Merge pull request 'add client tracing' (#341) from traceclient into v3

Reviewed-on: #341

.gitea/workflows/lint.yml

@@ -10,15 +10,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: setup-go
-      uses: https://gitea.com/actions/setup-go@v3
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.18
+        go-version: 1.21
     - name: checkout
-      uses: https://gitea.com/actions/checkout@v3
+      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
+        version: v1.52

.gitea/workflows/pr.yml

@@ -10,14 +10,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: checkout
-      uses: https://gitea.com/actions/checkout@v3
+      uses: actions/checkout@v3
     - name: setup-go
-      uses: https://gitea.com/actions/setup-go@v3
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.18
+        go-version: 1.21
     - name: deps
       run: go get -v -t -d ./...
     - name: test
       env:
         INTEGRATION_TESTS: yes
-      run: go test -mod readonly -v ./...
+      run: go test -mod readonly -v ./...

.gitignore

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

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/go.unistack.org/micro/v4?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/v4)](https://goreportcard.com/report/go.unistack.org/micro/v4) [![Coverage](https://codecov.io/gh/unistack-org/micro/branch/v4/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://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 is a standard library for microservices.
 

broker/broker.go

@@ -1,22 +1,25 @@
 // Package broker is an interface used for asynchronous messaging
-package broker // import "go.unistack.org/micro/v4/broker"
+package broker // import "go.unistack.org/micro/v3/broker"
 
 import (
 	"context"
 	"errors"
+	"time"
 
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 // DefaultBroker default memory broker
-var DefaultBroker = NewBroker()
+var DefaultBroker Broker = NewBroker()
 
 var (
 	// ErrNotConnected returns when broker used but not connected yet
 	ErrNotConnected = errors.New("broker not connected")
 	// ErrDisconnected returns when broker disconnected
 	ErrDisconnected = errors.New("broker disconnected")
+	// DefaultGracefulTimeout
+	DefaultGracefulTimeout = 5 * time.Second
 )
 
 // Broker is an interface used for asynchronous messaging.
@@ -45,6 +48,17 @@ type Broker interface {
 	String() string
 }
 
+type (
+	FuncPublish        func(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error
+	HookPublish        func(next FuncPublish) FuncPublish
+	FuncBatchPublish   func(ctx context.Context, msgs []*Message, opts ...PublishOption) error
+	HookBatchPublish   func(next FuncBatchPublish) FuncBatchPublish
+	FuncSubscribe      func(ctx context.Context, topic string, h Handler, opts ...SubscribeOption) (Subscriber, error)
+	HookSubscribe      func(next FuncSubscribe) FuncSubscribe
+	FuncBatchSubscribe func(ctx context.Context, topic string, h BatchHandler, opts ...SubscribeOption) (Subscriber, error)
+	HookBatchSubscribe func(next FuncBatchSubscribe) FuncBatchSubscribe
+)
+
 // Handler is used to process messages via a subscription of a topic.
 type Handler func(Event) error
 

broker/memory/memory.go

@@ -3,20 +3,25 @@ package broker
 import (
 	"context"
 	"sync"
-	"time"
 
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/metadata"
-	maddr "go.unistack.org/micro/v4/util/addr"
-	"go.unistack.org/micro/v4/util/id"
-	mnet "go.unistack.org/micro/v4/util/net"
-	"go.unistack.org/micro/v4/util/rand"
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v3/options"
+	maddr "go.unistack.org/micro/v3/util/addr"
+	"go.unistack.org/micro/v3/util/id"
+	mnet "go.unistack.org/micro/v3/util/net"
+	"go.unistack.org/micro/v3/util/rand"
 )
 
 type memoryBroker struct {
-	subscribers map[string][]*memorySubscriber
-	addr        string
-	opts        Options
+	funcPublish        broker.FuncPublish
+	funcBatchPublish   broker.FuncBatchPublish
+	funcSubscribe      broker.FuncSubscribe
+	funcBatchSubscribe broker.FuncBatchSubscribe
+	subscribers        map[string][]*memorySubscriber
+	addr               string
+	opts               broker.Options
 	sync.RWMutex
 	connected bool
 }
@@ -25,20 +30,20 @@ type memoryEvent struct {
 	err     error
 	message interface{}
 	topic   string
-	opts    Options
+	opts    broker.Options
 }
 
 type memorySubscriber struct {
 	ctx          context.Context
 	exit         chan bool
-	handler      Handler
-	batchhandler BatchHandler
+	handler      broker.Handler
+	batchhandler broker.BatchHandler
 	id           string
 	topic        string
-	opts         SubscribeOptions
+	opts         broker.SubscribeOptions
 }
 
-func (m *memoryBroker) Options() Options {
+func (m *memoryBroker) Options() broker.Options {
 	return m.opts
 }
 
@@ -47,6 +52,12 @@ func (m *memoryBroker) Address() string {
 }
 
 func (m *memoryBroker) Connect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
 	m.Lock()
 	defer m.Unlock()
 
@@ -71,6 +82,12 @@ func (m *memoryBroker) Connect(ctx context.Context) error {
 }
 
 func (m *memoryBroker) Disconnect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
 	m.Lock()
 	defer m.Unlock()
 
@@ -82,27 +99,54 @@ func (m *memoryBroker) Disconnect(ctx context.Context) error {
 	return nil
 }
 
-func (m *memoryBroker) Init(opts ...Option) error {
+func (m *memoryBroker) Init(opts ...broker.Option) error {
 	for _, o := range opts {
 		o(&m.opts)
 	}
+
+	m.funcPublish = m.fnPublish
+	m.funcBatchPublish = m.fnBatchPublish
+	m.funcSubscribe = m.fnSubscribe
+	m.funcBatchSubscribe = m.fnBatchSubscribe
+
+	m.opts.Hooks.EachNext(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case broker.HookPublish:
+			m.funcPublish = h(m.funcPublish)
+		case broker.HookBatchPublish:
+			m.funcBatchPublish = h(m.funcBatchPublish)
+		case broker.HookSubscribe:
+			m.funcSubscribe = h(m.funcSubscribe)
+		case broker.HookBatchSubscribe:
+			m.funcBatchSubscribe = h(m.funcBatchSubscribe)
+		}
+	})
+
 	return nil
 }
 
-func (m *memoryBroker) Publish(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error {
-	msg.Header.Set(metadata.HeaderTopic, topic)
-	return m.publish(ctx, []*Message{msg}, opts...)
+func (m *memoryBroker) Publish(ctx context.Context, topic string, msg *broker.Message, opts ...broker.PublishOption) error {
+	return m.funcPublish(ctx, topic, msg, opts...)
 }
 
-func (m *memoryBroker) BatchPublish(ctx context.Context, msgs []*Message, opts ...PublishOption) error {
+func (m *memoryBroker) fnPublish(ctx context.Context, topic string, msg *broker.Message, opts ...broker.PublishOption) error {
+	msg.Header.Set(metadata.HeaderTopic, topic)
+	return m.publish(ctx, []*broker.Message{msg}, opts...)
+}
+
+func (m *memoryBroker) BatchPublish(ctx context.Context, msgs []*broker.Message, opts ...broker.PublishOption) error {
+	return m.funcBatchPublish(ctx, msgs, opts...)
+}
+
+func (m *memoryBroker) fnBatchPublish(ctx context.Context, msgs []*broker.Message, opts ...broker.PublishOption) error {
 	return m.publish(ctx, msgs, opts...)
 }
 
-func (m *memoryBroker) publish(ctx context.Context, msgs []*Message, opts ...PublishOption) error {
+func (m *memoryBroker) publish(ctx context.Context, msgs []*broker.Message, opts ...broker.PublishOption) error {
 	m.RLock()
 	if !m.connected {
 		m.RUnlock()
-		return ErrNotConnected
+		return broker.ErrNotConnected
 	}
 	m.RUnlock()
 
@@ -112,9 +156,9 @@ func (m *memoryBroker) publish(ctx context.Context, msgs []*Message, opts ...Pub
 	case <-ctx.Done():
 		return ctx.Err()
 	default:
-		options := NewPublishOptions(opts...)
+		options := broker.NewPublishOptions(opts...)
 
-		msgTopicMap := make(map[string]Events)
+		msgTopicMap := make(map[string]broker.Events)
 		for _, v := range msgs {
 			p := &memoryEvent{opts: m.opts}
 
@@ -135,22 +179,13 @@ func (m *memoryBroker) publish(ctx context.Context, msgs []*Message, opts ...Pub
 		eh := m.opts.ErrorHandler
 
 		for t, ms := range msgTopicMap {
-			ts := time.Now()
-
-			m.opts.Meter.Counter(PublishMessageInflight, "endpoint", t).Add(len(ms))
-			m.opts.Meter.Counter(SubscribeMessageInflight, "endpoint", t).Add(len(ms))
-
 			m.RLock()
 			subs, ok := m.subscribers[t]
 			m.RUnlock()
 			if !ok {
-				m.opts.Meter.Counter(PublishMessageTotal, "endpoint", t, "status", "failure").Add(len(ms))
-				m.opts.Meter.Counter(PublishMessageInflight, "endpoint", t).Add(-len(ms))
-				m.opts.Meter.Counter(SubscribeMessageInflight, "endpoint", t).Add(-len(ms))
 				continue
 			}
 
-			m.opts.Meter.Counter(PublishMessageTotal, "endpoint", t, "status", "success").Add(len(ms))
 			for _, sub := range subs {
 				if sub.opts.BatchErrorHandler != nil {
 					beh = sub.opts.BatchErrorHandler
@@ -162,75 +197,51 @@ func (m *memoryBroker) publish(ctx context.Context, msgs []*Message, opts ...Pub
 				switch {
 				// batch processing
 				case sub.batchhandler != nil:
-
 					if err = sub.batchhandler(ms); err != nil {
-						m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "failure").Inc()
 						ms.SetError(err)
 						if beh != nil {
 							_ = beh(ms)
 						} else if m.opts.Logger.V(logger.ErrorLevel) {
 							m.opts.Logger.Error(m.opts.Context, err.Error())
 						}
-					} else {
-						if sub.opts.AutoAck {
-							if err = ms.Ack(); err != nil {
-								m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
-								m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "failure").Inc()
-							} else {
-								m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "success").Inc()
-							}
-						} else {
-							m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "success").Inc()
+					} else if sub.opts.AutoAck {
+						if err = ms.Ack(); err != nil {
+							m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
 						}
 					}
-					m.opts.Meter.Counter(PublishMessageInflight, "endpoint", t).Add(-len(ms))
-					m.opts.Meter.Counter(SubscribeMessageInflight, "endpoint", t).Add(-len(ms))
 					// single processing
 				case sub.handler != nil:
 					for _, p := range ms {
 						if err = sub.handler(p); err != nil {
-							m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "failure").Inc()
 							p.SetError(err)
 							if eh != nil {
 								_ = eh(p)
 							} else if m.opts.Logger.V(logger.ErrorLevel) {
 								m.opts.Logger.Error(m.opts.Context, err.Error())
 							}
-						} else {
-							if sub.opts.AutoAck {
-								if err = p.Ack(); err != nil {
-									m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
-									m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "failure").Inc()
-								} else {
-									m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "success").Inc()
-								}
-							} else {
-								m.opts.Meter.Counter(SubscribeMessageTotal, "endpoint", t, "status", "success").Inc()
+						} else if sub.opts.AutoAck {
+							if err = p.Ack(); err != nil {
+								m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
 							}
 						}
-						m.opts.Meter.Counter(PublishMessageInflight, "endpoint", t).Add(-1)
-						m.opts.Meter.Counter(SubscribeMessageInflight, "endpoint", t).Add(-1)
 					}
 				}
-
 			}
-			te := time.Since(ts)
-			m.opts.Meter.Summary(PublishMessageLatencyMicroseconds, "endpoint", t).Update(te.Seconds())
-			m.opts.Meter.Histogram(PublishMessageDurationSeconds, "endpoint", t).Update(te.Seconds())
-			m.opts.Meter.Summary(SubscribeMessageLatencyMicroseconds, "endpoint", t).Update(te.Seconds())
-			m.opts.Meter.Histogram(SubscribeMessageDurationSeconds, "endpoint", t).Update(te.Seconds())
 		}
-
 	}
 
