store/noop: fixup Exists

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

.github/workflows/job_coverage.yml

@@ -8,12 +8,11 @@ on:
       - '.gitea/**'
   pull_request:
     branches: [ main, v3, v4 ]
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
 
 jobs:
 
   build:
+    if: github.server_url != 'https://github.com'
     runs-on: ubuntu-latest
     steps:
     - name: checkout code
@@ -25,7 +24,7 @@ jobs:
       uses: actions/setup-go@v5
       with:
         cache-dependency-path: "**/*.sum"
-        go-version: 'stable' 
+        go-version: 'stable'
 
     - name: test coverage
       run: |
@@ -42,8 +41,8 @@ jobs:
       name: autocommit
       with:
         commit_message: Apply Code Coverage Badge
-        skip_fetch: true
+        skip_fetch: false
-        skip_checkout: true
+        skip_checkout: false
         file_pattern: ./README.md
 
     - name: push
@@ -51,4 +50,4 @@ jobs:
       uses: ad-m/github-push-action@master
       with:
         github_token: ${{ github.token }}
-        branch: ${{ github.ref }}
+        branch: ${{ github.ref }}

.github/workflows/job_lint.yml

@@ -20,10 +20,10 @@ jobs:
       uses: actions/setup-go@v5
       with:
         cache-dependency-path: "**/*.sum"
-        go-version: 'stable' 
+        go-version: 'stable'
     - name: setup deps
       run: go get -v ./...
     - name: run lint
-      uses: https://github.com/golangci/golangci-lint-action@v6
+      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_syncpull.yml

@@ -1,55 +0,0 @@
-name: syncpull
-
-on:
-  schedule:
-    - cron: '* * * * *'
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
-jobs:
-  pull:
-    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 }}" | tee -a /root/.netrc
-        echo "machine github.com login vtolstov password ${{ secrets.TOKEN_GITHUB }}" | tee -a /root/.netrc
-        env
-
-    - name: track master
-      run: |
-        git clone --depth=10 --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 merge --allow-unrelated-histories "upstream/master"
-        git push origin master --progress
-        cd ../
-        rm -rf repo
-
-    - name: track v3
-      run: |
-        git clone --depth=10 --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
-        git merge --allow-unrelated-histories "upstream/v3"
-        git push origin v3 --progress
-        cd ../
-        rm -rf repo
-
-    - name: track v4
-      run: |
-        git clone --depth=10 --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
-        git merge --allow-unrelated-histories "upstream/v4"
-        git push origin v4 --progress
-        cd ../
-        rm -rf repo

.github/workflows/job_tests.yml

@@ -32,19 +32,19 @@ jobs:
         go-version: 'stable'
     - name: setup go work
       env:
-        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+        GOWORK: ${{ github.workspace }}/go.work
       run: |
         go work init
         go work use .
         go work use micro-tests
     - name: setup deps
       env:
-        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+        GOWORK: ${{ github.workspace }}/go.work
       run: go get -v ./...
     - name: run tests
       env:
         INTEGRATION_TESTS: yes
-        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+        GOWORK: ${{ github.workspace }}/go.work
       run: |
         cd micro-tests
         go test -mod readonly -v ./... || true

README.md

@@ -1,5 +1,5 @@
 # Micro
-![Coverage](https://img.shields.io/badge/Coverage-45.6%25-yellow)
+![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)

broker/memory/memory.go

@@ -22,8 +22,8 @@ type Broker struct {
 	subscribers   map[string][]*Subscriber
 	addr          string
 	opts          broker.Options
-	sync.RWMutex
+	mu            sync.RWMutex
-	connected bool
+	connected     bool
 }
 
 type memoryMessage struct {
@@ -72,9 +72,9 @@ func (b *Broker) newCodec(ct string) (codec.Codec, error) {
 	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
 		ct = ct[:idx]
 	}
-	b.RLock()
+	b.mu.RLock()
 	c, ok := b.opts.Codecs[ct]
-	b.RUnlock()
+	b.mu.RUnlock()
 	if ok {
 		return c, nil
 	}
@@ -96,8 +96,8 @@ func (b *Broker) Connect(ctx context.Context) error {
 	default:
 	}
 
-	b.Lock()
+	b.mu.Lock()
-	defer b.Unlock()
+	defer b.mu.Unlock()
 
 	if b.connected {
 		return nil
@@ -126,8 +126,8 @@ func (b *Broker) Disconnect(ctx context.Context) error {
 	default:
 	}
 
-	b.Lock()
+	b.mu.Lock()
-	defer b.Unlock()
+	defer b.mu.Unlock()
 
 	if !b.connected {
 		return nil
@@ -159,6 +159,9 @@ func (b *Broker) Init(opts ...broker.Option) error {
 
 func (b *Broker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...broker.PublishOption) (broker.Message, error) {
 	options := broker.NewPublishOptions(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 {
@@ -180,12 +183,12 @@ func (b *Broker) fnPublish(ctx context.Context, topic string, messages ...broker
 }
 
 func (b *Broker) publish(ctx context.Context, topic string, messages ...broker.Message) error {
-	b.RLock()
+	b.mu.RLock()
 	if !b.connected {
-		b.RUnlock()
+		b.mu.RUnlock()
 		return broker.ErrNotConnected
 	}
-	b.RUnlock()
+	b.mu.RUnlock()
 
 	select {
 	case <-ctx.Done():
@@ -193,9 +196,9 @@ func (b *Broker) publish(ctx context.Context, topic string, messages ...broker.M
 	default:
 	}
 
-	b.RLock()
+	b.mu.RLock()
 	subs, ok := b.subscribers[topic]
-	b.RUnlock()
+	b.mu.RUnlock()
 	if !ok {
 		return nil
 	}
@@ -252,12 +255,12 @@ func (b *Broker) fnSubscribe(ctx context.Context, topic string, handler interfac
 		return nil, err
 	}
 
-	b.RLock()
+	b.mu.RLock()
 	if !b.connected {
-		b.RUnlock()
+		b.mu.RUnlock()
 		return nil, broker.ErrNotConnected
 	}
-	b.RUnlock()
+	b.mu.RUnlock()
 
 	sid, err := id.New()
 	if err != nil {
@@ -275,13 +278,13 @@ func (b *Broker) fnSubscribe(ctx context.Context, topic string, handler interfac
 		ctx:     ctx,
 	}
 
-	b.Lock()
+	b.mu.Lock()
 	b.subscribers[topic] = append(b.subscribers[topic], sub)
-	b.Unlock()
+	b.mu.Unlock()
 
 	go func() {
 		<-sub.exit
-		b.Lock()
+		b.mu.Lock()
 		newSubscribers := make([]*Subscriber, 0, len(b.subscribers)-1)
 		for _, sb := range b.subscribers[topic] {
 			if sb.id == sub.id {
@@ -290,7 +293,7 @@ func (b *Broker) fnSubscribe(ctx context.Context, topic string, handler interfac
 			newSubscribers = append(newSubscribers, sb)
 		}
 		b.subscribers[topic] = newSubscribers
-		b.Unlock()
+		b.mu.Unlock()
 	}()
 
 	return sub, nil

broker/noop.go

@@ -14,16 +14,16 @@ type NoopBroker struct {
 	funcPublish   FuncPublish
 	funcSubscribe FuncSubscribe
 	opts          Options
-	sync.RWMutex
+	mu            sync.RWMutex
 }
 
 func (b *NoopBroker) newCodec(ct string) (codec.Codec, error) {
 	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
 		ct = ct[:idx]
 	}
-	b.RLock()
+	b.mu.RLock()
 	c, ok := b.opts.Codecs[ct]
-	b.RUnlock()
+	b.mu.RUnlock()
 	if ok {
 		return c, nil
 	}
@@ -128,6 +128,9 @@ func (m *noopMessage) Unmarshal(dst interface{}, opts ...codec.Option) error {
 
 func (b *NoopBroker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...PublishOption) (Message, error) {
 	options := NewPublishOptions(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 {

broker/options.go

@@ -45,6 +45,9 @@ type Options struct {
 
 	// 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
@@ -57,14 +60,19 @@ func NewOptions(opts ...Option) Options {
 		Codecs:          make(map[string]codec.Codec),
 		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) {
@@ -72,6 +80,13 @@ func Context(ctx context.Context) Option {
 	}
 }
 
+// ContentType used by default if not specified
+func ContentType(ct string) Option {
+	return func(o *Options) {
+		o.ContentType = ct
+	}
+}
+
 // PublishOptions struct
 type PublishOptions struct {
 	// ContentType for message body

codec/codec.go

@@ -3,8 +3,6 @@ package codec
 
 import (
 	"errors"
-
-	"gopkg.in/yaml.v3"
 )
 
 var (
@@ -68,10 +66,10 @@ func (m *RawMessage) MarshalYAML() ([]byte, error) {
 }
 
 // UnmarshalYAML sets *m to a copy of data.
-func (m *RawMessage) UnmarshalYAML(n *yaml.Node) error {
+func (m *RawMessage) UnmarshalYAML(data []byte) error {
 	if m == nil {
 		return errors.New("RawMessage UnmarshalYAML on nil pointer")
 	}
-	*m = append((*m)[0:0], []byte(n.Value)...)
+	*m = append((*m)[0:0], data...)
 	return nil
 }

codec/frame.go

@@ -1,7 +1,5 @@
 package codec
 
-import "gopkg.in/yaml.v3"
-
 // Frame gives us the ability to define raw data to send over the pipes
 type Frame struct {
 	Data []byte
@@ -28,8 +26,8 @@ func (m *Frame) MarshalYAML() ([]byte, error) {
 }
 
