}
-	l.enc = json.NewEncoder(l.opts.Out)
-	return l
-}

logger/level.go

@@ -4,18 +4,20 @@ package logger
 type Level int8
 
 const (
-	// TraceLevel level usually used to find bugs, very verbose
+	// TraceLevel usually used to find bugs, very verbose
 	TraceLevel Level = iota - 2
-	// DebugLevel level used only when enabled debugging
+	// DebugLevel used only when enabled debugging
 	DebugLevel
-	// InfoLevel level used for general info about what's going on inside the application
+	// InfoLevel used for general info about what's going on inside the application
 	InfoLevel
-	// WarnLevel level used for non-critical entries
+	// WarnLevel used for non-critical entries
 	WarnLevel
-	// ErrorLevel level used for errors that should definitely be noted
+	// ErrorLevel used for errors that should definitely be noted
 	ErrorLevel
-	// FatalLevel level used for critical errors and then calls `os.Exit(1)`
+	// FatalLevel used for critical errors and then calls `os.Exit(1)`
 	FatalLevel
+	// NoneLevel used to disable logging
+	NoneLevel
 )
 
 // String returns logger level string representation
@@ -33,6 +35,8 @@ func (l Level) String() string {
 		return "error"
 	case FatalLevel:
 		return "fatal"
+	case NoneLevel:
+		return "none"
 	}
 	return "info"
 }
@@ -58,6 +62,8 @@ func ParseLevel(lvl string) Level {
 		return ErrorLevel
 	case FatalLevel.String():
 		return FatalLevel
+	case NoneLevel.String():
+		return NoneLevel
 	}
 	return InfoLevel
 }

logger/logger.go

@@ -1,18 +1,19 @@
 // Package logger provides a log interface
-package logger // import "go.unistack.org/micro/v3/logger"
+package logger
 
 import (
 	"context"
-	"os"
 )
 
+type ContextAttrFunc func(ctx context.Context) []interface{}
+
+var DefaultContextAttrFuncs []ContextAttrFunc
+
 var (
 	// DefaultLogger variable
-	DefaultLogger = NewLogger(WithLevel(ParseLevel(os.Getenv("MICRO_LOG_LEVEL"))))
+	DefaultLogger = NewLogger()
 	// DefaultLevel used by logger
 	DefaultLevel = InfoLevel
-	// DefaultCallerSkipCount used by logger
-	DefaultCallerSkipCount = 2
 )
 
 // Logger is a generic logging interface
@@ -30,111 +31,24 @@ type Logger interface {
 	// Fields set fields to always be logged with keyval pairs
 	Fields(fields ...interface{}) Logger
 	// Info level message
-	Info(ctx context.Context, args ...interface{})
+	Info(ctx context.Context, msg string, args ...interface{})
 	// Trace level message
-	Trace(ctx context.Context, args ...interface{})
+	Trace(ctx context.Context, msg string, args ...interface{})
 	// Debug level message
-	Debug(ctx context.Context, args ...interface{})
+	Debug(ctx context.Context, msg string, args ...interface{})
 	// Warn level message
-	Warn(ctx context.Context, args ...interface{})
+	Warn(ctx context.Context, msg string, args ...interface{})
 	// Error level message
-	Error(ctx context.Context, args ...interface{})
+	Error(ctx context.Context, msg string, args ...interface{})
 	// Fatal level message
-	Fatal(ctx context.Context, args ...interface{})
+	Fatal(ctx context.Context, msg string, args ...interface{})
-	// Infof level message
-	Infof(ctx context.Context, msg string, args ...interface{})
-	// Tracef level message
-	Tracef(ctx context.Context, msg string, args ...interface{})
-	// Debug level message
-	Debugf(ctx context.Context, msg string, args ...interface{})
-	// Warn level message
-	Warnf(ctx context.Context, msg string, args ...interface{})
-	// Error level message
-	Errorf(ctx context.Context, msg string, args ...interface{})
-	// Fatal level message
-	Fatalf(ctx context.Context, msg string, args ...interface{})
 	// Log logs message with needed level
-	Log(ctx context.Context, level Level, args ...interface{})
+	Log(ctx context.Context, level Level, msg string, args ...interface{})
-	// Logf logs message with needed level
+	// Name returns broker instance name
-	Logf(ctx context.Context, level Level, msg string, args ...interface{})
+	Name() string
-	// String returns the name of logger
+	// String returns the type of logger
 	String() string
 }
 
 // Field contains keyval pair
 type Field interface{}
-
-// Info writes msg to default logger on info level
-func Info(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Info(ctx, args...)
-}
-
-// Error writes msg to default logger on error level
-func Error(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Error(ctx, args...)
-}
-
-// Debug writes msg to default logger on debug level
-func Debug(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Debug(ctx, args...)
-}
-
-// Warn writes msg to default logger on warn level
-func Warn(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Warn(ctx, args...)
-}
-
-// Trace writes msg to default logger on trace level
-func Trace(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Trace(ctx, args...)
-}
-
-// Fatal writes msg to default logger on fatal level
-func Fatal(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Fatal(ctx, args...)
-}
-
-// Infof writes formatted msg to default logger on info level
-func Infof(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Infof(ctx, msg, args...)
-}
-
-// Errorf writes formatted msg to default logger on error level
-func Errorf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Errorf(ctx, msg, args...)
-}
-
-// Debugf writes formatted msg to default logger on debug level
-func Debugf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Debugf(ctx, msg, args...)
-}
-
-// Warnf writes formatted msg to default logger on warn level
-func Warnf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Warnf(ctx, msg, args...)
-}
-
-// Tracef writes formatted msg to default logger on trace level
-func Tracef(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Tracef(ctx, msg, args...)
-}
-
-// Fatalf writes formatted msg to default logger on fatal level
-func Fatalf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Fatalf(ctx, msg, args...)
-}
-
-// V returns true if passed level enabled in default logger
-func V(level Level) bool {
-	return DefaultLogger.V(level)
-}
-
-// Init initialize logger
-func Init(opts ...Option) error {
-	return DefaultLogger.Init(opts...)
-}
-
-// Fields create logger with specific fields
-func Fields(fields ...interface{}) Logger {
-	return DefaultLogger.Fields(fields...)
-}

logger/logger_test.go

@@ -1,138 +0,0 @@
-package logger
-
-import (
-	"bytes"
-	"context"
-	"log"
-	"testing"
-)
-
-func TestContext(t *testing.T) {
-	ctx := context.TODO()
-	buf := bytes.NewBuffer(nil)
-	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
-	if err := l.Init(); err != nil {
-		t.Fatal(err)
-	}
-
-	nl, ok := FromContext(NewContext(ctx, l.Fields("key", "val")))
-	if !ok {
-		t.Fatal("context without logger")
-	}
-	nl.Info(ctx, "message")
-	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
-		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
-	}
-}
-
-func TestFields(t *testing.T) {
-	ctx := context.TODO()
-	buf := bytes.NewBuffer(nil)
-	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
-	if err := l.Init(); err != nil {
-		t.Fatal(err)
-	}
-
-	nl := l.Fields("key", "val")
-
-	nl.Info(ctx, "message")
-	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
-		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
-	}
-}
-
-func TestFromContextWithFields(t *testing.T) {
-	ctx := context.TODO()
-	buf := bytes.NewBuffer(nil)
-	var ok bool
-	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
-	if err := l.Init(); err != nil {
-		t.Fatal(err)
-	}
-	nl := l.Fields("key", "val")
-
-	ctx = NewContext(ctx, nl)
-
-	l, ok = FromContext(ctx)
-	if !ok {
-		t.Fatalf("context does not have logger")
-	}
-
-	l.Info(ctx, "message")
-	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
-		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
-	}
-}
-
-func TestClone(t *testing.T) {
-	ctx := context.TODO()
-	buf := bytes.NewBuffer(nil)
-	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
-	if err := l.Init(); err != nil {
-		t.Fatal(err)
-	}
-	nl := l.Clone(WithLevel(ErrorLevel))
-	if err := nl.Init(); err != nil {
-		t.Fatal(err)
-	}
-	nl.Info(ctx, "info message")
-	if len(buf.Bytes()) != 0 {
-		t.Fatal("message must not be logged")
-	}
-	l.Info(ctx, "info message")
-	if len(buf.Bytes()) == 0 {
-		t.Fatal("message must be logged")
-	}
-}
-
-func TestRedirectStdLogger(t *testing.T) {
-	buf := bytes.NewBuffer(nil)
-	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
-	if err := l.Init(); err != nil {
-		t.Fatal(err)
-	}
-	fn := RedirectStdLogger(l, ErrorLevel)
-	defer fn()
-	log.Print("test")
-	if !bytes.Contains(buf.Bytes(), []byte(`"level":"error","msg":"test","timestamp"`)) {
-		t.Fatalf("logger error, buf %s", buf.Bytes())
-	}
-}
-
-func TestStdLogger(t *testing.T) {
-	buf := bytes.NewBuffer(nil)
-	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
-	if err := l.Init(); err != nil {
-		t.Fatal(err)
-	}
-	lg := NewStdLogger(l, ErrorLevel)
-	lg.Print("test")
-	if !bytes.Contains(buf.Bytes(), []byte(`"level":"error","msg":"test","timestamp"`)) {
-		t.Fatalf("logger error, buf %s", buf.Bytes())
-	}
-}
-
-func TestLogger(t *testing.T) {
-	ctx := context.TODO()
-	buf := bytes.NewBuffer(nil)
-	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
-	if err := l.Init(); err != nil {
-		t.Fatal(err)
-	}
-	l.Trace(ctx, "trace_msg1")
-	l.Warn(ctx, "warn_msg1")
-	l.Fields("error", "test").Info(ctx, "error message")
-	l.Warn(ctx, "first", " ", "second")
-	if !bytes.Contains(buf.Bytes(), []byte(`"level":"trace","msg":"trace_msg1"`)) {
-		t.Fatalf("logger error, buf %s", buf.Bytes())
-	}
-	if !bytes.Contains(buf.Bytes(), []byte(`"warn","msg":"warn_msg1"`)) {
-		t.Fatalf("logger error, buf %s", buf.Bytes())
-	}
-	if !bytes.Contains(buf.Bytes(), []byte(`"error":"test","level":"info","msg":"error message"`)) {
-		t.Fatalf("logger error, buf %s", buf.Bytes())
-	}
-	if !bytes.Contains(buf.Bytes(), []byte(`"level":"warn","msg":"first second"`)) {
-		t.Fatalf("logger error, buf %s", buf.Bytes())
-	}
-}