 	return nil
 }
 
-func (m *memoryBroker) BatchSubscribe(ctx context.Context, topic string, handler BatchHandler, opts ...SubscribeOption) (Subscriber, error) {
+func (m *memoryBroker) BatchSubscribe(ctx context.Context, topic string, handler broker.BatchHandler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	return m.funcBatchSubscribe(ctx, topic, handler, opts...)
+}
+
+func (m *memoryBroker) fnBatchSubscribe(ctx context.Context, topic string, handler broker.BatchHandler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
 	m.RLock()
 	if !m.connected {
 		m.RUnlock()
-		return nil, ErrNotConnected
+		return nil, broker.ErrNotConnected
 	}
 	m.RUnlock()
 
@@ -239,7 +250,7 @@ func (m *memoryBroker) BatchSubscribe(ctx context.Context, topic string, handler
 		return nil, err
 	}
 
-	options := NewSubscribeOptions(opts...)
+	options := broker.NewSubscribeOptions(opts...)
 
 	sub := &memorySubscriber{
 		exit:         make(chan bool, 1),
@@ -271,11 +282,15 @@ func (m *memoryBroker) BatchSubscribe(ctx context.Context, topic string, handler
 	return sub, nil
 }
 
-func (m *memoryBroker) Subscribe(ctx context.Context, topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
+func (m *memoryBroker) Subscribe(ctx context.Context, topic string, handler broker.Handler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	return m.funcSubscribe(ctx, topic, handler, opts...)
+}
+
+func (m *memoryBroker) fnSubscribe(ctx context.Context, topic string, handler broker.Handler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
 	m.RLock()
 	if !m.connected {
 		m.RUnlock()
-		return nil, ErrNotConnected
+		return nil, broker.ErrNotConnected
 	}
 	m.RUnlock()
 
@@ -284,7 +299,7 @@ func (m *memoryBroker) Subscribe(ctx context.Context, topic string, handler Hand
 		return nil, err
 	}
 
-	options := NewSubscribeOptions(opts...)
+	options := broker.NewSubscribeOptions(opts...)
 
 	sub := &memorySubscriber{
 		exit:    make(chan bool, 1),
@@ -328,12 +343,12 @@ func (m *memoryEvent) Topic() string {
 	return m.topic
 }
 
-func (m *memoryEvent) Message() *Message {
+func (m *memoryEvent) Message() *broker.Message {
 	switch v := m.message.(type) {
-	case *Message:
+	case *broker.Message:
 		return v
 	case []byte:
-		msg := &Message{}
+		msg := &broker.Message{}
 		if err := m.opts.Codec.Unmarshal(v, msg); err != nil {
 			if m.opts.Logger.V(logger.ErrorLevel) {
 				m.opts.Logger.Error(m.opts.Context, "[memory]: failed to unmarshal: %v", err)
@@ -358,7 +373,7 @@ func (m *memoryEvent) SetError(err error) {
 	m.err = err
 }
 
-func (m *memorySubscriber) Options() SubscribeOptions {
+func (m *memorySubscriber) Options() broker.SubscribeOptions {
 	return m.opts
 }
 
@@ -372,9 +387,9 @@ func (m *memorySubscriber) Unsubscribe(ctx context.Context) error {
 }
 
 // NewBroker return new memory broker
-func NewBroker(opts ...Option) Broker {
+func NewBroker(opts ...broker.Option) broker.Broker {
 	return &memoryBroker{
-		opts:        NewOptions(opts...),
+		opts:        broker.NewOptions(opts...),
 		subscribers: make(map[string][]*memorySubscriber),
 	}
 }

broker/memory/memory_test.go

@@ -5,13 +5,18 @@ import (
 	"fmt"
 	"testing"
 
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 func TestMemoryBatchBroker(t *testing.T) {
 	b := NewBroker()
 	ctx := context.Background()
 
+	if err := b.Init(); err != nil {
+		t.Fatalf("Unexpected init error %v", err)
+	}
+
 	if err := b.Connect(ctx); err != nil {
 		t.Fatalf("Unexpected connect error %v", err)
 	}
@@ -19,7 +24,7 @@ func TestMemoryBatchBroker(t *testing.T) {
 	topic := "test"
 	count := 10
 
-	fn := func(evts Events) error {
+	fn := func(evts broker.Events) error {
 		return evts.Ack()
 	}
 
@@ -28,9 +33,9 @@ func TestMemoryBatchBroker(t *testing.T) {
 		t.Fatalf("Unexpected error subscribing %v", err)
 	}
 
-	msgs := make([]*Message, 0, count)
+	msgs := make([]*broker.Message, 0, count)
 	for i := 0; i < count; i++ {
-		message := &Message{
+		message := &broker.Message{
 			Header: map[string]string{
 				metadata.HeaderTopic: topic,
 				"foo":                "bar",
@@ -58,6 +63,10 @@ func TestMemoryBroker(t *testing.T) {
 	b := NewBroker()
 	ctx := context.Background()
 
+	if err := b.Init(); err != nil {
+		t.Fatalf("Unexpected init error %v", err)
+	}
+
 	if err := b.Connect(ctx); err != nil {
 		t.Fatalf("Unexpected connect error %v", err)
 	}
@@ -65,7 +74,7 @@ func TestMemoryBroker(t *testing.T) {
 	topic := "test"
 	count := 10
 
-	fn := func(p Event) error {
+	fn := func(p broker.Event) error {
 		return nil
 	}
 
@@ -74,9 +83,9 @@ func TestMemoryBroker(t *testing.T) {
 		t.Fatalf("Unexpected error subscribing %v", err)
 	}
 
-	msgs := make([]*Message, 0, count)
+	msgs := make([]*broker.Message, 0, count)
 	for i := 0; i < count; i++ {
-		message := &Message{
+		message := &broker.Message{
 			Header: map[string]string{
 				metadata.HeaderTopic: topic,
 				"foo":                "bar",

broker/noop.go

@@ -0,0 +1,128 @@
+package broker
+
+import (
+	"context"
+	"strings"
+
+	"go.unistack.org/micro/v3/options"
+)
+
+type NoopBroker struct {
+	funcPublish        FuncPublish
+	funcBatchPublish   FuncBatchPublish
+	funcSubscribe      FuncSubscribe
+	funcBatchSubscribe FuncBatchSubscribe
+	opts               Options
+}
+
+func NewBroker(opts ...Option) *NoopBroker {
+	b := &NoopBroker{opts: NewOptions(opts...)}
+	b.funcPublish = b.fnPublish
+	b.funcBatchPublish = b.fnBatchPublish
+	b.funcSubscribe = b.fnSubscribe
+	b.funcBatchSubscribe = b.fnBatchSubscribe
+
+	return b
+}
+
+func (b *NoopBroker) Name() string {
+	return b.opts.Name
+}
+
+func (b *NoopBroker) String() string {
+	return "noop"
+}
+
+func (b *NoopBroker) Options() Options {
+	return b.opts
+}
+
+func (b *NoopBroker) Init(opts ...Option) error {
+	for _, opt := range opts {
+		opt(&b.opts)
+	}
+
+	b.funcPublish = b.fnPublish
+	b.funcBatchPublish = b.fnBatchPublish
+	b.funcSubscribe = b.fnSubscribe
+	b.funcBatchSubscribe = b.fnBatchSubscribe
+
+	b.opts.Hooks.EachNext(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookPublish:
+			b.funcPublish = h(b.funcPublish)
+		case HookBatchPublish:
+			b.funcBatchPublish = h(b.funcBatchPublish)
+		case HookSubscribe:
+			b.funcSubscribe = h(b.funcSubscribe)
+		case HookBatchSubscribe:
+			b.funcBatchSubscribe = h(b.funcBatchSubscribe)
+		}
+	})
+
+	return nil
+}
+
+func (b *NoopBroker) Connect(_ context.Context) error {
+	return nil
+}
+
+func (b *NoopBroker) Disconnect(_ context.Context) error {
+	return nil
+}
+
+func (b *NoopBroker) Address() string {
+	return strings.Join(b.opts.Addrs, ",")
+}
+
+func (b *NoopBroker) fnBatchPublish(_ context.Context, _ []*Message, _ ...PublishOption) error {
+	return nil
+}
+
+func (b *NoopBroker) BatchPublish(ctx context.Context, msgs []*Message, opts ...PublishOption) error {
+	return b.funcBatchPublish(ctx, msgs, opts...)
+}
+
+func (b *NoopBroker) fnPublish(_ context.Context, _ string, _ *Message, _ ...PublishOption) error {
+	return nil
+}
+
+func (b *NoopBroker) Publish(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error {
+	return b.funcPublish(ctx, topic, msg, opts...)
+}
+
+type NoopSubscriber struct {
+	ctx          context.Context
+	topic        string
+	handler      Handler
+	batchHandler BatchHandler
+	opts         SubscribeOptions
+}
+
+func (b *NoopBroker) fnBatchSubscribe(ctx context.Context, topic string, handler BatchHandler, opts ...SubscribeOption) (Subscriber, error) {
+	return &NoopSubscriber{ctx: ctx, topic: topic, opts: NewSubscribeOptions(opts...), batchHandler: handler}, nil
+}
+
+func (b *NoopBroker) BatchSubscribe(ctx context.Context, topic string, handler BatchHandler, opts ...SubscribeOption) (Subscriber, error) {
+	return b.funcBatchSubscribe(ctx, topic, handler, opts...)
+}
+
+func (b *NoopBroker) fnSubscribe(ctx context.Context, topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
+	return &NoopSubscriber{ctx: ctx, topic: topic, opts: NewSubscribeOptions(opts...), handler: handler}, nil
+}
+
+func (b *NoopBroker) Subscribe(ctx context.Context, topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
+	return b.funcSubscribe(ctx, topic, handler, opts...)
+}
+
+func (s *NoopSubscriber) Options() SubscribeOptions {
+	return s.opts
+}
+
+func (s *NoopSubscriber) Topic() string {
+	return s.topic
+}
+
+func (s *NoopSubscriber) Unsubscribe(_ context.Context) error {
+	return nil
+}

broker/noop_test.go

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

broker/options.go

@@ -5,30 +5,13 @@ import (
 	"crypto/tls"
 	"time"
 
