Merge pull request 'tracer: minimize overhead on noop tracer usage' (#381) from tr into v3

Reviewed-on: #381

.gitea/workflows/job_lint.yml

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

.gitea/workflows/job_test.yml

@@ -0,0 +1,34 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches:
+    - master
+    - v3
+    - v4
+  push:
+    branches:
+    - master
+    - v3
+    - v4
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+    - name: setup deps
+      run: go get -v ./...
+    - name: run test
+      env:
+        INTEGRATION_TESTS: yes
+      run: go test -mod readonly -v ./...

.gitea/workflows/job_tests.yml

@@ -0,0 +1,53 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches:
+    - master
+    - v3
+    - v4
+  push:
+    branches:
+    - master
+    - v3
+    - v4
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: checkout tests
+      uses: actions/checkout@v4
+      with:
+        ref: master
+        filter: 'blob:none'
+        repository: unistack-org/micro-tests
+        path: micro-tests
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+    - name: setup go work
+      env:
+        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+      run: |
+        go work init
+        go work use .
+        go work use micro-tests
+    - name: setup deps
+      env:
+        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+      run: go get -v ./...
+    - name: run tests
+      env:
+        INTEGRATION_TESTS: yes
+        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+      run: |
+        cd micro-tests
+        go test -mod readonly -v ./... || true

.gitea/workflows/lint.yml

@@ -1,24 +0,0 @@
-name: lint
-on:
-  pull_request:
-    branches:
-    - master
-    - v3
-jobs:
-  lint:
-    name: lint
-    runs-on: ubuntu-latest
-    steps:
-    - name: setup-go
-      uses: actions/setup-go@v3
-      with:
-        go-version: 1.21
-    - name: checkout
-      uses: actions/checkout@v3
-    - name: deps
-      run: go get -v -d ./...
-    - name: lint
-      uses: https://github.com/golangci/golangci-lint-action@v3.4.0
-      continue-on-error: true
-      with:
-        version: v1.52

.gitea/workflows/pr.yml

@@ -1,23 +0,0 @@
-name: pr
-on:
-  pull_request:
-    branches:
-    - master
-    - v3
-jobs:
-  test:
-    name: test
-    runs-on: ubuntu-latest
-    steps:
-    - name: checkout
-      uses: actions/checkout@v3
-    - name: setup-go
-      uses: actions/setup-go@v3
-      with:
-        go-version: 1.21
-    - name: deps
-      run: go get -v -t -d ./...
-    - name: test
-      env:
-        INTEGRATION_TESTS: yes
-      run: go test -mod readonly -v ./...

.golangci.yml

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

README.md

@@ -1,4 +1,4 @@
-# Micro [![License](https://img.shields.io/:license-apache-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![Doc](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/github.com/unistack-org/micro/v3?tab=overview) [![Status](https://github.com/unistack-org/micro/workflows/build/badge.svg?branch=master)](https://github.com/unistack-org/micro/actions?query=workflow%3Abuild+branch%3Amaster+event%3Apush) [![Lint](https://goreportcard.com/badge/go.unistack.org/micro/v3)](https://goreportcard.com/report/go.unistack.org/micro/v3) [![Coverage](https://codecov.io/gh/unistack-org/micro/branch/v3/graph/badge.svg?token=OZPO2LP7VS)](https://codecov.io/gh/unistack-org/micro)
+# Micro [![License](https://img.shields.io/:license-apache-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![Doc](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/github.com/unistack-org/micro/v3?tab=overview) [![Status](https://git.unistack.org/unistack-org/micro/actions/workflows/job_tests.yml/badge.svg?branch=v3)](https://git.unistack.org/unistack-org/micro/actions?query=workflow%3Abuild+branch%3Av3+event%3Apush) [![Lint](https://goreportcard.com/badge/go.unistack.org/micro/v3)](https://goreportcard.com/report/go.unistack.org/micro/v3)
 
 Micro is a standard library for microservices.
 

broker/broker.go

@@ -46,6 +46,12 @@ type Broker interface {
 	BatchSubscribe(ctx context.Context, topic string, h BatchHandler, opts ...SubscribeOption) (Subscriber, error)
 	// String type of broker
 	String() string
+	// Live returns broker liveness
+	Live() bool
+	// Ready returns broker readiness
+	Ready() bool
+	// Health returns broker health
+	Health() bool
 }
 
 type (

broker/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Broker, bool) {
 	return c, ok
 }
 
+// MustContext returns broker from passed context
+func MustContext(ctx context.Context) Broker {
+	b, ok := FromContext(ctx)
+	if !ok {
+		panic("missing broker")
+	}
+	return b
+}
+
 // NewContext savess broker in context
 func NewContext(ctx context.Context, s Broker) context.Context {
 	if ctx == nil {

broker/memory/memory.go

@@ -109,7 +109,7 @@ func (m *memoryBroker) Init(opts ...broker.Option) error {
 	m.funcSubscribe = m.fnSubscribe
 	m.funcBatchSubscribe = m.fnBatchSubscribe
 
-	m.opts.Hooks.EachNext(func(hook options.Hook) {
+	m.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case broker.HookPublish:
 			m.funcPublish = h(m.funcPublish)
@@ -339,6 +339,18 @@ func (m *memoryBroker) Name() string {
 	return m.opts.Name
 }
 
+func (m *memoryBroker) Live() bool {
+	return true
+}
+
+func (m *memoryBroker) Ready() bool {
+	return true
+}
+
+func (m *memoryBroker) Health() bool {
+	return true
+}
+
 func (m *memoryEvent) Topic() string {
 	return m.topic
 }

broker/memory/memory_test.go

@@ -74,7 +74,7 @@ func TestMemoryBroker(t *testing.T) {
 	topic := "test"
 	count := 10
 
-	fn := func(p broker.Event) error {
+	fn := func(_ broker.Event) error {
 		return nil
 	}
 

broker/noop.go

@@ -25,6 +25,18 @@ func NewBroker(opts ...Option) *NoopBroker {
 	return b
 }
 
+func (b *NoopBroker) Health() bool {
+	return true
+}
+
+func (b *NoopBroker) Live() bool {
+	return true
+}
+
+func (b *NoopBroker) Ready() bool {
+	return true
+}
+
 func (b *NoopBroker) Name() string {
 	return b.opts.Name
 }
@@ -47,7 +59,7 @@ func (b *NoopBroker) Init(opts ...Option) error {
 	b.funcSubscribe = b.fnSubscribe
 	b.funcBatchSubscribe = b.fnBatchSubscribe
 
-	b.opts.Hooks.EachNext(func(hook options.Hook) {
+	b.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case HookPublish:
 			b.funcPublish = h(b.funcPublish)

broker/options.go

@@ -16,6 +16,9 @@ import (
 
 // Options struct
 type Options struct {
+	// Name holds the broker name
+	Name string
+
 	// Tracer used for tracing
 	Tracer tracer.Tracer
 	// Register can be used for clustering
@@ -28,23 +31,25 @@ type Options struct {
 	Meter meter.Meter
 	// Context holds external options
 	Context context.Context
+
+	// Wait waits for a collection of goroutines to finish
+	Wait *sync.WaitGroup
 	// TLSConfig holds tls.TLSConfig options
 	TLSConfig *tls.Config
+
 	// ErrorHandler used when broker can't unmarshal incoming message
 	ErrorHandler Handler
 	// BatchErrorHandler used when broker can't unmashal incoming messages
 	BatchErrorHandler BatchHandler
-	// Name holds the broker name
-	Name string
+
 	// Addrs holds the broker address
 	Addrs []string
-	// Wait waits for a collection of goroutines to finish
-	Wait *sync.WaitGroup
-	// GracefulTimeout contains time to wait to finish in flight requests
-	GracefulTimeout time.Duration
 	// Hooks can be run before broker Publish/BatchPublish and
 	// Subscribe/BatchSubscribe methods
 	Hooks options.Hooks
+
+	// GracefulTimeout contains time to wait to finish in flight requests
+	GracefulTimeout time.Duration
 }
 
 // NewOptions create new Options

client/backoff.go

@@ -17,13 +17,13 @@ func BackoffExp(_ context.Context, _ Request, attempts int) (time.Duration, erro
 }
 
 // BackoffInterval specifies randomization interval for backoff func
-func BackoffInterval(min time.Duration, max time.Duration) BackoffFunc {
+func BackoffInterval(minTime time.Duration, maxTime time.Duration) BackoffFunc {
 	return func(_ context.Context, _ Request, attempts int) (time.Duration, error) {
 		td := time.Duration(math.Pow(float64(attempts), math.E)) * time.Millisecond * 100
-		if td < min {
-			return min, nil
-		} else if td > max {
-			return max, nil
+		if td < minTime {
+			return minTime, nil
+		} else if td > maxTime {
+			return maxTime, nil
 		}
 		return td, nil
 	}

client/backoff_test.go

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

client/context.go

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

client/noop.go

@@ -194,7 +194,7 @@ func (n *noopClient) Init(opts ...Option) error {
 	n.funcPublish = n.fnPublish
 	n.funcBatchPublish = n.fnBatchPublish
 
-	n.opts.Hooks.EachNext(func(hook options.Hook) {
+	n.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case HookCall:
 			n.funcCall = h(n.funcCall)
@@ -222,7 +222,7 @@ func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opt
 	ts := time.Now()
 	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
 	var sp tracer.Span
-	ctx, sp = n.opts.Tracer.Start(ctx, req.Endpoint()+" rpc-client",
+	ctx, sp = n.opts.Tracer.Start(ctx, "rpc-client",
 		tracer.WithSpanKind(tracer.SpanKindClient),
 		tracer.WithSpanLabels("endpoint", req.Endpoint()),
 	)
@@ -298,7 +298,7 @@ func (n *noopClient) fnCall(ctx context.Context, req Request, rsp interface{}, o
 		// call backoff first. Someone may want an initial start delay
 		t, err := callOpts.Backoff(ctx, req, i)
 		if err != nil {
-			return errors.InternalServerError("go.micro.client", err.Error())
+			return errors.InternalServerError("go.micro.client", "%s", err)
 		}
 
 		// only sleep if greater than 0
@@ -312,7 +312,7 @@ func (n *noopClient) fnCall(ctx context.Context, req Request, rsp interface{}, o
 			// TODO apply any filtering here
 			routes, err = n.opts.Lookup(ctx, req, callOpts)
 			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
+				return errors.InternalServerError("go.micro.client", "%s", err)
 			}
 
 			// balance the list of nodes
@@ -372,7 +372,7 @@ func (n *noopClient) fnCall(ctx context.Context, req Request, rsp interface{}, o
 	return gerr
 }
 
-func (n *noopClient) NewRequest(service, endpoint string, req interface{}, opts ...RequestOption) Request {
+func (n *noopClient) NewRequest(service, endpoint string, _ interface{}, _ ...RequestOption) Request {
 	return &noopRequest{service: service, endpoint: endpoint}
 }
 
@@ -385,7 +385,7 @@ func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption
 	ts := time.Now()
 	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
 	var sp tracer.Span
-	ctx, sp = n.opts.Tracer.Start(ctx, req.Endpoint()+" rpc-client",
+	ctx, sp = n.opts.Tracer.Start(ctx, "rpc-client",
 		tracer.WithSpanKind(tracer.SpanKindClient),
 		tracer.WithSpanLabels("endpoint", req.Endpoint()),
 	)
@@ -466,7 +466,7 @@ func (n *noopClient) fnStream(ctx context.Context, req Request, opts ...CallOpti
 		// call backoff first. Someone may want an initial start delay
 		t, cerr := callOpts.Backoff(ctx, req, i)
 		if cerr != nil {
-			return nil, errors.InternalServerError("go.micro.client", cerr.Error())
+			return nil, errors.InternalServerError("go.micro.client", "%s", cerr)
 		}
 
 		// only sleep if greater than 0
@@ -480,7 +480,7 @@ func (n *noopClient) fnStream(ctx context.Context, req Request, opts ...CallOpti
 			// TODO apply any filtering here
 			routes, err = n.opts.Lookup(ctx, req, callOpts)
 			if err != nil {
-				return nil, errors.InternalServerError("go.micro.client", err.Error())
+				return nil, errors.InternalServerError("go.micro.client", "%s", err)
 			}
 
 			// balance the list of nodes
@@ -546,7 +546,7 @@ func (n *noopClient) fnStream(ctx context.Context, req Request, opts ...CallOpti
 	return nil, grr
 }
 
-func (n *noopClient) stream(ctx context.Context, addr string, req Request, opts CallOptions) (Stream, error) {
+func (n *noopClient) stream(ctx context.Context, _ string, _ Request, _ CallOptions) (Stream, error) {
 	return &noopStream{ctx: ctx}, nil
 }
 
@@ -609,13 +609,13 @@ func (n *noopClient) publish(ctx context.Context, ps []Message, opts ...PublishO
 			// use codec for payload
 			cf, err := n.newCodec(p.ContentType())
 			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
+				return errors.InternalServerError("go.micro.client", "%s", err)
 			}
 
 			// set the body
 			b, err := cf.Marshal(p.Payload())
 			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
+				return errors.InternalServerError("go.micro.client", "%s", err)
 			}
 			body = b
 		}

client/options.go

@@ -11,7 +11,6 @@ import (
 	"go.unistack.org/micro/v3/logger"
 	"go.unistack.org/micro/v3/metadata"
 	"go.unistack.org/micro/v3/meter"
-	"go.unistack.org/micro/v3/network/transport"
 	"go.unistack.org/micro/v3/options"
 	"go.unistack.org/micro/v3/register"
 	"go.unistack.org/micro/v3/router"
@@ -22,8 +21,16 @@ import (
 
 // Options holds client options
 type Options struct {
-	// Transport used for transfer messages
-	Transport transport.Transport
+	// Codecs map
+	Codecs map[string]codec.Codec
+
+	// Proxy is used for proxy requests
+	Proxy string
+	// ContentType is used to select codec
+	ContentType string
+	// Name is the client name
+	Name string
+
 	// Selector used to select needed address
 	Selector selector.Selector
 	// Logger used to log messages
@@ -38,31 +45,28 @@ type Options struct {
 	Context context.Context
 	// Router used to get route
 	Router router.Router
+
 	// TLSConfig specifies tls.Config for secure connection
 	TLSConfig *tls.Config
-	// Codecs map
-	Codecs map[string]codec.Codec
+
 	// Lookup func used to get destination addr
 	Lookup LookupFunc
-	// Proxy is used for proxy requests
-	Proxy string
-	// ContentType is used to select codec
-	ContentType string
-	// Name is the client name
-	Name string
+	// ContextDialer used to connect
+	ContextDialer func(context.Context, string) (net.Conn, error)
+
 	// Wrappers contains wrappers
 	Wrappers []Wrapper
+	// Hooks can be run before broker Publish/BatchPublish and
+	// Subscribe/BatchSubscribe methods
+	Hooks options.Hooks
+
 	// CallOptions contains default CallOptions
 	CallOptions CallOptions
+
 	// PoolSize connection pool size
 	PoolSize int
 	// PoolTTL connection pool ttl
 	PoolTTL time.Duration
-	// ContextDialer used to connect
-	ContextDialer func(context.Context, string) (net.Conn, error)
-	// Hooks can be run before broker Publish/BatchPublish and
-	// Subscribe/BatchSubscribe methods
-	Hooks options.Hooks
 }
 
 // NewCallOptions creates new call options struct
@@ -76,6 +80,16 @@ func NewCallOptions(opts ...CallOption) CallOptions {
 
 // CallOptions holds client call options
 type CallOptions struct {
+	// RequestMetadata holds additional metadata for call
+	RequestMetadata metadata.Metadata
+
+	// Network name
+	Network string
+	// Content-Type
+	ContentType string
+	// AuthToken string
+	AuthToken string
+
 	// Selector selects addr
 	Selector selector.Selector
 	// Context used for deadline
@@ -83,33 +97,30 @@ type CallOptions struct {
 	// Router used for route
 	Router router.Router
 	// Retry func used for retries
+
+	// ResponseMetadata holds additional metadata from call
+	ResponseMetadata *metadata.Metadata
+
 	Retry RetryFunc
 	// Backoff func used for backoff when retry
 	Backoff BackoffFunc
-	// Network name
-	Network string
-	// Content-Type
-	ContentType string
-	// AuthToken string
-	AuthToken string
+	// ContextDialer used to connect
+	ContextDialer func(context.Context, string) (net.Conn, error)
+
 	// Address specifies static addr list
 	Address []string
 	// SelectOptions selector options
 	SelectOptions []selector.SelectOption
+
 	// StreamTimeout stream timeout
 	StreamTimeout time.Duration
 	// RequestTimeout request timeout
 	RequestTimeout time.Duration
-	// RequestMetadata holds additional metadata for call
-	RequestMetadata metadata.Metadata
-	// ResponseMetadata holds additional metadata from call
-	ResponseMetadata *metadata.Metadata
+
 	// DialTimeout dial timeout
 	DialTimeout time.Duration
 	// Retries specifies retries num
 	Retries int
-	// ContextDialer used to connect
-	ContextDialer func(context.Context, string) (net.Conn, error)
 }
 
 // ContextDialer pass ContextDialer to client
@@ -194,18 +205,16 @@ func NewOptions(opts ...Option) Options {
 			Retry:          DefaultRetry,
 			Retries:        DefaultRetries,
 			RequestTimeout: DefaultRequestTimeout,
-			DialTimeout:    transport.DefaultDialTimeout,
 		},
-		Lookup:    LookupRoute,
-		PoolSize:  DefaultPoolSize,
-		PoolTTL:   DefaultPoolTTL,
-		Selector:  random.NewSelector(),
-		Logger:    logger.DefaultLogger,
-		Broker:    broker.DefaultBroker,
-		Meter:     meter.DefaultMeter,
-		Tracer:    tracer.DefaultTracer,
-		Router:    router.DefaultRouter,
-		Transport: transport.DefaultTransport,
+		Lookup:   LookupRoute,
+		PoolSize: DefaultPoolSize,
+		PoolTTL:  DefaultPoolTTL,
+		Selector: random.NewSelector(),
+		Logger:   logger.DefaultLogger,
+		Broker:   broker.DefaultBroker,
+		Meter:    meter.DefaultMeter,
+		Tracer:   tracer.DefaultTracer,
+		Router:   router.DefaultRouter,
 	}
 
 	for _, o := range opts {
@@ -278,13 +287,6 @@ func PoolTTL(d time.Duration) Option {
 	}
 }
 