logger/noop.go

@@ -0,0 +1,78 @@
+package logger
+
+import (
+	"context"
+)
+
+const (
+	defaultCallerSkipCount = 2
+)
+
+type noopLogger struct {
+	opts Options
+}
+
+func NewLogger(opts ...Option) Logger {
+	options := NewOptions(opts...)
+	options.CallerSkipCount = defaultCallerSkipCount
+	return &noopLogger{opts: options}
+}
+
+func (l *noopLogger) V(_ Level) bool {
+	return false
+}
+
+func (l *noopLogger) Level(_ Level) {
+}
+
+func (l *noopLogger) Name() string {
+	return l.opts.Name
+}
+
+func (l *noopLogger) Init(opts ...Option) error {
+	for _, o := range opts {
+		o(&l.opts)
+	}
+	return nil
+}
+
+func (l *noopLogger) Clone(opts ...Option) Logger {
+	nl := &noopLogger{opts: l.opts}
+	for _, o := range opts {
+		o(&nl.opts)
+	}
+	return nl
+}
+
+func (l *noopLogger) Fields(_ ...interface{}) Logger {
+	return l
+}
+
+func (l *noopLogger) Options() Options {
+	return l.opts
+}
+
+func (l *noopLogger) String() string {
+	return "noop"
+}
+
+func (l *noopLogger) Log(ctx context.Context, lvl Level, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Info(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Debug(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Error(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Trace(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Warn(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Fatal(ctx context.Context, msg string, attrs ...interface{}) {
+}

logger/options.go

@@ -3,43 +3,130 @@ package logger
 import (
 	"context"
 	"io"
+	"log/slog"
 	"os"
+	"slices"
+	"time"
+
+	"go.unistack.org/micro/v4/meter"
 )
 
-// Option func
+// Option func signature
 type Option func(*Options)
 
 // Options holds logger options
 type Options struct {
+	// TimeKey is the key used for the time of the log call
+	TimeKey string
+	// LevelKey is the key used for the level of the log call
+	LevelKey string
+	// ErroreKey is the key used for the error of the log call
+	ErrorKey string
+	// MessageKey is the key used for the message of the log call
+	MessageKey string
+	// SourceKey is the key used for the source file and line of the log call
+	SourceKey string
+	// StacktraceKey is the key used for the stacktrace
+	StacktraceKey string
+	// Name holds the logger name
+	Name string
 	// Out holds the output writer
 	Out io.Writer
 	// Context holds exernal options
 	Context context.Context
+	// Meter used to count logs for specific level
+	Meter meter.Meter
+	// TimeFunc used to obtain current time
+	TimeFunc func() time.Time
 	// Fields holds additional metadata
 	Fields []interface{}
-	// Name holds the logger name
+	// ContextAttrFuncs contains funcs that executed before log func on context
-	Name string
+	ContextAttrFuncs []ContextAttrFunc
+	// callerSkipCount number of frmaes to skip
+	CallerSkipCount int
 	// The logging level the logger should log
 	Level Level
-	// CallerSkipCount number of frmaes to skip
+	// AddSource enabled writing source file and position in log
-	CallerSkipCount int
+	AddSource bool
+	// AddStacktrace controls writing of stacktaces on error
+	AddStacktrace bool
+	// DedupKeys deduplicate keys in log output
+	DedupKeys bool
+	// FatalFinalizers runs in order in [logger.Fatal] method
+	FatalFinalizers []func(context.Context)
+}
+
+var DefaultFatalFinalizer = func(ctx context.Context) {
+	os.Exit(1)
 }
 
 // NewOptions creates new options struct
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Level:           DefaultLevel,
+		Level:            DefaultLevel,
-		Fields:          make([]interface{}, 0, 6),
+		Fields:           make([]interface{}, 0, 6),
-		Out:             os.Stderr,
+		Out:              os.Stderr,
-		CallerSkipCount: DefaultCallerSkipCount,
+		Context:          context.Background(),
-		Context:         context.Background(),
+		ContextAttrFuncs: DefaultContextAttrFuncs,
+		AddSource:        true,
+		TimeFunc:         time.Now,
+		Meter:            meter.DefaultMeter,
+		FatalFinalizers:  []func(context.Context){DefaultFatalFinalizer},
 	}
+
+	WithMicroKeys()(&options)
+
 	for _, o := range opts {
 		o(&options)
 	}
+
 	return options
 }
 
+// WithFatalFinalizers set logger.Fatal finalizers
+func WithFatalFinalizers(fncs ...func(context.Context)) Option {
+	return func(o *Options) {
+		o.FatalFinalizers = fncs
+	}
+}
+
+// WithContextAttrFuncs appends default funcs for the context attrs filler
+func WithContextAttrFuncs(fncs ...ContextAttrFunc) Option {
+	return func(o *Options) {
+		o.ContextAttrFuncs = append(o.ContextAttrFuncs, fncs...)
+	}
+}
+
+// WithDedupKeys dont log duplicate keys
+func WithDedupKeys(b bool) Option {
+	return func(o *Options) {
+		o.DedupKeys = b
+	}
+}
+
+// WithAddFields add fields for the logger
+func WithAddFields(fields ...interface{}) Option {
+	return func(o *Options) {
+		if o.DedupKeys {
+			for i := 0; i < len(o.Fields); i += 2 {
+				for j := 0; j < len(fields); j += 2 {
+					iv, iok := o.Fields[i].(string)
+					jv, jok := fields[j].(string)
+					if iok && jok && iv == jv {
+						o.Fields[i+1] = fields[j+1]
+						fields = slices.Delete(fields, j, j+2)
+					}
+				}
+			}
+			if len(fields) > 0 {
+				o.Fields = append(o.Fields, fields...)
+			}
+		} else {
+			o.Fields = append(o.Fields, fields...)
+		}
+	}
+}
+
 // WithFields set default fields for the logger
 func WithFields(fields ...interface{}) Option {
 	return func(o *Options) {
@@ -61,10 +148,17 @@ func WithOutput(out io.Writer) Option {
 	}
 }
 
-// WithCallerSkipCount set frame count to skip
+// WithAddStacktrace controls writing stacktrace on error
-func WithCallerSkipCount(c int) Option {
+func WithAddStacktrace(v bool) Option {
 	return func(o *Options) {
-		o.CallerSkipCount = c
+		o.AddStacktrace = v
+	}
+}
+
+// WithAddSource controls writing source file and pos in log
+func WithAddSource(v bool) Option {
+	return func(o *Options) {
+		o.AddSource = v
 	}
 }
 