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/register"
-	"go.unistack.org/micro/v4/tracer"
-)
-
-var (
-	// PublishMessageDurationSeconds specifies meter metric name
-	PublishMessageDurationSeconds = "publish_message_duration_seconds"
-	// PublishMessageLatencyMicroseconds specifies meter metric name
-	PublishMessageLatencyMicroseconds = "publish_message_latency_microseconds"
-	// PublishMessageTotal specifies meter metric name
-	PublishMessageTotal = "publish_message_total"
-	// PublishMessageInflight specifies meter metric name
-	PublishMessageInflight = "publish_message_inflight"
-	// SubscribeMessageDurationSeconds specifies meter metric name
-	SubscribeMessageDurationSeconds = "subscribe_message_duration_seconds"
-	// SubscribeMessageLatencyMicroseconds specifies meter metric name
-	SubscribeMessageLatencyMicroseconds = "subscribe_message_latency_microseconds"
-	// SubscribeMessageTotal specifies meter metric name
-	SubscribeMessageTotal = "subscribe_message_total"
-	// SubscribeMessageInflight specifies meter metric name
-	SubscribeMessageInflight = "subscribe_message_inflight"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/options"
+	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v3/sync"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Options struct
@@ -55,17 +38,25 @@ type Options struct {
 	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
 }
 
 // NewOptions create new Options
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Register: register.DefaultRegister,
-		Logger:   logger.DefaultLogger,
-		Context:  context.Background(),
-		Meter:    meter.DefaultMeter,
-		Codec:    codec.DefaultCodec,
-		Tracer:   tracer.DefaultTracer,
+		Register:        register.DefaultRegister,
+		Logger:          logger.DefaultLogger,
+		Context:         context.Background(),
+		Meter:           meter.DefaultMeter,
+		Codec:           codec.DefaultCodec,
+		Tracer:          tracer.DefaultTracer,
+		GracefulTimeout: DefaultGracefulTimeout,
 	}
 	for _, o := range opts {
 		o(&options)
@@ -243,6 +234,13 @@ func Name(n string) Option {
 	}
 }
 
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}
+
 // SubscribeContext set context
 func SubscribeContext(ctx context.Context) SubscribeOption {
 	return func(o *SubscribeOptions) {

client/backoff.go

@@ -5,7 +5,7 @@ import (
 	"math"
 	"time"
 
-	"go.unistack.org/micro/v4/util/backoff"
+	"go.unistack.org/micro/v3/util/backoff"
 )
 
 // BackoffFunc is the backoff call func

client/client.go

@@ -1,12 +1,12 @@
 // Package client is an interface for an RPC client
-package client // import "go.unistack.org/micro/v4/client"
+package client // import "go.unistack.org/micro/v3/client"
 
 import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 var (
@@ -44,6 +44,17 @@ type Client interface {
 	String() string
 }
 
+type (
+	FuncCall         func(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error
+	HookCall         func(next FuncCall) FuncCall
+	FuncStream       func(ctx context.Context, req Request, opts ...CallOption) (Stream, error)
+	HookStream       func(next FuncStream) FuncStream
+	FuncPublish      func(ctx context.Context, msg Message, opts ...PublishOption) error
+	HookPublish      func(next FuncPublish) FuncPublish
+	FuncBatchPublish func(ctx context.Context, msg []Message, opts ...PublishOption) error
+	HookBatchPublish func(next FuncBatchPublish) FuncBatchPublish
+)
+
 // Message is the interface for publishing asynchronously
 type Message interface {
 	Topic() string

client/client_call_options_test.go

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

client/lookup.go

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

client/noop.go

@@ -3,13 +3,18 @@ package client
 import (
 	"context"
 	"fmt"
+	"os"
+	"strconv"
 	"time"
 
-	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/errors"
-	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v4/selector"
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/errors"
+	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v3/options"
+	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v3/semconv"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // DefaultCodecs will be used to encode/decode data
@@ -18,7 +23,11 @@ var DefaultCodecs = map[string]codec.Codec{
 }
 
 type noopClient struct {
-	opts Options
+	funcPublish      FuncPublish
+	funcBatchPublish FuncBatchPublish
+	funcCall         FuncCall
+	funcStream       FuncStream
+	opts             Options
 }
 
 type noopMessage struct {
@@ -39,16 +48,14 @@ type noopRequest struct {
 
 // NewClient returns new noop client
 func NewClient(opts ...Option) Client {
-	nc := &noopClient{opts: NewOptions(opts...)}
-	// wrap in reverse
+	n := &noopClient{opts: NewOptions(opts...)}
 
-	c := Client(nc)
+	n.funcCall = n.fnCall
+	n.funcStream = n.fnStream
+	n.funcPublish = n.fnPublish
+	n.funcBatchPublish = n.fnBatchPublish
 
-	for i := len(nc.opts.Wrappers); i > 0; i-- {
-		c = nc.opts.Wrappers[i-1](c)
-	}
-
-	return c
+	return n
 }
 
 func (n *noopClient) Name() string {
@@ -100,10 +107,13 @@ func (n *noopResponse) Read() ([]byte, error) {
 	return nil, nil
 }
 
-type noopStream struct{}
+type noopStream struct {
+	err error
+	ctx context.Context
+}
 
 func (n *noopStream) Context() context.Context {
-	return context.Background()
+	return n.ctx
 }
 
 func (n *noopStream) Request() Request {
@@ -131,15 +141,21 @@ func (n *noopStream) RecvMsg(interface{}) error {
 }
 
 func (n *noopStream) Error() error {
-	return nil
+	return n.err
 }
 
 func (n *noopStream) Close() error {
-	return nil
+	if sp, ok := tracer.SpanFromContext(n.ctx); ok && sp != nil {
+		if n.err != nil {
+			sp.SetStatus(tracer.SpanStatusError, n.err.Error())
+		}
+		sp.Finish()
+	}
+	return n.err
 }
 
 func (n *noopStream) CloseSend() error {
-	return nil
+	return n.err
 }
 
 func (n *noopMessage) Topic() string {
@@ -172,6 +188,25 @@ func (n *noopClient) Init(opts ...Option) error {
 	for _, o := range opts {
 		o(&n.opts)
 	}
+
+	n.funcCall = n.fnCall
+	n.funcStream = n.fnStream
+	n.funcPublish = n.fnPublish
+	n.funcBatchPublish = n.fnBatchPublish
+
+	n.opts.Hooks.EachNext(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookCall:
+			n.funcCall = h(n.funcCall)
+		case HookStream:
+			n.funcStream = h(n.funcStream)
+		case HookPublish:
+			n.funcPublish = h(n.funcPublish)
+		case HookBatchPublish:
+			n.funcBatchPublish = h(n.funcBatchPublish)
+		}
+	})
+
 	return nil
 }
 
@@ -184,6 +219,31 @@ func (n *noopClient) String() string {
 }
 
 func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error {
+	ts := time.Now()
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
+	var sp tracer.Span
+	ctx, sp = n.opts.Tracer.Start(ctx, req.Endpoint()+" rpc-client",
+		tracer.WithSpanKind(tracer.SpanKindClient),
+		tracer.WithSpanLabels("endpoint", req.Endpoint()),
+	)
+	err := n.funcCall(ctx, req, rsp, opts...)
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Dec()
+	te := time.Since(ts)
+	n.opts.Meter.Summary(semconv.ClientRequestLatencyMicroseconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+	n.opts.Meter.Histogram(semconv.ClientRequestDurationSeconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+
+	if me := errors.FromError(err); me == nil {
+		sp.Finish()
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "success", "code", strconv.Itoa(int(200))).Inc()
+	} else {
+		sp.SetStatus(tracer.SpanStatusError, err.Error())
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "failure", "code", strconv.Itoa(int(me.Code))).Inc()
+	}
+
+	return err
+}
+
+func (n *noopClient) fnCall(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error {
 	// make a copy of call opts
 	callOpts := n.opts.CallOptions
 	for _, opt := range opts {
@@ -212,11 +272,8 @@ func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opt
 	}
 
 	// make copy of call method
-	hcall := n.call
-
-	// wrap the call in reverse
-	for i := len(callOpts.CallWrappers); i > 0; i-- {
-		hcall = callOpts.CallWrappers[i-1](hcall)
+	hcall := func(ctx context.Context, addr string, req Request, rsp interface{}, opts CallOptions) error {
+		return nil
 	}
 
 	// use the router passed as a call option, or fallback to the rpc clients router
@@ -315,10 +372,6 @@ func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opt
 	return gerr
 }
 
-func (n *noopClient) call(ctx context.Context, addr string, req Request, rsp interface{}, opts CallOptions) error {
-	return nil
-}
-
 func (n *noopClient) NewRequest(service, endpoint string, req interface{}, opts ...RequestOption) Request {
 	return &noopRequest{service: service, endpoint: endpoint}
 }
@@ -329,6 +382,31 @@ func (n *noopClient) NewMessage(topic string, msg interface{}, opts ...MessageOp
 }
 
 func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption) (Stream, error) {
+	ts := time.Now()
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
+	var sp tracer.Span
+	ctx, sp = n.opts.Tracer.Start(ctx, req.Endpoint()+" rpc-client",
+		tracer.WithSpanKind(tracer.SpanKindClient),
+		tracer.WithSpanLabels("endpoint", req.Endpoint()),
+	)
+	stream, err := n.funcStream(ctx, req, opts...)
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Dec()
+	te := time.Since(ts)
+	n.opts.Meter.Summary(semconv.ClientRequestLatencyMicroseconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+	n.opts.Meter.Histogram(semconv.ClientRequestDurationSeconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+
+	if me := errors.FromError(err); me == nil {
+		sp.Finish()
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "success", "code", strconv.Itoa(int(200))).Inc()
+	} else {
+		sp.SetStatus(tracer.SpanStatusError, err.Error())
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "failure", "code", strconv.Itoa(int(me.Code))).Inc()
+	}
+
+	return stream, err
+}
+
+func (n *noopClient) fnStream(ctx context.Context, req Request, opts ...CallOption) (Stream, error) {
 	var err error
 