 // UnmarshalYAML set frame data
-func (m *Frame) UnmarshalYAML(n *yaml.Node) error {
+func (m *Frame) UnmarshalYAML(data []byte) error {
-	m.Data = []byte(n.Value)
+	m.Data = append((m.Data)[0:0], data...)
 	return nil
 }
 

go.mod

@@ -6,19 +6,19 @@ require (
 	dario.cat/mergo v1.0.1
 	github.com/DATA-DOG/go-sqlmock v1.5.2
 	github.com/KimMachineGun/automemlimit v0.7.0
-	github.com/ash3in/uuidv8 v1.2.0
+	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
 	github.com/spf13/cast v1.7.1
+	github.com/stretchr/testify v1.10.0
 	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
 	google.golang.org/grpc v1.69.4
 	google.golang.org/protobuf v1.36.3
-	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
@@ -26,9 +26,9 @@ require (
 	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/rogpeppe/go-internal v1.13.1 // indirect
-	github.com/stretchr/testify v1.10.0 // 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

@@ -4,12 +4,12 @@ github.com/DATA-DOG/go-sqlmock v1.5.2 h1:OcvFkGmslmlZibjAjaHm3L//6LiuBgolP7Oputl
 github.com/DATA-DOG/go-sqlmock v1.5.2/go.mod h1:88MAG/4G7SMwSE3CeA0ZKzrT5CiOU3OJ+JlNzwDqpNU=
 github.com/KimMachineGun/automemlimit v0.7.0 h1:7G06p/dMSf7G8E6oq+f2uOPuVncFyIlDI/pBWK49u88=
 github.com/KimMachineGun/automemlimit v0.7.0/go.mod h1:QZxpHaGOQoYvFhv/r4u3U0JTC2ZcOwbSr11UZF46UBM=
-github.com/ash3in/uuidv8 v1.2.0 h1:2oogGdtCPwaVtyvPPGin4TfZLtOGE5F+W++E880G6SI=
-github.com/ash3in/uuidv8 v1.2.0/go.mod h1:BnU0wJBxnzdEKmVg4xckBkD+VZuecTFTUP3M0dWgyY4=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
+github.com/goccy/go-yaml v1.17.1 h1:LI34wktB2xEE3ONG/2Ar54+/HJVBriAGJ55PHls4YuY=
+github.com/goccy/go-yaml v1.17.1/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
 github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
 github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=

hooks/metadata/metadata.go

@@ -36,8 +36,8 @@ func NewClientCallWrapper(keys ...string) client.CallWrapper {
 					omd = metadata.New(len(imd))
 				}
 				for _, k := range keys {
-					if v, ok := imd.Get(k); ok {
+					if v := imd.Get(k); v != nil {
-						omd.Add(k, v...)
+						omd.Set(k, v...)
 					}
 				}
 				if !ook {
@@ -59,8 +59,8 @@ func (w *wrapper) Call(ctx context.Context, req client.Request, rsp interface{},
 			omd = metadata.New(len(imd))
 		}
 		for _, k := range w.keys {
-			if v, ok := imd.Get(k); ok {
+			if v := imd.Get(k); v != nil {
-				omd.Add(k, v...)
+				omd.Set(k, v...)
 			}
 		}
 		if !ook {
@@ -80,8 +80,8 @@ func (w *wrapper) Stream(ctx context.Context, req client.Request, opts ...client
 			omd = metadata.New(len(imd))
 		}
 		for _, k := range w.keys {
-			if v, ok := imd.Get(k); ok {
+			if v := imd.Get(k); v != nil {
-				omd.Add(k, v...)
+				omd.Set(k, v...)
 			}
 		}
 		if !ook {
@@ -103,8 +103,8 @@ func NewServerHandlerWrapper(keys ...string) server.HandlerWrapper {
 					omd = metadata.New(len(imd))
 				}
 				for _, k := range keys {
-					if v, ok := imd.Get(k); ok {
+					if v := imd.Get(k); v != nil {
-						omd.Add(k, v...)
+						omd.Set(k, v...)
 					}
 				}
 				if !ook {

hooks/requestid/requestid.go

@@ -37,20 +37,9 @@ var DefaultMetadataFunc = func(ctx context.Context) (context.Context, error) {
 	}
 
 	if xid == "" {
-		var ids []string
+		xid = imd.GetJoined(DefaultMetadataKey)
-		if ids, iok = imd.Get(DefaultMetadataKey); iok {
+		if xid == "" {
-			for i := range ids {
+			xid = omd.GetJoined(DefaultMetadataKey)
-				if ids[i] != "" {
-					xid = ids[i]
-				}
-			}
-		}
-		if ids, ook = omd.Get(DefaultMetadataKey); ook {
-			for i := range ids {
-				if ids[i] != "" {
-					xid = ids[i]
-				}
-			}
 		}
 	}
 

hooks/requestid/requestid_test.go

@@ -2,6 +2,7 @@ package requestid
 
 import (
 	"context"
+	"slices"
 	"testing"
 
 	"go.unistack.org/micro/v4/metadata"
@@ -24,10 +25,10 @@ func TestDefaultMetadataFunc(t *testing.T) {
 		t.Fatalf("md missing in outgoing context")
 	}
 
-	_, iok := imd.Get(DefaultMetadataKey)
+	iv := imd.Get(DefaultMetadataKey)
-	_, ook := omd.Get(DefaultMetadataKey)
+	ov := omd.Get(DefaultMetadataKey)
 
-	if !iok || !ook {
+	if !slices.Equal(iv, ov) {
-		t.Fatalf("missing metadata key value")
+		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 +1,41 @@
+package sql
+
+import (
+	"context"
+	"database/sql"
+	"time"
+)
+
+type Statser interface {
+	Stats() sql.DBStats
+}
+
+func NewStatsMeter(ctx context.Context, db Statser, opts ...Option) {
+	options := NewOptions(opts...)
+
+	go func() {
+		ticker := time.NewTicker(options.MeterStatsInterval)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				if db == nil {
+					return
+				}
+				stats := db.Stats()
+				options.Meter.Counter(MaxOpenConnections).Set(uint64(stats.MaxOpenConnections))
+				options.Meter.Counter(OpenConnections).Set(uint64(stats.OpenConnections))
+				options.Meter.Counter(InuseConnections).Set(uint64(stats.InUse))
+				options.Meter.Counter(IdleConnections).Set(uint64(stats.Idle))
+				options.Meter.Counter(WaitConnections).Set(uint64(stats.WaitCount))
+				options.Meter.FloatCounter(BlockedSeconds).Set(stats.WaitDuration.Seconds())
+				options.Meter.Counter(MaxIdleClosed).Set(uint64(stats.MaxIdleClosed))
+				options.Meter.Counter(MaxIdletimeClosed).Set(uint64(stats.MaxIdleTimeClosed))
+				options.Meter.Counter(MaxLifetimeClosed).Set(uint64(stats.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...))
+}

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/slog/slog.go

@@ -34,6 +34,7 @@ var (
 	warnValue  = slog.StringValue("warn")
 	errorValue = slog.StringValue("error")
 	fatalValue = slog.StringValue("fatal")
+	noneValue  = slog.StringValue("none")
 )
 
 type wrapper struct {
@@ -85,6 +86,8 @@ func (s *slogLogger) renameAttr(_ []string, a slog.Attr) slog.Attr {
 			a.Value = errorValue
 		case lvl >= logger.FatalLevel:
 			a.Value = fatalValue
+		case lvl >= logger.NoneLevel:
+			a.Value = noneValue
 		default:
 			a.Value = infoValue
 		}
@@ -316,6 +319,8 @@ func loggerToSlogLevel(level logger.Level) slog.Level {
 		return slog.LevelDebug - 1
 	case logger.FatalLevel:
 		return slog.LevelError + 1
+	case logger.NoneLevel:
+		return slog.LevelError + 2
 	default:
 		return slog.LevelInfo
 	}
@@ -333,6 +338,8 @@ func slogToLoggerLevel(level slog.Level) logger.Level {
 		return logger.TraceLevel
 	case slog.LevelError + 1:
 		return logger.FatalLevel
+	case slog.LevelError + 2:
+		return logger.NoneLevel
 	default:
 		return logger.InfoLevel
 	}

logger/slog/slog_test.go

@@ -36,6 +36,24 @@ func TestStacktrace(t *testing.T) {
 	}
 }
 
+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)
@@ -406,7 +424,7 @@ func TestLogger(t *testing.T) {
 func Test_WithContextAttrFunc(t *testing.T) {
 	loggerContextAttrFuncs := []logger.ContextAttrFunc{
 		func(ctx context.Context) []interface{} {
-			md, ok := metadata.FromIncomingContext(ctx)
+			md, ok := metadata.FromOutgoingContext(ctx)
 			if !ok {
 				return nil
 			}
@@ -425,7 +443,7 @@ func Test_WithContextAttrFunc(t *testing.T) {
 	logger.DefaultContextAttrFuncs = append(logger.DefaultContextAttrFuncs, loggerContextAttrFuncs...)
 
 	ctx := context.TODO()
-	ctx = metadata.AppendIncomingContext(ctx, "X-Request-Id", uuid.New().String(),
+	ctx = metadata.AppendOutgoingContext(ctx, "X-Request-Id", uuid.New().String(),
 		"Source-Service", "Test-System")
 
 	buf := bytes.NewBuffer(nil)
@@ -445,9 +463,9 @@ func Test_WithContextAttrFunc(t *testing.T) {
 		t.Fatalf("logger info, buf %s", buf.Bytes())
 	}
 	buf.Reset()
-	imd, _ := metadata.FromIncomingContext(ctx)
+	omd, _ := metadata.FromOutgoingContext(ctx)
 	l.Info(ctx, "test message1")
-	imd.Set("Source-Service", "Test-System2")
+	omd.Set("Source-Service", "Test-System2")
 	l.Info(ctx, "test message2")
 