@@ -81,3 +175,70 @@ func WithName(n string) Option {
 		o.Name = n
 	}
 }
+
+// WithMeter sets the meter
+func WithMeter(m meter.Meter) Option {
+	return func(o *Options) {
+		o.Meter = m
+	}
+}
+
+// WithTimeFunc sets the func to obtain current time
+func WithTimeFunc(fn func() time.Time) Option {
+	return func(o *Options) {
+		o.TimeFunc = fn
+	}
+}
+
+func WithZapKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = "@timestamp"
+		o.LevelKey = slog.LevelKey
+		o.MessageKey = slog.MessageKey
+		o.SourceKey = "caller"
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+func WithZerologKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = slog.TimeKey
+		o.LevelKey = slog.LevelKey
+		o.MessageKey = "message"
+		o.SourceKey = "caller"
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+func WithSlogKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = slog.TimeKey
+		o.LevelKey = slog.LevelKey
+		o.MessageKey = slog.MessageKey
+		o.SourceKey = slog.SourceKey
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+func WithMicroKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = "timestamp"
+		o.LevelKey = slog.LevelKey
+		o.MessageKey = slog.MessageKey
+		o.SourceKey = "caller"
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+// WithAddCallerSkipCount add skip count for copy logger
+func WithAddCallerSkipCount(n int) Option {
+	return func(o *Options) {
+		if n > 0 {
+			o.CallerSkipCount += n
+		}
+	}
+}

logger/slog/slog.go

@@ -0,0 +1,381 @@
+package slog
+
+import (
+	"context"
+	"io"
+	"log/slog"
+	"reflect"
+	"regexp"
+	"runtime"
+	"strconv"
+	"sync"
+	"sync/atomic"
+
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/semconv"
+	"go.unistack.org/micro/v4/tracer"
+)
+
+const (
+	badKey = "!BADKEY"
+	// defaultCallerSkipCount used by logger
+	defaultCallerSkipCount = 3
+	timeFormat             = "2006-01-02T15:04:05.000000000Z07:00"
+)
+
+var reTrace = regexp.MustCompile(`.*/slog/logger\.go.*\n`)
+
+var (
+	traceValue = slog.StringValue("trace")
+	debugValue = slog.StringValue("debug")
+	infoValue  = slog.StringValue("info")
+	warnValue  = slog.StringValue("warn")
+	errorValue = slog.StringValue("error")
+	fatalValue = slog.StringValue("fatal")
+	noneValue  = slog.StringValue("none")
+)
+
+type wrapper struct {
+	h     slog.Handler
+	level atomic.Int64
+}
+
+func (h *wrapper) Enabled(ctx context.Context, level slog.Level) bool {
+	return level >= slog.Level(int(h.level.Load()))
+}
+
+func (h *wrapper) Handle(ctx context.Context, rec slog.Record) error {
+	return h.h.Handle(ctx, rec)
+}
+
+func (h *wrapper) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return h.h.WithAttrs(attrs)
+}
+
+func (h *wrapper) WithGroup(name string) slog.Handler {
+	return h.h.WithGroup(name)
+}
+
+func (s *slogLogger) renameAttr(_ []string, a slog.Attr) slog.Attr {
+	switch a.Key {
+	case slog.SourceKey:
+		source := a.Value.Any().(*slog.Source)
+		a.Value = slog.StringValue(source.File + ":" + strconv.Itoa(source.Line))
+		a.Key = s.opts.SourceKey
+	case slog.TimeKey:
+		a.Key = s.opts.TimeKey
+		a.Value = slog.StringValue(a.Value.Time().Format(timeFormat))
+	case slog.MessageKey:
+		a.Key = s.opts.MessageKey
+	case slog.LevelKey:
+		level := a.Value.Any().(slog.Level)
+		lvl := slogToLoggerLevel(level)
+		a.Key = s.opts.LevelKey
+		switch {
+		case lvl < logger.DebugLevel:
+			a.Value = traceValue
+		case lvl < logger.InfoLevel:
+			a.Value = debugValue
+		case lvl < logger.WarnLevel:
+			a.Value = infoValue
+		case lvl < logger.ErrorLevel:
+			a.Value = warnValue
+		case lvl < logger.FatalLevel:
+			a.Value = errorValue
+		case lvl >= logger.FatalLevel:
+			a.Value = fatalValue
+		case lvl >= logger.NoneLevel:
+			a.Value = noneValue
+		default:
+			a.Value = infoValue
+		}
+	}
+
+	return a
+}
+
+type slogLogger struct {
+	handler *wrapper
+	opts    logger.Options
+	mu      sync.RWMutex
+}
+
+func (s *slogLogger) Clone(opts ...logger.Option) logger.Logger {
+	s.mu.RLock()
+	options := s.opts
+	s.mu.RUnlock()
+
+	for _, o := range opts {
+		o(&options)
+	}
+
+	if len(options.ContextAttrFuncs) == 0 {
+		options.ContextAttrFuncs = logger.DefaultContextAttrFuncs
+	}
+
+	attrs, _ := s.argsAttrs(options.Fields)
+	l := &slogLogger{
+		handler: &wrapper{h: s.handler.h.WithAttrs(attrs)},
+		opts:    options,
+	}
+	l.handler.level.Store(int64(loggerToSlogLevel(options.Level)))
+
+	return l
+}
+
+func (s *slogLogger) V(level logger.Level) bool {
+	s.mu.Lock()
+	v := s.opts.Level.Enabled(level)
+	s.mu.Unlock()
+	return v
+}
+
+func (s *slogLogger) Level(level logger.Level) {
+	s.mu.Lock()
+	s.opts.Level = level
+	s.handler.level.Store(int64(loggerToSlogLevel(level)))
+	s.mu.Unlock()
+}
+
+func (s *slogLogger) Options() logger.Options {
+	return s.opts
+}
+
+func (s *slogLogger) Fields(fields ...interface{}) logger.Logger {
+	s.mu.RLock()
+	options := s.opts
+	s.mu.RUnlock()
+
+	l := &slogLogger{opts: options}
+	logger.WithAddFields(fields...)(&l.opts)
+
+	if len(options.ContextAttrFuncs) == 0 {
+		options.ContextAttrFuncs = logger.DefaultContextAttrFuncs
+	}
+
+	attrs, _ := s.argsAttrs(fields)
+	l.handler = &wrapper{h: s.handler.h.WithAttrs(attrs)}
+	l.handler.level.Store(int64(loggerToSlogLevel(l.opts.Level)))
+
+	return l
+}
+
+func (s *slogLogger) Init(opts ...logger.Option) error {
+	s.mu.Lock()
+
+	for _, o := range opts {
+		o(&s.opts)
+	}
+
+	if len(s.opts.ContextAttrFuncs) == 0 {
+		s.opts.ContextAttrFuncs = logger.DefaultContextAttrFuncs
+	}
+
+	handleOpt := &slog.HandlerOptions{