 	// make a copy of call opts
@@ -469,14 +547,22 @@ func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption
 }
 
 func (n *noopClient) stream(ctx context.Context, addr string, req Request, opts CallOptions) (Stream, error) {
-	return &noopStream{}, nil
+	return &noopStream{ctx: ctx}, nil
 }
 
 func (n *noopClient) BatchPublish(ctx context.Context, ps []Message, opts ...PublishOption) error {
+	return n.funcBatchPublish(ctx, ps, opts...)
+}
+
+func (n *noopClient) fnBatchPublish(ctx context.Context, ps []Message, opts ...PublishOption) error {
 	return n.publish(ctx, ps, opts...)
 }
 
 func (n *noopClient) Publish(ctx context.Context, p Message, opts ...PublishOption) error {
+	return n.funcPublish(ctx, p, opts...)
+}
+
+func (n *noopClient) fnPublish(ctx context.Context, p Message, opts ...PublishOption) error {
 	return n.publish(ctx, []Message{p}, opts...)
 }
 
@@ -485,21 +571,34 @@ func (n *noopClient) publish(ctx context.Context, ps []Message, opts ...PublishO
 
 	msgs := make([]*broker.Message, 0, len(ps))
 
+	// get proxy
+	exchange := ""
+	if v, ok := os.LookupEnv("MICRO_PROXY"); ok {
+		exchange = v
+	}
+	// get the exchange
+	if len(options.Exchange) > 0 {
+		exchange = options.Exchange
+	}
+
+	omd, ok := metadata.FromOutgoingContext(ctx)
+	if !ok {
+		omd = metadata.New(0)
+	}
+
 	for _, p := range ps {
-		md, ok := metadata.FromOutgoingContext(ctx)
-		if !ok {
-			md = metadata.New(0)
-		}
+		md := metadata.Copy(omd)
 		md[metadata.HeaderContentType] = p.ContentType()
-
 		topic := p.Topic()
-
-		// get the exchange
-		if len(options.Exchange) > 0 {
-			topic = options.Exchange
+		if len(exchange) > 0 {
+			topic = exchange
 		}
-
 		md[metadata.HeaderTopic] = topic
+		iter := p.Metadata().Iterator()
+		var k, v string
+		for iter.Next(&k, &v) {
+			md.Set(k, v)
+		}
 
 		var body []byte
 
@@ -524,6 +623,13 @@ func (n *noopClient) publish(ctx context.Context, ps []Message, opts ...PublishO
 		msgs = append(msgs, &broker.Message{Header: md, Body: body})
 	}
 
+	if len(msgs) == 1 {
+		return n.opts.Broker.Publish(ctx, msgs[0].Header[metadata.HeaderTopic], msgs[0],
+			broker.PublishContext(options.Context),
+			broker.PublishBodyOnly(options.BodyOnly),
+		)
+	}
+
 	return n.opts.Broker.BatchPublish(ctx, msgs,
 		broker.PublishContext(options.Context),
 		broker.PublishBodyOnly(options.BodyOnly),

client/noop_test.go

@@ -0,0 +1,35 @@
+package client
+
+import (
+	"context"
+	"testing"
+)
+
+type testHook struct {
+	f bool
+}
+
+func (t *testHook) Publish(fn FuncPublish) FuncPublish {
+	return func(ctx context.Context, msg Message, opts ...PublishOption) error {
+		t.f = true
+		return fn(ctx, msg, opts...)
+	}
+}
+
+func TestNoopHook(t *testing.T) {
+	h := &testHook{}
+
+	c := NewClient(Hooks(HookPublish(h.Publish)))
+
+	if err := c.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := c.Publish(context.TODO(), c.NewMessage("", nil, MessageContentType("application/octet-stream"))); err != nil {
+		t.Fatal(err)
+	}
+
+	if !h.f {
+		t.Fatal("hook not works")
+	}
+}

client/options.go

@@ -6,17 +6,18 @@ import (
 	"net"
 	"time"
 
-	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/network/transport"
-	"go.unistack.org/micro/v4/register"
-	"go.unistack.org/micro/v4/router"
-	"go.unistack.org/micro/v4/selector"
-	"go.unistack.org/micro/v4/selector/random"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/codec"
+	"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"
+	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v3/selector/random"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Options holds client options
@@ -59,6 +60,9 @@ type Options struct {
 	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
@@ -92,8 +96,6 @@ type CallOptions struct {
 	Address []string
 	// SelectOptions selector options
 	SelectOptions []selector.SelectOption
-	// CallWrappers call wrappers
-	CallWrappers []CallWrapper
 	// StreamTimeout stream timeout
 	StreamTimeout time.Duration
 	// RequestTimeout request timeout
@@ -185,7 +187,7 @@ func NewOptions(opts ...Option) Options {
 	options := Options{
 		Context:     context.Background(),
 		ContentType: DefaultContentType,
-		Codecs:      make(map[string]codec.Codec),
+		Codecs:      DefaultCodecs,
 		CallOptions: CallOptions{
 			Context:        context.Background(),
 			Backoff:        DefaultBackoff,
@@ -306,20 +308,6 @@ func Selector(s selector.Selector) Option {
 	}
 }
 
-// Wrap adds a wrapper to the list of options passed into the client
-func Wrap(w Wrapper) Option {
-	return func(o *Options) {
-		o.Wrappers = append(o.Wrappers, w)
-	}
-}
-
-// WrapCall adds a wrapper to the list of CallFunc wrappers
-func WrapCall(cw ...CallWrapper) Option {
-	return func(o *Options) {
-		o.CallOptions.CallWrappers = append(o.CallOptions.CallWrappers, cw...)
-	}
-}
-
 // Backoff is used to set the backoff function used when retrying Calls
 func Backoff(fn BackoffFunc) Option {
 	return func(o *Options) {
@@ -450,13 +438,6 @@ func WithAddress(a ...string) CallOption {
 	}
 }
 
-// WithCallWrapper is a CallOption which adds to the existing CallFunc wrappers
-func WithCallWrapper(cw ...CallWrapper) CallOption {
-	return func(o *CallOptions) {
-		o.CallWrappers = append(o.CallWrappers, cw...)
-	}
-}
-
 // WithBackoff is a CallOption which overrides that which
 // set in Options.CallOptions
 func WithBackoff(fn BackoffFunc) CallOption {
@@ -591,3 +572,10 @@ func RequestContentType(ct string) RequestOption {
 		o.ContentType = ct
 	}
 }
+
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}

client/retry.go

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

client/retry_test.go

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

client/test_request.go

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

cluster/cluster.go

@@ -0,0 +1,41 @@
+package cluster
+
+import (
+	"context"
+
+	"go.unistack.org/micro/v3/metadata"
+)
+
+// Message sent to member in cluster
+type Message interface {
+	// Header returns message headers
+	Header() metadata.Metadata
+	// Body returns broker message may be []byte slice or some go struct or interface
+	Body() interface{}
+}
+
+type Node interface {
+	// Name returns node name
+	Name() string
+	// Address returns node address
+	Address() string
+	// Metadata returns node metadata
+	Metadata() metadata.Metadata
+}
+
+// Cluster interface used for cluster communication across nodes
+type Cluster interface {
+	// Join is used to take an existing members and performing state sync
+	Join(ctx context.Context, addr ...string) error
+	// Leave broadcast a leave message and stop listeners
+	Leave(ctx context.Context) error
+	// Ping is used to probe live status of the node
+	Ping(ctx context.Context, node Node, payload []byte) error
+	// Members returns the cluster members
+	Members() ([]Node, error)
+	// Broadcast send message for all members in cluster, if filter is not nil, nodes may be filtered
+	// by key/value pairs
+	Broadcast(ctx context.Context, msg Message, filter ...string) error
+	// Unicast send message to single member in cluster
+	Unicast(ctx context.Context, node Node, msg Message) error
+}

codec/codec.go

@@ -1,11 +1,11 @@
 // Package codec is an interface for encoding messages
-package codec // import "go.unistack.org/micro/v4/codec"
+package codec // import "go.unistack.org/micro/v3/codec"
 
 import (
 	"errors"
 	"io"
 
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 // Message types

codec/frame.proto

@@ -1,4 +1,4 @@
-// Copyright 2021-2023 Unistack LLC
+// Copyright 2021 Unistack LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,7 +17,7 @@ syntax = "proto3";
 package micro.codec;
 
 option cc_enable_arenas = true;
-option go_package = "go.unistack.org/micro/v4/codec;codec";
+option go_package = "go.unistack.org/micro/v3/codec;codec";
 option java_multiple_files = true;
 option java_outer_classname = "MicroCodec";
 option java_package = "micro.codec";

codec/options.go

@@ -3,9 +3,9 @@ package codec
 import (
 	"context"
 
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Option func

config/config.go

@@ -1,5 +1,5 @@
 // Package config is an interface for dynamic configuration.
-package config // import "go.unistack.org/micro/v4/config"
+package config // import "go.unistack.org/micro/v3/config"
 
 import (
 	"context"
@@ -13,7 +13,7 @@ type Validator interface {
 }
 
 // DefaultConfig default config
-var DefaultConfig = NewConfig()
+var DefaultConfig Config = NewConfig()
 
 // DefaultWatcherMinInterval default min interval for poll changes
 var DefaultWatcherMinInterval = 5 * time.Second
@@ -50,6 +50,13 @@ type Config interface {
 	String() string
 }
 
+type (
+	FuncLoad func(ctx context.Context, opts ...LoadOption) error
+	HookLoad func(next FuncLoad) FuncLoad
+	FuncSave func(ctx context.Context, opts ...SaveOption) error
+	HookSave func(next FuncSave) FuncSave
+)
+
 // Watcher is the config watcher
 type Watcher interface {
 	// Next blocks until update happens or error returned

config/default.go

@@ -7,13 +7,18 @@ import (
 	"strings"
 	"time"
 
-	"github.com/imdario/mergo"
-	rutil "go.unistack.org/micro/v4/util/reflect"
-	mtime "go.unistack.org/micro/v4/util/time"
+	"dario.cat/mergo"
+	"github.com/google/uuid"
+	"go.unistack.org/micro/v3/options"
+	mid "go.unistack.org/micro/v3/util/id"
+	rutil "go.unistack.org/micro/v3/util/reflect"
+	mtime "go.unistack.org/micro/v3/util/time"
 )
 
 type defaultConfig struct {
-	opts Options
+	funcLoad FuncLoad
+	funcSave FuncSave
+	opts     Options
 }
 
 func (c *defaultConfig) Options() Options {
@@ -29,6 +34,18 @@ func (c *defaultConfig) Init(opts ...Option) error {
 		return err
 	}
 