 	// t.Logf("xxx %s", buf.Bytes())

metadata/context.go

@@ -0,0 +1,294 @@
+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 (
+	metadataCurrentKey  struct{}
+	metadataIncomingKey struct{}
+	metadataOutgoingKey struct{}
+
+	rawMetadata struct {
+		md    Metadata
+		added [][]string
+	}
+)
+
+// NewContext creates a new context with the provided Metadata attached.
+// The Metadata must not be modified after calling this function.
+func NewContext(ctx context.Context, md Metadata) context.Context {
+	return context.WithValue(ctx, metadataCurrentKey{}, rawMetadata{md: md})
+}
+
+// NewIncomingContext creates a new context with the provided incoming Metadata attached.
+// The Metadata must not be modified after calling this function.
+func NewIncomingContext(ctx context.Context, md Metadata) context.Context {
+	return context.WithValue(ctx, metadataIncomingKey{}, rawMetadata{md: md})
+}
+
+// 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 {
+	return context.WithValue(ctx, metadataOutgoingKey{}, rawMetadata{md: md})
+}
+
+// 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 {
+	if len(kv)%2 == 1 {
+		panic(fmt.Sprintf("metadata: AppendOutgoingContext got an odd number of input pairs for metadata: %d", len(kv)))
+	}
+	md, _ := ctx.Value(metadataOutgoingKey{}).(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, metadataOutgoingKey{}, rawMetadata{md: md.md, added: added})
+}
+
+// FromContext retrieves a deep copy of the metadata from the context and returns it
+// with a boolean indicating if it was found.
+func FromContext(ctx context.Context) (Metadata, bool) {
+	raw, ok := ctx.Value(metadataCurrentKey{}).(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: 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
+}

metadata/headers.go

@@ -2,18 +2,18 @@
 package metadata
 
 var (
-	// HeaderTopic is the header name that contains topic name
+	// HeaderTopic is the header name that contains topic name.
 	HeaderTopic = "Micro-Topic"
-	// HeaderContentType specifies content type of message
+	// HeaderContentType specifies content type of message.
 	HeaderContentType = "Content-Type"
-	// HeaderEndpoint specifies endpoint in service
+	// HeaderEndpoint specifies endpoint in service.
 	HeaderEndpoint = "Micro-Endpoint"
-	// HeaderService specifies service
+	// HeaderService specifies service.
 	HeaderService = "Micro-Service"
-	// HeaderTimeout specifies timeout of operation
+	// HeaderTimeout specifies timeout of operation.
 	HeaderTimeout = "Micro-Timeout"
-	// HeaderAuthorization specifies Authorization header
+	// HeaderAuthorization specifies Authorization header.
 	HeaderAuthorization = "Authorization"
-	// HeaderXRequestID specifies request id
+	// HeaderXRequestID specifies request id.
 	HeaderXRequestID = "X-Request-Id"
 )

metadata/helpers.go

@@ -0,0 +1,7 @@
+package metadata
+
+func copyOf(v []string) []string {
+	vals := make([]string, len(v))
+	copy(vals, v)
+	return vals
+}

metadata/iterator.go

@@ -0,0 +1,37 @@
+package metadata
+
+import "sort"
+
+type Iterator struct {
+	md   Metadata
+	keys []string
+	cur  int
+	cnt  int
+}
+
+// Next advances the iterator to the next element.
+func (iter *Iterator) Next(k *string, v *[]string) bool {
+	if iter.cur+1 > iter.cnt {
+		return false
+	}
+
+	if k != nil && v != nil {
+		*k = iter.keys[iter.cur]
+		vv := iter.md[*k]
+		*v = make([]string, len(vv))
+		copy(*v, vv)
+		iter.cur++
+	}
+	return true
+}
+
+// Iterator returns an iterator for iterating over metadata in sorted order.
+func (md Metadata) Iterator() *Iterator {
+	iter := &Iterator{md: md, cnt: len(md)}
+	iter.keys = make([]string, 0, iter.cnt)
+	for k := range md {
+		iter.keys = append(iter.keys, k)
+	}
+	sort.Strings(iter.keys)
+	return iter
+}

metadata/metadata.go

@@ -1,21 +1,18 @@
 package metadata
 
 import (
-	"context"
 	"fmt"
 	"net/textproto"
-	"sort"
 	"strings"
 )
 
-// defaultMetadataSize used when need to init new Metadata
+// defaultMetadataSize is used when initializing new Metadata.
 var defaultMetadataSize = 2
 
-// Metadata is a mapping from metadata keys to values. Users should use the following
+// Metadata maps keys to values. Use the New, NewWithMetadata and Pairs functions to create it.
-// two convenience functions New and Pairs to generate Metadata.
 type Metadata map[string][]string
 
-// New creates an zero Metadata.
+// New creates a zero-value Metadata with the specified size.
 func New(l int) Metadata {
 	if l == 0 {
 		l = defaultMetadataSize
@@ -24,7 +21,7 @@ func New(l int) Metadata {
 	return md
 }
 
-// NewWithMetadata creates an Metadata from a given key-value map.
+// NewWithMetadata creates a Metadata from the provided key-value map.
 func NewWithMetadata(m map[string]string) Metadata {
 	md := make(Metadata, len(m))
 	for key, val := range m {
@@ -33,8 +30,7 @@ func NewWithMetadata(m map[string]string) Metadata {
 	return md
 }
 
-// Pairs returns an Metadata formed by the mapping of key, value ...
+// Pairs returns a Metadata formed from the key-value mapping. It panics if the length of kv is odd.
-// Pairs panics if len(kv) is odd.
 func Pairs(kv ...string) Metadata {
 	if len(kv)%2 == 1 {
 		panic(fmt.Sprintf("metadata: Pairs got the odd number of input pairs for metadata: %d", len(kv)))
@@ -46,12 +42,19 @@ func Pairs(kv ...string) Metadata {
 	return md
 }
 
-// Len returns the number of items in Metadata.
+// Join combines multiple Metadatas into a single Metadata.
-func (md Metadata) Len() int {
+// The order of values for each key is determined by the order in which the Metadatas are provided to Join.
-	return len(md)
+func Join(mds ...Metadata) Metadata {
+	out := Metadata{}
+	for _, md := range mds {
+		for k, v := range md {
+			out[k] = append(out[k], v...)
+		}
+	}
+	return out
 }
 
-// Copy returns a copy of Metadata.
+// Copy returns a deep copy of Metadata.
 func Copy(src Metadata) Metadata {
 	out := make(Metadata, len(src))
 	for k, v := range src {
@@ -60,7 +63,7 @@ func Copy(src Metadata) Metadata {
 	return out
 }
 
-// Copy returns a copy of Metadata.
+// Copy returns a deep copy of Metadata.
 func (md Metadata) Copy() Metadata {
 	out := make(Metadata, len(md))
 	for k, v := range md {
@@ -69,7 +72,19 @@ func (md Metadata) Copy() Metadata {
 	return out
 }
 
-// AsMap returns a copy of Metadata with map[string]string.
+// CopyTo performs a deep copy of Metadata to the out.
+func (md Metadata) CopyTo(out Metadata) {
+	for k, v := range md {
+		out[k] = copyOf(v)
+	}
+}
+
+// Len returns the number of items in Metadata.
+func (md Metadata) Len() int {
+	return len(md)
+}
+
+// AsMap returns a deep copy of Metadata as a map[string]string
 func (md Metadata) AsMap() map[string]string {
 	out := make(map[string]string, len(md))
 	for k, v := range md {
@@ -78,8 +93,7 @@ func (md Metadata) AsMap() map[string]string {
 	return out
 }
 
-// AsHTTP1 returns a copy of Metadata
+// AsHTTP1 returns a deep copy of Metadata with keys converted to canonical MIME header key format.
-// with CanonicalMIMEHeaderKey.
 func (md Metadata) AsHTTP1() map[string][]string {
 	out := make(map[string][]string, len(md))
 	for k, v := range md {
@@ -88,8 +102,7 @@ func (md Metadata) AsHTTP1() map[string][]string {
 	return out
 }
 
-// AsHTTP1 returns a copy of Metadata
+// AsHTTP2 returns a deep copy of Metadata with keys converted to lowercase.
-// with strings.ToLower.
 func (md Metadata) AsHTTP2() map[string][]string {
 	out := make(map[string][]string, len(md))
 	for k, v := range md {
@@ -98,75 +111,35 @@ func (md Metadata) AsHTTP2() map[string][]string {
 	return out
 }
 
-// CopyTo copies Metadata to out.
+// Get retrieves the values for a given key, checking the key in three formats:
-func (md Metadata) CopyTo(out Metadata) {
+// - exact case,
-	for k, v := range md {
+// - lower case,
-		out[k] = copyOf(v)
+// - canonical MIME header key format.
-	}
+func (md Metadata) Get(k string) []string {
-}
-
-// Get obtains the values for a given key.
-func (md Metadata) MustGet(k string) []string {
-	v, ok := md.Get(k)
-	if !ok {
-		panic("missing metadata key")
-	}
-	return v
-}
-
-// Get obtains the values for a given key.
-func (md Metadata) Get(k string) ([]string, bool) {
 	v, ok := md[k]
 	if !ok {
 		v, ok = md[strings.ToLower(k)]
 	}
 	if !ok {
-		v, ok = md[textproto.CanonicalMIMEHeaderKey(k)]
+		v = md[textproto.CanonicalMIMEHeaderKey(k)]
-	}
-	return v, ok
-}
-
-// MustGetJoined obtains the values for a given key
-// with joined values with "," symbol
-func (md Metadata) MustGetJoined(k string) string {
-	v, ok := md.GetJoined(k)
-	if !ok {
-		panic("missing metadata key")
 	}
 	return v
 }
 
-// GetJoined obtains the values for a given key
+// GetJoined retrieves the values for a given key and joins them into a single string, separated by commas.
-// with joined values with "," symbol
+func (md Metadata) GetJoined(k string) string {
-func (md Metadata) GetJoined(k string) (string, bool) {
+	return strings.Join(md.Get(k), ",")
-	v, ok := md.Get(k)
-	if !ok {
-		return "", ok
-	}
-	return strings.Join(v, ","), true
 }
 