-// Transport to use for communication e.g http, rabbitmq, etc
-func Transport(t transport.Transport) Option {
-	return func(o *Options) {
-		o.Transport = t
-	}
-}
-
 // Register sets the routers register
 func Register(r register.Register) Option {
 	return func(o *Options) {
@@ -334,14 +336,6 @@ func TLSConfig(t *tls.Config) Option {
 	return func(o *Options) {
 		// set the internal tls
 		o.TLSConfig = t
-
-		// set the default transport if one is not
-		// already set. Required for Init call below.
-
-		// set the transport tls
-		_ = o.Transport.Init(
-			transport.TLSConfig(t),
-		)
 	}
 }
 
@@ -507,13 +501,6 @@ func WithAuthToken(t string) CallOption {
 	}
 }
 
-// WithNetwork is a CallOption which sets the network attribute
-func WithNetwork(n string) CallOption {
-	return func(o *CallOptions) {
-		o.Network = n
-	}
-}
-
 // WithRouter sets the router to use for this call
 func WithRouter(r router.Router) CallOption {
 	return func(o *CallOptions) {

cluster/cluster.go

@@ -38,4 +38,10 @@ type Cluster interface {
 	Broadcast(ctx context.Context, msg Message, filter ...string) error
 	// Unicast send message to single member in cluster
 	Unicast(ctx context.Context, node Node, msg Message) error
+	// Live returns cluster liveness
+	Live() bool
+	// Ready returns cluster readiness
+	Ready() bool
+	// Health returns cluster health
+	Health() bool
 }

codec/context.go

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

config/config.go

@@ -4,7 +4,6 @@ package config
 import (
 	"context"
 	"errors"
-	"fmt"
 	"reflect"
 	"time"
 )
@@ -14,7 +13,7 @@ type Validator interface {
 }
 
 // DefaultConfig default config
-var DefaultConfig Config = NewConfig()
+var DefaultConfig = NewConfig()
 
 // DefaultWatcherMinInterval default min interval for poll changes
 var DefaultWatcherMinInterval = 5 * time.Second
@@ -139,7 +138,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Error(ctx, fmt.Sprintf("%s BeforeLoad error", c.String()), err)
+				c.Options().Logger.Error(ctx, c.String()+" BeforeLoad error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -154,7 +153,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Error(ctx, fmt.Sprintf("%s AfterLoad error", c.String()), err)
+				c.Options().Logger.Error(ctx, c.String()+" AfterLoad error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -169,7 +168,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Error(ctx, fmt.Sprintf("%s BeforeSave error", c.String()), err)
+				c.Options().Logger.Error(ctx, c.String()+" BeforeSave error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -184,7 +183,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Error(ctx, fmt.Sprintf("%s AfterSave error", c.String()), err)
+				c.Options().Logger.Error(ctx, c.String()+" AfterSave error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -199,7 +198,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Error(ctx, fmt.Sprintf("%s BeforeInit error", c.String()), err)
+				c.Options().Logger.Error(ctx, c.String()+" BeforeInit error", err)
 				if !c.Options().AllowFail {
 					return err
 				}
@@ -214,7 +213,7 @@ var (
 				return nil
 			}
 			if err := fn(ctx, c); err != nil {
-				c.Options().Logger.Error(ctx, fmt.Sprintf("%s AfterInit error", c.String(), err), err)
+				c.Options().Logger.Error(ctx, c.String()+" AfterInit error", err)
 				if !c.Options().AllowFail {
 					return err
 				}

config/context.go

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

config/default.go

@@ -37,7 +37,7 @@ func (c *defaultConfig) Init(opts ...Option) error {
 	c.funcLoad = c.fnLoad
 	c.funcSave = c.fnSave
 
-	c.opts.Hooks.EachNext(func(hook options.Hook) {
+	c.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case HookLoad:
 			c.funcLoad = h(c.funcLoad)

config/default_test.go

@@ -3,6 +3,7 @@ package config_test
 import (
 	"context"
 	"fmt"
+	"reflect"
 	"testing"
 	"time"
 
@@ -12,15 +13,17 @@ import (
 )
 
 type cfg struct {
-	StringValue    string `default:"string_value"`
-	IgnoreValue    string `json:"-"`
-	StructValue    *cfgStructValue
-	IntValue       int             `default:"99"`
-	DurationValue  time.Duration   `default:"10s"`
-	MDurationValue mtime.Duration  `default:"10s"`
-	MapValue       map[string]bool `default:"key1=true,key2=false"`
-	UUIDValue      string          `default:"micro:generate uuid"`
-	IDValue        string          `default:"micro:generate id"`
+	MapValue    map[string]bool `default:"key1=true,key2=false"`
+	StructValue *cfgStructValue
+
+	StringValue string `default:"string_value"`
+	IgnoreValue string `json:"-"`
+	UUIDValue   string `default:"micro:generate uuid"`
+	IDValue     string `default:"micro:generate id"`
+
+	DurationValue  time.Duration  `default:"10s"`
+	MDurationValue mtime.Duration `default:"10s"`
+	IntValue       int            `default:"99"`
 }
 
 type cfgStructValue struct {
@@ -134,3 +137,13 @@ func TestValidate(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func Test_SizeOf(t *testing.T) {
+	st := cfg{}
+
+	tVal := reflect.TypeOf(st)
+	for i := 0; i < tVal.NumField(); i++ {
+		field := tVal.Field(i)
+		fmt.Printf("Field: %s, Offset: %d, Size: %d\n", field.Name, field.Offset, field.Type.Size())
+	}
+}

config/options.go

@@ -41,14 +41,16 @@ type Options struct {
 	BeforeInit []func(context.Context, Config) error
 	// AfterInit contains slice of funcs that runs after Init
 	AfterInit []func(context.Context, Config) error
-	// AllowFail flag to allow fail in config source
-	AllowFail bool
+
 	// SkipLoad runs only if condition returns true
 	SkipLoad func(context.Context, Config) bool
 	// SkipSave runs only if condition returns true
 	SkipSave func(context.Context, Config) bool
 	// Hooks can be run before/after config Save/Load
 	Hooks options.Hooks
+
+	// AllowFail flag to allow fail in config source
+	AllowFail bool
 }
 
 // Option function signature
@@ -278,10 +280,10 @@ func WatchCoalesce(b bool) WatchOption {
 }
 
 // WatchInterval specifies min and max time.Duration for pulling changes
-func WatchInterval(min, max time.Duration) WatchOption {
+func WatchInterval(minTime, maxTime time.Duration) WatchOption {
 	return func(o *WatchOptions) {
-		o.MinInterval = min
-		o.MaxInterval = max
+		o.MinInterval = minTime
+		o.MaxInterval = maxTime
 	}
 }
 

errors/errors_test.go

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

flow/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Flow, bool) {
 	return c, ok
 }
 
+// MustContext returns Flow from context
+func MustContext(ctx context.Context) Flow {
+	f, ok := FromContext(ctx)
+	if !ok {
+		panic("missing flow")
+	}
+	return f
+}
+
 // NewContext stores Flow to context
 func NewContext(ctx context.Context, f Flow) context.Context {
 	if ctx == nil {

fsm/default.go

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

go.mod

@@ -1,32 +1,43 @@
 module go.unistack.org/micro/v3
 
-go 1.22
+go 1.22.0
+
+toolchain go1.23.4
 
 require (
-	dario.cat/mergo v1.0.0
+	dario.cat/mergo v1.0.1
 	github.com/DATA-DOG/go-sqlmock v1.5.0
 	github.com/KimMachineGun/automemlimit v0.6.1
-	github.com/google/uuid v1.3.0
+	github.com/google/uuid v1.6.0
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5
 	go.uber.org/automaxprocs v1.6.0
 	go.unistack.org/micro-proto/v3 v3.4.1
-	golang.org/x/sync v0.3.0
-	google.golang.org/grpc v1.57.0
-	google.golang.org/protobuf v1.33.0
+	golang.org/x/sync v0.10.0
+	google.golang.org/grpc v1.68.1
+	google.golang.org/protobuf v1.35.2
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
-	github.com/cilium/ebpf v0.9.1 // indirect
-	github.com/containerd/cgroups/v3 v3.0.1 // indirect
-	github.com/coreos/go-systemd/v22 v22.3.2 // indirect
-	github.com/docker/go-units v0.4.0 // indirect
-	github.com/godbus/dbus/v5 v5.0.4 // indirect
-	github.com/golang/protobuf v1.5.3 // indirect
-	github.com/opencontainers/runtime-spec v1.0.2 // indirect
+	github.com/cilium/ebpf v0.16.0 // indirect
+	github.com/containerd/cgroups/v3 v3.0.4 // indirect
+	github.com/containerd/log v0.1.0 // indirect
+	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/docker/go-units v0.5.0 // indirect
+	github.com/godbus/dbus/v5 v5.1.0 // indirect
+	github.com/moby/sys/userns v0.1.0 // indirect
+	github.com/opencontainers/runtime-spec v1.2.0 // indirect
 	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 // indirect
-	github.com/sirupsen/logrus v1.8.1 // indirect
-	golang.org/x/net v0.14.0 // indirect
-	golang.org/x/sys v0.11.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20230526203410-71b5a4ffd15e // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/rogpeppe/go-internal v1.13.1 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	github.com/stretchr/testify v1.10.0 // indirect
+	go.uber.org/goleak v1.3.0 // indirect
+	golang.org/x/exp v0.0.0-20241210194714-1829a127f884 // indirect
+	golang.org/x/net v0.32.0 // indirect
+	golang.org/x/sys v0.28.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20241209162323-e6fa225c2576 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 )

go.sum

@@ -1,78 +1,97 @@
-dario.cat/mergo v1.0.0 h1:AGCNq9Evsj31mOgNPcLyXc+4PNABt905YmuqPYYpBWk=
-dario.cat/mergo v1.0.0/go.mod h1:uNxQE+84aUszobStD9th8a29P2fMDhsBdgRYvZOxGmk=
+dario.cat/mergo v1.0.1 h1:Ra4+bf83h2ztPIQYNP99R6m+Y7KfnARDfID+a+vLl4s=
+dario.cat/mergo v1.0.1/go.mod h1:uNxQE+84aUszobStD9th8a29P2fMDhsBdgRYvZOxGmk=
 github.com/DATA-DOG/go-sqlmock v1.5.0 h1:Shsta01QNfFxHCfpW6YH2STWB0MudeXXEWMr20OEh60=
 github.com/DATA-DOG/go-sqlmock v1.5.0/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
 github.com/KimMachineGun/automemlimit v0.6.1 h1:ILa9j1onAAMadBsyyUJv5cack8Y1WT26yLj/V+ulKp8=
 github.com/KimMachineGun/automemlimit v0.6.1/go.mod h1:T7xYht7B8r6AG/AqFcUdc7fzd2bIdBKmepfP2S1svPY=
-github.com/cilium/ebpf v0.9.1 h1:64sn2K3UKw8NbP/blsixRpF3nXuyhz/VjRlRzvlBRu4=
-github.com/cilium/ebpf v0.9.1/go.mod h1:+OhNOIXx/Fnu1IE8bJz2dzOA+VSfyTfdNUVdlQnxUFY=
-github.com/containerd/cgroups/v3 v3.0.1 h1:4hfGvu8rfGIwVIDd+nLzn/B9ZXx4BcCjzt5ToenJRaE=
-github.com/containerd/cgroups/v3 v3.0.1/go.mod h1:/vtwk1VXrtoa5AaZLkypuOJgA/6DyPMZHJPGQNtlHnw=
-github.com/coreos/go-systemd/v22 v22.3.2 h1:D9/bQk5vlXQFZ6Kwuu6zaiXJ9oTPe68++AzAJc1DzSI=
-github.com/coreos/go-systemd/v22 v22.3.2/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/cilium/ebpf v0.16.0 h1:+BiEnHL6Z7lXnlGUsXQPPAE7+kenAd4ES8MQ5min0Ok=
+github.com/cilium/ebpf v0.16.0/go.mod h1:L7u2Blt2jMM/vLAVgjxluxtBKlz3/GWjB0dMOEngfwE=
+github.com/containerd/cgroups/v3 v3.0.4 h1:2fs7l3P0Qxb1nKWuJNFiwhp2CqiKzho71DQkDrHJIo4=
+github.com/containerd/cgroups/v3 v3.0.4/go.mod h1:SA5DLYnXO8pTGYiAHXz94qvLQTKfVM5GEVisn4jpins=
+github.com/containerd/log v0.1.0 h1:TCJt7ioM2cr/tfR8GPbGf9/VRAX8D2B4PjzCpfX540I=
+github.com/containerd/log v0.1.0/go.mod h1:VRRf09a7mHDIRezVKTRCrOq78v577GXq3bSa3EhrzVo=
+github.com/coreos/go-systemd/v22 v22.5.0 h1:RrqgGjYQKalulkV8NGVIfkXQf6YYmOyiJKk8iXXhfZs=
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/docker/go-units v0.4.0 h1:3uh0PgVws3nIA0Q+MwDC8yjEPf9zjRfZZWXZYDct3Tw=
-github.com/docker/go-units v0.4.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
-github.com/frankban/quicktest v1.14.0 h1:+cqqvzZV87b4adx/5ayVOaYZ2CrvM4ejQvUdBzPPUss=
-github.com/frankban/quicktest v1.14.0/go.mod h1:NeW+ay9A/U67EYXNFA1nPE8e/tnQv/09mUdL/ijj8og=
-github.com/godbus/dbus/v5 v5.0.4 h1:9349emZab16e7zQvpmsbtjc18ykshndd8y2PG3sgJbA=
+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/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4=
+github.com/docker/go-units v0.5.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
+github.com/go-quicktest/qt v1.101.0 h1:O1K29Txy5P2OK0dGo59b7b0LR6wKfIhttaAhHUyn7eI=
+github.com/go-quicktest/qt v1.101.0/go.mod h1:14Bz/f7NwaXPtdYEgzsx46kqSxVwTbzVZsDC26tQJow=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
-github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
-github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
-github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
-github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
-github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
-github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
-github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
+github.com/godbus/dbus/v5 v5.1.0 h1:4KLkAxT3aOY8Li4FRJe/KvhoNFFxo0m6fNuFUO8QJUk=
+github.com/godbus/dbus/v5 v5.1.0/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+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=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/josharian/native v1.1.0 h1:uuaP0hAbW7Y4l0ZRQ6C9zfb7Mg1mbFKry/xzDAfmtLA=
+github.com/josharian/native v1.1.0/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
+github.com/jsimonetti/rtnetlink/v2 v2.0.1 h1:xda7qaHDSVOsADNouv7ukSuicKZO7GgVUCXxpaIEIlM=
+github.com/jsimonetti/rtnetlink/v2 v2.0.1/go.mod h1:7MoNYNbb3UaDHtF8udiJo/RH6VsTKP1pqKLUTVCvToE=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
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 github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
 github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 h1:onHthvaw9LFnH4t2DcNVpwGmV9E1BkGknEliJkfwQj0=
 github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58/go.mod h1:DXv8WO4yhMYhSNPKjeNKa5WY9YCIEBRbNzFFPJbWO6Y=
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 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
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 github.com/prashantv/gostub v1.1.0 h1:BTyx3RfQjRHnUWaGF9oQos79AlQ5k8WNktv7VGvVH4g=
 github.com/prashantv/gostub v1.1.0/go.mod h1:A5zLQHz7ieHGG7is6LLXLz7I8+3LZzsrV0P1IAHhP5U=
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 github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5 h1:G/FZtUu7a6NTWl3KUHMV9jkLAh/Rvtf03NWMHaEDl+E=
 github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5/go.mod h1:7RTUFBdIRC9nZ7/3RyRNH1bdqIShrDejd1YbLwgPS+I=
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+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.uber.org/automaxprocs v1.6.0 h1:O3y2/QNTOdbF+e/dpXNNW7Rx2hZ4sTIPyybbxyNqTUs=
 go.uber.org/automaxprocs v1.6.0/go.mod h1:ifeIMSnPZuznNm6jmdzmU3/bfk01Fe2fotchwEFJ8r8=
-go.uber.org/goleak v1.1.12 h1:gZAh5/EyT/HQwlpkCy6wTpqfH9H8Lz8zbm3dZh+OyzA=
-go.uber.org/goleak v1.1.12/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.unistack.org/micro-proto/v3 v3.4.1 h1:UTjLSRz2YZuaHk9iSlVqqsA50JQNAEK2ZFboGqtEa9Q=
 go.unistack.org/micro-proto/v3 v3.4.1/go.mod h1:okx/cnOhzuCX0ggl/vToatbCupi0O44diiiLLsZ93Zo=
-golang.org/x/net v0.14.0 h1:BONx9s002vGdD9umnlX1Po8vOZmrgH34qlHcD1MfK14=
-golang.org/x/net v0.14.0/go.mod h1:PpSgVXXLK0OxS0F31C1/tv6XNguvCrnXIDrFMspZIUI=
-golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
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-golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=
-golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/text v0.12.0 h1:k+n5B8goJNdU7hSvEtMUz3d1Q6D/XW4COJSJR6fN0mc=
-golang.org/x/text v0.12.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20230526203410-71b5a4ffd15e h1:NumxXLPfHSndr3wBBdeKiVHjGVFzi9RX2HwwQke94iY=
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-google.golang.org/grpc v1.57.0 h1:kfzNeI/klCGD2YPMUlaGNT3pxvYfga7smW3Vth8Zsiw=
-google.golang.org/grpc v1.57.0/go.mod h1:Sd+9RMTACXwmub0zcNY2c4arhtrbBYD1AUHI/dt16Mo=
-google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
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+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

logger/context.go

@@ -4,17 +4,6 @@ import "context"
 
 type loggerKey struct{}
 
-// MustContext returns logger from passed context or DefaultLogger if empty
-func MustContext(ctx context.Context) Logger {
-	if ctx == nil {
-		return DefaultLogger
-	}
-	if l, ok := ctx.Value(loggerKey{}).(Logger); ok && l != nil {
-		return l
-	}
-	return DefaultLogger
-}
-
 // FromContext returns logger from passed context
 func FromContext(ctx context.Context) (Logger, bool) {
 	if ctx == nil {
@@ -24,6 +13,15 @@ func FromContext(ctx context.Context) (Logger, bool) {
 	return l, ok
 }
 