+	c.funcLoad = c.fnLoad
+	c.funcSave = c.fnSave
+
+	c.opts.Hooks.EachNext(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookLoad:
+			c.funcLoad = h(c.funcLoad)
+		case HookSave:
+			c.funcSave = h(c.funcSave)
+		}
+	})
+
 	if err := DefaultAfterInit(c.opts.Context, c); err != nil && !c.opts.AllowFail {
 		return err
 	}
@@ -37,7 +54,17 @@ func (c *defaultConfig) Init(opts ...Option) error {
 }
 
 func (c *defaultConfig) Load(ctx context.Context, opts ...LoadOption) error {
-	if err := DefaultBeforeLoad(ctx, c); err != nil && !c.opts.AllowFail {
+	return c.funcLoad(ctx, opts...)
+}
+
+func (c *defaultConfig) fnLoad(ctx context.Context, opts ...LoadOption) error {
+	var err error
+
+	if c.opts.SkipLoad != nil && c.opts.SkipLoad(ctx, c) {
+		return nil
+	}
+
+	if err = DefaultBeforeLoad(ctx, c); err != nil && !c.opts.AllowFail {
 		return err
 	}
 
@@ -124,6 +151,20 @@ func fillValue(value reflect.Value, val string) error {
 		}
 		value.Set(reflect.ValueOf(v))
 	case reflect.String:
+		switch val {
+		case "micro:generate uuid":
+			uid, err := uuid.NewRandom()
+			if err != nil {
+				return err
+			}
+			val = uid.String()
+		case "micro:generate id":
+			uid, err := mid.New()
+			if err != nil {
+				return err
+			}
+			val = uid
+		}
 		value.Set(reflect.ValueOf(val))
 	case reflect.Float32:
 		v, err := strconv.ParseFloat(val, 32)
@@ -169,7 +210,7 @@ func fillValue(value reflect.Value, val string) error {
 				return err
 			}
 			value.Set(reflect.ValueOf(v))
-		case value.Type().String() == "time.Duration" && value.Type().PkgPath() == "go.unistack.org/micro/v4/util/time":
+		case value.Type().String() == "time.Duration" && value.Type().PkgPath() == "go.unistack.org/micro/v3/util/time":
 			v, err := mtime.ParseDuration(val)
 			if err != nil {
 				return err
@@ -213,6 +254,7 @@ func fillValue(value reflect.Value, val string) error {
 		}
 		value.Set(reflect.ValueOf(v))
 	}
+
 	return nil
 }
 
@@ -276,6 +318,14 @@ func fillValues(valueOf reflect.Value, tname string) error {
 }
 
 func (c *defaultConfig) Save(ctx context.Context, opts ...SaveOption) error {
+	return c.funcSave(ctx, opts...)
+}
+
+func (c *defaultConfig) fnSave(ctx context.Context, opts ...SaveOption) error {
+	if c.opts.SkipSave != nil && c.opts.SkipSave(ctx, c) {
+		return nil
+	}
+
 	if err := DefaultBeforeSave(ctx, c); err != nil {
 		return err
 	}
@@ -295,7 +345,7 @@ func (c *defaultConfig) Name() string {
 	return c.opts.Name
 }
 
-func (c *defaultConfig) Watch(ctx context.Context, opts ...WatchOption) (Watcher, error) {
+func (c *defaultConfig) Watch(_ context.Context, _ ...WatchOption) (Watcher, error) {
 	return nil, ErrWatcherNotImplemented
 }
 
@@ -305,5 +355,9 @@ func NewConfig(opts ...Option) Config {
 	if len(options.StructTag) == 0 {
 		options.StructTag = "default"
 	}
-	return &defaultConfig{opts: options}
+	c := &defaultConfig{opts: options}
+	c.funcLoad = c.fnLoad
+	c.funcSave = c.fnSave
+
+	return c
 }

config/default_test.go

@@ -6,17 +6,21 @@ import (
 	"testing"
 	"time"
 
-	"go.unistack.org/micro/v4/config"
-	mtime "go.unistack.org/micro/v4/util/time"
+	"go.unistack.org/micro/v3/config"
+	mid "go.unistack.org/micro/v3/util/id"
+	mtime "go.unistack.org/micro/v3/util/time"
 )
 
 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"`
+	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"`
 }
 
 type cfgStructValue struct {
@@ -37,6 +41,35 @@ func (c *cfgStructValue) Validate() error {
 	return nil
 }
 
+type testHook struct {
+	f bool
+}
+
+func (t *testHook) Load(fn config.FuncLoad) config.FuncLoad {
+	return func(ctx context.Context, opts ...config.LoadOption) error {
+		t.f = true
+		return fn(ctx, opts...)
+	}
+}
+
+func TestHook(t *testing.T) {
+	h := &testHook{}
+
+	c := config.NewConfig(config.Struct(h), config.Hooks(config.HookLoad(h.Load)))
+
+	if err := c.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := c.Load(context.TODO()); err != nil {
+		t.Fatal(err)
+	}
+
+	if !h.f {
+		t.Fatal("hook not works")
+	}
+}
+
 func TestDefault(t *testing.T) {
 	ctx := context.Background()
 	conf := &cfg{IntValue: 10}
@@ -67,6 +100,21 @@ func TestDefault(t *testing.T) {
 	if conf.StringValue != "after_load" {
 		t.Fatal("AfterLoad option not working")
 	}
+	if len(conf.MapValue) != 2 {
+		t.Fatalf("map value invalid: %#+v\n", conf.MapValue)
+	}
+
+	if conf.UUIDValue == "" {
+		t.Fatalf("uuid value empty")
+	} else if len(conf.UUIDValue) != 36 {
+		t.Fatalf("uuid value invalid: %s", conf.UUIDValue)
+	}
+
+	if conf.IDValue == "" {
+		t.Fatalf("id value empty")
+	} else if len(conf.IDValue) != mid.DefaultSize {
+		t.Fatalf("id value invalid: %s", conf.IDValue)
+	}
 	_ = conf
 	// t.Logf("%#+v\n", conf)
 }

config/options.go

@@ -4,10 +4,11 @@ import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/options"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Options hold the config options
@@ -42,6 +43,12 @@ type Options struct {
 	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
 }
 
 // Option function signature
@@ -68,9 +75,9 @@ type LoadOption func(o *LoadOptions)
 // LoadOptions struct
 type LoadOptions struct {
 	Struct   interface{}
+	Context  context.Context
 	Override bool
 	Append   bool
-	Context  context.Context
 }
 
 // NewLoadOptions create LoadOptions struct with provided opts
@@ -284,3 +291,10 @@ func WatchStruct(src interface{}) WatchOption {
 		o.Struct = src
 	}
 }
+
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}

database/dsn.go

@@ -0,0 +1,157 @@
+package database
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+var (
+	ErrInvalidDSNAddr      = errors.New("invalid dsn addr")
+	ErrInvalidDSNUnescaped = errors.New("dsn must be escaped")
+	ErrInvalidDSNNoSlash   = errors.New("dsn must contains slash")
+)
+
+type Config struct {
+	TLSConfig *tls.Config
+	Username  string
+	Password  string
+	Scheme    string
+	Host      string
+	Port      string
+	Database  string
+	Params    []string
+}
+
+func (cfg *Config) FormatDSN() string {
+	var s strings.Builder
+
+	if len(cfg.Scheme) > 0 {
+		s.WriteString(cfg.Scheme + "://")
+	}
+	// [username[:password]@]
+	if len(cfg.Username) > 0 {
+		s.WriteString(cfg.Username)
+		if len(cfg.Password) > 0 {
+			s.WriteByte(':')
+			s.WriteString(url.PathEscape(cfg.Password))
+		}
+		s.WriteByte('@')
+	}
+
+	// [host:port]
+	if len(cfg.Host) > 0 {
+		s.WriteString(cfg.Host)
+		if len(cfg.Port) > 0 {
+			s.WriteByte(':')
+			s.WriteString(cfg.Port)
+		}
+	}
+
+	// /dbname
+	s.WriteByte('/')
+	s.WriteString(url.PathEscape(cfg.Database))
+
+	for i := 0; i < len(cfg.Params); i += 2 {
+		if i == 0 {
+			s.WriteString("?")
+		} else {
+			s.WriteString("&")
+		}
+		s.WriteString(cfg.Params[i])
+		s.WriteString("=")
+		s.WriteString(cfg.Params[i+1])
+	}
+
+	return s.String()
+}
+
+func ParseDSN(dsn string) (*Config, error) {
+	cfg := &Config{}
+
+	// [user[:password]@][net[(addr)]]/dbname[?param1=value1&paramN=valueN]
+	// Find last '/' that goes before dbname
+	foundSlash := false
+	for i := len(dsn) - 1; i >= 0; i-- {
+		if dsn[i] == '/' {
+			foundSlash = true
+			var j, k int
+
+			// left part is empty if i <= 0
+			if i > 0 {
+				// Find the first ':' in dsn
+				for j = i; j >= 0; j-- {
+					if dsn[j] == ':' {
+						cfg.Scheme = dsn[0:j]
+					}
+				}
+
+				// [username[:password]@][host]
+				// Find the last '@' in dsn[:i]
+				for j = i; j >= 0; j-- {
+					if dsn[j] == '@' {
+						// username[:password]
+						// Find the second ':' in dsn[:j]
+						for k = 0; k < j; k++ {
+							if dsn[k] == ':' {
+								if cfg.Scheme == dsn[:k] {
+									continue
+								}
+								var err error
+								cfg.Password, err = url.PathUnescape(dsn[k+1 : j])
+								if err != nil {
+									return nil, err
+								}
+								break
+							}
+						}
+						cfg.Username = dsn[len(cfg.Scheme)+3 : k]
+						break
+					}
+				}
+
+				for k = j + 1; k < i; k++ {
+					if dsn[k] == ':' {
+						cfg.Host = dsn[j+1 : k]
+						cfg.Port = dsn[k+1 : i]
+						break
+					}
+				}
+
+			}
+
+			// dbname[?param1=value1&...&paramN=valueN]
+			// Find the first '?' in dsn[i+1:]
+			for j = i + 1; j < len(dsn); j++ {
+				if dsn[j] == '?' {
+					parts := strings.Split(dsn[j+1:], "&")
+					cfg.Params = make([]string, 0, len(parts)*2)
+					for _, p := range parts {
+						k, v, found := strings.Cut(p, "=")
+						if !found {
+							continue
+						}
+						cfg.Params = append(cfg.Params, k, v)
+					}
+
+					break
+				}
+			}
+			var err error
+			dbname := dsn[i+1 : j]
+			if cfg.Database, err = url.PathUnescape(dbname); err != nil {
+				return nil, fmt.Errorf("invalid dbname %q: %w", dbname, err)
+			}
+
+			break
+		}
+	}
+
+	if !foundSlash && len(dsn) > 0 {
+		return nil, ErrInvalidDSNNoSlash
+	}
+
+	return cfg, nil
+}

database/dsn_test.go

@@ -0,0 +1,31 @@
+package database
+
+import (
+	"net/url"
+	"testing"
+)
+
+func TestParseDSN(t *testing.T) {
+	cfg, err := ParseDSN("postgres://username:p@ssword#@host:12345/dbname?key1=val2&key2=val2")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.Password != "p@ssword#" {
+		t.Fatalf("parsing error")
+	}
+}
+
+func TestFormatDSN(t *testing.T) {
+	src := "postgres://username:p@ssword#@host:12345/dbname?key1=val2&key2=val2"
+	cfg, err := ParseDSN(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dst, err := url.PathUnescape(cfg.FormatDSN())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if src != dst {
+		t.Fatalf("\n%s\n%s", src, dst)
+	}
+}

errors/errors.go

@@ -1,14 +1,20 @@
 // Package errors provides a way to return detailed information
 // for an RPC request error. The error is normally JSON encoded.
-package errors // import "go.unistack.org/micro/v4/errors"
+package errors // import "go.unistack.org/micro/v3/errors"
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"io"
 	"net/http"
 	"strconv"
 	"strings"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 var (
@@ -256,6 +262,10 @@ func CodeIn(err interface{}, codes ...int32) bool {
 