+		ReplaceAttr: s.renameAttr,
+		Level:       loggerToSlogLevel(logger.TraceLevel),
+		AddSource:   s.opts.AddSource,
+	}
+
+	attrs, _ := s.argsAttrs(s.opts.Fields)
+
+	var h slog.Handler
+	if s.opts.Context != nil {
+		if v, ok := s.opts.Context.Value(handlerKey{}).(slog.Handler); ok && v != nil {
+			h = v
+		}
+
+		if fn := s.opts.Context.Value(handlerFnKey{}); fn != nil {
+			if rfn := reflect.ValueOf(fn); rfn.Kind() == reflect.Func {
+				if ret := rfn.Call([]reflect.Value{reflect.ValueOf(s.opts.Out), reflect.ValueOf(handleOpt)}); len(ret) == 1 {
+					if iface, ok := ret[0].Interface().(slog.Handler); ok && iface != nil {
+						h = iface
+					}
+				}
+			}
+		}
+	}
+
+	if h == nil {
+		h = slog.NewJSONHandler(s.opts.Out, handleOpt)
+	}
+
+	s.handler = &wrapper{h: h.WithAttrs(attrs)}
+	s.handler.level.Store(int64(loggerToSlogLevel(s.opts.Level)))
+	s.mu.Unlock()
+
+	return nil
+}
+
+func (s *slogLogger) Log(ctx context.Context, lvl logger.Level, msg string, attrs ...interface{}) {
+	s.printLog(ctx, lvl, msg, attrs...)
+}
+
+func (s *slogLogger) Info(ctx context.Context, msg string, attrs ...interface{}) {
+	s.printLog(ctx, logger.InfoLevel, msg, attrs...)
+}
+
+func (s *slogLogger) Debug(ctx context.Context, msg string, attrs ...interface{}) {
+	s.printLog(ctx, logger.DebugLevel, msg, attrs...)
+}
+
+func (s *slogLogger) Trace(ctx context.Context, msg string, attrs ...interface{}) {
+	s.printLog(ctx, logger.TraceLevel, msg, attrs...)
+}
+
+func (s *slogLogger) Error(ctx context.Context, msg string, attrs ...interface{}) {
+	s.printLog(ctx, logger.ErrorLevel, msg, attrs...)
+}
+
+func (s *slogLogger) Fatal(ctx context.Context, msg string, attrs ...interface{}) {
+	s.printLog(ctx, logger.FatalLevel, msg, attrs...)
+	for _, fn := range s.opts.FatalFinalizers {
+		fn(ctx)
+	}
+	if closer, ok := s.opts.Out.(io.Closer); ok {
+		closer.Close()
+	}
+}
+
+func (s *slogLogger) Warn(ctx context.Context, msg string, attrs ...interface{}) {
+	s.printLog(ctx, logger.WarnLevel, msg, attrs...)
+}
+
+func (s *slogLogger) Name() string {
+	return s.opts.Name
+}
+
+func (s *slogLogger) String() string {
+	return "slog"
+}
+
+func (s *slogLogger) printLog(ctx context.Context, lvl logger.Level, msg string, args ...interface{}) {
+	if !s.V(lvl) {
+		return
+	}
+	var argError error
+
+	s.opts.Meter.Counter(semconv.LoggerMessageTotal, "level", lvl.String()).Inc()
+
+	attrs, err := s.argsAttrs(args)
+	if err != nil {
+		argError = err
+	}
+	if argError != nil {
+		if span, ok := tracer.SpanFromContext(ctx); ok {
+			span.SetStatus(tracer.SpanStatusError, argError.Error())
+		}
+	}
+
+	for _, fn := range s.opts.ContextAttrFuncs {
+		ctxAttrs, err := s.argsAttrs(fn(ctx))
+		if err != nil {
+			argError = err
+		}
+		attrs = append(attrs, ctxAttrs...)
+	}
+	if argError != nil {
+		if span, ok := tracer.SpanFromContext(ctx); ok {
+			span.SetStatus(tracer.SpanStatusError, argError.Error())
+		}
+	}
+
+	if s.opts.AddStacktrace && (lvl == logger.FatalLevel || lvl == logger.ErrorLevel) {
+		stackInfo := make([]byte, 1024*1024)
+		if stackSize := runtime.Stack(stackInfo, false); stackSize > 0 {
+			traceLines := reTrace.Split(string(stackInfo[:stackSize]), -1)
+			if len(traceLines) != 0 {
+				attrs = append(attrs, slog.String(s.opts.StacktraceKey, traceLines[len(traceLines)-1]))
+			}
+		}
+	}
+
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, printLog, LogLvlMethod]
+	r := slog.NewRecord(s.opts.TimeFunc(), loggerToSlogLevel(lvl), msg, pcs[0])
+	r.AddAttrs(attrs...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func NewLogger(opts ...logger.Option) logger.Logger {
+	s := &slogLogger{
+		opts: logger.NewOptions(opts...),
+	}
+	s.opts.CallerSkipCount = defaultCallerSkipCount
+
+	return s
+}
+
+func loggerToSlogLevel(level logger.Level) slog.Level {
+	switch level {
+	case logger.DebugLevel:
+		return slog.LevelDebug
+	case logger.WarnLevel:
+		return slog.LevelWarn
+	case logger.ErrorLevel:
+		return slog.LevelError
+	case logger.TraceLevel:
+		return slog.LevelDebug - 1
+	case logger.FatalLevel:
+		return slog.LevelError + 1
+	case logger.NoneLevel:
+		return slog.LevelError + 2
+	default:
+		return slog.LevelInfo
+	}
+}
+
+func slogToLoggerLevel(level slog.Level) logger.Level {
+	switch level {
+	case slog.LevelDebug:
+		return logger.DebugLevel
+	case slog.LevelWarn:
+		return logger.WarnLevel
+	case slog.LevelError:
+		return logger.ErrorLevel
+	case slog.LevelDebug - 1:
+		return logger.TraceLevel
+	case slog.LevelError + 1:
+		return logger.FatalLevel
+	case slog.LevelError + 2:
+		return logger.NoneLevel
+	default:
+		return logger.InfoLevel
+	}
+}
+
+func (s *slogLogger) argsAttrs(args []interface{}) ([]slog.Attr, error) {
+	attrs := make([]slog.Attr, 0, len(args))
+	var err error
+
+	for idx := 0; idx < len(args); idx++ {
+		switch arg := args[idx].(type) {
+		case slog.Attr:
+			attrs = append(attrs, arg)
+		case string:
+			if idx+1 < len(args) {
+				attrs = append(attrs, slog.Any(arg, args[idx+1]))
+				idx++
+			} else {
+				attrs = append(attrs, slog.String(badKey, arg))
+			}
+		case error:
+			attrs = append(attrs, slog.String(s.opts.ErrorKey, arg.Error()))
+			err = arg
+		}
+	}
+
+	return attrs, err
+}
+
+type handlerKey struct{}
+
+func WithHandler(h slog.Handler) logger.Option {
+	return logger.SetOption(handlerKey{}, h)
+}
+
+type handlerFnKey struct{}
+
+func WithHandlerFunc(fn any) logger.Option {
+	return logger.SetOption(handlerFnKey{}, fn)
+}