+// MustContext returns logger from passed context or DefaultLogger if empty
+func MustContext(ctx context.Context) Logger {
+	l, ok := FromContext(ctx)
+	if !ok {
+		panic("missing logger")
+	}
+	return l
+}
+
 // NewContext stores logger into passed context
 func NewContext(ctx context.Context, l Logger) context.Context {
 	if ctx == nil {

logger/logger.go

@@ -11,7 +11,7 @@ var DefaultContextAttrFuncs []ContextAttrFunc
 
 var (
 	// DefaultLogger variable
-	DefaultLogger Logger = NewLogger()
+	DefaultLogger = NewLogger()
 	// DefaultLevel used by logger
 	DefaultLevel = InfoLevel
 )

logger/options.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"log/slog"
 	"os"
+	"slices"
 	"time"
 
 	"go.unistack.org/micro/v3/meter"
@@ -15,18 +16,6 @@ type Option func(*Options)
 
 // Options holds logger options
 type Options struct {
-	// Out holds the output writer
-	Out io.Writer
-	// Context holds exernal options
-	Context context.Context
-	// Name holds the logger name
-	Name string
-	// Fields holds additional metadata
-	Fields []interface{}
-	// callerSkipCount number of frmaes to skip
-	CallerSkipCount int
-	// ContextAttrFuncs contains funcs that executed before log func on context
-	ContextAttrFuncs []ContextAttrFunc
 	// TimeKey is the key used for the time of the log call
 	TimeKey string
 	// LevelKey is the key used for the level of the log call
@@ -39,16 +28,33 @@ type Options struct {
 	SourceKey string
 	// StacktraceKey is the key used for the stacktrace
 	StacktraceKey string
-	// AddStacktrace controls writing of stacktaces on error
-	AddStacktrace bool
-	// AddSource enabled writing source file and position in log
-	AddSource bool
-	// The logging level the logger should log
-	Level Level
-	// TimeFunc used to obtain current time
-	TimeFunc func() time.Time
+	// Name holds the logger name
+	Name string
+
+	// Out holds the output writer
+	Out io.Writer
+	// Context holds exernal options
+	Context context.Context
 	// Meter used to count logs for specific level
 	Meter meter.Meter
+	// TimeFunc used to obtain current time
+	TimeFunc func() time.Time
+
+	// Fields holds additional metadata
+	Fields []interface{}
+	// ContextAttrFuncs contains funcs that executed before log func on context
+	ContextAttrFuncs []ContextAttrFunc
+
+	// callerSkipCount number of frmaes to skip
+	CallerSkipCount int
+	// The logging level the logger should log
+	Level Level
+	// AddSource enabled writing source file and position in log
+	AddSource bool
+	// AddStacktrace controls writing of stacktaces on error
+	AddStacktrace bool
+	// DedupKeys deduplicate keys in log output
+	DedupKeys bool
 }
 
 // NewOptions creates new options struct
@@ -80,6 +86,35 @@ func WithContextAttrFuncs(fncs ...ContextAttrFunc) Option {
 	}
 }
 
+// WithDedupKeys dont log duplicate keys
+func WithDedupKeys(b bool) Option {
+	return func(o *Options) {
+		o.DedupKeys = b
+	}
+}
+
+// WithAddFields add fields for the logger
+func WithAddFields(fields ...interface{}) Option {
+	return func(o *Options) {
+		if o.DedupKeys {
+			for i := 0; i < len(o.Fields); i += 2 {
+				for j := 0; j < len(fields); j += 2 {
+					iv, iok := o.Fields[i].(string)
+					jv, jok := fields[j].(string)
+					if iok && jok && iv == jv {
+						fields = slices.Delete(fields, j, j+2)
+					}
+				}
+			}
+			if len(fields) > 0 {
+				o.Fields = append(o.Fields, fields...)
+			}
+		} else {
+			o.Fields = append(o.Fields, fields...)
+		}
+	}
+}
+
 // WithFields set default fields for the logger
 func WithFields(fields ...interface{}) Option {
 	return func(o *Options) {
@@ -146,8 +181,8 @@ func WithTimeFunc(fn func() time.Time) Option {
 func WithZapKeys() Option {
 	return func(o *Options) {
 		o.TimeKey = "@timestamp"
-		o.LevelKey = "level"
-		o.MessageKey = "msg"
+		o.LevelKey = slog.LevelKey
+		o.MessageKey = slog.MessageKey
 		o.SourceKey = "caller"
 		o.StacktraceKey = "stacktrace"
 		o.ErrorKey = "error"
@@ -156,8 +191,8 @@ func WithZapKeys() Option {
 
 func WithZerologKeys() Option {
 	return func(o *Options) {
-		o.TimeKey = "time"
-		o.LevelKey = "level"
+		o.TimeKey = slog.TimeKey
+		o.LevelKey = slog.LevelKey
 		o.MessageKey = "message"
 		o.SourceKey = "caller"
 		o.StacktraceKey = "stacktrace"
@@ -179,8 +214,8 @@ func WithSlogKeys() Option {
 func WithMicroKeys() Option {
 	return func(o *Options) {
 		o.TimeKey = "timestamp"
-		o.LevelKey = "level"
-		o.MessageKey = "msg"
+		o.LevelKey = slog.LevelKey
+		o.MessageKey = slog.MessageKey
 		o.SourceKey = "caller"
 		o.StacktraceKey = "stacktrace"
 		o.ErrorKey = "error"

logger/slog/slog.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"log/slog"
 	"os"
+	"reflect"
 	"regexp"
 	"runtime"
 	"strconv"
@@ -46,11 +47,11 @@ func (h *wrapper) Handle(ctx context.Context, rec slog.Record) error {
 }
 
 func (h *wrapper) WithAttrs(attrs []slog.Attr) slog.Handler {
-	return h.WithAttrs(attrs)
+	return h.h.WithAttrs(attrs)
 }
 
 func (h *wrapper) WithGroup(name string) slog.Handler {
-	return h.WithGroup(name)
+	return h.h.WithGroup(name)
 }
 
 func (s *slogLogger) renameAttr(_ []string, a slog.Attr) slog.Attr {
@@ -89,7 +90,6 @@ func (s *slogLogger) renameAttr(_ []string, a slog.Attr) slog.Attr {
 }
 
 type slogLogger struct {
-	leveler *slog.LevelVar
 	handler *wrapper
 	opts    logger.Options
 	mu      sync.RWMutex
@@ -142,6 +142,7 @@ func (s *slogLogger) Fields(fields ...interface{}) logger.Logger {
 	s.mu.RUnlock()
 
 	l := &slogLogger{opts: options}
+	logger.WithAddFields(fields...)(&l.opts)
 
 	if len(options.ContextAttrFuncs) == 0 {
 		options.ContextAttrFuncs = logger.DefaultContextAttrFuncs
@@ -172,7 +173,29 @@ func (s *slogLogger) Init(opts ...logger.Option) error {
 	}
 
 	attrs, _ := s.argsAttrs(s.opts.Fields)
-	s.handler = &wrapper{h: slog.NewJSONHandler(s.opts.Out, handleOpt).WithAttrs(attrs)}
+
+	var h slog.Handler
+	if s.opts.Context != nil {
+		if v, ok := s.opts.Context.Value(handlerKey{}).(slog.Handler); ok && v != nil {
+			h = v
+		}
+
+		if fn := s.opts.Context.Value(handlerFnKey{}); fn != nil {
+			if rfn := reflect.ValueOf(fn); rfn.Kind() == reflect.Func {
+				if ret := rfn.Call([]reflect.Value{reflect.ValueOf(s.opts.Out), reflect.ValueOf(handleOpt)}); len(ret) == 1 {
+					if iface, ok := ret[0].Interface().(slog.Handler); ok && iface != nil {
+						h = iface
+					}
+				}
+			}
+		}
+	}
+
+	if h == nil {
+		h = slog.NewJSONHandler(s.opts.Out, handleOpt)
+	}
+
+	s.handler = &wrapper{h: h.WithAttrs(attrs)}
 	s.handler.level.Store(int64(loggerToSlogLevel(s.opts.Level)))
 	s.mu.Unlock()
 
@@ -318,7 +341,7 @@ func (s *slogLogger) argsAttrs(args []interface{}) ([]slog.Attr, error) {
 		case string:
 			if idx+1 < len(args) {
 				attrs = append(attrs, slog.Any(arg, args[idx+1]))
-				idx += 1
+				idx++
 			} else {
 				attrs = append(attrs, slog.String(badKey, arg))
 			}
@@ -330,3 +353,15 @@ func (s *slogLogger) argsAttrs(args []interface{}) ([]slog.Attr, error) {
 
 	return attrs, err
 }
+
+type handlerKey struct{}
+
+func WithHandler(h slog.Handler) logger.Option {
+	return logger.SetOption(handlerKey{}, h)
+}
+
+type handlerFnKey struct{}
+
+func WithHandlerFunc(fn any) logger.Option {
+	return logger.SetOption(handlerFnKey{}, fn)
+}

logger/slog/slog_test.go

@@ -6,15 +6,112 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"log/slog"
 	"strings"
 	"testing"
 
 	"github.com/google/uuid"
-	"go.unistack.org/micro/v3/metadata"
-
 	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/metadata"
 )
 
+func TestWithFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithDedupKeys(true),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	l = l.Fields("key1", "val2")
+
+	l.Info(ctx, "msg2")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`msg=msg2 key1=val1`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestWithDedupKeysWithAddFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+		logger.WithDedupKeys(true),
+	)
+	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	if err := l.Init(logger.WithAddFields("key2", "val2")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg2")
+
+	if err := l.Init(logger.WithAddFields("key2", "val3", "key1", "val4")); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg3")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`msg=msg3 key1=val1 key2=val2`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestWithHandlerFunc(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf),
+		WithHandlerFunc(slog.NewTextHandler),
+	)
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`msg=msg1`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestWithAddFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.InfoLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Info(ctx, "msg1")
+
+	if err := l.Init(logger.WithAddFields("key1", "val1")); err != nil {
+		t.Fatal(err)
+	}
+	l.Info(ctx, "msg2")
+
+	if err := l.Init(logger.WithAddFields("key2", "val2")); err != nil {
+		t.Fatal(err)
+	}
+	l.Info(ctx, "msg3")
+
+	if !bytes.Contains(buf.Bytes(), []byte(`"key1"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"key2"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
 func TestMultipleFieldsWithLevel(t *testing.T) {
 	ctx := context.TODO()
 	buf := bytes.NewBuffer(nil)
@@ -87,7 +184,7 @@ func TestErrorf(t *testing.T) {
 
 	buf := bytes.NewBuffer(nil)
 	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf), logger.WithAddStacktrace(true))
-	if err := l.Init(logger.WithContextAttrFuncs(func(ctx context.Context) []interface{} {
+	if err := l.Init(logger.WithContextAttrFuncs(func(_ context.Context) []interface{} {
 		return nil
 	})); err != nil {
 		t.Fatal(err)

logger/unwrap/unwrap.go

@@ -36,14 +36,14 @@ var (
 	circularShortBytes = []byte("<shown>")
 	invalidAngleBytes  = []byte("<invalid>")
 	filteredBytes      = []byte("<filtered>")
-	openBracketBytes   = []byte("[")
-	closeBracketBytes  = []byte("]")
-	percentBytes       = []byte("%")
-	precisionBytes     = []byte(".")
-	openAngleBytes     = []byte("<")
-	closeAngleBytes    = []byte(">")
-	openMapBytes       = []byte("{")
-	closeMapBytes      = []byte("}")
+	// openBracketBytes   = []byte("[")
+	// closeBracketBytes  = []byte("]")
+	percentBytes    = []byte("%")
+	precisionBytes  = []byte(".")
+	openAngleBytes  = []byte("<")
+	closeAngleBytes = []byte(">")
+	openMapBytes    = []byte("{")
+	closeMapBytes   = []byte("}")
 )
 
 type protoMessage interface {
@@ -52,13 +52,15 @@ type protoMessage interface {
 }
 
 type Wrapper struct {
-	val              interface{}
-	s                fmt.State
-	pointers         map[uintptr]int
-	opts             *Options
+	pointers map[uintptr]int
+	takeMap  map[int]bool
+
+	val  interface{}
+	s    fmt.State
+	opts *Options
+
 	depth            int
 	ignoreNextType   bool
-	takeMap          map[int]bool
 	protoWrapperType bool
 	sqlWrapperType   bool
 }

logger/unwrap/unwrap_test.go

@@ -82,12 +82,12 @@ func TestTagged(t *testing.T) {
 func TestTaggedNested(t *testing.T) {
 	type val struct {
 		key string `logger:"take"`
-		val string `logger:"omit"`
+		// val string `logger:"omit"`
 		unk string
 	}
 	type str struct {
-		key string `logger:"omit"`
-		val *val   `logger:"take"`
+		// key string `logger:"omit"`
+		val *val `logger:"take"`
 	}
 
 	var iface interface{}

metadata/context.go

@@ -24,6 +24,17 @@ func FromIncomingContext(ctx context.Context) (Metadata, bool) {
 	return md.md, ok
 }
 
+// MustIncomingContext returns metadata from incoming ctx
+// returned metadata shoud not be modified or race condition happens.
+// If metadata not exists panics.
+func MustIncomingContext(ctx context.Context) Metadata {
+	md, ok := FromIncomingContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
 // FromOutgoingContext returns metadata from outgoing ctx
 // returned metadata shoud not be modified or race condition happens
 func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
@@ -37,6 +48,17 @@ func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
 	return md.md, ok
 }
 
+// MustOutgoingContext returns metadata from outgoing ctx
+// returned metadata shoud not be modified or race condition happens.
+// If metadata not exists panics.
+func MustOutgoingContext(ctx context.Context) Metadata {
+	md, ok := FromOutgoingContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
 // FromContext returns metadata from the given context
 // returned metadata shoud not be modified or race condition happens
 func FromContext(ctx context.Context) (Metadata, bool) {
@@ -50,15 +72,22 @@ func FromContext(ctx context.Context) (Metadata, bool) {
 	return md.md, ok
 }
 
+// MustContext returns metadata from the given context
+// returned metadata shoud not be modified or race condition happens
+func MustContext(ctx context.Context) Metadata {
+	md, ok := FromContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
 // NewContext creates a new context with the given metadata
 func NewContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	ctx = context.WithValue(ctx, mdKey{}, &rawMetadata{md})
-	ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{})
-	ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{})
-	return ctx
+	return context.WithValue(ctx, mdKey{}, &rawMetadata{md})
 }
 
 // SetOutgoingContext modify outgoing context with given metadata
@@ -90,11 +119,7 @@ func NewIncomingContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{md})
-	if v, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata); !ok || v == nil {
-		ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{})
-	}
-	return ctx
+	return context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{md})
 }
 
 // NewOutgoingContext creates a new context with outcoming metadata attached
@@ -102,11 +127,7 @@ func NewOutgoingContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{md})
-	if v, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata); !ok || v == nil {
-		ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{})
-	}
-	return ctx
+	return context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{md})
 }
 
 // AppendOutgoingContext apends new md to context
@@ -122,7 +143,7 @@ func AppendOutgoingContext(ctx context.Context, kv ...string) context.Context {
 	for k, v := range md {
 		omd.Set(k, v)
 	}
-	return NewOutgoingContext(ctx, omd)
+	return ctx
 }
 
 // AppendIncomingContext apends new md to context
@@ -138,5 +159,21 @@ func AppendIncomingContext(ctx context.Context, kv ...string) context.Context {
 	for k, v := range md {
 		omd.Set(k, v)
 	}
-	return NewIncomingContext(ctx, omd)
+	return ctx
+}
+
+// AppendContext apends new md to context
+func AppendContext(ctx context.Context, kv ...string) context.Context {
+	md, ok := Pairs(kv...)
+	if !ok {
+		return ctx
+	}
+	omd, ok := FromContext(ctx)
+	if !ok {
+		return NewContext(ctx, md)
+	}
+	for k, v := range md {
+		omd.Set(k, v)
+	}
+	return ctx
 }

metadata/metadata.go

@@ -4,6 +4,7 @@ package metadata
 import (
 	"net/textproto"
 	"sort"
+	"strings"
 )
 
 var (
@@ -66,6 +67,14 @@ func (md Metadata) Iterator() *Iterator {
 	return iter
 }
 
+func (md Metadata) MustGet(key string) string {
+	val, ok := md.Get(key)
+	if !ok {
+		panic("missing metadata key")
+	}
+	return val
+}
+
 // Get returns value from metadata by key
 func (md Metadata) Get(key string) (string, bool) {
 	// fast path
@@ -73,6 +82,9 @@ func (md Metadata) Get(key string) (string, bool) {
 	if !ok {
 		// slow path
 		val, ok = md[textproto.CanonicalMIMEHeaderKey(key)]
+		if !ok {
+			val, ok = md[strings.ToLower(key)]
+		}
 	}
 	return val, ok
 }
@@ -94,14 +106,23 @@ func (md Metadata) Del(keys ...string) {
 		delete(md, key)
 		// slow path
 		delete(md, textproto.CanonicalMIMEHeaderKey(key))
+		// very slow path
+		delete(md, strings.ToLower(key))
+	}
+}
+
+// Copy makes a copy of the metadata
+func (md Metadata) CopyTo(dst Metadata) {
+	for k, v := range md {
+		dst[k] = v
 	}
 }
 
 // Copy makes a copy of the metadata
 func Copy(md Metadata, exclude ...string) Metadata {
 	nmd := New(len(md))
-	for key, val := range md {
-		nmd.Set(key, val)
+	for k, v := range md {
+		nmd[k] = v
 	}
 	nmd.Del(exclude...)
 	return nmd
@@ -125,7 +146,7 @@ func Merge(omd Metadata, mmd Metadata, overwrite bool) Metadata {
 		case ok && !overwrite:
 			continue
 		case val != "":
-			nmd.Set(key, val)
+			nmd[key] = val
 		case ok && val == "":
 			nmd.Del(key)
 		}
@@ -139,6 +160,8 @@ func Pairs(kv ...string) (Metadata, bool) {
 		return nil, false
 	}
 	md := New(len(kv) / 2)
-	md.Set(kv...)
+	for idx := 0; idx < len(kv); idx += 2 {
+		md[kv[idx]] = kv[idx+1]
+	}
 	return md, true
 }

metadata/metadata_test.go

@@ -5,6 +5,37 @@ import (
 	"testing"
 )
 