 // FromError try to convert go error to *Error
 func FromError(err error) *Error {
+	if err == nil {
+		return nil
+	}
+
 	if verr, ok := err.(*Error); ok && verr != nil {
 		return verr
 	}
@@ -340,3 +350,135 @@ func addslashes(str string) string {
 	}
 	return buf.String()
 }
+
+type retryableError struct {
+	err error
+}
+
+// Retryable returns error that can be retried later
+func Retryable(err error) error {
+	return &retryableError{err: err}
+}
+
+type IsRetryableFunc func(error) bool
+
+var (
+	RetrayableOracleErrors = []IsRetryableFunc{
+		func(err error) bool {
+			errmsg := err.Error()
+			switch {
+			case strings.Contains(errmsg, `ORA-`):
+				return true
+			case strings.Contains(errmsg, `can not assign`):
+				return true
+			case strings.Contains(errmsg, `can't assign`):
+				return true
+			}
+			return false
+		},
+	}
+	RetrayablePostgresErrors = []IsRetryableFunc{
+		func(err error) bool {
+			errmsg := err.Error()
+			switch {
+			case strings.Contains(errmsg, `number of field descriptions must equal number of`):
+				return true
+			case strings.Contains(errmsg, `not a pointer`):
+				return true
+			case strings.Contains(errmsg, `values, but dst struct has only`):
+				return true
+			case strings.Contains(errmsg, `struct doesn't have corresponding row field`):
+				return true
+			case strings.Contains(errmsg, `cannot find field`):
+				return true
+			case strings.Contains(errmsg, `cannot scan`) || strings.Contains(errmsg, `cannot convert`):
+				return true
+			case strings.Contains(errmsg, `failed to connect to`):
+				return true
+			}
+			return false
+		},
+	}
+	RetryableMicroErrors = []IsRetryableFunc{
+		func(err error) bool {
+			switch verr := err.(type) {
+			case *Error:
+				switch verr.Code {
+				case 401, 403, 408, 500, 501, 502, 503, 504:
+					return true
+				default:
+					return false
+				}
+			case *retryableError:
+				return true
+			}
+			return false
+		},
+	}
+	RetryableGoErrors = []IsRetryableFunc{
+		func(err error) bool {
+			switch verr := err.(type) {
+			case interface{ SafeToRetry() bool }:
+				return verr.SafeToRetry()
+			case interface{ Timeout() bool }:
+				return verr.Timeout()
+			}
+			switch {
+			case errors.Is(err, io.EOF), errors.Is(err, io.ErrUnexpectedEOF):
+				return true
+			case errors.Is(err, context.DeadlineExceeded):
+				return true
+			case errors.Is(err, io.ErrClosedPipe), errors.Is(err, io.ErrShortBuffer), errors.Is(err, io.ErrShortWrite):
+				return true
+			}
+			return false
+		},
+	}
+	RetryableGrpcErrors = []IsRetryableFunc{
+		func(err error) bool {
+			st, ok := status.FromError(err)
+			if !ok {
+				return false
+			}
+			switch st.Code() {
+			case codes.Unavailable, codes.ResourceExhausted:
+				return true
+			case codes.DeadlineExceeded:
+				return true
+			case codes.Internal:
+				switch {
+				case strings.Contains(st.Message(), `transport: received the unexpected content-type "text/html; charset=UTF-8"`):
+					return true
+				case strings.Contains(st.Message(), io.ErrUnexpectedEOF.Error()):
+					return true
+				case strings.Contains(st.Message(), `stream terminated by RST_STREAM with error code: INTERNAL_ERROR`):
+					return true
+				}
+			}
+			return false
+		},
+	}
+)
+
+// Unwrap provides error wrapping
+func (e *retryableError) Unwrap() error {
+	return e.err
+}
+
+// Error returns the error string
+func (e *retryableError) Error() string {
+	if e.err == nil {
+		return ""
+	}
+	return e.err.Error()
+}
+
+// IsRetryable checks error for ability to retry later
+func IsRetryable(err error, fns ...IsRetryableFunc) bool {
+	for _, fn := range fns {
+		if ok := fn(err); ok {
+			return true
+		}
+	}
+	return false
+}

errors/errors.proto

@@ -1,4 +1,4 @@
-// Copyright 2021-2023 Unistack LLC
+// Copyright 2021 Unistack LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,7 +17,7 @@ syntax = "proto3";
 package micro.errors;
 
 option cc_enable_arenas = true;
-option go_package = "go.unistack.org/micro/v4/errors;errors";
+option go_package = "go.unistack.org/micro/v3/errors;errors";
 option java_multiple_files = true;
 option java_outer_classname = "MicroErrors";
 option java_package = "micro.errors";

errors/errors_test.go

@@ -8,6 +8,13 @@ import (
 	"testing"
 )
 
+func TestIsRetrayable(t *testing.T) {
+	err := fmt.Errorf("ORA-")
+	if !IsRetryable(err, RetrayableOracleErrors...) {
+		t.Fatalf("IsRetrayable not works")
+	}
+}
+
 func TestMarshalJSON(t *testing.T) {
 	e := InternalServerError("id", "err: %v", fmt.Errorf("err: %v", `xxx: "UNIX_TIMESTAMP": invalid identifier`))
 	_, err := json.Marshal(e)

event.go

@@ -3,7 +3,7 @@ package micro
 import (
 	"context"
 
-	"go.unistack.org/micro/v4/client"
+	"go.unistack.org/micro/v3/client"
 )
 
 // Event is used to publish messages to a topic

flow/default.go

@@ -6,12 +6,12 @@ import (
 	"sync"
 
 	"github.com/silas/dag"
-	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v4/store"
-	"go.unistack.org/micro/v4/util/id"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v3/store"
+	"go.unistack.org/micro/v3/util/id"
 )
 
 type microFlow struct {

flow/flow.go

@@ -1,5 +1,5 @@
 // Package flow is an interface used for saga pattern microservice workflow
-package flow // import "go.unistack.org/micro/v4/flow"
+package flow // import "go.unistack.org/micro/v3/flow"
 
 import (
 	"context"
@@ -7,7 +7,7 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 var (

flow/options.go

@@ -4,11 +4,11 @@ import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/store"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/store"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Option func

fsm/fsm.go

@@ -1,4 +1,4 @@
-package fsm // import "go.unistack.org/micro/v4/fsm"
+package fsm // import "go.unistack.org/micro/v3/fsm"
 
 import (
 	"context"

fsm/fsm_test.go

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

go.mod

@@ -1,10 +1,20 @@
-module go.unistack.org/micro/v4
+module go.unistack.org/micro/v3
 
 go 1.20
 
 require (
+	dario.cat/mergo v1.0.0
 	github.com/DATA-DOG/go-sqlmock v1.5.0
-	github.com/imdario/mergo v0.3.14
+	github.com/google/uuid v1.3.0
 	github.com/patrickmn/go-cache v2.1.0+incompatible
-	github.com/silas/dag v0.0.0-20211117232152-9d50aa809f35
+	github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5
+	golang.org/x/sync v0.3.0
+	google.golang.org/grpc v1.57.0
+	google.golang.org/protobuf v1.31.0
+)
+
+require (
+	github.com/golang/protobuf v1.5.3 // indirect
+	golang.org/x/net v0.14.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20230526203410-71b5a4ffd15e // indirect
 )

go.sum

@@ -1,11 +1,33 @@
+dario.cat/mergo v1.0.0 h1:AGCNq9Evsj31mOgNPcLyXc+4PNABt905YmuqPYYpBWk=
+dario.cat/mergo v1.0.0/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/imdario/mergo v0.3.14 h1:fOqeC1+nCuuk6PKQdg9YmosXX7Y7mHX6R/0ZldI9iHo=
-github.com/imdario/mergo v0.3.14/go.mod h1:WBLT9ZmE3lPoWsEzCh9LPo3TiwVN+ZKEjmz+hD27ysY=
+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/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 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/silas/dag v0.0.0-20211117232152-9d50aa809f35 h1:4mohWoM/UGg1BvFFiqSPRl5uwJY3rVV0HQX0ETqauqQ=
-github.com/silas/dag v0.0.0-20211117232152-9d50aa809f35/go.mod h1:7RTUFBdIRC9nZ7/3RyRNH1bdqIShrDejd1YbLwgPS+I=
+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=
+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=
+golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=
+golang.org/x/text v0.12.0 h1:k+n5B8goJNdU7hSvEtMUz3d1Q6D/XW4COJSJR6fN0mc=
+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=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20230526203410-71b5a4ffd15e/go.mod h1:66JfowdXAEgad5O9NnYcsNPLCPZJD++2L9X0PCMODrA=
+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=
+google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.31.0 h1:g0LDEJHgrBl9N9r17Ru3sqWhkIx2NB67okBHPwC7hs8=
+google.golang.org/protobuf v1.31.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

logger/default.go

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

logger/logger.go

@@ -1,14 +1,17 @@
 // Package logger provides a log interface
-package logger // import "go.unistack.org/micro/v4/logger"
+package logger // import "go.unistack.org/micro/v3/logger"
 
 import (
 	"context"
-	"os"
 )
 
+type ContextAttrFunc func(ctx context.Context) []interface{}
+
+var DefaultContextAttrFuncs []ContextAttrFunc
+
 var (
 	// DefaultLogger variable
-	DefaultLogger = NewLogger(WithLevel(ParseLevel(os.Getenv("MICRO_LOG_LEVEL"))))
+	DefaultLogger Logger = NewLogger()
 	// DefaultLevel used by logger
 	DefaultLevel = InfoLevel
 	// DefaultCallerSkipCount used by logger
@@ -57,7 +60,9 @@ type Logger interface {
 	Log(ctx context.Context, level Level, args ...interface{})
 	// Logf logs message with needed level
 	Logf(ctx context.Context, level Level, msg string, args ...interface{})
-	// String returns the name of logger
+	// Name returns broker instance name
+	Name() string
+	// String returns the type of logger
 	String() string
 }
 