logger/slog/slog_test.go

@@ -0,0 +1,493 @@
+package slog
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"log/slog"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/util/buffer"
+)
+
+// always first to have proper check
+func TestStacktrace(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.DebugLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithAddStacktrace(true),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Error(ctx, "msg1", errors.New("err"))
+
+	if !bytes.Contains(buf.Bytes(), []byte(`slog_test.go:32`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestNoneLevel(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.NoneLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithAddStacktrace(true),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Error(ctx, "msg1", errors.New("err"))
+
+	if buf.Len() != 0 {
+		t.Fatalf("logger none level not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestDelayedBuffer(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	dbuf := buffer.NewDelayedBuffer(100, 100*time.Millisecond, buf)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(dbuf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithAddStacktrace(true),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Error(ctx, "msg1", errors.New("err"))
+	time.Sleep(120 * time.Millisecond)
+	if !bytes.Contains(buf.Bytes(), []byte(`key1=val1`)) {
+		t.Fatalf("logger delayed buffer not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestTime(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithAddStacktrace(true),
+		logger.WithTimeFunc(func() time.Time {
+			return time.Unix(0, 0).UTC()
+		}),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Error(ctx, "msg1", errors.New("err"))
+
+	if !bytes.Contains(buf.Bytes(), []byte(`timestamp=1970-01-01T00:00:00.000000000Z`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestWithFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithDedupKeys(true),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	l = l.Fields("key1", "val2")
+
+	l.Info(ctx, "msg2")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`msg=msg2 key1=val1`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestWithDedupKeysWithAddFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithDedupKeys(true),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	if err := l.Init(logger.WithAddFields("key2", "val2")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg2")
+
+	if err := l.Init(logger.WithAddFields("key2", "val3", "key1", "val4")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg3")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`msg=msg3 key1=val4 key2=val3`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestWithHandlerFunc(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+	)
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`msg=msg1`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestWithAddFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	if err := l.Init(logger.WithAddFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+	l.Info(ctx, "msg2")
+
+	if err := l.Init(logger.WithAddFields("key2", "val2")); err != nil {
+		t.Fatal(err)
+	}
+	l.Info(ctx, "msg3")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`"key1"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"key2"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestMultipleFieldsWithLevel(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l = l.Fields("key", "val")
+
+	l.Info(ctx, "msg1")
+	nl := l.Clone(logger.WithLevel(logger.DebugLevel))
+	nl.Debug(ctx, "msg2")
+	l.Debug(ctx, "msg3")
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"msg1"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"msg2"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+	if bytes.Contains(buf.Bytes(), []byte(`"msg3"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestMultipleFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l = l.Fields("key", "val")
+
+	l = l.Fields("key1", "val1")
+
+	l.Info(ctx, "msg")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"key1":"val1"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestError(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf), logger.WithAddStacktrace(true))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Error(ctx, "message", fmt.Errorf("error message"))
+	if !bytes.Contains(buf.Bytes(), []byte(`"stacktrace":"`)) {
+		t.Fatalf("logger stacktrace not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"error":"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestErrorf(t *testing.T) {
+	ctx := context.TODO()
+
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf), logger.WithAddStacktrace(true))
+	if err := l.Init(logger.WithContextAttrFuncs(func(_ context.Context) []interface{} {
+		return nil
+	})); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Log(ctx, logger.ErrorLevel, "message", errors.New("error msg"))
+
+	l.Log(ctx, logger.ErrorLevel, "", errors.New("error msg"))
+	if !bytes.Contains(buf.Bytes(), []byte(`"error":"error msg"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+
+	if !bytes.Contains(buf.Bytes(), []byte(`"stacktrace":"`)) {
+		t.Fatalf("logger stacktrace not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"error":"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestContext(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	nl, ok := logger.FromContext(logger.NewContext(ctx, l.Fields("key", "val")))
+	if !ok {
+		t.Fatal("context without logger")
+	}
+	nl.Info(ctx, "message")
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	nl := l.Fields("key", "val")
+
+	nl.Info(ctx, "message")
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestFromContextWithFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	var ok bool
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	nl := l.Fields("key", "val")
+
+	ctx = logger.NewContext(ctx, nl)
+
+	l, ok = logger.FromContext(ctx)
+	if !ok {
+		t.Fatalf("context does not have logger")
+	}
+
+	l.Info(ctx, "message")
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
+
+	l.Info(ctx, "test", "uncorrected number attributes")
+	if !bytes.Contains(buf.Bytes(), []byte(`"!BADKEY":"uncorrected number attributes"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestClone(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	nl := l.Clone(logger.WithLevel(logger.ErrorLevel))
+	if err := nl.Init(); err != nil {
+		t.Fatal(err)
+	}
+	nl.Info(ctx, "info message")
+	if len(buf.Bytes()) != 0 {
+		t.Fatal("message must not be logged")
+	}
+	l.Info(ctx, "info message")
+	if len(buf.Bytes()) == 0 {
+		t.Fatal("message must be logged")
+	}
+}
+
+func TestRedirectStdLogger(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	fn := logger.RedirectStdLogger(l, logger.ErrorLevel)
+	defer fn()
+	log.Print("test")
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"error"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"test"`))) {
+		t.Fatalf("logger error, buf %s", buf.Bytes())
+	}
+}
+
+func TestStdLogger(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	lg := logger.NewStdLogger(l, logger.ErrorLevel)
+	lg.Print("test")
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"error"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"test"`))) {
+		t.Fatalf("logger error, buf %s", buf.Bytes())
+	}
+}
+
+func TestLogger(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	l.Trace(ctx, "trace_msg1")
+	l.Warn(ctx, "warn_msg1")
+	l.Fields("error", "test").Info(ctx, "error message")
+	l.Warn(ctx, "first second")
+
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"trace"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"trace_msg1"`))) {
+		t.Fatalf("logger tracer, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"warn"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"warn_msg1"`))) {
+		t.Fatalf("logger warn, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"info"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"error message","error":"test"`))) {
+		t.Fatalf("logger info, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"warn"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"first second"`))) {
+		t.Fatalf("logger warn, buf %s", buf.Bytes())
+	}
+}
+
+func Test_WithContextAttrFunc(t *testing.T) {
+	loggerContextAttrFuncs := []logger.ContextAttrFunc{
+		func(ctx context.Context) []interface{} {
+			md, ok := metadata.FromOutgoingContext(ctx)
+			if !ok {
+				return nil
+			}
+			attrs := make([]interface{}, 0, 10)
+			for k, v := range md {
+				key := strings.ToLower(k)
+				switch key {
+				case "x-request-id", "phone", "external-Id", "source-service", "x-app-install-id", "client-id", "client-ip":
+					attrs = append(attrs, key, v[0])
+				}
+			}
+			return attrs
+		},
+	}
+
+	logger.DefaultContextAttrFuncs = append(logger.DefaultContextAttrFuncs, loggerContextAttrFuncs...)
+
+	ctx := context.TODO()
+	ctx = metadata.AppendOutgoingContext(ctx, "X-Request-Id", uuid.New().String(),
+		"Source-Service", "Test-System")
+
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "test message")
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"info"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"test message"`))) {
+		t.Fatalf("logger info, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"x-request-id":"`))) {
+		t.Fatalf("logger info, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"source-service":"Test-System"`))) {
+		t.Fatalf("logger info, buf %s", buf.Bytes())
+	}
+	buf.Reset()
+	omd, _ := metadata.FromOutgoingContext(ctx)
+	l.Info(ctx, "test message1")
+	omd.Set("Source-Service", "Test-System2")
+	l.Info(ctx, "test message2")
+
+	// t.Logf("xxx %s", buf.Bytes())
+}
+
+func TestFatalFinalizers(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(
+		logger.WithLevel(logger.TraceLevel),
+		logger.WithOutput(buf),
+	)
+	if err := l.Init(
+		logger.WithFatalFinalizers(func(ctx context.Context) {
+			l.Info(ctx, "fatal finalizer")
+		})); err != nil {
+		t.Fatal(err)
+	}
+	l.Fatal(ctx, "info_msg1")
+	if !bytes.Contains(buf.Bytes(), []byte("fatal finalizer")) {
+		t.Fatalf("logger dont have fatal message, buf %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte("info_msg1")) {
+		t.Fatalf("logger dont have info_msg1 message, buf %s", buf.Bytes())
+	}
+}

logger/unwrap/unwrap.go

@@ -8,7 +8,7 @@ import (
 	"strconv"
 	"strings"
 
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
 )
 
 const sf = "0-+# "
@@ -36,14 +36,14 @@ var (
 	circularShortBytes = []byte("<shown>")
 	invalidAngleBytes  = []byte("<invalid>")
 	filteredBytes      = []byte("<filtered>")
-	openBracketBytes   = []byte("[")
+	// openBracketBytes   = []byte("[")
-	closeBracketBytes  = []byte("]")
+	// closeBracketBytes  = []byte("]")
-	percentBytes       = []byte("%")
+	percentBytes    = []byte("%")
-	precisionBytes     = []byte(".")
+	precisionBytes  = []byte(".")
-	openAngleBytes     = []byte("<")
+	openAngleBytes  = []byte("<")
-	closeAngleBytes    = []byte(">")
+	closeAngleBytes = []byte(">")
-	openMapBytes       = []byte("{")
+	openMapBytes    = []byte("{")
-	closeMapBytes      = []byte("}")
+	closeMapBytes   = []byte("}")
 )
 
 type protoMessage interface {
@@ -52,13 +52,15 @@ type protoMessage interface {
 }
 
 type Wrapper struct {
-	val              interface{}
+	pointers map[uintptr]int
-	s                fmt.State
+	takeMap  map[int]bool
-	pointers         map[uintptr]int
+
-	opts             *Options
+	val  interface{}
+	s    fmt.State
+	opts *Options
+
 	depth            int
 	ignoreNextType   bool
-	takeMap          map[int]bool
 	protoWrapperType bool
 	sqlWrapperType   bool
 }

logger/unwrap/unwrap_test.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"testing"
 
-	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
 )
 
 func TestUnwrap(t *testing.T) {
@@ -82,12 +82,12 @@ func TestTagged(t *testing.T) {
 func TestTaggedNested(t *testing.T) {
 	type val struct {
 		key string `logger:"take"`
-		val string `logger:"omit"`
+		// val string `logger:"omit"`
 		unk string
 	}
 	type str struct {
-		key string `logger:"omit"`
+		// key string `logger:"omit"`
-		val *val   `logger:"take"`
+		val *val `logger:"take"`
 	}
 