+func TestLowercase(t *testing.T) {
+	md := New(1)
+	md["x-request-id"] = "12345"
+	v, ok := md.Get("X-Request-Id")
+	if !ok || v == "" {
+		t.Fatalf("metadata invalid %#+v", md)
+	}
+}
+
+func TestMultipleUsage(t *testing.T) {
+	ctx := context.TODO()
+	md := New(0)
+	md.Set("key1_1", "val1_1", "key1_2", "val1_2", "key1_3", "val1_3")
+	ctx = NewIncomingContext(ctx, Copy(md))
+	ctx = NewOutgoingContext(ctx, Copy(md))
+	imd, _ := FromIncomingContext(ctx)
+	omd, _ := FromOutgoingContext(ctx)
+	_ = func(x context.Context) context.Context {
+		m, _ := FromIncomingContext(x)
+		m.Del("key1_2")
+		return ctx
+	}(ctx)
+	_ = func(x context.Context) context.Context {
+		m, _ := FromIncomingContext(x)
+		m.Del("key1_3")
+		return ctx
+	}(ctx)
+	_ = imd
+	_ = omd
+}
+
 func TestMetadataSetMultiple(t *testing.T) {
 	md := New(4)
 	md.Set("key1", "val1", "key2", "val2", "key3")
@@ -57,6 +88,13 @@ func TestPassing(t *testing.T) {
 
 	ctx = NewIncomingContext(ctx, md1)
 	testCtx(ctx)
+	_, ok := FromOutgoingContext(ctx)
+	if ok {
+		t.Fatalf("create outgoing context")
+	}
+
+	ctx = NewOutgoingContext(ctx, New(1))
+	testCtx(ctx)
 	md, ok := FromOutgoingContext(ctx)
 	if !ok {
 		t.Fatalf("missing metadata from outgoing context")
@@ -80,7 +118,7 @@ func TestMerge(t *testing.T) {
 	}
 }
 
-func TestIterator(t *testing.T) {
+func TestIterator(_ *testing.T) {
 	md := Metadata{
 		"1Last":   "last",
 		"2First":  "first",

meter/context.go

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

meter/meter.go

@@ -11,7 +11,7 @@ import (
 
 var (
 	// DefaultMeter is the default meter
-	DefaultMeter Meter = NewMeter()
+	DefaultMeter = NewMeter()
 	// DefaultAddress data will be made available on this host:port
 	DefaultAddress = ":9090"
 	// DefaultPath the meter endpoint where the Meter data will be made available

meter/noop.go

@@ -37,32 +37,32 @@ func (r *noopMeter) Init(opts ...Option) error {
 }
 
 // Counter implements the Meter interface
-func (r *noopMeter) Counter(name string, labels ...string) Counter {
+func (r *noopMeter) Counter(_ string, labels ...string) Counter {
 	return &noopCounter{labels: labels}
 }
 
 // FloatCounter implements the Meter interface
-func (r *noopMeter) FloatCounter(name string, labels ...string) FloatCounter {
+func (r *noopMeter) FloatCounter(_ string, labels ...string) FloatCounter {
 	return &noopFloatCounter{labels: labels}
 }
 
 // Gauge implements the Meter interface
-func (r *noopMeter) Gauge(name string, f func() float64, labels ...string) Gauge {
+func (r *noopMeter) Gauge(_ string, _ func() float64, labels ...string) Gauge {
 	return &noopGauge{labels: labels}
 }
 
 // Summary implements the Meter interface
-func (r *noopMeter) Summary(name string, labels ...string) Summary {
+func (r *noopMeter) Summary(_ string, labels ...string) Summary {
 	return &noopSummary{labels: labels}
 }
 
 // SummaryExt implements the Meter interface
-func (r *noopMeter) SummaryExt(name string, window time.Duration, quantiles []float64, labels ...string) Summary {
+func (r *noopMeter) SummaryExt(_ string, _ time.Duration, _ []float64, labels ...string) Summary {
 	return &noopSummary{labels: labels}
 }
 
 // Histogram implements the Meter interface
-func (r *noopMeter) Histogram(name string, labels ...string) Histogram {
+func (r *noopMeter) Histogram(_ string, labels ...string) Histogram {
 	return &noopHistogram{labels: labels}
 }
 
@@ -77,7 +77,7 @@ func (r *noopMeter) Set(opts ...Option) Meter {
 	return m
 }
 
-func (r *noopMeter) Write(w io.Writer, opts ...Option) error {
+func (r *noopMeter) Write(_ io.Writer, _ ...Option) error {
 	return nil
 }
 

micro.go

@@ -65,6 +65,8 @@ func As(b any, target any) bool {
 			break
 		case targetType.Implements(routerType):
 			break
+		case targetType.Implements(tracerType):
+			break
 		default:
 			return false
 		}
@@ -76,19 +78,21 @@ func As(b any, target any) bool {
 	return false
 }
 
-var brokerType = reflect.TypeOf((*broker.Broker)(nil)).Elem()
-var loggerType = reflect.TypeOf((*logger.Logger)(nil)).Elem()
-var clientType = reflect.TypeOf((*client.Client)(nil)).Elem()
-var serverType = reflect.TypeOf((*server.Server)(nil)).Elem()
-var codecType = reflect.TypeOf((*codec.Codec)(nil)).Elem()
-var flowType = reflect.TypeOf((*flow.Flow)(nil)).Elem()
-var fsmType = reflect.TypeOf((*fsm.FSM)(nil)).Elem()
-var meterType = reflect.TypeOf((*meter.Meter)(nil)).Elem()
-var registerType = reflect.TypeOf((*register.Register)(nil)).Elem()
-var resolverType = reflect.TypeOf((*resolver.Resolver)(nil)).Elem()
-var routerType = reflect.TypeOf((*router.Router)(nil)).Elem()
-var selectorType = reflect.TypeOf((*selector.Selector)(nil)).Elem()
-var storeType = reflect.TypeOf((*store.Store)(nil)).Elem()
-var syncType = reflect.TypeOf((*sync.Sync)(nil)).Elem()
-var tracerType = reflect.TypeOf((*tracer.Tracer)(nil)).Elem()
-var serviceType = reflect.TypeOf((*Service)(nil)).Elem()
+var (
+	brokerType   = reflect.TypeOf((*broker.Broker)(nil)).Elem()
+	loggerType   = reflect.TypeOf((*logger.Logger)(nil)).Elem()
+	clientType   = reflect.TypeOf((*client.Client)(nil)).Elem()
+	serverType   = reflect.TypeOf((*server.Server)(nil)).Elem()
+	codecType    = reflect.TypeOf((*codec.Codec)(nil)).Elem()
+	flowType     = reflect.TypeOf((*flow.Flow)(nil)).Elem()
+	fsmType      = reflect.TypeOf((*fsm.FSM)(nil)).Elem()
+	meterType    = reflect.TypeOf((*meter.Meter)(nil)).Elem()
+	registerType = reflect.TypeOf((*register.Register)(nil)).Elem()
+	resolverType = reflect.TypeOf((*resolver.Resolver)(nil)).Elem()
+	routerType   = reflect.TypeOf((*router.Router)(nil)).Elem()
+	selectorType = reflect.TypeOf((*selector.Selector)(nil)).Elem()
+	storeType    = reflect.TypeOf((*store.Store)(nil)).Elem()
+	syncType     = reflect.TypeOf((*sync.Sync)(nil)).Elem()
+	tracerType   = reflect.TypeOf((*tracer.Tracer)(nil)).Elem()
+	serviceType  = reflect.TypeOf((*Service)(nil)).Elem()
+)

micro_test.go

@@ -18,26 +18,27 @@ func TestAs(t *testing.T) {
 	testCases := []struct {
 		b      any
 		target any
-		match  bool
 		want   any
+
+		match bool
 	}{
 		{
-			broTarget,
-			&b,
-			true,
-			broTarget,
+			b:      broTarget,
+			target: &b,
+			match:  true,
+			want:   broTarget,
 		},
 		{
-			nil,
-			&b,
-			false,
-			nil,
+			b:      nil,
+			target: &b,
+			match:  false,
+			want:   nil,
 		},
 		{
-			fsmTarget,
-			&b,
-			false,
-			nil,
+			b:      fsmTarget,
+			target: &b,
+			match:  false,
+			want:   nil,
 		},
 	}
 	for i, tc := range testCases {
@@ -66,7 +67,13 @@ type bro struct {
 
 func (p *bro) Name() string { return p.name }
 
-func (p *bro) Init(opts ...broker.Option) error { return nil }
+func (p *bro) Live() bool { return true }
+
+func (p *bro) Ready() bool { return true }
+
+func (p *bro) Health() bool { return true }
+
+func (p *bro) Init(_ ...broker.Option) error { return nil }
 
 // Options returns broker options
 func (p *bro) Options() broker.Options { return broker.Options{} }
@@ -75,28 +82,28 @@ func (p *bro) Options() broker.Options { return broker.Options{} }
 func (p *bro) Address() string { return "" }
 
 // Connect connects to broker
-func (p *bro) Connect(ctx context.Context) error { return nil }
+func (p *bro) Connect(_ context.Context) error { return nil }
 
 // Disconnect disconnect from broker
-func (p *bro) Disconnect(ctx context.Context) error { return nil }
+func (p *bro) Disconnect(_ context.Context) error { return nil }
 
 // Publish message, msg can be single broker.Message or []broker.Message
-func (p *bro) Publish(ctx context.Context, topic string, msg *broker.Message, opts ...broker.PublishOption) error {
+func (p *bro) Publish(_ context.Context, _ string, _ *broker.Message, _ ...broker.PublishOption) error {
 	return nil
 }
 
 // BatchPublish messages to broker with multiple topics
-func (p *bro) BatchPublish(ctx context.Context, msgs []*broker.Message, opts ...broker.PublishOption) error {
+func (p *bro) BatchPublish(_ context.Context, _ []*broker.Message, _ ...broker.PublishOption) error {
 	return nil
 }
 
 // BatchSubscribe subscribes to topic messages via handler
-func (p *bro) BatchSubscribe(ctx context.Context, topic string, h broker.BatchHandler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+func (p *bro) BatchSubscribe(_ context.Context, _ string, _ broker.BatchHandler, _ ...broker.SubscribeOption) (broker.Subscriber, error) {
 	return nil, nil
 }
 
 // Subscribe subscribes to topic message via handler
-func (p *bro) Subscribe(ctx context.Context, topic string, handler broker.Handler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+func (p *bro) Subscribe(_ context.Context, _ string, _ broker.Handler, _ ...broker.SubscribeOption) (broker.Subscriber, error) {
 	return nil, nil
 }
 
@@ -107,9 +114,9 @@ type fsmT struct {
 	name string
 }
 
-func (f *fsmT) Start(ctx context.Context, a interface{}, o ...Option) (interface{}, error) {
+func (f *fsmT) Start(_ context.Context, _ interface{}, _ ...Option) (interface{}, error) {
 	return nil, nil
 }
-func (f *fsmT) Current() string                  { return f.name }
-func (f *fsmT) Reset()                           {}
-func (f *fsmT) State(s string, sf fsm.StateFunc) {}
+func (f *fsmT) Current() string                 { return f.name }
+func (f *fsmT) Reset()                          {}
+func (f *fsmT) State(_ string, _ fsm.StateFunc) {}

mtls/options.go

@@ -8,19 +8,20 @@ import (
 
 // CertificateOptions holds options for x509.CreateCertificate
 type CertificateOptions struct {
-	Organization          []string
-	OrganizationalUnit    []string
-	CommonName            string
-	OCSPServer            []string
-	IssuingCertificateURL []string
 	SerialNumber          *big.Int
 	NotAfter              time.Time
 	NotBefore             time.Time
-	SignatureAlgorithm    x509.SignatureAlgorithm
-	PublicKeyAlgorithm    x509.PublicKeyAlgorithm
+	CommonName            string
+	Organization          []string
+	OrganizationalUnit    []string
+	OCSPServer            []string
+	IssuingCertificateURL []string
 	ExtKeyUsage           []x509.ExtKeyUsage
-	KeyUsage              x509.KeyUsage
-	IsCA                  bool
+
+	SignatureAlgorithm x509.SignatureAlgorithm
+	PublicKeyAlgorithm x509.PublicKeyAlgorithm
+	KeyUsage           x509.KeyUsage
+	IsCA               bool
 }
 
 // CertificateOrganizationalUnit set OrganizationalUnit in certificate subject

network/transport/transport.go

@@ -10,7 +10,7 @@ import (
 
 var (
 	// DefaultTransport is the global default transport
-	DefaultTransport Transport = NewTransport()
+	DefaultTransport = NewTransport()
 	// DefaultDialTimeout the default dial timeout
 	DefaultDialTimeout = time.Second * 5
 )

network/tunnel/broker/broker.go

@@ -45,6 +45,18 @@ type (
 	tunnelAddr struct{}
 )
 
+func (t *tunBroker) Live() bool {
+	return true
+}
+
+func (t *tunBroker) Ready() bool {
+	return true
+}
+
+func (t *tunBroker) Health() bool {
+	return true
+}
+
 func (t *tunBroker) Init(opts ...broker.Option) error {
 	for _, o := range opts {
 		o(&t.opts)
@@ -72,7 +84,7 @@ func (t *tunBroker) Disconnect(ctx context.Context) error {
 	return t.tunnel.Close(ctx)
 }
 
-func (t *tunBroker) BatchPublish(ctx context.Context, msgs []*broker.Message, opts ...broker.PublishOption) error {
+func (t *tunBroker) BatchPublish(ctx context.Context, msgs []*broker.Message, _ ...broker.PublishOption) error {
 	// TODO: this is probably inefficient, we might want to just maintain an open connection
 	// it may be easier to add broadcast to the tunnel
 	topicMap := make(map[string]tunnel.Session)
@@ -102,7 +114,7 @@ func (t *tunBroker) BatchPublish(ctx context.Context, msgs []*broker.Message, op
 	return nil
 }
 
-func (t *tunBroker) Publish(ctx context.Context, topic string, m *broker.Message, opts ...broker.PublishOption) error {
+func (t *tunBroker) Publish(ctx context.Context, topic string, m *broker.Message, _ ...broker.PublishOption) error {
 	// TODO: this is probably inefficient, we might want to just maintain an open connection
 	// it may be easier to add broadcast to the tunnel
 	c, err := t.tunnel.Dial(ctx, topic, tunnel.DialMode(tunnel.Multicast))

options.go

@@ -269,7 +269,7 @@ func Logger(l logger.Logger, opts ...LoggerOption) Option {
 				}
 			}
 		}
-		
+
 		for _, trc := range o.Tracers {
 			for _, ot := range lopts.tracers {
 				if trc.Name() == ot || all {
@@ -294,8 +294,8 @@ type loggerOptions struct {
 	brokers   []string
 	registers []string
 	stores    []string
-	meters    []string
-	tracers   []string
+	// meters    []string
+	tracers []string
 }
 
 /*

profiler/noop.go

@@ -15,6 +15,6 @@ func (p *noopProfiler) String() string {
 }
 
 // NewProfiler returns new noop profiler
-func NewProfiler(opts ...Option) Profiler {
+func NewProfiler(_ ...Option) Profiler {
 	return &noopProfiler{}
 }

profiler/profile.go

@@ -12,7 +12,7 @@ type Profiler interface {
 }
 
 // DefaultProfiler holds the default profiler
-var DefaultProfiler Profiler = NewProfiler()
+var DefaultProfiler = NewProfiler()
 
 // Options holds the options for profiler
 type Options struct {

register/context.go

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

register/memory/memory.go

@@ -31,10 +31,10 @@ type record struct {
 }
 
 type memory struct {
-	sync.RWMutex
 	records  map[string]services
 	watchers map[string]*watcher
 	opts     register.Options
+	sync.RWMutex
 }
 
 // services is a KV map with service name as the key and a map of records as the value
@@ -100,11 +100,11 @@ func (m *memory) sendEvent(r *register.Result) {
 	}
 }
 
-func (m *memory) Connect(ctx context.Context) error {
+func (m *memory) Connect(_ context.Context) error {
 	return nil
 }
 
-func (m *memory) Disconnect(ctx context.Context) error {
+func (m *memory) Disconnect(_ context.Context) error {
 	return nil
 }
 
@@ -124,7 +124,7 @@ func (m *memory) Options() register.Options {
 	return m.opts
 }
 
-func (m *memory) Register(ctx context.Context, s *register.Service, opts ...register.RegisterOption) error {
+func (m *memory) Register(_ context.Context, s *register.Service, opts ...register.RegisterOption) error {
 	m.Lock()
 	defer m.Unlock()
 
@@ -469,9 +469,7 @@ func serviceToRecord(s *register.Service, ttl time.Duration) *record {
 	}
 
 	endpoints := make([]*register.Endpoint, len(s.Endpoints))
-	for i, e := range s.Endpoints {
-		endpoints[i] = e
-	}
+	copy(endpoints, s.Endpoints)
 
 	return &record{
 		Name:      s.Name,

register/memory/memory_test.go

@@ -208,9 +208,9 @@ func TestMemoryRegistryTTLConcurrent(t *testing.T) {
 		}
 	}
 
-	//if len(os.Getenv("IN_TRAVIS_CI")) == 0 {
+	// if len(os.Getenv("IN_TRAVIS_CI")) == 0 {
 	//	t.Logf("test will wait %v, then check TTL timeouts", waitTime)
-	//}
+	// }
 
 	errChan := make(chan error, concurrency)
 	syncChan := make(chan struct{})
@@ -290,27 +290,29 @@ func TestWatcher(t *testing.T) {
 
 	ctx := context.TODO()
 	m := NewRegister()
-	m.Init()
-	m.Connect(ctx)
+	if err := m.Init(); err != nil {
+		t.Fatal(err)
+	}
+	if err := m.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
 	wc, err := m.Watch(ctx)
 	if err != nil {
 		t.Fatalf("cant watch: %v", err)
 	}
 	defer wc.Stop()
 