@@ -65,76 +70,106 @@ type Logger interface {
 type Field interface{}
 
 // Info writes msg to default logger on info level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Info(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Info(ctx, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Info(ctx, args...)
 }
 
 // Error writes msg to default logger on error level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Error(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Error(ctx, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Error(ctx, args...)
 }
 
 // Debug writes msg to default logger on debug level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Debug(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Debug(ctx, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Debug(ctx, args...)
 }
 
 // Warn writes msg to default logger on warn level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Warn(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Warn(ctx, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Warn(ctx, args...)
 }
 
 // Trace writes msg to default logger on trace level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Trace(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Trace(ctx, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Trace(ctx, args...)
 }
 
 // Fatal writes msg to default logger on fatal level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Fatal(ctx context.Context, args ...interface{}) {
-	DefaultLogger.Fatal(ctx, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Fatal(ctx, args...)
 }
 
 // Infof writes formatted msg to default logger on info level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Infof(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Infof(ctx, msg, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Infof(ctx, msg, args...)
 }
 
 // Errorf writes formatted msg to default logger on error level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Errorf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Errorf(ctx, msg, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Errorf(ctx, msg, args...)
 }
 
 // Debugf writes formatted msg to default logger on debug level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Debugf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Debugf(ctx, msg, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Debugf(ctx, msg, args...)
 }
 
 // Warnf writes formatted msg to default logger on warn level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Warnf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Warnf(ctx, msg, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Warnf(ctx, msg, args...)
 }
 
 // Tracef writes formatted msg to default logger on trace level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Tracef(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Tracef(ctx, msg, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Tracef(ctx, msg, args...)
 }
 
 // Fatalf writes formatted msg to default logger on fatal level
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Fatalf(ctx context.Context, msg string, args ...interface{}) {
-	DefaultLogger.Fatalf(ctx, msg, args...)
+	DefaultLogger.Clone(WithCallerSkipCount(DefaultCallerSkipCount+1)).Fatalf(ctx, msg, args...)
 }
 
 // V returns true if passed level enabled in default logger
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func V(level Level) bool {
 	return DefaultLogger.V(level)
 }
 
 // Init initialize logger
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Init(opts ...Option) error {
 	return DefaultLogger.Init(opts...)
 }
 
 // Fields create logger with specific fields
+//
+// Deprecated: Dont use logger methods directly, use instance of logger to avoid additional allocations
 func Fields(fields ...interface{}) Logger {
 	return DefaultLogger.Fields(fields...)
 }

logger/logger_test.go

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

logger/noop.go

@@ -0,0 +1,94 @@
+package logger
+
+import (
+	"context"
+)
+
+type noopLogger struct {
+	opts Options
+}
+
+func NewLogger(opts ...Option) Logger {
+	options := NewOptions(opts...)
+	return &noopLogger{opts: options}
+}
+
+func (l *noopLogger) V(_ Level) bool {
+	return false
+}
+
+func (l *noopLogger) Level(_ Level) {
+}
+
+func (l *noopLogger) Name() string {
+	return l.opts.Name
+}
+
+func (l *noopLogger) Init(opts ...Option) error {
+	for _, o := range opts {
+		o(&l.opts)
+	}
+	return nil
+}
+
+func (l *noopLogger) Clone(opts ...Option) Logger {
+	nl := &noopLogger{opts: l.opts}
+	for _, o := range opts {
+		o(&nl.opts)
+	}
+	return nl
+}
+
+func (l *noopLogger) Fields(_ ...interface{}) Logger {
+	return l
+}
+
+func (l *noopLogger) Options() Options {
+	return l.opts
+}
+
+func (l *noopLogger) String() string {
+	return "noop"
+}
+
+func (l *noopLogger) Log(ctx context.Context, lvl Level, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Info(ctx context.Context, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Debug(ctx context.Context, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Error(ctx context.Context, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Trace(ctx context.Context, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Warn(ctx context.Context, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Fatal(ctx context.Context, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Logf(ctx context.Context, lvl Level, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Infof(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Debugf(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Errorf(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Tracef(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Warnf(ctx context.Context, msg string, attrs ...interface{}) {
+}
+
+func (l *noopLogger) Fatalf(ctx context.Context, msg string, attrs ...interface{}) {
+}

logger/options.go

@@ -3,10 +3,12 @@ package logger
 import (
 	"context"
 	"io"
+	"log/slog"
 	"os"
+	"time"
 )
 
-// Option func
+// Option func signature
 type Option func(*Options)
 
 // Options holds logger options
@@ -15,31 +17,65 @@ type Options struct {
 	Out io.Writer
 	// Context holds exernal options
 	Context context.Context
-	// Fields holds additional metadata
-	Fields []interface{}
 	// Name holds the logger name
 	Name string
-	// The logging level the logger should log
-	Level Level
+	// 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
+	LevelKey string
+	// ErroreKey is the key used for the error of the log call
+	ErrorKey string
+	// MessageKey is the key used for the message of the log call
+	MessageKey string
+	// SourceKey is the key used for the source file and line of the log call
+	SourceKey string
+	// StacktraceKey is the key used for the stacktrace
+	StacktraceKey string
+	// 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
 }
 
 // NewOptions creates new options struct
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Level:           DefaultLevel,
-		Fields:          make([]interface{}, 0, 6),
-		Out:             os.Stderr,
-		CallerSkipCount: DefaultCallerSkipCount,
-		Context:         context.Background(),
+		Level:            DefaultLevel,
+		Fields:           make([]interface{}, 0, 6),
+		Out:              os.Stderr,
+		CallerSkipCount:  DefaultCallerSkipCount,
+		Context:          context.Background(),
+		ContextAttrFuncs: DefaultContextAttrFuncs,
+		AddSource:        true,
+		TimeFunc:         time.Now,
 	}
+
+	WithMicroKeys()(&options)
+
 	for _, o := range opts {
 		o(&options)
 	}
+
 	return options
 }
 
+// WithContextAttrFuncs appends default funcs for the context arrts filler
+func WithContextAttrFuncs(fncs ...ContextAttrFunc) Option {
+	return func(o *Options) {
+		o.ContextAttrFuncs = append(o.ContextAttrFuncs, fncs...)
+	}
+}
+
 // WithFields set default fields for the logger
 func WithFields(fields ...interface{}) Option {
 	return func(o *Options) {
@@ -61,6 +97,20 @@ func WithOutput(out io.Writer) Option {
 	}
 }
 
+// WitAddStacktrace controls writing stacktrace on error
+func WithAddStacktrace(v bool) Option {
+	return func(o *Options) {
+		o.AddStacktrace = v
+	}
+}
+
+// WitAddSource controls writing source file and pos in log
+func WithAddSource(v bool) Option {
+	return func(o *Options) {
+		o.AddSource = v
+	}
+}
+
 // WithCallerSkipCount set frame count to skip
 func WithCallerSkipCount(c int) Option {
 	return func(o *Options) {
@@ -81,3 +131,61 @@ func WithName(n string) Option {
 		o.Name = n
 	}
 }
+
+// WithTimeFunc sets the func to obtain current time
+func WithTimeFunc(fn func() time.Time) Option {
+	return func(o *Options) {
+		o.TimeFunc = fn
+	}
+}
+
+func WithZapKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = "@timestamp"
+		o.LevelKey = "level"
+		o.MessageKey = "msg"
+		o.SourceKey = "caller"
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+func WithZerologKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = "time"
+		o.LevelKey = "level"
+		o.MessageKey = "message"
+		o.SourceKey = "caller"
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+func WithSlogKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = slog.TimeKey
+		o.LevelKey = slog.LevelKey
+		o.MessageKey = slog.MessageKey
+		o.SourceKey = slog.SourceKey
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+func WithMicroKeys() Option {
+	return func(o *Options) {
+		o.TimeKey = "timestamp"
+		o.LevelKey = "level"
+		o.MessageKey = "msg"
+		o.SourceKey = "caller"
+		o.StacktraceKey = "stacktrace"
+		o.ErrorKey = "error"
+	}
+}
+
+// WithAddCallerSkipCount add skip count for copy logger
+func WithAddCallerSkipCount(n int) Option {
+	return func(o *Options) {
+		o.CallerSkipCount += n
+	}
+}