-// Set sets the value of a given key with a slice of values.
+// Set assigns the values to the given key.
-func (md Metadata) Add(key string, vals ...string) {
+func (md Metadata) Set(key string, vals ...string) {
 	if len(vals) == 0 {
 		return
 	}
 	md[key] = vals
 }
 
-// Set sets the value of a given key with a slice of values.
+// Append adds values to the existing values for the given key.
-func (md Metadata) Set(kvs ...string) {
-	if len(kvs)%2 == 1 {
-		panic(fmt.Sprintf("metadata: Set got an odd number of input pairs for metadata: %d", len(kvs)))
-	}
-
-	for i := 0; i < len(kvs); i += 2 {
-		md[kvs[i]] = append(md[kvs[i]], kvs[i+1])
-	}
-}
-
-// Append adds the values to key k, not overwriting what was already stored at
-// that key.
 func (md Metadata) Append(key string, vals ...string) {
 	if len(vals) == 0 {
 		return
@@ -174,7 +147,10 @@ func (md Metadata) Append(key string, vals ...string) {
 	md[key] = append(md[key], vals...)
 }
 
-// Del removes the values for a given keys k.
+// Del removes the values for the given keys k. It checks and removes the keys in the following formats:
+// - exact case,
+// - lower case,
+// - canonical MIME header key format.
 func (md Metadata) Del(k ...string) {
 	for i := range k {
 		delete(md, k[i])
@@ -182,321 +158,3 @@ func (md Metadata) Del(k ...string) {
 		delete(md, textproto.CanonicalMIMEHeaderKey(k[i]))
 	}
 }
-
-// Join joins any number of Metadatas into a single Metadata.
-//
-// The order of values for each key is determined by the order in which the Metadatas
-// containing those values are presented to Join.
-func Join(mds ...Metadata) Metadata {
-	out := Metadata{}
-	for _, Metadata := range mds {
-		for k, v := range Metadata {
-			out[k] = append(out[k], v...)
-		}
-	}
-	return out
-}
-
-type (
-	metadataIncomingKey struct{}
-	metadataOutgoingKey struct{}
-	metadataCurrentKey  struct{}
-)
-
-// NewContext creates a new context with Metadata attached. Metadata must
-// not be modified after calling this function.
-func NewContext(ctx context.Context, md Metadata) context.Context {
-	return context.WithValue(ctx, metadataCurrentKey{}, rawMetadata{md: md})
-}
-
-// NewIncomingContext creates a new context with incoming Metadata attached. Metadata must
-// not be modified after calling this function.
-func NewIncomingContext(ctx context.Context, md Metadata) context.Context {
-	return context.WithValue(ctx, metadataIncomingKey{}, rawMetadata{md: md})
-}
-
-// NewOutgoingContext creates a new context with outgoing Metadata attached. If used
-// in conjunction with AppendOutgoingContext, NewOutgoingContext will
-// overwrite any previously-appended metadata. Metadata must not be modified after
-// calling this function.
-func NewOutgoingContext(ctx context.Context, md Metadata) context.Context {
-	return context.WithValue(ctx, metadataOutgoingKey{}, rawMetadata{md: md})
-}
-
-// AppendContext returns a new context with the provided kv merged
-// with any existing metadata in the context. Please refer to the documentation
-// of Pairs for a description of kv.
-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})
-}
-
-// AppendIncomingContext returns a new context with the provided kv merged
-// with any existing metadata in the context. Please refer to the documentation
-// of Pairs for a description of kv.
-func AppendIncomingContext(ctx context.Context, kv ...string) context.Context {
-	if len(kv)%2 == 1 {
-		panic(fmt.Sprintf("metadata: AppendIncomingContext got an odd number of input pairs for metadata: %d", len(kv)))
-	}
-	md, _ := ctx.Value(metadataIncomingKey{}).(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, metadataIncomingKey{}, rawMetadata{md: md.md, added: added})
-}
-
-// AppendOutgoingContext returns a new context with the provided kv merged
-// with any existing metadata in the context. Please refer to the documentation
-// of Pairs for a description of kv.
-func AppendOutgoingContext(ctx context.Context, kv ...string) context.Context {
-	if len(kv)%2 == 1 {
-		panic(fmt.Sprintf("metadata: AppendOutgoingContext got an odd number of input pairs for metadata: %d", len(kv)))
-	}
-	md, _ := ctx.Value(metadataOutgoingKey{}).(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, metadataOutgoingKey{}, rawMetadata{md: md.md, added: added})
-}
-
-// FromContext returns the metadata in ctx if it exists.
-func FromContext(ctx context.Context) (Metadata, bool) {
-	raw, ok := ctx.Value(metadataCurrentKey{}).(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: 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 returns the metadata in ctx.
-func MustContext(ctx context.Context) Metadata {
-	md, ok := FromContext(ctx)
-	if !ok {
-		panic("missing metadata")
-	}
-	return md
-}
-
-// FromIncomingContext returns the incoming metadata in ctx if it exists.
-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 returns the incoming metadata in ctx.
-func MustIncomingContext(ctx context.Context) Metadata {
-	md, ok := FromIncomingContext(ctx)
-	if !ok {
-		panic("missing metadata")
-	}
-	return md
-}
-
-// ValueFromIncomingContext returns the metadata value corresponding to the metadata
-// key from the incoming metadata if it exists. Keys are matched in a case insensitive
-// manner.
-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
-}
-
-// ValueFromCurrentContext returns the metadata value corresponding to the metadata
-// key from the incoming metadata if it exists. Keys are matched in a case insensitive
-// manner.
-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
-}
-
-// MustOutgoingContext returns the outgoing metadata in ctx.
-func MustOutgoingContext(ctx context.Context) Metadata {
-	md, ok := FromOutgoingContext(ctx)
-	if !ok {
-		panic("missing metadata")
-	}
-	return md
-}
-
-// ValueFromOutgoingContext returns the metadata value corresponding to the metadata
-// key from the incoming metadata if it exists. Keys are matched in a case insensitive
-// manner.
-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
-}
-
-func copyOf(v []string) []string {
-	vals := make([]string, len(v))
-	copy(vals, v)
-	return vals
-}
-
-// FromOutgoingContext returns the outgoing metadata in ctx if it exists.
-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
-}
-
-type rawMetadata struct {
-	md    Metadata
-	added [][]string
-}
-
-// Iterator used to iterate over metadata with order
-type Iterator struct {
-	md   Metadata
-	keys []string
-	cur  int
-	cnt  int
-}
-
-// Next advance iterator to next element
-func (iter *Iterator) Next(k *string, v *[]string) bool {
-	if iter.cur+1 > iter.cnt {
-		return false
-	}
-
-	if k != nil && v != nil {
-		*k = iter.keys[iter.cur]
-		vv := iter.md[*k]
-		*v = make([]string, len(vv))
-		copy(*v, vv)
-		iter.cur++
-	}
-	return true
-}
-
-// Iterator returns the itarator for metadata in sorted order
-func (md Metadata) Iterator() *Iterator {
-	iter := &Iterator{md: md, cnt: len(md)}
-	iter.keys = make([]string, 0, iter.cnt)
-	for k := range md {
-		iter.keys = append(iter.keys, k)
-	}
-	sort.Strings(iter.keys)
-	return iter
-}

metadata/metadata_test.go

@@ -5,6 +5,15 @@ import (
 	"testing"
 )
 
+func TesSet(t *testing.T) {
+	md := Pairs("key1", "val1", "key2", "val2")
+	md.Set("key1", "val2", "val3")
+	v := md.GetJoined("X-Request-Id")
+	if v != "val2, val3" {
+		t.Fatal("set not works")
+	}
+}
+
 /*
 func TestAppendOutgoingContextModify(t *testing.T) {
 	md := Pairs("key1", "val1")
@@ -19,8 +28,8 @@ func TestAppendOutgoingContextModify(t *testing.T) {
 func TestLowercase(t *testing.T) {
 	md := New(1)
 	md["x-request-id"] = []string{"12345"}
-	v, ok := md.GetJoined("X-Request-Id")
+	v := md.GetJoined("X-Request-Id")
-	if !ok || v == "" {
+	if v == "" {
 		t.Fatalf("metadata invalid %#+v", md)
 	}
 }
@@ -47,33 +56,9 @@ func TestMultipleUsage(t *testing.T) {
 	_ = omd
 }
 
-func TestMetadataSetMultiple(t *testing.T) {
-	md := New(4)
-	md.Set("key1", "val1", "key2", "val2")
-
-	if v, ok := md.GetJoined("key1"); !ok || v != "val1" {
-		t.Fatalf("invalid kv %#+v", md)
-	}
-	if v, ok := md.GetJoined("key2"); !ok || v != "val2" {
-		t.Fatalf("invalid kv %#+v", md)
-	}
-}
-
-func TestAppend(t *testing.T) {
-	ctx := context.Background()
-	ctx = AppendIncomingContext(ctx, "key1", "val1", "key2", "val2")
-	md, ok := FromIncomingContext(ctx)
-	if !ok {
-		t.Fatal("metadata empty")
-	}
-	if _, ok := md.Get("key1"); !ok {
-		t.Fatal("key1 not found")
-	}
-}
-
 func TestPairs(t *testing.T) {
 	md := Pairs("key1", "val1", "key2", "val2")
-	if _, ok := md.Get("key1"); !ok {
+	if v := md.Get("key1"); v == nil {
 		t.Fatal("key1 not found")
 	}
 }
@@ -97,7 +82,7 @@ func TestPassing(t *testing.T) {
 	if !ok {
 		t.Fatalf("missing metadata from outgoing context")
 	}
-	if v, ok := md.Get("Key1"); !ok || v[0] != "Val1" {
+	if v := md.Get("Key1"); v == nil || v[0] != "Val1" {
 		t.Fatalf("invalid metadata value %#+v", md)
 	}
 }
@@ -127,21 +112,21 @@ func TestIterator(t *testing.T) {
 func TestMedataCanonicalKey(t *testing.T) {
 	md := New(1)
 	md.Set("x-request-id", "12345")
-	v, ok := md.GetJoined("x-request-id")
+	v := md.GetJoined("x-request-id")
-	if !ok {
+	if v == "" {
 		t.Fatalf("failed to get x-request-id")
 	} else if v != "12345" {
 		t.Fatalf("invalid metadata value: %s != %s", "12345", v)
 	}
 