+	cherr := make(chan error, 10)
 	var wg sync.WaitGroup
 	wg.Add(1)
 	go func() {
-		for {
-			_, err := wc.Next()
-			if err != nil {
-				t.Fatal("unexpected err", err)
-			}
-			// t.Logf("changes %#+v", ch.Service)
-			wc.Stop()
-			wg.Done()
-			return
+		_, err := wc.Next()
+		if err != nil {
+			cherr <- fmt.Errorf("unexpected err %v", err)
 		}
+		// t.Logf("changes %#+v", ch.Service)
+		wc.Stop()
+		wg.Done()
 	}()
 
 	if err := m.Register(ctx, testSrv); err != nil {

register/register.go

@@ -18,7 +18,7 @@ var DefaultDomain = "micro"
 
 var (
 	// DefaultRegister is the global default register
-	DefaultRegister Register = NewRegister()
+	DefaultRegister = NewRegister()
 	// ErrNotFound returned when LookupService is called and no services found
 	ErrNotFound = errors.New("service not found")
 	// ErrWatcherStopped returned when when watcher is stopped
@@ -29,17 +29,32 @@ var (
 // and an abstraction over varying implementations
 // {consul, etcd, zookeeper, ...}
 type Register interface {
+	// Name returns register name
 	Name() string
+	// Init initialize register
 	Init(...Option) error
+	// Options returns options for register
 	Options() Options
+	// Connect initialize connect to register
 	Connect(context.Context) error
+	// Disconnect initialize discconection from register
 	Disconnect(context.Context) error
+	// Register service in registry
 	Register(context.Context, *Service, ...RegisterOption) error
+	// Deregister service from registry
 	Deregister(context.Context, *Service, ...DeregisterOption) error
+	// LookupService in registry
 	LookupService(context.Context, string, ...LookupOption) ([]*Service, error)
+	// ListServices in registry
 	ListServices(context.Context, ...ListOption) ([]*Service, error)
+	// Watch registry events
 	Watch(context.Context, ...WatchOption) (Watcher, error)
+	// String returns registry string representation
 	String() string
+	// Live returns register liveness
+	// Live() bool
+	// Ready returns register readiness
+	// Ready() bool
 }
 
 // Service holds service register info

resolver/dns/dns.go

@@ -12,9 +12,9 @@ import (
 
 // Resolver is a DNS network resolve
 type Resolver struct {
-	sync.RWMutex
 	goresolver *net.Resolver
 	Address    string
+	mu         sync.RWMutex
 }
 
 // Resolve tries to resolve endpoint address
@@ -39,12 +39,12 @@ func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
 		return []*resolver.Record{rec}, nil
 	}
 
-	r.RLock()
+	r.mu.RLock()
 	goresolver := r.goresolver
-	r.RUnlock()
+	r.mu.RUnlock()
 
 	if goresolver == nil {
-		r.Lock()
+		r.mu.Lock()
 		r.goresolver = &net.Resolver{
 			Dial: func(ctx context.Context, _ string, _ string) (net.Conn, error) {
 				d := net.Dialer{
@@ -53,7 +53,7 @@ func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
 				return d.DialContext(ctx, "udp", r.Address)
 			},
 		}
-		r.Unlock()
+		r.mu.Unlock()
 	}
 
 	addrs, err := goresolver.LookupIP(context.TODO(), "ip", host)

resolver/noop/noop.go

@@ -9,6 +9,6 @@ import (
 type Resolver struct{}
 
 // Resolve returns the list of nodes
-func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
+func (r *Resolver) Resolve(_ string) ([]*resolver.Record, error) {
 	return []*resolver.Record{}, nil
 }

router/context.go

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

router/router.go

@@ -7,7 +7,7 @@ import (
 
 var (
 	// DefaultRouter is the global default router
-	DefaultRouter Router = NewRouter()
+	DefaultRouter = NewRouter()
 	// DefaultNetwork is default micro network
 	DefaultNetwork = "micro"
 	// ErrRouteNotFound is returned when no route was found in the routing table

selector/random/random.go

@@ -25,7 +25,7 @@ func (r *random) Select(routes []string, opts ...selector.SelectOption) (selecto
 	}, nil
 }
 
-func (r *random) Record(addr string, err error) error {
+func (r *random) Record(_ string, _ error) error {
 	return nil
 }
 

selector/roundrobin/roundrobin.go

@@ -6,14 +6,14 @@ import (
 )
 
 // NewSelector returns an initialised round robin selector
-func NewSelector(opts ...selector.Option) selector.Selector {
+func NewSelector(_ ...selector.Option) selector.Selector {
 	return new(roundrobin)
 }
 
 type roundrobin struct{}
 
 // Select return routes based on algo
-func (r *roundrobin) Select(routes []string, opts ...selector.SelectOption) (selector.Next, error) {
+func (r *roundrobin) Select(routes []string, _ ...selector.SelectOption) (selector.Next, error) {
 	if len(routes) == 0 {
 		return nil, selector.ErrNoneAvailable
 	}
@@ -28,7 +28,7 @@ func (r *roundrobin) Select(routes []string, opts ...selector.SelectOption) (sel
 	}, nil
 }
 
-func (r *roundrobin) Record(addr string, err error) error { return nil }
+func (r *roundrobin) Record(_ string, _ error) error { return nil }
 
 func (r *roundrobin) Reset() error { return nil }
 

semconv/cache.go

@@ -0,0 +1,14 @@
+package semconv
+
+var (
+	// CacheRequestDurationSeconds specifies meter metric name
+	CacheRequestDurationSeconds = "micro_cache_request_duration_seconds"
+	// CacheRequestLatencyMicroseconds specifies meter metric name
+	CacheRequestLatencyMicroseconds = "micro_cache_request_latency_microseconds"
+	// CacheRequestTotal specifies meter metric name
+	CacheRequestTotal = "micro_cache_request_total"
+	// CacheRequestInflight specifies meter metric name
+	CacheRequestInflight = "micro_cache_request_inflight"
+	// CacheItemsTotal specifies total cache items
+	CacheItemsTotal = "micro_cache_items_total"
+)

semconv/metadata.go

@@ -0,0 +1,18 @@
+package semconv
+
+var (
+	// HeaderTopic is the header name that contains topic name
+	HeaderTopic = "Micro-Topic"
+	// HeaderContentType specifies content type of message
+	HeaderContentType = "Content-Type"
+	// HeaderEndpoint specifies endpoint in service
+	HeaderEndpoint = "Micro-Endpoint"
+	// HeaderService specifies service
+	HeaderService = "Micro-Service"
+	// HeaderTimeout specifies timeout of operation
+	HeaderTimeout = "Micro-Timeout"
+	// HeaderAuthorization specifies Authorization header
+	HeaderAuthorization = "Authorization"
+	// HeaderXRequestID specifies request id
+	HeaderXRequestID = "X-Request-Id"
+)

semconv/store.go

@@ -3,7 +3,7 @@ package semconv
 var (
 	// StoreRequestDurationSeconds specifies meter metric name
 	StoreRequestDurationSeconds = "micro_store_request_duration_seconds"
-	// ClientRequestLatencyMicroseconds specifies meter metric name
+	// StoreRequestLatencyMicroseconds specifies meter metric name
 	StoreRequestLatencyMicroseconds = "micro_store_request_latency_microseconds"
 	// StoreRequestTotal specifies meter metric name
 	StoreRequestTotal = "micro_store_request_total"

server/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Server, bool) {
 	return c, ok
 }
 
+// MustContext returns Server from context
+func MustContext(ctx context.Context) Server {
+	s, ok := FromContext(ctx)
+	if !ok {
+		panic("missing server")
+	}
+	return s
+}
+
 // NewContext stores Server to context
 func NewContext(ctx context.Context, s Server) context.Context {
 	if ctx == nil {

server/noop.go

@@ -121,6 +121,18 @@ func (n *noopServer) newCodec(contentType string) (codec.Codec, error) {
 	return nil, codec.ErrUnknownContentType
 }
 
+func (n *noopServer) Live() bool {
+	return true
+}
+
+func (n *noopServer) Ready() bool {
+	return true
+}
+
+func (n *noopServer) Health() bool {
+	return true
+}
+
 func (n *noopServer) Handle(handler Handler) error {
 	n.h = handler
 	return nil
@@ -159,7 +171,6 @@ type rpcMessage struct {
 	header      metadata.Metadata
 	topic       string
 	contentType string
-	body        []byte
 }
 
 func (r *rpcMessage) ContentType() string {
@@ -712,7 +723,7 @@ func (n *noopServer) createSubHandler(sb *subscriber, opts Options) broker.Handl
 				return nil
 			}
 
-			opts.Hooks.EachNext(func(hook options.Hook) {
+			opts.Hooks.EachPrev(func(hook options.Hook) {
 				if h, ok := hook.(HookSubHandler); ok {
 					fn = h(fn)
 				}
@@ -764,13 +775,16 @@ func (s *subscriber) Options() SubscriberOptions {
 }
 
 type subscriber struct {
+	topic string
+
 	typ        reflect.Type
 	subscriber interface{}
-	topic      string
-	endpoints  []*register.Endpoint
-	handlers   []*handler
-	opts       SubscriberOptions
-	rcvr       reflect.Value
+
+	endpoints []*register.Endpoint
+	handlers  []*handler
+
+	rcvr reflect.Value
+	opts SubscriberOptions
 }
 
 type handler struct {

server/noop_test.go

@@ -9,6 +9,7 @@ import (
 	"go.unistack.org/micro/v3/client"
 	"go.unistack.org/micro/v3/codec"
 	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/options"
 	"go.unistack.org/micro/v3/server"
 )
 
@@ -38,7 +39,9 @@ func TestNoopSub(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	logger.DefaultLogger.Init(logger.WithLevel(logger.ErrorLevel))
+	if err := logger.DefaultLogger.Init(logger.WithLevel(logger.ErrorLevel)); err != nil {
+		t.Fatal(err)
+	}
 	s := server.NewServer(
 		server.Broker(b),
 		server.Codec("application/octet-stream", codec.NewCodec()),
@@ -82,3 +85,40 @@ func TestNoopSub(t *testing.T) {
 		}
 	}()
 }
+
+func TestHooks_Wrap(t *testing.T) {
+	n := 5
+	fn1 := func(next server.FuncSubHandler) server.FuncSubHandler {
+		return func(ctx context.Context, msg server.Message) (err error) {
+			n *= 2
+			return next(ctx, msg)
+		}
+	}
+	fn2 := func(next server.FuncSubHandler) server.FuncSubHandler {
+		return func(ctx context.Context, msg server.Message) (err error) {
+			n -= 10
+			return next(ctx, msg)
+		}
+	}
+
+	hs := &options.Hooks{}
+	hs.Append(server.HookSubHandler(fn1), server.HookSubHandler(fn2))
+
+	var fn = func(ctx context.Context, msg server.Message) error {
+		return nil
+	}
+
+	hs.EachPrev(func(hook options.Hook) {
+		if h, ok := hook.(server.HookSubHandler); ok {
+			fn = h(fn)
+		}
+	})
+
+	if err := fn(nil, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if n != 0 {
+		t.Fatalf("uncorrected hooks call")
+	}
+}

server/options.go

@@ -12,7 +12,6 @@ import (
 	"go.unistack.org/micro/v3/logger"
 	"go.unistack.org/micro/v3/metadata"
 	"go.unistack.org/micro/v3/meter"
-	"go.unistack.org/micro/v3/network/transport"
 	"go.unistack.org/micro/v3/options"
 	"go.unistack.org/micro/v3/register"
 	msync "go.unistack.org/micro/v3/sync"
@@ -25,38 +24,11 @@ type Option func(*Options)
 
 // Options server struct
 type Options struct {
-	// Context holds the external options and can be used for server shutdown
-	Context context.Context
-	// Broker holds the server broker
-	Broker broker.Broker
-	// Register holds the register
-	Register register.Register
-	// Tracer holds the tracer
-	Tracer tracer.Tracer
-	// Logger holds the logger
-	Logger logger.Logger
-	// Meter holds the meter
-	Meter meter.Meter
-	// Transport holds the transport
-	Transport transport.Transport
-
-	/*
-		// Router for requests
-		Router Router
-	*/
-
-	// Listener may be passed if already created
-	Listener net.Listener
-	// Wait group
-	Wait *msync.WaitGroup
-	// TLSConfig specifies tls.Config for secure serving
-	TLSConfig *tls.Config
-	// Metadata holds the server metadata
-	Metadata metadata.Metadata
-	// RegisterCheck run before register server
-	RegisterCheck func(context.Context) error
 	// Codecs map to handle content-type
 	Codecs map[string]codec.Codec
+	// Metadata holds the server metadata
+	Metadata metadata.Metadata
+
 	// ID holds the id of the server
 	ID string
 	// Namespace for te server
@@ -69,21 +41,46 @@ type Options struct {
 	Advertise string
 	// Version holds the server version
 	Version string
-	// RegisterAttempts holds the number of register attempts before error
-	RegisterAttempts int
+
+	// Context holds the external options and can be used for server shutdown
+	Context context.Context
+	// Broker holds the server broker
+	Broker broker.Broker
+	// Register holds the register
+	Register register.Register
+	// Tracer holds the tracer
+	Tracer tracer.Tracer
+	// Logger holds the logger
+	Logger logger.Logger
+	// Meter holds the meter
+	Meter meter.Meter
+	// Listener may be passed if already created
+	Listener net.Listener
+
+	// TLSConfig specifies tls.Config for secure serving
+	TLSConfig *tls.Config
+	// Wait group
+	Wait *msync.WaitGroup
+
+	// RegisterCheck run before register server
+	RegisterCheck func(context.Context) error
+
+	// Hooks may contains hook actions that performs before/after server handler
+	// or server subscriber handler
+	Hooks options.Hooks
+
 	// RegisterInterval holds he interval for re-register
 	RegisterInterval time.Duration
 	// RegisterTTL specifies TTL for register record
 	RegisterTTL time.Duration
+	// GracefulTimeout timeout for graceful stop server
+	GracefulTimeout time.Duration
 	// MaxConn limits number of connections
 	MaxConn int
 	// DeregisterAttempts holds the number of deregister attempts before error
 	DeregisterAttempts int
-	// Hooks may contains hook actions that performs before/after server handler
-	// or server subscriber handler
-	Hooks options.Hooks
-	// GracefulTimeout timeout for graceful stop server
-	GracefulTimeout time.Duration
+	// RegisterAttempts holds the number of register attempts before error
+	RegisterAttempts int
 }
 
 // NewOptions returns new options struct with default or passed values
@@ -100,7 +97,6 @@ func NewOptions(opts ...Option) Options {
 		Tracer:           tracer.DefaultTracer,
 		Broker:           broker.DefaultBroker,
 		Register:         register.DefaultRegister,
-		Transport:        transport.DefaultTransport,
 		Address:          DefaultAddress,
 		Name:             DefaultName,
 		Version:          DefaultVersion,
@@ -209,13 +205,6 @@ func Tracer(t tracer.Tracer) Option {
 	}
 }
 
-// Transport mechanism for communication e.g http, rabbitmq, etc
-func Transport(t transport.Transport) Option {
-	return func(o *Options) {
-		o.Transport = t
-	}
-}
-
 // Metadata associated with the server
 func Metadata(md metadata.Metadata) Option {
 	return func(o *Options) {
@@ -249,14 +238,6 @@ func TLSConfig(t *tls.Config) Option {
 	return func(o *Options) {
 		// set the internal tls
 		o.TLSConfig = t
-
-		// set the default transport if one is not
-		// already set. Required for Init call below.
-
-		// set the transport tls
-		_ = o.Transport.Init(
-			transport.TLSConfig(t),
-		)
 	}
 }
 
@@ -337,14 +318,14 @@ type SubscriberOptions struct {
 	Context context.Context
 	// Queue holds the subscription queue
 	Queue string
+	// BatchWait flag specifies max wait time for batch filling
+	BatchWait time.Duration
+	// BatchSize flag specifies max size of batch
+	BatchSize int
 	// AutoAck flag for auto ack messages after processing
 	AutoAck bool
 	// BodyOnly flag specifies that message without headers
 	BodyOnly bool
-	// BatchSize flag specifies max size of batch
-	BatchSize int
-	// BatchWait flag specifies max wait time for batch filling
-	BatchWait time.Duration
 }
 
 // NewSubscriberOptions create new SubscriberOptions

server/server.go

@@ -12,7 +12,7 @@ import (
 
 // DefaultServer default server
 var (
-	DefaultServer Server = NewServer()
+	DefaultServer = NewServer()
 )
 
 var (
@@ -62,6 +62,12 @@ type Server interface {
 	Stop() error
 	// Server implementation
 	String() string
+	// Live returns server liveness
+	Live() bool
+	// Ready returns server readiness
+	Ready() bool
+	// Health returns server health
+	Health() bool
 }
 
 type (

service.go

@@ -1,9 +1,11 @@
 // Package micro is a pluggable framework for microservices
-package micro // import "go.unistack.org/micro/v3"
+package micro
 
 import (
 	"fmt"
+	"net"
 	"sync"
+	"time"
 
 	"github.com/KimMachineGun/automemlimit/memlimit"
 	"go.uber.org/automaxprocs/maxprocs"
@@ -17,11 +19,12 @@ import (
 	"go.unistack.org/micro/v3/server"
 	"go.unistack.org/micro/v3/store"
 	"go.unistack.org/micro/v3/tracer"
+	utildns "go.unistack.org/micro/v3/util/dns"
 )
 
 func init() {
-	maxprocs.Set()
-	memlimit.SetGoMemLimitWithOpts(
+	_, _ = maxprocs.Set()
+	_, _ = memlimit.SetGoMemLimitWithOpts(
 		memlimit.WithRatio(0.9),
 		memlimit.WithProvider(
 			memlimit.ApplyFallback(
@@ -30,6 +33,11 @@ func init() {
 			),
 		),
 	)
+
+	net.DefaultResolver = utildns.NewNetResolver(
+		utildns.Timeout(1*time.Second),
+		utildns.MinCacheTTL(5*time.Second),
+	)
 }
 
 // Service is an interface that wraps the lower level components.
@@ -72,8 +80,14 @@ type Service interface {
 	Start() error
 	// Stop the service
 	Stop() error
-	// The service implementation
+	// String service representation
 	String() string
+	// Live returns service liveness
+	Live() bool
+	// Ready returns service readiness
+	Ready() bool
+	// Health returns service health
+	Health() bool
 }
 
 // RegisterHandler is syntactic sugar for registering a handler
@@ -101,9 +115,7 @@ func (s *service) Name() string {
 	return s.opts.Name
 }
 
-// Init initialises options. Additionally it calls cmd.Init
-// which parses command line flags. cmd.Init is only called
-// on first Init.
+// Init initialises options.
 //
 //nolint:gocyclo
 func (s *service) Init(opts ...Option) error {
@@ -252,6 +264,63 @@ func (s *service) String() string {
 	return s.opts.Name
 }
 