 	var iface interface{}

logger/wrapper/wrapper.go

@@ -1,399 +0,0 @@
-// Package wrapper provides wrapper for Logger
-package wrapper
-
-import (
-	"context"
-	"fmt"
-
-	"go.unistack.org/micro/v3/client"
-	"go.unistack.org/micro/v3/logger"
-	"go.unistack.org/micro/v3/server"
-)
-
-var (
-	// DefaultClientCallObserver called by wrapper in client Call
-	DefaultClientCallObserver = func(ctx context.Context, req client.Request, rsp interface{}, opts []client.CallOption, err error) []string {
-		labels := []string{"service", req.Service(), "endpoint", req.Endpoint()}
-		if err != nil {
-			labels = append(labels, "error", err.Error())
-		}
-		return labels
-	}
-
-	// DefaultClientStreamObserver called by wrapper in client Stream
-	DefaultClientStreamObserver = func(ctx context.Context, req client.Request, opts []client.CallOption, stream client.Stream, err error) []string {
-		labels := []string{"service", req.Service(), "endpoint", req.Endpoint()}
-		if err != nil {
-			labels = append(labels, "error", err.Error())
-		}
-		return labels
-	}
-
-	// DefaultClientPublishObserver called by wrapper in client Publish
-	DefaultClientPublishObserver = func(ctx context.Context, msg client.Message, opts []client.PublishOption, err error) []string {
-		labels := []string{"endpoint", msg.Topic()}
-		if err != nil {
-			labels = append(labels, "error", err.Error())
-		}
-		return labels
-	}
-
-	// DefaultServerHandlerObserver called by wrapper in server Handler
-	DefaultServerHandlerObserver = func(ctx context.Context, req server.Request, rsp interface{}, err error) []string {
-		labels := []string{"service", req.Service(), "endpoint", req.Endpoint()}
-		if err != nil {
-			labels = append(labels, "error", err.Error())
-		}
-		return labels
-	}
-
-	// DefaultServerSubscriberObserver called by wrapper in server Subscriber
-	DefaultServerSubscriberObserver = func(ctx context.Context, msg server.Message, err error) []string {
-		labels := []string{"endpoint", msg.Topic()}
-		if err != nil {
-			labels = append(labels, "error", err.Error())
-		}
-		return labels
-	}
-
-	// DefaultClientCallFuncObserver called by wrapper in client CallFunc
-	DefaultClientCallFuncObserver = func(ctx context.Context, addr string, req client.Request, rsp interface{}, opts client.CallOptions, err error) []string {
-		labels := []string{"service", req.Service(), "endpoint", req.Endpoint()}
-		if err != nil {
-			labels = append(labels, "error", err.Error())
-		}
-		return labels
-	}
-
-	// DefaultSkipEndpoints wrapper not called for this endpoints
-	DefaultSkipEndpoints = []string{"Meter.Metrics", "Health.Live", "Health.Ready", "Health.Version"}
-)
-
-type lWrapper struct {
-	client.Client
-	serverHandler    server.HandlerFunc
-	serverSubscriber server.SubscriberFunc
-	clientCallFunc   client.CallFunc
-	opts             Options
-}
-
-type (
-	// ClientCallObserver func signature
-	ClientCallObserver func(context.Context, client.Request, interface{}, []client.CallOption, error) []string
-	// ClientStreamObserver func signature
-	ClientStreamObserver func(context.Context, client.Request, []client.CallOption, client.Stream, error) []string
-	// ClientPublishObserver func signature
-	ClientPublishObserver func(context.Context, client.Message, []client.PublishOption, error) []string
-	// ClientCallFuncObserver func signature
-	ClientCallFuncObserver func(context.Context, string, client.Request, interface{}, client.CallOptions, error) []string
-	// ServerHandlerObserver func signature
-	ServerHandlerObserver func(context.Context, server.Request, interface{}, error) []string
-	// ServerSubscriberObserver func signature
-	ServerSubscriberObserver func(context.Context, server.Message, error) []string
-)
-
-// Options struct for wrapper
-type Options struct {
-	// Logger that used for log
-	Logger logger.Logger
-	// ServerHandlerObservers funcs
-	ServerHandlerObservers []ServerHandlerObserver
-	// ServerSubscriberObservers funcs
-	ServerSubscriberObservers []ServerSubscriberObserver
-	// ClientCallObservers funcs
-	ClientCallObservers []ClientCallObserver
-	// ClientStreamObservers funcs
-	ClientStreamObservers []ClientStreamObserver
-	// ClientPublishObservers funcs
-	ClientPublishObservers []ClientPublishObserver
-	// ClientCallFuncObservers funcs
-	ClientCallFuncObservers []ClientCallFuncObserver
-	// SkipEndpoints
-	SkipEndpoints []string
-	// Level for logger
-	Level logger.Level
-	// Enabled flag
-	Enabled bool
-}
-
-// Option func signature
-type Option func(*Options)
-
-// NewOptions creates Options from Option slice
-func NewOptions(opts ...Option) Options {
-	options := Options{
-		Logger:                    logger.DefaultLogger,
-		Level:                     logger.TraceLevel,
-		ClientCallObservers:       []ClientCallObserver{DefaultClientCallObserver},
-		ClientStreamObservers:     []ClientStreamObserver{DefaultClientStreamObserver},
-		ClientPublishObservers:    []ClientPublishObserver{DefaultClientPublishObserver},
-		ClientCallFuncObservers:   []ClientCallFuncObserver{DefaultClientCallFuncObserver},
-		ServerHandlerObservers:    []ServerHandlerObserver{DefaultServerHandlerObserver},
-		ServerSubscriberObservers: []ServerSubscriberObserver{DefaultServerSubscriberObserver},
-		SkipEndpoints:             DefaultSkipEndpoints,
-	}
-
-	for _, o := range opts {
-		o(&options)
-	}
-
-	return options
-}
-
-// WithEnabled enable/diable flag
-func WithEnabled(b bool) Option {
-	return func(o *Options) {
-		o.Enabled = b
-	}
-}
-
-// WithLevel log level
-func WithLevel(l logger.Level) Option {
-	return func(o *Options) {
-		o.Level = l
-	}
-}
-
-// WithLogger logger
-func WithLogger(l logger.Logger) Option {
-	return func(o *Options) {
-		o.Logger = l
-	}
-}
-
-// WithClientCallObservers funcs
-func WithClientCallObservers(ob ...ClientCallObserver) Option {
-	return func(o *Options) {
-		o.ClientCallObservers = ob
-	}
-}
-
-// WithClientStreamObservers funcs
-func WithClientStreamObservers(ob ...ClientStreamObserver) Option {
-	return func(o *Options) {
-		o.ClientStreamObservers = ob
-	}
-}
-
-// WithClientPublishObservers funcs
-func WithClientPublishObservers(ob ...ClientPublishObserver) Option {
-	return func(o *Options) {
-		o.ClientPublishObservers = ob
-	}
-}
-
-// WithClientCallFuncObservers funcs
-func WithClientCallFuncObservers(ob ...ClientCallFuncObserver) Option {
-	return func(o *Options) {
-		o.ClientCallFuncObservers = ob
-	}
-}
-
-// WithServerHandlerObservers funcs
-func WithServerHandlerObservers(ob ...ServerHandlerObserver) Option {
-	return func(o *Options) {
-		o.ServerHandlerObservers = ob
-	}
-}
-
-// WithServerSubscriberObservers funcs
-func WithServerSubscriberObservers(ob ...ServerSubscriberObserver) Option {
-	return func(o *Options) {
-		o.ServerSubscriberObservers = ob
-	}
-}
-
-// SkipEndpoins
-func SkipEndpoints(eps ...string) Option {
-	return func(o *Options) {
-		o.SkipEndpoints = append(o.SkipEndpoints, eps...)
-	}
-}
-
-func (l *lWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
-	err := l.Client.Call(ctx, req, rsp, opts...)
-
-	endpoint := fmt.Sprintf("%s.%s", req.Service(), req.Endpoint())
-	for _, ep := range l.opts.SkipEndpoints {
-		if ep == endpoint {
-			return err
-		}
-	}
-
-	if !l.opts.Enabled {
-		return err
-	}
-
-	var labels []string
-	for _, o := range l.opts.ClientCallObservers {
-		labels = append(labels, o(ctx, req, rsp, opts, err)...)
-	}
-	l.opts.Logger.Fields(labels).Log(ctx, l.opts.Level)
-
-	return err
-}
-
-func (l *lWrapper) Stream(ctx context.Context, req client.Request, opts ...client.CallOption) (client.Stream, error) {
-	stream, err := l.Client.Stream(ctx, req, opts...)
-
-	endpoint := fmt.Sprintf("%s.%s", req.Service(), req.Endpoint())
-	for _, ep := range l.opts.SkipEndpoints {
-		if ep == endpoint {
-			return stream, err
-		}
-	}
-
-	if !l.opts.Enabled {
-		return stream, err
-	}
-
-	var labels []string
-	for _, o := range l.opts.ClientStreamObservers {
-		labels = append(labels, o(ctx, req, opts, stream, err)...)
-	}
-	l.opts.Logger.Fields(labels).Log(ctx, l.opts.Level)
-
-	return stream, err
-}
-
-func (l *lWrapper) Publish(ctx context.Context, msg client.Message, opts ...client.PublishOption) error {
-	err := l.Client.Publish(ctx, msg, opts...)
-
-	endpoint := msg.Topic()
-	for _, ep := range l.opts.SkipEndpoints {
-		if ep == endpoint {
-			return err
-		}
-	}
-
-	if !l.opts.Enabled {
-		return err
-	}
-
-	var labels []string
-	for _, o := range l.opts.ClientPublishObservers {
-		labels = append(labels, o(ctx, msg, opts, err)...)
-	}
-	l.opts.Logger.Fields(labels).Log(ctx, l.opts.Level)
-
-	return err
-}
-
-func (l *lWrapper) ServerHandler(ctx context.Context, req server.Request, rsp interface{}) error {
-	err := l.serverHandler(ctx, req, rsp)
-
-	endpoint := req.Endpoint()
-	for _, ep := range l.opts.SkipEndpoints {
-		if ep == endpoint {
-			return err
-		}
-	}
-
-	if !l.opts.Enabled {
-		return err
-	}
-
-	var labels []string
-	for _, o := range l.opts.ServerHandlerObservers {
-		labels = append(labels, o(ctx, req, rsp, err)...)
-	}
-	l.opts.Logger.Fields(labels).Log(ctx, l.opts.Level)
-
-	return err
-}
-
-func (l *lWrapper) ServerSubscriber(ctx context.Context, msg server.Message) error {
-	err := l.serverSubscriber(ctx, msg)
-
-	endpoint := msg.Topic()
-	for _, ep := range l.opts.SkipEndpoints {
-		if ep == endpoint {
-			return err
-		}
-	}
-
-	if !l.opts.Enabled {
-		return err
-	}
-
-	var labels []string
-	for _, o := range l.opts.ServerSubscriberObservers {
-		labels = append(labels, o(ctx, msg, err)...)
-	}
-	l.opts.Logger.Fields(labels).Log(ctx, l.opts.Level)
-
-	return err
-}
-
-// NewClientWrapper accepts an open options and returns a Client Wrapper
-func NewClientWrapper(opts ...Option) client.Wrapper {
-	return func(c client.Client) client.Client {
-		options := NewOptions()
-		for _, o := range opts {
-			o(&options)
-		}
-		return &lWrapper{opts: options, Client: c}
-	}
-}
-
-// NewClientCallWrapper accepts an options and returns a Call Wrapper
-func NewClientCallWrapper(opts ...Option) client.CallWrapper {
-	return func(h client.CallFunc) client.CallFunc {
-		options := NewOptions()
-		for _, o := range opts {
-			o(&options)
-		}
-
-		l := &lWrapper{opts: options, clientCallFunc: h}
-		return l.ClientCallFunc
-	}
-}
-
-func (l *lWrapper) ClientCallFunc(ctx context.Context, addr string, req client.Request, rsp interface{}, opts client.CallOptions) error {
-	err := l.clientCallFunc(ctx, addr, req, rsp, opts)
-
-	endpoint := fmt.Sprintf("%s.%s", req.Service(), req.Endpoint())
-	for _, ep := range l.opts.SkipEndpoints {
-		if ep == endpoint {
-			return err
-		}
-	}
-
-	if !l.opts.Enabled {
-		return err
-	}
-
-	var labels []string
-	for _, o := range l.opts.ClientCallFuncObservers {
-		labels = append(labels, o(ctx, addr, req, rsp, opts, err)...)
-	}
-	l.opts.Logger.Fields(labels).Log(ctx, l.opts.Level)
-
-	return err
-}
-
-// NewServerHandlerWrapper accepts an options and returns a Handler Wrapper
-func NewServerHandlerWrapper(opts ...Option) server.HandlerWrapper {
-	return func(h server.HandlerFunc) server.HandlerFunc {
-		options := NewOptions()
-		for _, o := range opts {
-			o(&options)
-		}
-
-		l := &lWrapper{opts: options, serverHandler: h}
-		return l.ServerHandler
-	}
-}
-
-// NewServerSubscriberWrapper accepts an options and returns a Subscriber Wrapper
-func NewServerSubscriberWrapper(opts ...Option) server.SubscriberWrapper {
-	return func(h server.SubscriberFunc) server.SubscriberFunc {
-		options := NewOptions()
-		for _, o := range opts {
-			o(&options)
-		}
-
-		l := &lWrapper{opts: options, serverSubscriber: h}
-		return l.ServerSubscriber
-	}
-}