-	v, ok = md.GetJoined("X-Request-Id")
+	v = md.GetJoined("X-Request-Id")
-	if !ok {
+	if v == "" {
 		t.Fatalf("failed to get x-request-id")
 	} else if v != "12345" {
 		t.Fatalf("invalid metadata value: %s != %s", "12345", v)
 	}
-	v, ok = md.GetJoined("X-Request-ID")
+	v = md.GetJoined("X-Request-ID")
-	if !ok {
+	if v == "" {
 		t.Fatalf("failed to get x-request-id")
 	} else if v != "12345" {
 		t.Fatalf("invalid metadata value: %s != %s", "12345", v)
@@ -153,8 +138,8 @@ func TestMetadataSet(t *testing.T) {
 
 	md.Set("Key", "val")
 
-	val, ok := md.GetJoined("Key")
+	val := md.GetJoined("Key")
-	if !ok {
+	if val == "" {
 		t.Fatal("key Key not found")
 	}
 	if val != "val" {
@@ -169,8 +154,8 @@ func TestMetadataDelete(t *testing.T) {
 	}
 
 	md.Del("Baz")
-	_, ok := md.Get("Baz")
+	v := md.Get("Baz")
-	if ok {
+	if v != nil {
 		t.Fatal("key Baz not deleted")
 	}
 }
@@ -269,20 +254,6 @@ func TestNewOutgoingContext(t *testing.T) {
 	}
 }
 
-func TestAppendIncomingContext(t *testing.T) {
-	md := New(1)
-	md.Set("key1", "val1")
-	ctx := AppendIncomingContext(context.TODO(), "key2", "val2")
-
-	nmd, ok := FromIncomingContext(ctx)
-	if nmd == nil || !ok {
-		t.Fatal("AppendIncomingContext not works")
-	}
-	if v, ok := nmd.GetJoined("key2"); !ok || v != "val2" {
-		t.Fatal("AppendIncomingContext not works")
-	}
-}
-
 func TestAppendOutgoingContext(t *testing.T) {
 	md := New(1)
 	md.Set("key1", "val1")
@@ -292,7 +263,7 @@ func TestAppendOutgoingContext(t *testing.T) {
 	if nmd == nil || !ok {
 		t.Fatal("AppendOutgoingContext not works")
 	}
-	if v, ok := nmd.GetJoined("key2"); !ok || v != "val2" {
+	if v := nmd.GetJoined("key2"); v != "val2" {
 		t.Fatal("AppendOutgoingContext not works")
 	}
 }

profiler/http/http.go

@@ -11,8 +11,8 @@ import (
 )
 
 type httpProfile struct {
-	server *http.Server
+	server  *http.Server
-	sync.Mutex
+	mu      sync.Mutex
 	running bool
 }
 
@@ -21,8 +21,8 @@ var DefaultAddress = ":6060"
 
 // Start the profiler
 func (h *httpProfile) Start() error {
-	h.Lock()
+	h.mu.Lock()
-	defer h.Unlock()
+	defer h.mu.Unlock()
 
 	if h.running {
 		return nil
@@ -30,9 +30,9 @@ func (h *httpProfile) Start() error {
 
 	go func() {
 		if err := h.server.ListenAndServe(); err != nil {
-			h.Lock()
+			h.mu.Lock()
 			h.running = false
-			h.Unlock()
+			h.mu.Unlock()
 		}
 	}()
 
@@ -43,8 +43,8 @@ func (h *httpProfile) Start() error {
 
 // Stop the profiler
 func (h *httpProfile) Stop() error {
-	h.Lock()
+	h.mu.Lock()
-	defer h.Unlock()
+	defer h.mu.Unlock()
 
 	if !h.running {
 		return nil

profiler/pprof/pprof.go

@@ -17,7 +17,7 @@ type profiler struct {
 	cpuFile *os.File
 	memFile *os.File
 	opts    profile.Options
-	sync.Mutex
+	mu      sync.Mutex
 	running bool
 }
 
@@ -39,8 +39,8 @@ func (p *profiler) writeHeap(f *os.File) {
 }
 
 func (p *profiler) Start() error {
-	p.Lock()
+	p.mu.Lock()
-	defer p.Unlock()
+	defer p.mu.Unlock()
 
 	if p.running {
 		return nil
@@ -86,8 +86,8 @@ func (p *profiler) Start() error {
 }
 
 func (p *profiler) Stop() error {
-	p.Lock()
+	p.mu.Lock()
-	defer p.Unlock()
+	defer p.mu.Unlock()
 
 	select {
 	case <-p.exit:

register/memory/memory.go

@@ -33,7 +33,7 @@ type memory struct {
 	records  map[string]services
 	watchers map[string]*watcher
 	opts     register.Options
-	sync.RWMutex
+	mu       sync.RWMutex
 }
 
 // services is a KV map with service name as the key and a map of records as the value
@@ -57,7 +57,7 @@ func (m *memory) ttlPrune() {
 	defer prune.Stop()
 
 	for range prune.C {
-		m.Lock()
+		m.mu.Lock()
 		for namespace, services := range m.records {
 			for service, versions := range services {
 				for version, record := range versions {
@@ -72,24 +72,24 @@ func (m *memory) ttlPrune() {
 				}
 			}
 		}
-		m.Unlock()
+		m.mu.Unlock()
 	}
 }
 
 func (m *memory) sendEvent(r *register.Result) {
-	m.RLock()
+	m.mu.RLock()
 	watchers := make([]*watcher, 0, len(m.watchers))
 	for _, w := range m.watchers {
 		watchers = append(watchers, w)
 	}
-	m.RUnlock()
+	m.mu.RUnlock()
 
 	for _, w := range watchers {
 		select {
 		case <-w.exit:
-			m.Lock()
+			m.mu.Lock()
 			delete(m.watchers, w.id)
-			m.Unlock()
+			m.mu.Unlock()
 		default:
 			select {
 			case w.res <- r:
@@ -113,8 +113,8 @@ func (m *memory) Init(opts ...register.Option) error {
 	}
 
 	// add services
-	m.Lock()
+	m.mu.Lock()
-	defer m.Unlock()
+	defer m.mu.Unlock()
 
 	return nil
 }
@@ -124,8 +124,8 @@ func (m *memory) Options() register.Options {
 }
 
 func (m *memory) Register(_ context.Context, s *register.Service, opts ...register.RegisterOption) error {
-	m.Lock()
+	m.mu.Lock()
-	defer m.Unlock()
+	defer m.mu.Unlock()
 
 	options := register.NewRegisterOptions(opts...)
 
@@ -197,8 +197,8 @@ func (m *memory) Register(_ context.Context, s *register.Service, opts ...regist
 }
 
 func (m *memory) Deregister(ctx context.Context, s *register.Service, opts ...register.DeregisterOption) error {
-	m.Lock()
+	m.mu.Lock()
-	defer m.Unlock()
+	defer m.mu.Unlock()
 
 	options := register.NewDeregisterOptions(opts...)
 
@@ -264,9 +264,9 @@ func (m *memory) LookupService(ctx context.Context, name string, opts ...registe
 
 	// if it's a wildcard domain, return from all domains
 	if options.Namespace == register.WildcardNamespace {
-		m.RLock()
+		m.mu.RLock()
 		recs := m.records
-		m.RUnlock()
+		m.mu.RUnlock()
 
 		var services []*register.Service
 
@@ -286,8 +286,8 @@ func (m *memory) LookupService(ctx context.Context, name string, opts ...registe
 		return services, nil
 	}
 
-	m.RLock()
+	m.mu.RLock()
-	defer m.RUnlock()
+	defer m.mu.RUnlock()
 
 	// check the domain exists
 	services, ok := m.records[options.Namespace]
@@ -319,9 +319,9 @@ func (m *memory) ListServices(ctx context.Context, opts ...register.ListOption)
 
 	// if it's a wildcard domain, list from all domains
 	if options.Namespace == register.WildcardNamespace {
-		m.RLock()
+		m.mu.RLock()
 		recs := m.records
-		m.RUnlock()
+		m.mu.RUnlock()
 
 		var services []*register.Service
 
@@ -336,8 +336,8 @@ func (m *memory) ListServices(ctx context.Context, opts ...register.ListOption)
 		return services, nil
 	}
 
-	m.RLock()
+	m.mu.RLock()
-	defer m.RUnlock()
+	defer m.mu.RUnlock()
 
 	// ensure the domain exists
 	services, ok := m.records[options.Namespace]
@@ -371,9 +371,9 @@ func (m *memory) Watch(ctx context.Context, opts ...register.WatchOption) (regis
 		wo:   wo,
 	}
 
-	m.Lock()
+	m.mu.Lock()
 	m.watchers[w.id] = w
-	m.Unlock()
+	m.mu.Unlock()
 
 	return w, nil
 }

register/register.go

@@ -69,7 +69,8 @@ type Service struct {
 type Node struct {
 	Metadata metadata.Metadata `json:"metadata,omitempty"`
 	ID       string            `json:"id,omitempty"`
-	Address  string            `json:"address,omitempty"`
+	// Address also prefixed with scheme like grpc://xx.xx.xx.xx:1234
+	Address string `json:"address,omitempty"`
 }
 
 // Option func signature

server/noop.go

@@ -51,13 +51,13 @@ func (r *rpcHandler) Options() HandlerOptions {
 }
 
 type noopServer struct {
-	h        Handler
+	h          Handler
-	wg       *sync.WaitGroup
+	wg         *sync.WaitGroup
-	rsvc     *register.Service
+	rsvc       *register.Service
-	handlers map[string]Handler
+	handlers   map[string]Handler
-	exit     chan chan error
+	exit       chan chan error
-	opts     Options
+	opts       Options
-	sync.RWMutex
+	mu         sync.RWMutex
 	registered bool
 	started    bool
 }
@@ -125,10 +125,10 @@ func (n *noopServer) String() string {
 