+func (s *service) Live() bool {
+	for _, v := range s.opts.Brokers {
+		if !v.Live() {
+			return false
+		}
+	}
+	for _, v := range s.opts.Servers {
+		if !v.Live() {
+			return false
+		}
+	}
+	for _, v := range s.opts.Stores {
+		if !v.Live() {
+			return false
+		}
+	}
+	return true
+}
+
+func (s *service) Ready() bool {
+	for _, v := range s.opts.Brokers {
+		if !v.Ready() {
+			return false
+		}
+	}
+	for _, v := range s.opts.Servers {
+		if !v.Ready() {
+			return false
+		}
+	}
+	for _, v := range s.opts.Stores {
+		if !v.Ready() {
+			return false
+		}
+	}
+	return true
+}
+
+func (s *service) Health() bool {
+	for _, v := range s.opts.Brokers {
+		if !v.Health() {
+			return false
+		}
+	}
+	for _, v := range s.opts.Servers {
+		if !v.Health() {
+			return false
+		}
+	}
+	for _, v := range s.opts.Stores {
+		if !v.Health() {
+			return false
+		}
+	}
+	return true
+}
+
 //nolint:gocyclo
 func (s *service) Start() error {
 	var err error
@@ -281,10 +350,6 @@ func (s *service) Start() error {
 		config.Loggers[0].Info(s.opts.Context, fmt.Sprintf("starting [service] %s version %s", s.Options().Name, s.Options().Version))
 	}
 
-	if len(s.opts.Servers) == 0 {
-		return fmt.Errorf("cant start nil server")
-	}
-
 	for _, reg := range s.opts.Registers {
 		if err = reg.Connect(s.opts.Context); err != nil {
 			return err

service_test.go

@@ -121,8 +121,10 @@ func TestNewService(t *testing.T) {
 	}
 	tests := []struct {
 		name string
-		args args
+
 		want Service
+
+		args args
 	}{
 		{
 			name: "NewService",
@@ -146,9 +148,10 @@ func Test_service_Name(t *testing.T) {
 		opts Options
 	}
 	tests := []struct {
-		name   string
+		name string
+		want string
+
 		fields fields
-		want   string
 	}{
 		{
 			name: "Test_service_Name",
@@ -245,10 +248,12 @@ func Test_service_Broker(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want broker.Broker
+
 		fields fields
 		args   args
-		want   broker.Broker
 	}{
 		{
 			name: "service.Broker",
@@ -301,10 +306,12 @@ func Test_service_Tracer(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want tracer.Tracer
+
 		fields fields
 		args   args
-		want   tracer.Tracer
 	}{
 		{
 			name: "service.Tracer",
@@ -338,10 +345,11 @@ func Test_service_Config(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+		want config.Config
+
 		fields fields
 		args   args
-		want   config.Config
 	}{
 		{
 			name: "service.Config",
@@ -375,10 +383,12 @@ func Test_service_Client(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want client.Client
+
 		fields fields
 		args   args
-		want   client.Client
 	}{
 		{
 			name: "service.Client",
@@ -412,10 +422,12 @@ func Test_service_Server(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want server.Server
+
 		fields fields
 		args   args
-		want   server.Server
 	}{
 		{
 			name: "service.Server",
@@ -449,10 +461,12 @@ func Test_service_Store(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want store.Store
+
 		fields fields
 		args   args
-		want   store.Store
 	}{
 		{
 			name: "service.Store",
@@ -486,10 +500,12 @@ func Test_service_Register(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want register.Register
+
 		fields fields
 		args   args
-		want   register.Register
 	}{
 		{
 			name: "service.Register",
@@ -523,10 +539,12 @@ func Test_service_Logger(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want logger.Logger
+
 		fields fields
 		args   args
-		want   logger.Logger
 	}{
 		{
 			name: "service.Logger",
@@ -560,10 +578,12 @@ func Test_service_Router(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want router.Router
+
 		fields fields
 		args   args
-		want   router.Router
 	}{
 		{
 			name: "service.Router",
@@ -597,10 +617,12 @@ func Test_service_Meter(t *testing.T) {
 		names []string
 	}
 	tests := []struct {
-		name   string
+		name string
+
+		want meter.Meter
+
 		fields fields
 		args   args
-		want   meter.Meter
 	}{
 		{
 			name: "service.Meter",
@@ -631,8 +653,8 @@ func Test_service_String(t *testing.T) {
 	}
 	tests := []struct {
 		name   string
-		fields fields
 		want   string
+		fields fields
 	}{
 		{
 			name: "service.String",

store/context.go

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

store/memory/memory.go

@@ -96,15 +96,15 @@ func (m *memoryStore) list(prefix string, limit, offset uint) []string {
 	if limit != 0 || offset != 0 {
 		sort.Slice(allKeys, func(i, j int) bool { return allKeys[i] < allKeys[j] })
 		sort.Slice(allKeys, func(i, j int) bool { return allKeys[i] < allKeys[j] })
-		end := len(allKeys)
+		end := uint(len(allKeys))
 		if limit > 0 {
-			calcLimit := int(offset + limit)
+			calcLimit := offset + limit
 			if calcLimit < end {
 				end = calcLimit
 			}
 		}
 
-		if int(offset) >= end {
+		if offset >= end {
 			return nil
 		}
 		return allKeys[offset:end]
@@ -123,7 +123,7 @@ func (m *memoryStore) Init(opts ...store.Option) error {
 	m.funcList = m.fnList
 	m.funcDelete = m.fnDelete
 
-	m.opts.Hooks.EachNext(func(hook options.Hook) {
+	m.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case store.HookRead:
 			m.funcRead = h(m.funcRead)
@@ -149,6 +149,18 @@ func (m *memoryStore) Name() string {
 	return m.opts.Name
 }
 
+func (m *memoryStore) Live() bool {
+	return true
+}
+
+func (m *memoryStore) Ready() bool {
+	return true
+}
+
+func (m *memoryStore) Health() bool {
+	return true
+}
+
 func (m *memoryStore) Exists(ctx context.Context, key string, opts ...store.ExistsOption) error {
 	if m.opts.LazyConnect {
 		if err := m.connect(ctx); err != nil {
@@ -279,3 +291,16 @@ func (m *memoryStore) connect(ctx context.Context) error {
 	m.isConnected.CompareAndSwap(0, 1)
 	return nil
 }
+
+func (m *memoryStore) Watch(ctx context.Context, opts ...store.WatchOption) (store.Watcher, error) {
+	return &watcher{}, nil
+}
+
+type watcher struct{}
+
+func (w *watcher) Next() (store.Event, error) {
+	return nil, nil
+}
+
+func (w *watcher) Stop() {
+}

store/noop.go

@@ -2,24 +2,43 @@ package store
 
 import (
 	"context"
+	"sync"
 	"sync/atomic"
 
 	"go.unistack.org/micro/v3/options"
+	"go.unistack.org/micro/v3/util/id"
 )
 
 var _ Store = (*noopStore)(nil)
 
 type noopStore struct {
-	funcRead    FuncRead
-	funcWrite   FuncWrite
-	funcExists  FuncExists
-	funcList    FuncList
-	funcDelete  FuncDelete
+	watchers map[string]Watcher
+
+	funcRead   FuncRead
+	funcWrite  FuncWrite
+	funcExists FuncExists
+	funcList   FuncList
+	funcDelete FuncDelete
+
 	opts        Options
 	isConnected atomic.Int32
+
+	mu sync.Mutex
 }
 
-func NewStore(opts ...Option) *noopStore {
+func (n *noopStore) Live() bool {
+	return true
+}
+
+func (n *noopStore) Ready() bool {
+	return true
+}
+
+func (n *noopStore) Health() bool {
+	return true
+}
+
+func NewStore(opts ...Option) Store {
 	options := NewOptions(opts...)
 	return &noopStore{opts: options}
 }
@@ -35,7 +54,7 @@ func (n *noopStore) Init(opts ...Option) error {
 	n.funcList = n.fnList
 	n.funcDelete = n.fnDelete
 
-	n.opts.Hooks.EachNext(func(hook options.Hook) {
+	n.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case HookRead:
 			n.funcRead = h(n.funcRead)
@@ -78,7 +97,7 @@ func (n *noopStore) Read(ctx context.Context, key string, val interface{}, opts
 	return n.funcRead(ctx, key, val, opts...)
 }
 
-func (n *noopStore) fnRead(ctx context.Context, key string, val interface{}, opts ...ReadOption) error {
+func (n *noopStore) fnRead(ctx context.Context, _ string, _ interface{}, _ ...ReadOption) error {
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
@@ -96,7 +115,7 @@ func (n *noopStore) Delete(ctx context.Context, key string, opts ...DeleteOption
 	return n.funcDelete(ctx, key, opts...)
 }
 
-func (n *noopStore) fnDelete(ctx context.Context, key string, opts ...DeleteOption) error {
+func (n *noopStore) fnDelete(ctx context.Context, _ string, _ ...DeleteOption) error {
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
@@ -114,7 +133,7 @@ func (n *noopStore) Exists(ctx context.Context, key string, opts ...ExistsOption
 	return n.funcExists(ctx, key, opts...)
 }
 
-func (n *noopStore) fnExists(ctx context.Context, key string, opts ...ExistsOption) error {
+func (n *noopStore) fnExists(ctx context.Context, _ string, _ ...ExistsOption) error {
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
@@ -132,7 +151,7 @@ func (n *noopStore) Write(ctx context.Context, key string, val interface{}, opts
 	return n.funcWrite(ctx, key, val, opts...)
 }
 
-func (n *noopStore) fnWrite(ctx context.Context, key string, val interface{}, opts ...WriteOption) error {
+func (n *noopStore) fnWrite(ctx context.Context, _ string, _ interface{}, _ ...WriteOption) error {
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
@@ -182,3 +201,41 @@ func (n *noopStore) connect(ctx context.Context) error {
 
 	return nil
 }
+
+type watcher struct {
+	opts WatchOptions
+	ch   chan Event
+	exit chan bool
+	id   string
+}
+
+func (n *noopStore) Watch(_ context.Context, opts ...WatchOption) (Watcher, error) {
+	id, err := id.New()
+	if err != nil {
+		return nil, err
+	}
+	wo, err := NewWatchOptions(opts...)
+	if err != nil {
+		return nil, err
+	}
+	// construct the watcher
+	w := &watcher{
+		exit: make(chan bool),
+		ch:   make(chan Event),
+		id:   id,
+		opts: wo,
+	}
+
+	n.mu.Lock()
+	n.watchers[w.id] = w
+	n.mu.Unlock()
+
+	return w, nil
+}
+
+func (w *watcher) Next() (Event, error) {
+	return nil, nil
+}
+
+func (w *watcher) Stop() {
+}

store/options.go

@@ -15,6 +15,13 @@ import (
 
 // Options contains configuration for the Store
 type Options struct {
+	// Name specifies store name
+	Name string
+	// Namespace of the records
+	Namespace string
+	// Separator used as key parts separator
+	Separator string
+
 	// Meter used for metrics
 	Meter meter.Meter
 	// Tracer used for tracing
@@ -25,22 +32,17 @@ type Options struct {
 	Codec codec.Codec
 	// Logger used for logging
 	Logger logger.Logger
+
 	// TLSConfig holds tls.TLSConfig options
 	TLSConfig *tls.Config
-	// Name specifies store name
-	Name string
-	// Namespace of the records
-	Namespace string
-	// Separator used as key parts separator
-	Separator string
+
 	// Addrs contains store address
 	Addrs []string
-	// Wrappers store wrapper that called before actual functions
-	// Wrappers []Wrapper
-	// Timeout specifies timeout duration for all operations
-	Timeout time.Duration
 	// Hooks can be run before/after store Read/List/Write/Exists/Delete
 	Hooks options.Hooks
+
+	// Timeout specifies timeout duration for all operations
+	Timeout time.Duration
 	// LazyConnect creates a connection when using store
 	LazyConnect bool
 }

store/store.go

@@ -4,17 +4,19 @@ package store
 import (
 	"context"
 	"errors"
+	"time"
 )
 
 var (
+	ErrWatcherStopped = errors.New("watcher stopped")
 	// ErrNotConnected is returned when a store is not connected
-	ErrNotConnected = errors.New("not conected")
+	ErrNotConnected = errors.New("not connected")
 	// ErrNotFound is returned when a key doesn't exist
 	ErrNotFound = errors.New("not found")
 	// ErrInvalidKey is returned when a key has empty or have invalid format
 	ErrInvalidKey = errors.New("invalid key")
 	// DefaultStore is the global default store
-	DefaultStore Store = NewStore()
+	DefaultStore = NewStore()
 	// DefaultSeparator is the gloabal default key parts separator
 	DefaultSeparator = "/"
 )
@@ -43,6 +45,14 @@ type Store interface {
 	Disconnect(ctx context.Context) error
 	// String returns the name of the implementation.
 	String() string
+	// Watch returns events watcher
+	Watch(ctx context.Context, opts ...WatchOption) (Watcher, error)
+	// Live returns store liveness
+	Live() bool
+	// Ready returns store readiness
+	Ready() bool
+	// Health returns store health
+	Health() bool
 }
 
 type (
@@ -57,3 +67,45 @@ type (
 	FuncList   func(ctx context.Context, opts ...ListOption) ([]string, error)
 	HookList   func(next FuncList) FuncList
 )
+
+type EventType int
+
+const (
+	EventTypeUnknown = iota
+	EventTypeConnect
+	EventTypeDisconnect
+	EventTypeOpError
+)
+
+type Event interface {
+	Timestamp() time.Time
+	Error() error
+	Type() EventType
+}
+
+type Watcher interface {
+	// Next is a blocking call
+	Next() (Event, error)
+	// Stop stops the watcher
+	Stop()
+}
+
+type WatchOption func(*WatchOptions) error
+
+type WatchOptions struct{}
+
+func NewWatchOptions(opts ...WatchOption) (WatchOptions, error) {
+	options := WatchOptions{}
+	var err error
+	for _, o := range opts {
+		if err = o(&options); err != nil {
+			break
+		}
+	}
+
+	return options, err
+}
+
+func Watch(context.Context) (Watcher, error) {
+	return nil, nil
+}

store/wrapper.go

@@ -67,16 +67,18 @@ func (w *NamespaceStore) String() string {
 	return w.s.String()
 }
 
-// type NamespaceWrapper struct{}
-
-// func NewNamespaceWrapper() Wrapper {
-//	return &NamespaceWrapper{}
-// }
-
-/*
-func (w *OmitWrapper) Logf(fn LogfFunc) LogfFunc {
-	return func(ctx context.Context, level Level, msg string, args ...interface{}) {
-		fn(ctx, level, msg, getArgs(args)...)
-	}
+func (w *NamespaceStore) Watch(ctx context.Context, opts ...WatchOption) (Watcher, error) {
+	return w.s.Watch(ctx, opts...)
+}
+
+func (w *NamespaceStore) Live() bool {
+	return w.s.Live()
+}
+
+func (w *NamespaceStore) Ready() bool {
+	return w.s.Ready()
+}
+
+func (w *NamespaceStore) Health() bool {
+	return w.s.Health()
 }
-*/

sync/memory.go

@@ -6,9 +6,10 @@ import (
 )
 
 type memorySync struct {
-	mtx     gosync.RWMutex
 	locks   map[string]*memoryLock
 	options Options
+
+	mtx gosync.RWMutex
 }
 
 type memoryLock struct {

tracer/context.go

@@ -18,6 +18,15 @@ func FromContext(ctx context.Context) (Tracer, bool) {
 	return nil, false
 }
 
+// MustContext returns a tracer from context
+func MustContext(ctx context.Context) Tracer {
+	t, ok := FromContext(ctx)
+	if !ok {
+		panic("missing tracer")
+	}
+	return t
+}
+
 // NewContext saves the tracer in the context
 func NewContext(ctx context.Context, tracer Tracer) context.Context {
 	if ctx == nil {
@@ -28,6 +37,15 @@ func NewContext(ctx context.Context, tracer Tracer) context.Context {
 
 type spanKey struct{}
 
+// SpanFromContext returns a span from context
+func SpanMustContext(ctx context.Context) Span {
+	sp, ok := SpanFromContext(ctx)
+	if !ok {
+		panic("missing span")
+	}
+	return sp
+}
+
 // SpanFromContext returns a span from context
 func SpanFromContext(ctx context.Context) (Span, bool) {
 	if ctx == nil {

tracer/memory/memory.go

@@ -25,6 +25,7 @@ func (t *Tracer) Start(ctx context.Context, name string, opts ...tracer.SpanOpti
 		name:      name,
 		ctx:       ctx,
 		tracer:    t,
+		labels:    options.Labels,
 		kind:      options.Kind,
 		startTime: time.Now(),
 	}
@@ -37,6 +38,14 @@ func (t *Tracer) Start(ctx context.Context, name string, opts ...tracer.SpanOpti
 	return tracer.NewSpanContext(ctx, span), span
 }
 
+type memoryStringer struct {
+	s string
+}
+
+func (s memoryStringer) String() string {
+	return s.s
+}
+
 func (t *Tracer) Flush(_ context.Context) error {
 	return nil
 }
@@ -52,14 +61,6 @@ func (t *Tracer) Name() string {
 	return t.opts.Name
 }
 
-type noopStringer struct {
-	s string
-}
-
-func (s noopStringer) String() string {
-	return s.s
-}
-
 type Span struct {
 	ctx        context.Context
 	tracer     tracer.Tracer
@@ -67,8 +68,8 @@ type Span struct {
 	statusMsg  string
 	startTime  time.Time
 	finishTime time.Time
-	traceID    noopStringer
-	spanID     noopStringer
+	traceID    memoryStringer
+	spanID     memoryStringer
 	events     []*Event
 	labels     []interface{}
 	logs       []interface{}

tracer/noop.go

@@ -2,6 +2,7 @@ package tracer
 
 import (
 	"context"
+	"time"
 
 	"go.unistack.org/micro/v3/util/id"
 )
@@ -20,18 +21,18 @@ func (t *noopTracer) Spans() []Span {
 func (t *noopTracer) Start(ctx context.Context, name string, opts ...SpanOption) (context.Context, Span) {
 	options := NewSpanOptions(opts...)
 	span := &noopSpan{
-		name:   name,
-		ctx:    ctx,
-		tracer: t,
-		labels: options.Labels,
-		kind:   options.Kind,
+		name:      name,
+		ctx:       ctx,
+		tracer:    t,
+		startTime: time.Now(),
+		labels:    options.Labels,
+		kind:      options.Kind,
 	}
 	span.spanID.s, _ = id.New()
 	span.traceID.s, _ = id.New()
 	if span.ctx == nil {
 		span.ctx = context.Background()
 	}
-	t.spans = append(t.spans, span)
 	return NewSpanContext(ctx, span), span
 }
 