metadata/context.go

@@ -1,142 +1,294 @@
-// Package metadata is a way of defining message headers
 package metadata
 
 import (
 	"context"
+	"fmt"
+	"strings"
 )
 
+// In the metadata package, context and metadata are treated as immutable.
+// Deep copies of metadata are made to keep things safe and correct.
+// If a user takes a map and changes it across threads, it's their responsibility.
+//
+// 1. Incoming Context
+//
+// This context is provided by an external system and populated by the server or broker of the micro framework.
+// It should not be modified. The idea is to extract all necessary data from it,
+// validate the data, and transfer it into the current context.
+// After that, only the current context should be used throughout the code.
+//
+// 2. Current Context
+//
+// This is the context used during the execution flow.
+// You can add any needed metadata to it and pass it through your code.
+//
+// 3. Outgoing Context
+//
+// This context is for sending data to external systems.
+// You can add what you need before sending it out.
+// But it’s usually better to build and prepare this context right before making the external call,
+// instead of changing it in many places.
+//
+// Execution Flow:
+//
+// [External System]
+//       ↓
+// [Incoming Context]
+//       ↓
+// [Extract & Validate Metadata from Incoming Context]
+//       ↓
+// [Prepare Current Context]
+//       ↓
+// [Enrich Current Context]
+//       ↓
+// [Business Logic]
+//       ↓
+// [Prepare Outgoing Context]
+//       ↓
+// [External System Call]
+
 type (
-	mdIncomingKey struct{}
+	metadataCurrentKey  struct{}
-	mdOutgoingKey struct{}
+	metadataIncomingKey struct{}
-	mdKey         struct{}
+	metadataOutgoingKey struct{}
+
+	rawMetadata struct {
+		md    Metadata
+		added [][]string
+	}
 )
 
-// FromIncomingContext returns metadata from incoming ctx
+// NewContext creates a new context with the provided Metadata attached.
-// returned metadata shoud not be modified or race condition happens
+// The Metadata must not be modified after calling this function.
-func FromIncomingContext(ctx context.Context) (Metadata, bool) {
-	if ctx == nil {
-		return nil, false
-	}
-	md, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata)
-	if !ok || md.md == nil {
-		return nil, false
-	}
-	return md.md, ok
-}
-
-// FromOutgoingContext returns metadata from outgoing ctx
-// returned metadata shoud not be modified or race condition happens
-func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
-	if ctx == nil {
-		return nil, false
-	}
-	md, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata)
-	if !ok || md.md == nil {
-		return nil, false
-	}
-	return md.md, ok
-}
-
-// FromContext returns metadata from the given context
-// returned metadata shoud not be modified or race condition happens
-func FromContext(ctx context.Context) (Metadata, bool) {
-	if ctx == nil {
-		return nil, false
-	}
-	md, ok := ctx.Value(mdKey{}).(*rawMetadata)
-	if !ok || md.md == nil {
-		return nil, false
-	}
-	return md.md, ok
-}
-
-// NewContext creates a new context with the given metadata
 func NewContext(ctx context.Context, md Metadata) context.Context {
-	if ctx == nil {
+	return context.WithValue(ctx, metadataCurrentKey{}, rawMetadata{md: md})
-		ctx = context.Background()
-	}
-	ctx = context.WithValue(ctx, mdKey{}, &rawMetadata{md})
-	ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{})
-	ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{})
-	return ctx
 }
 
-// SetOutgoingContext modify outgoing context with given metadata
+// NewIncomingContext creates a new context with the provided incoming Metadata attached.
-func SetOutgoingContext(ctx context.Context, md Metadata) bool {
+// The Metadata must not be modified after calling this function.
-	if ctx == nil {
-		return false
-	}
-	if omd, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata); ok {
-		omd.md = md
-		return true
-	}
-	return false
-}
-
-// SetIncomingContext modify incoming context with given metadata
-func SetIncomingContext(ctx context.Context, md Metadata) bool {
-	if ctx == nil {
-		return false
-	}
-	if omd, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata); ok {
-		omd.md = md
-		return true
-	}
-	return false
-}
-
-// NewIncomingContext creates a new context with incoming metadata attached
 func NewIncomingContext(ctx context.Context, md Metadata) context.Context {
-	if ctx == nil {
+	return context.WithValue(ctx, metadataIncomingKey{}, rawMetadata{md: md})
-		ctx = context.Background()
-	}
-	ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{md})
-	if v, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata); !ok || v == nil {
-		ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{})
-	}
-	return ctx
 }
 
-// NewOutgoingContext creates a new context with outcoming metadata attached
+// NewOutgoingContext creates a new context with the provided outgoing Metadata attached.
+// The Metadata must not be modified after calling this function.
 func NewOutgoingContext(ctx context.Context, md Metadata) context.Context {
-	if ctx == nil {
+	return context.WithValue(ctx, metadataOutgoingKey{}, rawMetadata{md: md})
-		ctx = context.Background()
-	}
-	ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{md})
-	if v, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata); !ok || v == nil {
-		ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{})
-	}
-	return ctx
 }
 