 //nolint:gocyclo
 func (n *noopServer) Register() error {
-	n.RLock()
+	n.mu.RLock()
 	rsvc := n.rsvc
 	config := n.opts
-	n.RUnlock()
+	n.mu.RUnlock()
 
 	// if service already filled, reuse it and return early
 	if rsvc != nil {
@@ -144,9 +144,9 @@ func (n *noopServer) Register() error {
 		return err
 	}
 
-	n.RLock()
+	n.mu.RLock()
 	registered := n.registered
-	n.RUnlock()
+	n.mu.RUnlock()
 
 	if !registered {
 		if config.Logger.V(logger.InfoLevel) {
@@ -164,8 +164,8 @@ func (n *noopServer) Register() error {
 		return nil
 	}
 
-	n.Lock()
+	n.mu.Lock()
-	defer n.Unlock()
+	defer n.mu.Unlock()
 
 	n.registered = true
 	if cacheService {
@@ -178,9 +178,9 @@ func (n *noopServer) Register() error {
 func (n *noopServer) Deregister() error {
 	var err error
 
-	n.RLock()
+	n.mu.RLock()
 	config := n.opts
-	n.RUnlock()
+	n.mu.RUnlock()
 
 	service, err := NewRegisterService(n)
 	if err != nil {
@@ -195,29 +195,29 @@ func (n *noopServer) Deregister() error {
 		return err
 	}
 
-	n.Lock()
+	n.mu.Lock()
 	n.rsvc = nil
 
 	if !n.registered {
-		n.Unlock()
+		n.mu.Unlock()
 		return nil
 	}
 
 	n.registered = false
 
-	n.Unlock()
+	n.mu.Unlock()
 	return nil
 }
 
 //nolint:gocyclo
 func (n *noopServer) Start() error {
-	n.RLock()
+	n.mu.RLock()
 	if n.started {
-		n.RUnlock()
+		n.mu.RUnlock()
 		return nil
 	}
 	config := n.Options()
-	n.RUnlock()
+	n.mu.RUnlock()
 
 	// use 127.0.0.1 to avoid scan of all network interfaces
 	addr, err := maddr.Extract("127.0.0.1")
@@ -235,11 +235,11 @@ func (n *noopServer) Start() error {
 		config.Logger.Info(n.opts.Context, "server [noop] Listening on "+config.Address)
 	}
 
-	n.Lock()
+	n.mu.Lock()
 	if len(config.Advertise) == 0 {
 		config.Advertise = config.Address
 	}
-	n.Unlock()
+	n.mu.Unlock()
 
 	// use RegisterCheck func before register
 	// nolint: nestif
@@ -273,9 +273,9 @@ func (n *noopServer) Start() error {
 			select {
 			// register self on interval
 			case <-t.C:
-				n.RLock()
+				n.mu.RLock()
 				registered := n.registered
-				n.RUnlock()
+				n.mu.RUnlock()
 				rerr := config.RegisterCheck(config.Context)
 				// nolint: nestif
 				if rerr != nil && registered {
@@ -332,29 +332,29 @@ func (n *noopServer) Start() error {
 	}()
 
 	// mark the server as started
-	n.Lock()
+	n.mu.Lock()
 	n.started = true
-	n.Unlock()
+	n.mu.Unlock()
 
 	return nil
 }
 
 func (n *noopServer) Stop() error {
-	n.RLock()
+	n.mu.RLock()
 	if !n.started {
-		n.RUnlock()
+		n.mu.RUnlock()
 		return nil
 	}
-	n.RUnlock()
+	n.mu.RUnlock()
 
 	ch := make(chan error)
 	n.exit <- ch
 
 	err := <-ch
-	n.Lock()
+	n.mu.Lock()
 	n.rsvc = nil
 	n.started = false
-	n.Unlock()
+	n.mu.Unlock()
 
 	return err
 }

service.go

@@ -96,9 +96,9 @@ func RegisterHandler(s server.Server, h interface{}, opts ...server.HandlerOptio
 }
 
 type service struct {
-	done chan struct{}
+	done    chan struct{}
-	opts Options
+	opts    Options
-	sync.RWMutex
+	mu      sync.RWMutex
 	stopped bool
 }
 
@@ -321,9 +321,9 @@ func (s *service) Health() bool {
 func (s *service) Start() error {
 	var err error
 
-	s.RLock()
+	s.mu.RLock()
 	config := s.opts
-	s.RUnlock()
+	s.mu.RUnlock()
 
 	for _, cfg := range s.opts.Configs {
 		if cfg.Options().Struct == nil {
@@ -380,9 +380,9 @@ func (s *service) Start() error {
 }
 
 func (s *service) Stop() error {
-	s.RLock()
+	s.mu.RLock()
 	config := s.opts
-	s.RUnlock()
+	s.mu.RUnlock()
 
 	if config.Loggers[0].V(logger.InfoLevel) {
 		config.Loggers[0].Info(s.opts.Context, fmt.Sprintf("stoppping [service] %s", s.Name()))
@@ -457,13 +457,13 @@ func (s *service) Run() error {
 // notifyShutdown marks the service as stopped and closes the done channel.
 // It ensures the channel is closed only once, preventing multiple closures.
 func (s *service) notifyShutdown() {
-	s.Lock()
+	s.mu.Lock()
 	if s.stopped {
-		s.Unlock()
+		s.mu.Unlock()
 		return
 	}
 	s.stopped = true
-	s.Unlock()
+	s.mu.Unlock()
 
 	close(s.done)
 }

store/noop.go

@@ -6,6 +6,7 @@ import (
 	"sync/atomic"
 
 	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/store"
 	"go.unistack.org/micro/v4/util/id"
 )
 
@@ -139,7 +140,7 @@ func (n *noopStore) fnExists(ctx context.Context, _ string, _ ...ExistsOption) e
 		return ctx.Err()
 	default:
 	}
-	return nil
+	return store.ErrNotFound
 }
 
 func (n *noopStore) Write(ctx context.Context, key string, val interface{}, opts ...WriteOption) error {

sync/memory.go

@@ -9,7 +9,7 @@ type memorySync struct {
 	locks   map[string]*memoryLock
 	options Options
 
-	mtx gosync.RWMutex
+	mu gosync.RWMutex
 }
 
 type memoryLock struct {
@@ -74,7 +74,7 @@ func (m *memorySync) Options() Options {
 
 func (m *memorySync) Lock(id string, opts ...LockOption) error {
 	// lock our access
-	m.mtx.Lock()
+	m.mu.Lock()
 
 	var options LockOptions
 	for _, o := range opts {
@@ -90,11 +90,11 @@ func (m *memorySync) Lock(id string, opts ...LockOption) error {
 			release: make(chan bool),
 		}
 		// unlock
-		m.mtx.Unlock()
+		m.mu.Unlock()
 		return nil
 	}
 
-	m.mtx.Unlock()
+	m.mu.Unlock()
 
 	// set wait time
 	var wait <-chan time.Time
@@ -124,12 +124,12 @@ lockLoop:
 		// wait for the lock to be released
 		select {
 		case <-lk.release:
-			m.mtx.Lock()
+			m.mu.Lock()
 
 			// someone locked before us
 			lk, ok = m.locks[id]
 			if ok {
-				m.mtx.Unlock()
+				m.mu.Unlock()
 				continue
 			}
 
@@ -141,7 +141,7 @@ lockLoop:
 				release: make(chan bool),
 			}
 
-			m.mtx.Unlock()
+			m.mu.Unlock()
 
 			break lockLoop
 		case <-ttl:
@@ -160,8 +160,8 @@ lockLoop:
 }
 
 func (m *memorySync) Unlock(id string) error {
-	m.mtx.Lock()
+	m.mu.Lock()
-	defer m.mtx.Unlock()
+	defer m.mu.Unlock()
 
 	lk, ok := m.locks[id]
 	// no lock exists

tracer/memory/memory.go

@@ -46,6 +46,10 @@ func (s memoryStringer) String() string {
 	return s.s
 }
 
+func (t *Tracer) Enabled() bool {
+	return t.opts.Enabled
+}
+
 func (t *Tracer) Flush(_ context.Context) error {
 	return nil
 }

tracer/noop.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v4/util/id"
+	"github.com/google/uuid"
 )
 
 var _ Tracer = (*noopTracer)(nil)
@@ -18,6 +18,12 @@ func (t *noopTracer) Spans() []Span {
 	return t.spans
 }
 
+var uuidNil = uuid.Nil.String()
+
+func (t *noopTracer) Enabled() bool {
+	return t.opts.Enabled
+}
+
 func (t *noopTracer) Start(ctx context.Context, name string, opts ...SpanOption) (context.Context, Span) {
 	options := NewSpanOptions(opts...)
 	span := &noopSpan{
@@ -28,8 +34,8 @@ func (t *noopTracer) Start(ctx context.Context, name string, opts ...SpanOption)
 		labels:    options.Labels,
 		kind:      options.Kind,
 	}
-	span.spanID.s, _ = id.New()
+	span.spanID.s = uuidNil
-	span.traceID.s, _ = id.New()
+	span.traceID.s = uuidNil
 	if span.ctx == nil {
 		span.ctx = context.Background()
 	}

tracer/options.go

@@ -142,6 +142,8 @@ type Options struct {
 	Name string
 	// ContextAttrFuncs contains funcs that provides tracing
 	ContextAttrFuncs []ContextAttrFunc
+	// Enabled specify trace status
+	Enabled bool
 }
 