@@ -58,23 +59,18 @@ func (t *noopTracer) Name() string {
 	return t.opts.Name
 }
 
-type noopEvent struct {
-	name   string
-	labels []interface{}
-}
-
 type noopSpan struct {
-	ctx       context.Context
-	tracer    Tracer
-	name      string
-	statusMsg string
-	traceID   noopStringer
-	spanID    noopStringer
-	events    []*noopEvent
-	labels    []interface{}
-	logs      []interface{}
-	kind      SpanKind
-	status    SpanStatus
+	ctx        context.Context
+	tracer     Tracer
+	name       string
+	statusMsg  string
+	startTime  time.Time
+	finishTime time.Time
+	traceID    noopStringer
+	spanID     noopStringer
+	labels     []interface{}
+	kind       SpanKind
+	status     SpanStatus
 }
 
 func (s *noopSpan) TraceID() string {
@@ -86,6 +82,7 @@ func (s *noopSpan) SpanID() string {
 }
 
 func (s *noopSpan) Finish(_ ...SpanOption) {
+	s.finishTime = time.Now()
 }
 
 func (s *noopSpan) Context() context.Context {
@@ -97,8 +94,6 @@ func (s *noopSpan) Tracer() Tracer {
 }
 
 func (s *noopSpan) AddEvent(name string, opts ...EventOption) {
-	options := NewEventOptions(opts...)
-	s.events = append(s.events, &noopEvent{name: name, labels: options.Labels})
 }
 
 func (s *noopSpan) SetName(name string) {
@@ -106,7 +101,6 @@ func (s *noopSpan) SetName(name string) {
 }
 
 func (s *noopSpan) AddLogs(kv ...interface{}) {
-	s.logs = append(s.logs, kv...)
 }
 
 func (s *noopSpan) AddLabels(kv ...interface{}) {

util/dns/cache.go

@@ -0,0 +1,409 @@
+package dns
+
+import (
+	"context"
+	"math"
+	"net"
+	"sync"
+	"time"
+
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/semconv"
+)
+
+// DialFunc is a [net.Resolver.Dial] function.
+type DialFunc func(ctx context.Context, network, address string) (net.Conn, error)
+
+// NewNetResolver creates a caching [net.Resolver] that uses parent to resolve names.
+func NewNetResolver(opts ...Option) *net.Resolver {
+	options := Options{Resolver: &net.Resolver{}}
+
+	for _, o := range opts {
+		o(&options)
+	}
+
+	if options.Meter == nil {
+		options.Meter = meter.DefaultMeter
+		opts = append(opts, Meter(options.Meter))
+	}
+
+	return &net.Resolver{
+		PreferGo:     true,
+		StrictErrors: options.Resolver.StrictErrors,
+		Dial:         NewNetDialer(options.Resolver.Dial, append(opts, Resolver(options.Resolver))...),
+	}
+}
+
+// NewNetDialer adds caching to a [net.Resolver.Dial] function.
+func NewNetDialer(parent DialFunc, opts ...Option) DialFunc {
+	cache := cache{dial: parent, opts: Options{}}
+	for _, o := range opts {
+		o(&cache.opts)
+	}
+	if cache.opts.MaxCacheEntries == 0 {
+		cache.opts.MaxCacheEntries = DefaultMaxCacheEntries
+	}
+	return func(_ context.Context, network, address string) (net.Conn, error) {
+		conn := &dnsConn{}
+		conn.roundTrip = cachingRoundTrip(&cache, network, address)
+		return conn, nil
+	}
+}
+
+const DefaultMaxCacheEntries = 300
+
+// A Option customizes the resolver cache.
+type Option func(*Options)
+
+type Options struct {
+	Resolver        *net.Resolver
+	MaxCacheEntries int
+	MaxCacheTTL     time.Duration
+	MinCacheTTL     time.Duration
+	NegativeCache   bool
+	PreferIPV4      bool
+	PreferIPV6      bool
+	Timeout         time.Duration
+	Meter           meter.Meter
+}
+
+// MaxCacheEntries sets the maximum number of entries to cache.
+// If zero, [DefaultMaxCacheEntries] is used; negative means no limit.
+func MaxCacheEntries(n int) Option {
+	return func(o *Options) {
+		o.MaxCacheEntries = n
+	}
+}
+
+// MaxCacheTTL sets the maximum time-to-live for entries in the cache.
+func MaxCacheTTL(td time.Duration) Option {
+	return func(o *Options) {
+		o.MaxCacheTTL = td
+	}
+}
+
+// MinCacheTTL sets the minimum time-to-live for entries in the cache.
+func MinCacheTTL(td time.Duration) Option {
+	return func(o *Options) {
+		o.MinCacheTTL = td
+	}
+}
+
+// NegativeCache sets whether to cache negative responses.
+func NegativeCache(b bool) Option {
+	return func(o *Options) {
+		o.NegativeCache = b
+	}
+}
+
+// Meter sets meter.Meter
+func Meter(m meter.Meter) Option {
+	return func(o *Options) {
+		o.Meter = m
+	}
+}
+
+// Timeout sets upstream *net.Resolver timeout
+func Timeout(td time.Duration) Option {
+	return func(o *Options) {
+		o.Timeout = td
+	}
+}
+
+// Resolver sets upstream *net.Resolver.
+func Resolver(r *net.Resolver) Option {
+	return func(o *Options) {
+		o.Resolver = r
+	}
+}
+
+// PreferIPV4 resolve ipv4 records.
+func PreferIPV4(b bool) Option {
+	return func(o *Options) {
+		o.PreferIPV4 = b
+	}
+}
+
+// PreferIPV6 resolve ipv4 records.
+func PreferIPV6(b bool) Option {
+	return func(o *Options) {
+		o.PreferIPV6 = b
+	}
+}
+
+type cache struct {
+	entries map[string]cacheEntry
+	dial    DialFunc
+
+	opts Options
+
+	sync.RWMutex
+}
+
+type cacheEntry struct {
+	deadline time.Time
+	value    string
+}
+
+func (c *cache) put(req string, res string) {
+	// ignore uncacheable/unparseable answers
+	if invalid(req, res) {
+		return
+	}
+
+	// ignore errors (if requested)
+	if nameError(res) && !c.opts.NegativeCache {
+		return
+	}
+
+	// ignore uncacheable/unparseable answers
+	ttl := getTTL(res)
+	if ttl <= 0 {
+		return
+	}
+
+	// adjust TTL
+	if ttl < c.opts.MinCacheTTL {
+		ttl = c.opts.MinCacheTTL
+	}
+	// maxTTL overrides minTTL
+	if ttl > c.opts.MaxCacheTTL && c.opts.MaxCacheTTL != 0 {
+		ttl = c.opts.MaxCacheTTL
+	}
+
+	c.Lock()
+	if c.entries == nil {
+		c.entries = make(map[string]cacheEntry)
+	}
+
+	// do some cache evition
+	var tested, evicted int
+	for k, e := range c.entries {
+		if time.Until(e.deadline) <= 0 {
+			c.opts.Meter.Counter(semconv.CacheItemsTotal, "type", "dns").Dec()
+			c.opts.Meter.Counter(semconv.CacheRequestTotal, "type", "dns", "method", "evict").Inc()
+			// delete expired entry
+			delete(c.entries, k)
+			evicted++
+		}
+		tested++
+
+		if tested < 8 {
+			continue
+		}
+		if evicted == 0 && c.opts.MaxCacheEntries > 0 && len(c.entries) >= c.opts.MaxCacheEntries {
+			c.opts.Meter.Counter(semconv.CacheItemsTotal, "type", "dns").Dec()
+			c.opts.Meter.Counter(semconv.CacheRequestTotal, "type", "dns", "method", "evict").Inc()
+			// delete at least one entry
+			delete(c.entries, k)
+		}
+		break
+	}
+
+	// remove message IDs
+	c.entries[req[2:]] = cacheEntry{
+		deadline: time.Now().Add(ttl),
+		value:    res[2:],
+	}
+
+	c.opts.Meter.Counter(semconv.CacheItemsTotal, "type", "dns").Inc()
+	c.Unlock()
+}
+
+func (c *cache) get(req string) (res string) {
+	// ignore invalid messages
+	if len(req) < 12 {
+		return ""
+	}
+	if req[2] >= 0x7f {
+		return ""
+	}
+
+	c.RLock()
+	defer c.RUnlock()
+
+	if c.entries == nil {
+		return ""
+	}
+
+	// remove message ID
+	entry, ok := c.entries[req[2:]]
+	if ok && time.Until(entry.deadline) > 0 {
+		// prepend correct ID
+		return req[:2] + entry.value
+	}
+
+	return ""
+}
+
+func invalid(req string, res string) bool {
+	if len(req) < 12 || len(res) < 12 { // header size
+		return true
+	}
+	if req[0] != res[0] || req[1] != res[1] { // IDs match
+		return true
+	}
+	if req[2] >= 0x7f || res[2] < 0x7f { // query, response
+		return true
+	}
+	if req[2]&0x7a != 0 || res[2]&0x7a != 0 { // standard query, not truncated
+		return true
+	}
+	if res[3]&0xf != 0 && res[3]&0xf != 3 { // no error, or name error
+		return true
+	}
+	return false
+}
+
+func nameError(res string) bool {
+	return res[3]&0xf == 3
+}
+
+func getTTL(msg string) time.Duration {
+	ttl := math.MaxInt32
+
+	qdcount := getUint16(msg[4:])
+	ancount := getUint16(msg[6:])
+	nscount := getUint16(msg[8:])
+	arcount := getUint16(msg[10:])
+	rdcount := ancount + nscount + arcount
+
+	msg = msg[12:] // skip header
+
+	// skip questions
+	for i := 0; i < qdcount; i++ {
+		name := getNameLen(msg)
+		if name < 0 || name+4 > len(msg) {
+			return -1
+		}
+		msg = msg[name+4:]
+	}
+
+	// parse records
+	for i := 0; i < rdcount; i++ {
+		name := getNameLen(msg)
+		if name < 0 || name+10 > len(msg) {
+			return -1
+		}
+		rtyp := getUint16(msg[name+0:])
+		rttl := getUint32(msg[name+4:])
+		rlen := getUint16(msg[name+8:])
+		if name+10+rlen > len(msg) {
+			return -1
+		}
+		// skip EDNS OPT since it doesn't have a TTL
+		if rtyp != 41 && rttl < ttl {
+			ttl = rttl
+		}
+		msg = msg[name+10+rlen:]
+	}
+
+	return time.Duration(ttl) * time.Second
+}
+
+func getNameLen(msg string) int {
+	i := 0
+	for i < len(msg) {
+		if msg[i] == 0 {
+			// end of name
+			i++
+			break
+		}
+		if msg[i] >= 0xc0 {
+			// compressed name
+			i += 2
+			break
+		}
+		if msg[i] >= 0x40 {
+			// reserved
+			return -1
+		}
+		i += int(msg[i] + 1)
+	}
+	return i
+}
+
+func getUint16(s string) int {
+	return int(s[1]) | int(s[0])<<8
+}
+
+func getUint32(s string) int {
+	return int(s[3]) | int(s[2])<<8 | int(s[1])<<16 | int(s[0])<<24
+}
+
+func cachingRoundTrip(cache *cache, network, address string) roundTripper {
+	return func(ctx context.Context, req string) (res string, err error) {
+		cache.opts.Meter.Counter(semconv.CacheRequestInflight, "type", "dns").Inc()
+		defer cache.opts.Meter.Counter(semconv.CacheRequestInflight, "type", "dns").Dec()
+		// check cache
+		if res = cache.get(req); res != "" {
+			return res, nil
+		}
+		cache.opts.Meter.Counter(semconv.CacheRequestTotal, "type", "dns", "method", "get", "status", "miss").Inc()
+		ts := time.Now()
+		defer func() {
+			cache.opts.Meter.Summary(semconv.CacheRequestLatencyMicroseconds, "type", "dns", "method", "get").UpdateDuration(ts)
+			cache.opts.Meter.Histogram(semconv.CacheRequestDurationSeconds, "type", "dns", "method", "get").UpdateDuration(ts)
+		}()
+
+		switch {
+		case cache.opts.PreferIPV4 && cache.opts.PreferIPV6:
+			network = "udp"
+		case cache.opts.PreferIPV4:
+			network = "udp4"
+		case cache.opts.PreferIPV6:
+			network = "udp6"
+		default:
+			network = "udp"
+		}
+
+		if cache.opts.Timeout > 0 {
+			var cancel func()
+			ctx, cancel = context.WithTimeout(ctx, cache.opts.Timeout)
+			defer cancel()
+		}
+
+		// dial connection
+		var conn net.Conn
+		if cache.dial != nil {
+			conn, err = cache.dial(ctx, network, address)
+		} else {
+			var d net.Dialer
+			conn, err = d.DialContext(ctx, network, address)
+		}
+
+		if err != nil {
+			return "", err
+		}
+
+		ctx, cancel := context.WithCancel(ctx)
+		go func() {
+			<-ctx.Done()
+			conn.Close()
+		}()
+		defer cancel()
+
+		if t, ok := ctx.Deadline(); ok {
+			err = conn.SetDeadline(t)
+			if err != nil {
+				return "", err
+			}
+		}
+
+		// send request
+		err = writeMessage(conn, req)
+		if err != nil {
+			return "", err
+		}
+
+		// read response
+		res, err = readMessage(conn)
+		if err != nil {
+			return "", err
+		}
+
+		// cache response
+		cache.put(req, res)
+		return res, nil
+	}
+}

util/dns/cache_test.go

@@ -0,0 +1,20 @@
+package dns
+
+import (
+	"net"
+	"testing"
+)
+
+func TestCache(t *testing.T) {
+	net.DefaultResolver = NewNetResolver(PreferIPV4(true))
+
+	_, err := net.LookupHost("unistack.org")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = net.LookupHost("unistack.org")
+	if err != nil {
+		t.Fatal(err)
+	}
+}

util/dns/conn.go

@@ -0,0 +1,183 @@
+package dns
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"net"
+	"strings"
+	"sync"
+	"time"
+)
+
+type dnsConn struct {
+	ctx       context.Context
+	cancel    context.CancelFunc
+	roundTrip roundTripper
+
+	deadline time.Time
+
+	ibuf bytes.Buffer
+	obuf bytes.Buffer
+
+	sync.Mutex
+}
+
+type roundTripper func(ctx context.Context, req string) (res string, err error)
+
+func (c *dnsConn) Read(b []byte) (n int, err error) {
+	imsg, n, err := c.drainBuffers(b)
+	if n != 0 || err != nil {
+		return n, err
+	}
+
+	ctx, cancel := c.childContext()
+	omsg, err := c.roundTrip(ctx, imsg)
+	cancel()
+	if err != nil {
+		return 0, err
+	}
+
+	return c.fillBuffer(b, omsg)
+}
+
+func (c *dnsConn) Write(b []byte) (n int, err error) {
+	c.Lock()
+	defer c.Unlock()
+	return c.ibuf.Write(b)
+}
+
+func (c *dnsConn) Close() error {
+	c.Lock()
+	cancel := c.cancel
+	c.Unlock()
+
+	if cancel != nil {
+		cancel()
+	}
+	return nil
+}
+
+func (c *dnsConn) LocalAddr() net.Addr {
+	return nil
+}
+
+func (c *dnsConn) RemoteAddr() net.Addr {
+	return nil
+}
+
+func (c *dnsConn) SetDeadline(t time.Time) error {
+	var err error
+	if err = c.SetReadDeadline(t); err != nil {
+		return err
+	}
+	if err = c.SetWriteDeadline(t); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (c *dnsConn) SetReadDeadline(t time.Time) error {
+	c.Lock()
+	c.deadline = t
+	c.Unlock()
+	return nil
+}
+
+func (c *dnsConn) SetWriteDeadline(_ time.Time) error {
+	// writes do not timeout
+	return nil
+}
+
+func (c *dnsConn) drainBuffers(b []byte) (string, int, error) {
+	c.Lock()
+	defer c.Unlock()
+
+	// drain the output buffer
+	if c.obuf.Len() > 0 {
+		n, err := c.obuf.Read(b)
+		return "", n, err
+	}
+
+	// otherwise, get the next message from the input buffer
+	sz := c.ibuf.Next(2)
+	if len(sz) < 2 {
+		return "", 0, io.ErrUnexpectedEOF
+	}
+
+	size := int64(sz[0])<<8 | int64(sz[1])
+
+	var str strings.Builder
+	_, err := io.CopyN(&str, &c.ibuf, size)
+	if err == io.EOF {
+		return "", 0, io.ErrUnexpectedEOF
+	}
+	if err != nil {
+		return "", 0, err
+	}
+	return str.String(), 0, nil
+}
+
+func (c *dnsConn) fillBuffer(b []byte, str string) (int, error) {
+	c.Lock()
+	defer c.Unlock()
+	c.obuf.WriteByte(byte(len(str) >> 8))
+	c.obuf.WriteByte(byte(len(str)))
+	c.obuf.WriteString(str)
+	return c.obuf.Read(b)
+}
+
+func (c *dnsConn) childContext() (context.Context, context.CancelFunc) {
+	c.Lock()
+	defer c.Unlock()
+	if c.ctx == nil {
+		c.ctx, c.cancel = context.WithCancel(context.Background())
+	}
+	return context.WithDeadline(c.ctx, c.deadline)
+}
+
+func writeMessage(conn net.Conn, msg string) error {
+	var buf []byte
+	if _, ok := conn.(net.PacketConn); ok {
+		buf = []byte(msg)
+	} else {
+		buf = make([]byte, len(msg)+2)
+		buf[0] = byte(len(msg) >> 8)
+		buf[1] = byte(len(msg))
+		copy(buf[2:], msg)
+	}
+	// SHOULD do a single write on TCP (RFC 7766, section 8).
+	// MUST do a single write on UDP.
+	_, err := conn.Write(buf)
+	return err
+}
+
+func readMessage(c net.Conn) (string, error) {
+	if _, ok := c.(net.PacketConn); ok {
+		// RFC 1035 specifies 512 as the maximum message size for DNS over UDP.
+		// RFC 6891 OTOH suggests 4096 as the maximum payload size for EDNS.
+		b := make([]byte, 4096)
+		n, err := c.Read(b)
+		if err != nil {
+			return "", err
+		}
+		return string(b[:n]), nil
+	}
+	var sz [2]byte
+	_, err := io.ReadFull(c, sz[:])
+	if err != nil {
+		return "", err
+	}
+
+	size := int64(sz[0])<<8 | int64(sz[1])
+
+	var str strings.Builder
+	_, err = io.CopyN(&str, c, size)
+	if err == io.EOF {
+		return "", io.ErrUnexpectedEOF
+	}
+	if err != nil {
+		return "", err
+	}
+	return str.String(), nil
+}

util/grpc/tracer.go

@@ -71,7 +71,7 @@ func (h *serverHandler) HandleRPC(ctx context.Context, rs stats.RPCStats) {
 }
 