-// AppendOutgoingContext apends new md to context
+// AppendContext returns a new context with the provided key-value pairs (kv)
+// merged with any existing metadata in the context. For a description of kv,
+// please refer to the Pairs documentation.
+func AppendContext(ctx context.Context, kv ...string) context.Context {
+	if len(kv)%2 == 1 {
+		panic(fmt.Sprintf("metadata: AppendContext got an odd number of input pairs for metadata: %d", len(kv)))
+	}
+	md, _ := ctx.Value(metadataCurrentKey{}).(rawMetadata)
+	added := make([][]string, len(md.added)+1)
+	copy(added, md.added)
+	kvCopy := make([]string, 0, len(kv))
+	for i := 0; i < len(kv); i += 2 {
+		kvCopy = append(kvCopy, strings.ToLower(kv[i]), kv[i+1])
+	}
+	added[len(added)-1] = kvCopy
+	return context.WithValue(ctx, metadataCurrentKey{}, rawMetadata{md: md.md, added: added})
+}
+
+// AppendOutgoingContext returns a new context with the provided key-value pairs (kv)
+// merged with any existing metadata in the context. For a description of kv,
+// please refer to the Pairs documentation.
 func AppendOutgoingContext(ctx context.Context, kv ...string) context.Context {
-	md, ok := Pairs(kv...)
+	if len(kv)%2 == 1 {
-	if !ok {
+		panic(fmt.Sprintf("metadata: AppendOutgoingContext got an odd number of input pairs for metadata: %d", len(kv)))
-		return ctx
 	}
-	omd, ok := FromOutgoingContext(ctx)
+	md, _ := ctx.Value(metadataOutgoingKey{}).(rawMetadata)
-	if !ok {
+	added := make([][]string, len(md.added)+1)
-		return NewOutgoingContext(ctx, md)
+	copy(added, md.added)
+	kvCopy := make([]string, 0, len(kv))
+	for i := 0; i < len(kv); i += 2 {
+		kvCopy = append(kvCopy, strings.ToLower(kv[i]), kv[i+1])
 	}
-	for k, v := range md {
+	added[len(added)-1] = kvCopy
-		omd.Set(k, v)
+	return context.WithValue(ctx, metadataOutgoingKey{}, rawMetadata{md: md.md, added: added})
-	}
-	return NewOutgoingContext(ctx, omd)
 }
 
-// AppendIncomingContext apends new md to context
+// FromContext retrieves a deep copy of the metadata from the context and returns it
-func AppendIncomingContext(ctx context.Context, kv ...string) context.Context {
+// with a boolean indicating if it was found.
-	md, ok := Pairs(kv...)
+func FromContext(ctx context.Context) (Metadata, bool) {
+	raw, ok := ctx.Value(metadataCurrentKey{}).(rawMetadata)
 	if !ok {
-		return ctx
+		return nil, false
 	}
-	omd, ok := FromIncomingContext(ctx)
+	metadataSize := len(raw.md)
-	if !ok {
+	for i := range raw.added {
-		return NewIncomingContext(ctx, md)
+		metadataSize += len(raw.added[i]) / 2
 	}
-	for k, v := range md {
+
-		omd.Set(k, v)
+	out := make(Metadata, metadataSize)
+	for k, v := range raw.md {
+		out[k] = copyOf(v)
 	}
-	return NewIncomingContext(ctx, omd)
+	for _, added := range raw.added {
+		if len(added)%2 == 1 {
+			panic(fmt.Sprintf("metadata: FromContext got an odd number of input pairs for metadata: %d", len(added)))
+		}
+
+		for i := 0; i < len(added); i += 2 {
+			out[added[i]] = append(out[added[i]], added[i+1])
+		}
+	}
+	return out, true
+}
+
+// MustContext retrieves a deep copy of the metadata from the context and panics
+// if the metadata is not found.
+func MustContext(ctx context.Context) Metadata {
+	md, ok := FromContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
+// FromIncomingContext retrieves a deep copy of the metadata from the context and returns it
+// with a boolean indicating if it was found.
+func FromIncomingContext(ctx context.Context) (Metadata, bool) {
+	raw, ok := ctx.Value(metadataIncomingKey{}).(rawMetadata)
+	if !ok {
+		return nil, false
+	}
+	metadataSize := len(raw.md)
+	for i := range raw.added {
+		metadataSize += len(raw.added[i]) / 2
+	}
+
+	out := make(Metadata, metadataSize)
+	for k, v := range raw.md {
+		out[k] = copyOf(v)
+	}
+	for _, added := range raw.added {
+		if len(added)%2 == 1 {
+			panic(fmt.Sprintf("metadata: FromIncomingContext got an odd number of input pairs for metadata: %d", len(added)))
+		}
+
+		for i := 0; i < len(added); i += 2 {
+			out[added[i]] = append(out[added[i]], added[i+1])
+		}
+	}
+	return out, true
+}
+
+// MustIncomingContext retrieves a deep copy of the metadata from the context and panics
+// if the metadata is not found.
+func MustIncomingContext(ctx context.Context) Metadata {
+	md, ok := FromIncomingContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
+// FromOutgoingContext retrieves a deep copy of the metadata from the context and returns it
+// with a boolean indicating if it was found.
+func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
+	raw, ok := ctx.Value(metadataOutgoingKey{}).(rawMetadata)
+	if !ok {
+		return nil, false
+	}
+
+	metadataSize := len(raw.md)
+	for i := range raw.added {
+		metadataSize += len(raw.added[i]) / 2
+	}
+
+	out := make(Metadata, metadataSize)
+	for k, v := range raw.md {
+		out[k] = copyOf(v)
+	}
+	for _, added := range raw.added {
+		if len(added)%2 == 1 {
+			panic(fmt.Sprintf("metadata: FromOutgoingContext got an odd number of input pairs for metadata: %d", len(added)))
+		}
+
+		for i := 0; i < len(added); i += 2 {
+			out[added[i]] = append(out[added[i]], added[i+1])
+		}
+	}
+	return out, ok
+}
+
+// MustOutgoingContext retrieves a deep copy of the metadata from the context and panics
+// if the metadata is not found.
+func MustOutgoingContext(ctx context.Context) Metadata {
+	md, ok := FromOutgoingContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
+// ValueFromCurrentContext retrieves a deep copy of the metadata for the given key
+// from the context, performing a case-insensitive search if needed. Returns nil if not found.
+func ValueFromCurrentContext(ctx context.Context, key string) []string {
+	md, ok := ctx.Value(metadataCurrentKey{}).(rawMetadata)
+	if !ok {
+		return nil
+	}
+
+	if v, ok := md.md[key]; ok {
+		return copyOf(v)
+	}
+	for k, v := range md.md {
+		// Case-insensitive comparison: Metadata is a map, and there's no guarantee
+		// that the Metadata attached to the context is created using our helper
+		// functions.
+		if strings.EqualFold(k, key) {
+			return copyOf(v)
+		}
+	}
+	return nil
+}
+
+// ValueFromIncomingContext retrieves a deep copy of the metadata for the given key
+// from the context, performing a case-insensitive search if needed. Returns nil if not found.
+func ValueFromIncomingContext(ctx context.Context, key string) []string {
+	raw, ok := ctx.Value(metadataIncomingKey{}).(rawMetadata)
+	if !ok {
+		return nil
+	}
+
+	if v, ok := raw.md[key]; ok {
+		return copyOf(v)
+	}
+	for k, v := range raw.md {
+		// Case-insensitive comparison: Metadata is a map, and there's no guarantee
+		// that the Metadata attached to the context is created using our helper
+		// functions.
+		if strings.EqualFold(k, key) {
+			return copyOf(v)
+		}
+	}
+	return nil
+}
+
+// ValueFromOutgoingContext retrieves a deep copy of the metadata for the given key
+// from the context, performing a case-insensitive search if needed. Returns nil if not found.
+func ValueFromOutgoingContext(ctx context.Context, key string) []string {
+	md, ok := ctx.Value(metadataOutgoingKey{}).(rawMetadata)
+	if !ok {
+		return nil
+	}
+
+	if v, ok := md.md[key]; ok {
+		return copyOf(v)
+	}
+	for k, v := range md.md {
+		// Case-insensitive comparison: Metadata is a map, and there's no guarantee
+		// that the Metadata attached to the context is created using our helper
+		// functions.
+		if strings.EqualFold(k, key) {
+			return copyOf(v)
+		}
+	}
+	return nil
 }