 // Option func signature
@@ -181,6 +183,7 @@ func NewOptions(opts ...Option) Options {
 		Logger:           logger.DefaultLogger,
 		Context:          context.Background(),
 		ContextAttrFuncs: DefaultContextAttrFuncs,
+		Enabled:          true,
 	}
 	for _, o := range opts {
 		o(&options)
@@ -194,3 +197,10 @@ func Name(n string) Option {
 		o.Name = n
 	}
 }
+
+// Disabled disable tracer
+func Disabled(b bool) Option {
+	return func(o *Options) {
+		o.Enabled = !b
+	}
+}

tracer/tracer.go

@@ -51,6 +51,8 @@ type Tracer interface {
 	// Extract(ctx context.Context)
 	// Flush flushes spans
 	Flush(ctx context.Context) error
+	// Enabled returns tracer status
+	Enabled() bool
 }
 
 type Span interface {

util/buffer/seeker_buffer.go

@@ -67,6 +67,12 @@ func (b *SeekerBuffer) Close() error {
 	return nil
 }
 
+// Reset clears all the data out of the buffer and sets the read position to 0.
+func (b *SeekerBuffer) Reset() {
+	b.data = nil
+	b.pos = 0
+}
+
 // Len returns the length of data remaining to be read.
 func (b *SeekerBuffer) Len() int {
 	return len(b.data[b.pos:])

util/dns/cache.go

@@ -137,7 +137,7 @@ type cache struct {
 
 	opts Options
 
-	sync.RWMutex
+	mu sync.RWMutex
 }
 
 type cacheEntry struct {
@@ -171,7 +171,7 @@ func (c *cache) put(req string, res string) {
 		ttl = c.opts.MaxCacheTTL
 	}
 
-	c.Lock()
+	c.mu.Lock()
 	if c.entries == nil {
 		c.entries = make(map[string]cacheEntry)
 	}
@@ -207,7 +207,7 @@ func (c *cache) put(req string, res string) {
 	}
 
 	c.opts.Meter.Counter(semconv.CacheItemsTotal, "type", "dns").Inc()
-	c.Unlock()
+	c.mu.Unlock()
 }
 
 func (c *cache) get(req string) (res string) {
@@ -219,8 +219,8 @@ func (c *cache) get(req string) (res string) {
 		return ""
 	}
 
-	c.RLock()
+	c.mu.RLock()
-	defer c.RUnlock()
+	defer c.mu.RUnlock()
 
 	if c.entries == nil {
 		return ""

util/dns/conn.go

@@ -20,7 +20,7 @@ type dnsConn struct {
 	ibuf bytes.Buffer
 	obuf bytes.Buffer
 
-	sync.Mutex
+	mu sync.Mutex
 }
 
 type roundTripper func(ctx context.Context, req string) (res string, err error)
@@ -42,15 +42,15 @@ func (c *dnsConn) Read(b []byte) (n int, err error) {
 }
 
 func (c *dnsConn) Write(b []byte) (n int, err error) {
-	c.Lock()
+	c.mu.Lock()
-	defer c.Unlock()
+	defer c.mu.Unlock()
 	return c.ibuf.Write(b)
 }
 
 func (c *dnsConn) Close() error {
-	c.Lock()
+	c.mu.Lock()
 	cancel := c.cancel
-	c.Unlock()
+	c.mu.Unlock()
 
 	if cancel != nil {
 		cancel()
@@ -78,9 +78,9 @@ func (c *dnsConn) SetDeadline(t time.Time) error {
 }
 
 func (c *dnsConn) SetReadDeadline(t time.Time) error {
-	c.Lock()
+	c.mu.Lock()
 	c.deadline = t
-	c.Unlock()
+	c.mu.Unlock()
 	return nil
 }
 
@@ -90,8 +90,8 @@ func (c *dnsConn) SetWriteDeadline(_ time.Time) error {
 }
 
 func (c *dnsConn) drainBuffers(b []byte) (string, int, error) {
-	c.Lock()
+	c.mu.Lock()
-	defer c.Unlock()
+	defer c.mu.Unlock()
 
 	// drain the output buffer
 	if c.obuf.Len() > 0 {
@@ -119,8 +119,8 @@ func (c *dnsConn) drainBuffers(b []byte) (string, int, error) {
 }
 
 func (c *dnsConn) fillBuffer(b []byte, str string) (int, error) {
-	c.Lock()
+	c.mu.Lock()
-	defer c.Unlock()
+	defer c.mu.Unlock()
 	c.obuf.WriteByte(byte(len(str) >> 8))
 	c.obuf.WriteByte(byte(len(str)))
 	c.obuf.WriteString(str)
@@ -128,8 +128,8 @@ func (c *dnsConn) fillBuffer(b []byte, str string) (int, error) {
 }
 
 func (c *dnsConn) childContext() (context.Context, context.CancelFunc) {
-	c.Lock()
+	c.mu.Lock()
-	defer c.Unlock()
+	defer c.mu.Unlock()
 	if c.ctx == nil {
 		c.ctx, c.cancel = context.WithCancel(context.Background())
 	}

util/http/clienttracer.go

@@ -52,7 +52,7 @@ type clientTracer struct {
 	tr          tracer.Tracer
 	activeHooks map[string]context.Context
 	root        tracer.Span
-	mtx         sync.Mutex
+	mu          sync.Mutex
 }
 
 func NewClientTrace(ctx context.Context, tr tracer.Tracer) *httptrace.ClientTrace {
@@ -83,8 +83,8 @@ func NewClientTrace(ctx context.Context, tr tracer.Tracer) *httptrace.ClientTrac
 }
 
 func (ct *clientTracer) start(hook, spanName string, attrs ...interface{}) {
-	ct.mtx.Lock()
+	ct.mu.Lock()
-	defer ct.mtx.Unlock()
+	defer ct.mu.Unlock()
 
 	if hookCtx, found := ct.activeHooks[hook]; !found {
 		var sp tracer.Span
@@ -104,8 +104,8 @@ func (ct *clientTracer) start(hook, spanName string, attrs ...interface{}) {
 }
 
 func (ct *clientTracer) end(hook string, err error, attrs ...interface{}) {
-	ct.mtx.Lock()
+	ct.mu.Lock()
-	defer ct.mtx.Unlock()
+	defer ct.mu.Unlock()
 	if ctx, ok := ct.activeHooks[hook]; ok { // nolint:nestif
 		if span, ok := tracer.SpanFromContext(ctx); ok {
 			if err != nil {
@@ -136,8 +136,8 @@ func (ct *clientTracer) getParentContext(hook string) context.Context {
 }
 
 func (ct *clientTracer) span(hook string) (tracer.Span, bool) {
-	ct.mtx.Lock()
+	ct.mu.Lock()
-	defer ct.mtx.Unlock()
+	defer ct.mu.Unlock()
 	if ctx, ok := ct.activeHooks[hook]; ok {
 		return tracer.SpanFromContext(ctx)
 	}

util/id/id.go

@@ -2,12 +2,8 @@ package id
 
 import (
 	"crypto/rand"
-	"encoding/binary"
 	"errors"
-	"fmt"
-	"time"
 
-	uuidv8 "github.com/ash3in/uuidv8"
 	"github.com/google/uuid"
 	nanoid "github.com/matoous/go-nanoid"
 )
@@ -25,6 +21,7 @@ type Type int
 const (
 	TypeUnspecified Type = iota
 	TypeNanoid
+	TypeUUIDv7
 	TypeUUIDv8
 )
 
@@ -58,14 +55,14 @@ func (g *Generator) New() (string, error) {
 		}
 
 		return nanoid.Generate(g.opts.NanoidAlphabet, g.opts.NanoidSize)
-	case TypeUUIDv8:
+	case TypeUUIDv7:
-		timestamp := uint64(time.Now().UnixNano())
+		uid, err := uuid.NewV7()
-		clockSeq := make([]byte, 2)
+		if err != nil {
-		if _, err := rand.Read(clockSeq); err != nil {
+			return "", err
-			return "", fmt.Errorf("failed to generate random clock sequence: %w", err)
 		}
-		clockSeqValue := binary.BigEndian.Uint16(clockSeq) & 0x0FFF // Mask to 12 bits
+		return uid.String(), nil
-		return uuidv8.NewWithParams(timestamp, clockSeqValue, g.opts.UUIDNode[:], uuidv8.TimestampBits48)
+	case TypeUUIDv8:
+		return "", errors.New("unsupported uuid version v8")
 	}
 	return "", errors.New("invalid option, Type unspecified")
 }
@@ -82,16 +79,15 @@ func New(opts ...Option) (string, error) {
 		if options.NanoidSize <= 0 {
 			return "", errors.New("invalid option, NanoidSize must be positive integer")
 		}
-
 		return nanoid.Generate(options.NanoidAlphabet, options.NanoidSize)
-	case TypeUUIDv8:
+	case TypeUUIDv7:
-		timestamp := uint64(time.Now().UnixNano())
+		uid, err := uuid.NewV7()
-		clockSeq := make([]byte, 2)
+		if err != nil {
-		if _, err := rand.Read(clockSeq); err != nil {
+			return "", err
-			return "", fmt.Errorf("failed to generate random clock sequence: %w", err)
 		}
-		clockSeqValue := binary.BigEndian.Uint16(clockSeq) & 0x0FFF // Mask to 12 bits
+		return uid.String(), nil
-		return uuidv8.NewWithParams(timestamp, clockSeqValue, options.UUIDNode[:], uuidv8.TimestampBits48)
+	case TypeUUIDv8:
+		return "", errors.New("unsupported uuid version v8")
 	}
 
 	return "", errors.New("invalid option, Type unspecified")
@@ -145,7 +141,7 @@ func WithUUIDNode(node [6]byte) Option {
 // NewOptions returns new Options struct filled by opts
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Type:           TypeUUIDv8,
+		Type:           TypeUUIDv7,
 		NanoidAlphabet: DefaultNanoidAlphabet,
 		NanoidSize:     DefaultNanoidSize,
 		UUIDNode:       generatedNode,

util/reflect/struct.go

@@ -489,35 +489,74 @@ func URLMap(query string) (map[string]interface{}, error) {
 	return mp.(map[string]interface{}), nil
 }
 