 // TagConn can attach some information to the given context.
-func (h *serverHandler) TagConn(ctx context.Context, info *stats.ConnTagInfo) context.Context {
+func (h *serverHandler) TagConn(ctx context.Context, _ *stats.ConnTagInfo) context.Context {
 	if span, ok := tracer.SpanFromContext(ctx); ok {
 		attrs := peerAttr(peerFromCtx(ctx))
 		span.AddLabels(attrs...)
@@ -80,7 +80,7 @@ func (h *serverHandler) TagConn(ctx context.Context, info *stats.ConnTagInfo) co
 }
 
 // HandleConn processes the Conn stats.
-func (h *serverHandler) HandleConn(ctx context.Context, info stats.ConnStats) {
+func (h *serverHandler) HandleConn(_ context.Context, _ stats.ConnStats) {
 }
 
 type clientHandler struct {

util/http/trie.go

@@ -665,12 +665,12 @@ func patParamKeys(pattern string) ([]string, error) {
 // longestPrefix finds the length of the shared prefix
 // of two strings
 func longestPrefix(k1, k2 string) int {
-	max := len(k1)
-	if l := len(k2); l < max {
-		max = l
+	maxLen := len(k1)
+	if l := len(k2); l < maxLen {
+		maxLen = l
 	}
 	var i int
-	for i = 0; i < max; i++ {
+	for i = 0; i < maxLen; i++ {
 		if k1[i] != k2[i] {
 			break
 		}

util/io/io.go

@@ -1,40 +0,0 @@
-// Package io is for io management
-package io
-
-import (
-	"io"
-
-	"go.unistack.org/micro/v3/network/transport"
-)
-
-type rwc struct {
-	socket transport.Socket
-}
-
-func (r *rwc) Read(p []byte) (n int, err error) {
-	m := new(transport.Message)
-	if err := r.socket.Recv(m); err != nil {
-		return 0, err
-	}
-	copy(p, m.Body)
-	return len(m.Body), nil
-}
-
-func (r *rwc) Write(p []byte) (n int, err error) {
-	err = r.socket.Send(&transport.Message{
-		Body: p,
-	})
-	if err != nil {
-		return 0, err
-	}
-	return len(p), nil
-}
-
-func (r *rwc) Close() error {
-	return r.socket.Close()
-}
-
-// NewRWC returns a new ReadWriteCloser
-func NewRWC(sock transport.Socket) io.ReadWriteCloser {
-	return &rwc{sock}
-}

util/jitter/random.go

@@ -14,7 +14,7 @@ func Random(d time.Duration) time.Duration {
 	return time.Duration(v)
 }
 
-func RandomInterval(min, max time.Duration) time.Duration {
+func RandomInterval(minTime, maxTime time.Duration) time.Duration {
 	var rng rand.Rand
-	return time.Duration(rng.Int63n(max.Nanoseconds()-min.Nanoseconds())+min.Nanoseconds()) * time.Nanosecond
+	return time.Duration(rng.Int63n(maxTime.Nanoseconds()-minTime.Nanoseconds())+minTime.Nanoseconds()) * time.Nanosecond
 }

util/jitter/ticker.go

@@ -16,7 +16,6 @@ type Ticker struct {
 	C    chan time.Time
 	min  int64
 	max  int64
-	exp  int64
 	exit bool
 	rng  rand.Rand
 }
@@ -24,12 +23,12 @@ type Ticker struct {
 // NewTickerContext returns a pointer to an initialized instance of the Ticker.
 // It works like NewTicker except that it has ability to close via context.
 // Also it works fine with context.WithTimeout to handle max time to run ticker.
-func NewTickerContext(ctx context.Context, min, max time.Duration) *Ticker {
+func NewTickerContext(ctx context.Context, minTime, maxTime time.Duration) *Ticker {
 	ticker := &Ticker{
 		C:    make(chan time.Time),
 		done: make(chan chan struct{}),
-		min:  min.Nanoseconds(),
-		max:  max.Nanoseconds(),
+		min:  minTime.Nanoseconds(),
+		max:  maxTime.Nanoseconds(),
 		ctx:  ctx,
 	}
 	go ticker.run()
@@ -39,12 +38,12 @@ func NewTickerContext(ctx context.Context, min, max time.Duration) *Ticker {
 // NewTicker returns a pointer to an initialized instance of the Ticker.
 // Min and max are durations of the shortest and longest allowed
 // ticks. Ticker will run in a goroutine until explicitly stopped.
-func NewTicker(min, max time.Duration) *Ticker {
+func NewTicker(minTime, maxTime time.Duration) *Ticker {
 	ticker := &Ticker{
 		C:    make(chan time.Time),
 		done: make(chan chan struct{}),
-		min:  min.Nanoseconds(),
-		max:  max.Nanoseconds(),
+		min:  minTime.Nanoseconds(),
+		max:  maxTime.Nanoseconds(),
 		ctx:  context.Background(),
 	}
 	go ticker.run()

util/jitter/ticker_test.go

@@ -31,26 +31,26 @@ loop:
 func TestTicker(t *testing.T) {
 	t.Parallel()
 
-	min := time.Duration(10)
-	max := time.Duration(20)
+	minTime := time.Duration(10)
+	maxTime := time.Duration(20)
 
 	// tick can take a little longer since we're not adjusting it to account for
 	// processing.
 	precision := time.Duration(4)
 
-	rt := NewTicker(min*time.Millisecond, max*time.Millisecond)
+	rt := NewTicker(minTime*time.Millisecond, maxTime*time.Millisecond)
 	for i := 0; i < 5; i++ {
 		t0 := time.Now()
 		t1 := <-rt.C
 		td := t1.Sub(t0)
-		if td < min*time.Millisecond {
+		if td < minTime*time.Millisecond {
 			t.Fatalf("tick was shorter than expected: %s", td)
-		} else if td > (max+precision)*time.Millisecond {
+		} else if td > (maxTime+precision)*time.Millisecond {
 			t.Fatalf("tick was longer than expected: %s", td)
 		}
 	}
 	rt.Stop()
-	time.Sleep((max + precision) * time.Millisecond)
+	time.Sleep((maxTime + precision) * time.Millisecond)
 	select {
 	case v, ok := <-rt.C:
 		if ok || !v.IsZero() {

util/net/net.go

@@ -48,19 +48,19 @@ func Listen(addr string, fn func(string) (net.Listener, error)) (net.Listener, e
 	// we have a port range
 
 	// extract min port
-	min, err := strconv.Atoi(prange[0])
+	minPort, err := strconv.Atoi(prange[0])
 	if err != nil {
 		return nil, errors.New("unable to extract port range")
 	}
 
 	// extract max port
-	max, err := strconv.Atoi(prange[1])
+	maxPort, err := strconv.Atoi(prange[1])
 	if err != nil {
 		return nil, errors.New("unable to extract port range")
 	}
 
 	// range the ports
-	for port := min; port <= max; port++ {
+	for port := minPort; port <= maxPort; port++ {
 		// try bind to host:port
 		ln, err := fn(HostPort(host, port))
 		if err == nil {
@@ -68,7 +68,7 @@ func Listen(addr string, fn func(string) (net.Listener, error)) (net.Listener, e
 		}
 
 		// hit max port
-		if port == max {
+		if port == maxPort {
 			return nil, err
 		}
 	}

util/pool/default.go

@@ -1,118 +0,0 @@
-package pool
-
-import (
-	"context"
-	"sync"
-	"time"
-
-	"go.unistack.org/micro/v3/network/transport"
-	"go.unistack.org/micro/v3/util/id"
-)
-
-type pool struct {
-	tr    transport.Transport
-	conns map[string][]*poolConn
-	size  int
-	ttl   time.Duration
-	sync.Mutex
-}
-
-type poolConn struct {
-	created time.Time
-	transport.Client
-	id string
-}
-
-func newPool(options Options) *pool {
-	return &pool{
-		size:  options.Size,
-		tr:    options.Transport,
-		ttl:   options.TTL,
-		conns: make(map[string][]*poolConn),
-	}
-}
-
-func (p *pool) Close() error {
-	p.Lock()
-	for k, c := range p.conns {
-		for _, conn := range c {
-			conn.Client.Close()
-		}
-		delete(p.conns, k)
-	}
-	p.Unlock()
-	return nil
-}
-
-// NoOp the Close since we manage it
-func (p *poolConn) Close() error {
-	return nil
-}
-
-func (p *poolConn) ID() string {
-	return p.id
-}
-
-func (p *poolConn) Created() time.Time {
-	return p.created
-}
-
-func (p *pool) Get(ctx context.Context, addr string, opts ...transport.DialOption) (Conn, error) {
-	p.Lock()
-	conns := p.conns[addr]
-
-	// while we have conns check age and then return one
-	// otherwise we'll create a new conn
-	for len(conns) > 0 {
-		conn := conns[len(conns)-1]
-		conns = conns[:len(conns)-1]
-		p.conns[addr] = conns
-
-		// if conn is old kill it and move on
-		if d := time.Since(conn.Created()); d > p.ttl {
-			conn.Client.Close()
-			continue
-		}
-
-		// we got a good conn, lets unlock and return it
-		p.Unlock()
-
-		return conn, nil
-	}
-
-	p.Unlock()
-
-	// create new conn
-	c, err := p.tr.Dial(ctx, addr, opts...)
-	if err != nil {
-		return nil, err
-	}
-	id, err := id.New()
-	if err != nil {
-		return nil, err
-	}
-	return &poolConn{
-		Client:  c,
-		id:      id,
-		created: time.Now(),
-	}, nil
-}
-
-func (p *pool) Release(conn Conn, err error) error {
-	// don't store the conn if it has errored
-	if err != nil {
-		return conn.(*poolConn).Client.Close()
-	}
-
-	// otherwise put it back for reuse
-	p.Lock()
-	conns := p.conns[conn.Remote()]
-	if len(conns) >= p.size {
-		p.Unlock()
-		return conn.(*poolConn).Client.Close()
-	}
-	p.conns[conn.Remote()] = append(conns, conn.(*poolConn))
-	p.Unlock()
-
-	return nil
-}

util/pool/default_test.go

@@ -1,92 +0,0 @@
-//go:build ignore
-// +build ignore
-
-package pool
-
-import (
-	"testing"
-	"time"
-
-	"go.unistack.org/micro/v3/network/transport"
-	"go.unistack.org/micro/v3/network/transport/memory"
-)
-
-func testPool(t *testing.T, size int, ttl time.Duration) {
-	// mock transport
-	tr := memory.NewTransport()
-
-	options := Options{
-		TTL:       ttl,
-		Size:      size,
-		Transport: tr,
-	}
-	// zero pool
-	p := newPool(options)
-
-	// listen
-	l, err := tr.Listen(":0")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer l.Close()
-
-	// accept loop
-	go func() {
-		for {
-			if err := l.Accept(func(s transport.Socket) {
-				for {
-					var msg transport.Message
-					if err := s.Recv(&msg); err != nil {
-						return
-					}
-					if err := s.Send(&msg); err != nil {
-						return
-					}
-				}
-			}); err != nil {
-				return
-			}
-		}
-	}()
-
-	for i := 0; i < 10; i++ {
-		// get a conn
-		c, err := p.Get(l.Addr())
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		msg := &transport.Message{
-			Body: []byte(`hello world`),
-		}
-
-		if err := c.Send(msg); err != nil {
-			t.Fatal(err)
-		}
-
-		var rcv transport.Message
-
-		if err := c.Recv(&rcv); err != nil {
-			t.Fatal(err)
-		}
-
-		if string(rcv.Body) != string(msg.Body) {
-			t.Fatalf("got %v, expected %v", rcv.Body, msg.Body)
-		}
-
-		// release the conn
-		p.Release(c, nil)
-
-		p.Lock()
-		if i := len(p.conns[l.Addr()]); i > size {
-			p.Unlock()
-			t.Fatalf("pool size %d is greater than expected %d", i, size)
-		}
-		p.Unlock()
-	}
-}
-
-func TestClientPool(t *testing.T) {
-	testPool(t, 0, time.Minute)
-	testPool(t, 2, time.Minute)
-}

util/pool/options.go

@@ -1,38 +0,0 @@
-package pool
-
-import (
-	"time"
-
-	"go.unistack.org/micro/v3/network/transport"
-)
-
-// Options struct
-type Options struct {
-	Transport transport.Transport
-	TTL       time.Duration
-	Size      int
-}
-
-// Option func signature
-type Option func(*Options)
-
-// Size sets the size
-func Size(i int) Option {
-	return func(o *Options) {
-		o.Size = i
-	}
-}
-
-// Transport sets the transport
-func Transport(t transport.Transport) Option {
-	return func(o *Options) {
-		o.Transport = t
-	}
-}
-
-// TTL specifies ttl
-func TTL(t time.Duration) Option {
-	return func(o *Options) {
-		o.TTL = t
-	}
-}

util/pool/pool.go

@@ -1,38 +0,0 @@
-// Package pool is a connection pool
-package pool
-
-import (
-	"context"
-	"time"
-
-	"go.unistack.org/micro/v3/network/transport"
-)
-
-// Pool is an interface for connection pooling
-type Pool interface {
-	// Close the pool
-	Close() error
-	// Get a connection
-	Get(ctx context.Context, addr string, opts ...transport.DialOption) (Conn, error)
-	// Release the connection
-	Release(c Conn, status error) error
-}
-
-// Conn conn pool interface
-type Conn interface {
-	// unique id of connection
-	ID() string
-	// time it was created
-	Created() time.Time
-	// embedded connection
-	transport.Client
-}
-
-// NewPool creates new connection pool
-func NewPool(opts ...Option) Pool {
-	options := Options{}
-	for _, o := range opts {
-		o(&options)
-	}
-	return newPool(options)
-}

util/reflect/path.go

@@ -155,7 +155,7 @@ func indexFunction(v reflect.Value) func(i int) reflect.Value {
 			return v.MapIndex(keys[i])
 		}
 	}
-	return func(i int) reflect.Value { return reflect.Value{} }
+	return func(_ int) reflect.Value { return reflect.Value{} }
 }
 
 func mergeValue(values []reflect.Value) reflect.Value {

util/reflect/reflect.go

@@ -91,7 +91,7 @@ func Merge(dst interface{}, mp map[string]interface{}, opts ...Option) error {
 	}
 
 	if mapper, ok := dst.(map[string]interface{}); ok {
-		dst = mergeMap(mapper, mp, 0)
+		mergeMap(mapper, mp, 0)
 		return nil
 	}
 

util/reflect/reflect_test.go

@@ -1,9 +1,38 @@
 package reflect
 
 import (
+	"fmt"
 	"testing"
 )
 
+func TestMergeMapStringInterface(t *testing.T) {
+	var dst interface{} //nolint:gosimple
+	dst = map[string]interface{}{
+		"xx": 11,
+	}
+
+	src := map[string]interface{}{
+		"zz": "aa",
+	}
+
+	if err := Merge(dst, src); err != nil {
+		t.Fatal(err)
+	}
+
+	mp, ok := dst.(map[string]interface{})
+	if !ok || mp == nil {
+		t.Fatalf("xxx %#+v\n", dst)
+	}
+
+	if fmt.Sprintf("%v", mp["xx"]) != "11" {
+		t.Fatalf("xxx zzzz %#+v", mp)
+	}
+
+	if fmt.Sprintf("%v", mp["zz"]) != "aa" {
+		t.Fatalf("xxx zzzz %#+v", mp)
+	}
+}
+
 func TestMergeMap(t *testing.T) {
 	src := map[string]interface{}{
 		"skey1": "sval1",
@@ -101,16 +130,16 @@ func TestMergeString(t *testing.T) {
 
 func TestMergeNested(t *testing.T) {
 	type CallReqNested struct {
+		Nested     *CallReqNested `json:"nested2"`
 		StringArgs []string       `json:"string_args"`
 		Uint64Args []uint64       `json:"uint64_args"`
-		Nested     *CallReqNested `json:"nested2"`
 	}
 
 	type CallReq struct {
+		Nested *CallReqNested `json:"nested"`
 		Name   string         `json:"name"`
 		Req    string         `json:"req"`
 		Arg2   int            `json:"arg2"`
-		Nested *CallReqNested `json:"nested"`
 	}
 
 	dst := &CallReq{

util/register/util.go

@@ -109,12 +109,11 @@ func Merge(olist []*register.Service, nlist []*register.Service) []*register.Ser
 				seen = true
 				srv = append(srv, sp)
 				break
-			} else {
-				sp := &register.Service{}
-				// make copy
-				*sp = *o
-				srv = append(srv, sp)
 			}
+			sp := &register.Service{}
+			// make copy
+			*sp = *o
+			srv = append(srv, sp)
 		}
 		if !seen {
 			srv = append(srv, Copy([]*register.Service{n})...)
@@ -153,14 +152,14 @@ func Remove(old, del []*register.Service) []*register.Service {
 
 // WaitService using register wait for service to appear with min/max interval for check and optional timeout.
 // Timeout can be 0 to wait infinitive.
-func WaitService(ctx context.Context, reg register.Register, name string, min time.Duration, max time.Duration, timeout time.Duration, opts ...register.LookupOption) error {
+func WaitService(ctx context.Context, reg register.Register, name string, minTime time.Duration, maxTime time.Duration, timeout time.Duration, opts ...register.LookupOption) error {
 	if timeout > 0 {
 		var cancel context.CancelFunc
 		ctx, cancel = context.WithTimeout(ctx, timeout)
 		defer cancel()
 	}
 
-	ticker := jitter.NewTickerContext(ctx, min, max)
+	ticker := jitter.NewTickerContext(ctx, minTime, maxTime)
 	defer ticker.Stop()
 
 	for {

util/ring/buffer.go

@@ -10,10 +10,11 @@ import (
 
 // Buffer is ring buffer
 type Buffer struct {
-	sync.RWMutex
 	streams map[string]*Stream
 	vals    []*Entry
 	size    int
+
+	sync.RWMutex
 }
 
 // Entry is ring buffer data entry