-// FlattenMap expand key.subkey to nested map
+// FlattenMap flattens a nested map into a single-level map using dot notation for nested keys.
-func FlattenMap(a map[string]interface{}) map[string]interface{} {
+// In case of key conflicts, all nested levels will be discarded in favor of the first-level key.
-	// preprocess map
+//
-	nb := make(map[string]interface{}, len(a))
+// Example #1:
-	for k, v := range a {
+//
-		ps := strings.Split(k, ".")
+//	Input:
-		if len(ps) == 1 {
+//	  {
-			nb[k] = v
+//	    "user.name": "alex",
+//	    "user.document.id": "document_id"
+//	    "user.document.number": "document_number"
+//	  }
+//	Output:
+//	  {
+//	    "user": {
+//	      "name": "alex",
+//	      "document": {
+//	        "id": "document_id"
+//	        "number": "document_number"
+//	      }
+//	    }
+//	  }
+//
+// Example #2 (with conflicts):
+//
+//	Input:
+//	  {
+//	    "user": "alex",
+//	    "user.document.id": "document_id"
+//	    "user.document.number": "document_number"
+//	  }
+//	Output:
+//	  {
+//	    "user": "alex"
+//	  }
+func FlattenMap(input map[string]interface{}) map[string]interface{} {
+	result := make(map[string]interface{})
+
+	for k, v := range input {
+		parts := strings.Split(k, ".")
+
+		if len(parts) == 1 {
+			result[k] = v
 			continue
 		}
-		em := make(map[string]interface{})
+
-		em[ps[len(ps)-1]] = v
+		current := result
-		for i := len(ps) - 2; i > 0; i-- {
+
-			nm := make(map[string]interface{})
+		for i, part := range parts {
-			nm[ps[i]] = em
+			// last element in the path
-			em = nm
+			if i == len(parts)-1 {
-		}
+				current[part] = v
-		if vm, ok := nb[ps[0]]; ok {
+				break
-			// nested map
+			}
-			nm := vm.(map[string]interface{})
+
-			for vk, vv := range em {
+			// initialize map for current level if not exist
-				nm[vk] = vv
+			if _, ok := current[part]; !ok {
+				current[part] = make(map[string]interface{})
+			}
+
+			if nested, ok := current[part].(map[string]interface{}); ok {
+				current = nested // continue to the nested map
+			} else {
+				break // if current element is not a map, ignore it
 			}
-			nb[ps[0]] = nm
-		} else {
-			nb[ps[0]] = em
 		}
 	}
-	return nb
+
+	return result
 }
 
 /*

util/reflect/struct_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
 	rutil "go.unistack.org/micro/v4/util/reflect"
 )
 
@@ -319,3 +320,140 @@ func TestIsZero(t *testing.T) {
 
 	// t.Logf("XX %#+v\n", ok)
 }
+
+func TestFlattenMap(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    map[string]interface{}
+		expected map[string]interface{}
+	}{
+		{
+			name:     "empty map",
+			input:    map[string]interface{}{},
+			expected: map[string]interface{}{},
+		},
+		{
+			name:     "nil map",
+			input:    nil,
+			expected: map[string]interface{}{},
+		},
+		{
+			name: "single level",
+			input: map[string]interface{}{
+				"username": "username",
+				"password": "password",
+			},
+			expected: map[string]interface{}{
+				"username": "username",
+				"password": "password",
+			},
+		},
+		{
+			name: "two level",
+			input: map[string]interface{}{
+				"order_id":      "order_id",
+				"user.name":     "username",
+				"user.password": "password",
+			},
+			expected: map[string]interface{}{
+				"order_id": "order_id",
+				"user": map[string]interface{}{
+					"name":     "username",
+					"password": "password",
+				},
+			},
+		},
+		{
+			name: "three level",
+			input: map[string]interface{}{
+				"order_id":             "order_id",
+				"user.name":            "username",
+				"user.password":        "password",
+				"user.document.id":     "document_id",
+				"user.document.number": "document_number",
+			},
+			expected: map[string]interface{}{
+				"order_id": "order_id",
+				"user": map[string]interface{}{
+					"name":     "username",
+					"password": "password",
+					"document": map[string]interface{}{
+						"id":     "document_id",
+						"number": "document_number",
+					},
+				},
+			},
+		},
+		{
+			name: "four level",
+			input: map[string]interface{}{
+				"order_id":                    "order_id",
+				"user.name":                   "username",
+				"user.password":               "password",
+				"user.document.id":            "document_id",
+				"user.document.number":        "document_number",
+				"user.info.permissions.read":  "available",
+				"user.info.permissions.write": "available",
+			},
+			expected: map[string]interface{}{
+				"order_id": "order_id",
+				"user": map[string]interface{}{
+					"name":     "username",
+					"password": "password",
+					"document": map[string]interface{}{
+						"id":     "document_id",
+						"number": "document_number",
+					},
+					"info": map[string]interface{}{
+						"permissions": map[string]interface{}{
+							"read":  "available",
+							"write": "available",
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "key conflicts",
+			input: map[string]interface{}{
+				"user":          "user",
+				"user.name":     "username",
+				"user.password": "password",
+			},
+			expected: map[string]interface{}{
+				"user": "user",
+			},
+		},
+		{
+			name: "overwriting conflicts",
+			input: map[string]interface{}{
+				"order_id":             "order_id",
+				"user.document.id":     "document_id",
+				"user.document.number": "document_number",
+				"user.info.address":    "address",
+				"user.info.phone":      "phone",
+			},
+			expected: map[string]interface{}{
+				"order_id": "order_id",
+				"user": map[string]interface{}{
+					"document": map[string]interface{}{
+						"id":     "document_id",
+						"number": "document_number",
+					},
+					"info": map[string]interface{}{
+						"address": "address",
+						"phone":   "phone",
+					},
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			for range 100 { // need to exclude the impact of key order in the map on the test.
+				require.Equal(t, tt.expected, rutil.FlattenMap(tt.input))
+			}
+		})
+	}
+}

util/ring/buffer.go

@@ -14,7 +14,7 @@ type Buffer struct {
 	vals    []*Entry
 	size    int
 
-	sync.RWMutex
+	mu sync.RWMutex
 }
 
 // Entry is ring buffer data entry
@@ -35,8 +35,8 @@ type Stream struct {
 
 // Put adds a new value to ring buffer
 func (b *Buffer) Put(v interface{}) {
-	b.Lock()
+	b.mu.Lock()
-	defer b.Unlock()
+	defer b.mu.Unlock()
 
 	// append to values
 	entry := &Entry{
@@ -63,8 +63,8 @@ func (b *Buffer) Put(v interface{}) {
 
 // Get returns the last n entries
 func (b *Buffer) Get(n int) []*Entry {
-	b.RLock()
+	b.mu.RLock()
-	defer b.RUnlock()
+	defer b.mu.RUnlock()
 
 	// reset any invalid values
 	if n > len(b.vals) || n < 0 {
@@ -80,8 +80,8 @@ func (b *Buffer) Get(n int) []*Entry {
 
 // Since returns the entries since a specific time
 func (b *Buffer) Since(t time.Time) []*Entry {
-	b.RLock()
+	b.mu.RLock()
-	defer b.RUnlock()
+	defer b.mu.RUnlock()
 
 	// return all the values
 	if t.IsZero() {
@@ -109,8 +109,8 @@ func (b *Buffer) Since(t time.Time) []*Entry {
 // Stream logs from the buffer
 // Close the channel when you want to stop
 func (b *Buffer) Stream() (<-chan *Entry, chan bool) {
-	b.Lock()
+	b.mu.Lock()
-	defer b.Unlock()
+	defer b.mu.Unlock()
 
 	entries := make(chan *Entry, 128)
 	id := id.MustNew()

util/stream/stream.go

@@ -24,7 +24,7 @@ type stream struct {
 	err     error
 	request *request
 
-	sync.RWMutex
+	mu sync.RWMutex
 }
 
 type request struct {
@@ -57,9 +57,9 @@ func (s *stream) Request() server.Request {
 func (s *stream) Send(v interface{}) error {
 	err := s.Stream.SendMsg(v)
 	if err != nil {
-		s.Lock()
+		s.mu.Lock()
 		s.err = err
-		s.Unlock()
+		s.mu.Unlock()
 	}
 	return err
 }
@@ -68,17 +68,17 @@ func (s *stream) Send(v interface{}) error {
 func (s *stream) Recv(v interface{}) error {
 	err := s.Stream.RecvMsg(v)
 	if err != nil {
-		s.Lock()
+		s.mu.Lock()
 		s.err = err
-		s.Unlock()
+		s.mu.Unlock()
 	}
 	return err
 }
 
 // Error returns error that stream holds
 func (s *stream) Error() error {
-	s.RLock()
+	s.mu.RLock()
-	defer s.RUnlock()
+	defer s.mu.RUnlock()
 	return s.err
 }
 

util/time/duration.go

@@ -6,7 +6,7 @@ import (
 	"strconv"
 	"time"
 
-	"gopkg.in/yaml.v3"
+	"github.com/goccy/go-yaml"
 )
 
 type Duration int64
@@ -58,9 +58,9 @@ func (d Duration) MarshalYAML() (interface{}, error) {
 	return time.Duration(d).String(), nil
 }
 
-func (d *Duration) UnmarshalYAML(n *yaml.Node) error {
+func (d *Duration) UnmarshalYAML(data []byte) error {
 	var v interface{}
-	if err := yaml.Unmarshal([]byte(n.Value), &v); err != nil {
+	if err := yaml.Unmarshal(data, &v); err != nil {
 		return err
 	}
 	switch value := v.(type) {

util/time/duration_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 	"time"
 
-	"gopkg.in/yaml.v3"
+	"github.com/goccy/go-yaml"
 )
 
 func TestMarshalYAML(t *testing.T) {