logger/slog/slog.go

@@ -0,0 +1,568 @@
+package slog
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"os"
+	"regexp"
+	"runtime"
+	"strconv"
+	"sync"
+
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/tracer"
+)
+
+var reTrace = regexp.MustCompile(`.*/slog/logger\.go.*\n`)
+
+var (
+	traceValue = slog.StringValue("trace")
+	debugValue = slog.StringValue("debug")
+	infoValue  = slog.StringValue("info")
+	warnValue  = slog.StringValue("warn")
+	errorValue = slog.StringValue("error")
+	fatalValue = slog.StringValue("fatal")
+)
+
+func (s *slogLogger) renameAttr(_ []string, a slog.Attr) slog.Attr {
+	switch a.Key {
+	case slog.SourceKey:
+		source := a.Value.Any().(*slog.Source)
+		a.Value = slog.StringValue(source.File + ":" + strconv.Itoa(source.Line))
+		a.Key = s.opts.SourceKey
+	case slog.TimeKey:
+		a.Key = s.opts.TimeKey
+	case slog.MessageKey:
+		a.Key = s.opts.MessageKey
+	case slog.LevelKey:
+		level := a.Value.Any().(slog.Level)
+		lvl := slogToLoggerLevel(level)
+		a.Key = s.opts.LevelKey
+		switch {
+		case lvl < logger.DebugLevel:
+			a.Value = traceValue
+		case lvl < logger.InfoLevel:
+			a.Value = debugValue
+		case lvl < logger.WarnLevel:
+			a.Value = infoValue
+		case lvl < logger.ErrorLevel:
+			a.Value = warnValue
+		case lvl < logger.FatalLevel:
+			a.Value = errorValue
+		case lvl >= logger.FatalLevel:
+			a.Value = fatalValue
+		default:
+			a.Value = infoValue
+		}
+	}
+
+	return a
+}
+
+type slogLogger struct {
+	leveler *slog.LevelVar
+	handler slog.Handler
+	opts    logger.Options
+	mu      sync.RWMutex
+}
+
+func (s *slogLogger) Clone(opts ...logger.Option) logger.Logger {
+	s.mu.RLock()
+	options := s.opts
+	s.mu.RUnlock()
+
+	for _, o := range opts {
+		o(&options)
+	}
+
+	l := &slogLogger{
+		opts: options,
+	}
+
+	l.leveler = new(slog.LevelVar)
+	handleOpt := &slog.HandlerOptions{
+		ReplaceAttr: l.renameAttr,
+		Level:       l.leveler,
+		AddSource:   l.opts.AddSource,
+	}
+	l.leveler.Set(loggerToSlogLevel(l.opts.Level))
+	l.handler = slog.New(slog.NewJSONHandler(options.Out, handleOpt)).With(options.Fields...).Handler()
+
+	return l
+}
+
+func (s *slogLogger) V(level logger.Level) bool {
+	return s.opts.Level.Enabled(level)
+}
+
+func (s *slogLogger) Level(level logger.Level) {
+	s.leveler.Set(loggerToSlogLevel(level))
+}
+
+func (s *slogLogger) Options() logger.Options {
+	return s.opts
+}
+
+func (s *slogLogger) Fields(attrs ...interface{}) logger.Logger {
+	s.mu.RLock()
+	level := s.leveler.Level()
+	options := s.opts
+	s.mu.RUnlock()
+
+	l := &slogLogger{opts: options}
+	l.leveler = new(slog.LevelVar)
+	l.leveler.Set(level)
+
+	handleOpt := &slog.HandlerOptions{
+		ReplaceAttr: l.renameAttr,
+		Level:       l.leveler,
+		AddSource:   l.opts.AddSource,
+	}
+
+	l.handler = slog.New(slog.NewJSONHandler(l.opts.Out, handleOpt)).With(attrs...).Handler()
+
+	return l
+}
+
+func (s *slogLogger) Init(opts ...logger.Option) error {
+	s.mu.Lock()
+
+	if len(s.opts.ContextAttrFuncs) == 0 {
+		s.opts.ContextAttrFuncs = logger.DefaultContextAttrFuncs
+	}
+
+	for _, o := range opts {
+		o(&s.opts)
+	}
+
+	s.leveler = new(slog.LevelVar)
+	handleOpt := &slog.HandlerOptions{
+		ReplaceAttr: s.renameAttr,
+		Level:       s.leveler,
+		AddSource:   s.opts.AddSource,
+	}
+	s.leveler.Set(loggerToSlogLevel(s.opts.Level))
+	s.handler = slog.New(slog.NewJSONHandler(s.opts.Out, handleOpt)).With(s.opts.Fields...).Handler()
+	s.mu.Unlock()
+
+	return nil
+}
+
+func (s *slogLogger) Log(ctx context.Context, lvl logger.Level, attrs ...interface{}) {
+	if !s.V(lvl) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), loggerToSlogLevel(lvl), fmt.Sprintf("%s", attrs[0]), pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	if s.opts.AddStacktrace && lvl == logger.ErrorLevel {
+		stackInfo := make([]byte, 1024*1024)
+		if stackSize := runtime.Stack(stackInfo, false); stackSize > 0 {
+			traceLines := reTrace.Split(string(stackInfo[:stackSize]), -1)
+			if len(traceLines) != 0 {
+				attrs = append(attrs, slog.String(s.opts.StacktraceKey, traceLines[len(traceLines)-1]))
+			}
+		}
+	}
+	r.Add(attrs[1:]...)
+	r.Attrs(func(a slog.Attr) bool {
+		if a.Key == s.opts.ErrorKey {
+			if span, ok := tracer.SpanFromContext(ctx); ok {
+				span.SetStatus(tracer.SpanStatusError, a.Value.String())
+				return false
+			}
+		}
+		return true
+	})
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Logf(ctx context.Context, lvl logger.Level, msg string, attrs ...interface{}) {
+	if !s.V(lvl) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), loggerToSlogLevel(lvl), msg, pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	if s.opts.AddStacktrace && lvl == logger.ErrorLevel {
+		stackInfo := make([]byte, 1024*1024)
+		if stackSize := runtime.Stack(stackInfo, false); stackSize > 0 {
+			traceLines := reTrace.Split(string(stackInfo[:stackSize]), -1)
+			if len(traceLines) != 0 {
+				attrs = append(attrs, (slog.String(s.opts.StacktraceKey, traceLines[len(traceLines)-1])))
+			}
+		}
+	}
+	r.Add(attrs[1:]...)
+	r.Attrs(func(a slog.Attr) bool {
+		if a.Key == s.opts.ErrorKey {
+			if span, ok := tracer.SpanFromContext(ctx); ok {
+				span.SetStatus(tracer.SpanStatusError, a.Value.String())
+				return false
+			}
+		}
+		return true
+	})
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Info(ctx context.Context, attrs ...interface{}) {
+	if !s.V(logger.InfoLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelInfo, fmt.Sprintf("%s", attrs[0]), pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs[1:]...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Infof(ctx context.Context, msg string, attrs ...interface{}) {
+	if !s.V(logger.InfoLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelInfo, msg, pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Debug(ctx context.Context, attrs ...interface{}) {
+	if !s.V(logger.DebugLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelDebug, fmt.Sprintf("%s", attrs[0]), pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs[1:]...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Debugf(ctx context.Context, msg string, attrs ...interface{}) {
+	if !s.V(logger.DebugLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelDebug, msg, pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Trace(ctx context.Context, attrs ...interface{}) {
+	if !s.V(logger.TraceLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelDebug-1, fmt.Sprintf("%s", attrs[0]), pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs[1:]...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Tracef(ctx context.Context, msg string, attrs ...interface{}) {
+	if !s.V(logger.TraceLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelDebug-1, msg, pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs[1:]...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Error(ctx context.Context, attrs ...interface{}) {
+	if !s.V(logger.ErrorLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelError, fmt.Sprintf("%s", attrs[0]), pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	if s.opts.AddStacktrace {
+		stackInfo := make([]byte, 1024*1024)
+		if stackSize := runtime.Stack(stackInfo, false); stackSize > 0 {
+			traceLines := reTrace.Split(string(stackInfo[:stackSize]), -1)
+			if len(traceLines) != 0 {
+				attrs = append(attrs, slog.String("stacktrace", traceLines[len(traceLines)-1]))
+			}
+		}
+	}
+	r.Add(attrs[1:]...)
+	r.Attrs(func(a slog.Attr) bool {
+		if a.Key == s.opts.ErrorKey {
+			if span, ok := tracer.SpanFromContext(ctx); ok {
+				span.SetStatus(tracer.SpanStatusError, a.Value.String())
+				return false
+			}
+		}
+		return true
+	})
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Errorf(ctx context.Context, msg string, attrs ...interface{}) {
+	if !s.V(logger.ErrorLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelError, msg, pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	if s.opts.AddStacktrace {
+		stackInfo := make([]byte, 1024*1024)
+		if stackSize := runtime.Stack(stackInfo, false); stackSize > 0 {
+			traceLines := reTrace.Split(string(stackInfo[:stackSize]), -1)
+			if len(traceLines) != 0 {
+				attrs = append(attrs, slog.String("stacktrace", traceLines[len(traceLines)-1]))
+			}
+		}
+	}
+	r.Add(attrs...)
+	r.Attrs(func(a slog.Attr) bool {
+		if a.Key == s.opts.ErrorKey {
+			if span, ok := tracer.SpanFromContext(ctx); ok {
+				span.SetStatus(tracer.SpanStatusError, a.Value.String())
+				return false
+			}
+		}
+		return true
+	})
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Fatal(ctx context.Context, attrs ...interface{}) {
+	if !s.V(logger.FatalLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelError+1, fmt.Sprintf("%s", attrs[0]), pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs[1:]...)
+	_ = s.handler.Handle(ctx, r)
+	os.Exit(1)
+}
+
+func (s *slogLogger) Fatalf(ctx context.Context, msg string, attrs ...interface{}) {
+	if !s.V(logger.FatalLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelError+1, msg, pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs...)
+	_ = s.handler.Handle(ctx, r)
+	os.Exit(1)
+}
+
+func (s *slogLogger) Warn(ctx context.Context, attrs ...interface{}) {
+	if !s.V(logger.WarnLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelWarn, fmt.Sprintf("%s", attrs[0]), pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs[1:]...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Warnf(ctx context.Context, msg string, attrs ...interface{}) {
+	if !s.V(logger.WarnLevel) {
+		return
+	}
+	var pcs [1]uintptr
+	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
+	r := slog.NewRecord(s.opts.TimeFunc(), slog.LevelWarn, msg, pcs[0])
+	for _, fn := range s.opts.ContextAttrFuncs {
+		attrs = append(attrs, fn(ctx)...)
+	}
+
+	for idx, attr := range attrs {
+		if ve, ok := attr.(error); ok && ve != nil {
+			attrs[idx] = slog.String(s.opts.ErrorKey, ve.Error())
+			break
+		}
+	}
+	r.Add(attrs[1:]...)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Name() string {
+	return s.opts.Name
+}
+
+func (s *slogLogger) String() string {
+	return "slog"
+}
+
+func NewLogger(opts ...logger.Option) logger.Logger {
+	s := &slogLogger{
+		opts: logger.NewOptions(opts...),
+	}
+
+	return s
+}
+
+func loggerToSlogLevel(level logger.Level) slog.Level {
+	switch level {
+	case logger.DebugLevel:
+		return slog.LevelDebug
+	case logger.WarnLevel:
+		return slog.LevelWarn
+	case logger.ErrorLevel:
+		return slog.LevelError
+	case logger.TraceLevel:
+		return slog.LevelDebug - 1
+	case logger.FatalLevel:
+		return slog.LevelError + 1
+	default:
+		return slog.LevelInfo
+	}
+}
+
+func slogToLoggerLevel(level slog.Level) logger.Level {
+	switch level {
+	case slog.LevelDebug:
+		return logger.DebugLevel
+	case slog.LevelWarn:
+		return logger.WarnLevel
+	case slog.LevelError:
+		return logger.ErrorLevel
+	case slog.LevelDebug - 1:
+		return logger.TraceLevel
+	case slog.LevelError + 1:
+		return logger.FatalLevel
+	default:
+		return logger.InfoLevel
+	}
+}

logger/slog/slog_test.go

@@ -0,0 +1,176 @@
+package slog
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log"
+	"testing"
+
+	"go.unistack.org/micro/v3/logger"
+)
+
+func TestError(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf), logger.WithAddStacktrace(true))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Error(ctx, "message", fmt.Errorf("error message"))
+	if !bytes.Contains(buf.Bytes(), []byte(`"stacktrace":"`)) {
+		t.Fatalf("logger stacktrace not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"error":"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestErrorf(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf), logger.WithAddStacktrace(true))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	l.Errorf(ctx, "message", fmt.Errorf("error message"))
+	if !bytes.Contains(buf.Bytes(), []byte(`"stacktrace":"`)) {
+		t.Fatalf("logger stacktrace not works, buf contains: %s", buf.Bytes())
+	}
+	if !bytes.Contains(buf.Bytes(), []byte(`"error":"`)) {
+		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestContext(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	nl, ok := logger.FromContext(logger.NewContext(ctx, l.Fields("key", "val")))
+	if !ok {
+		t.Fatal("context without logger")
+	}
+	nl.Info(ctx, "message")
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	nl := l.Fields("key", "val")
+
+	nl.Info(ctx, "message")
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestFromContextWithFields(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	var ok bool
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	nl := l.Fields("key", "val")
+
+	ctx = logger.NewContext(ctx, nl)
+
+	l, ok = logger.FromContext(ctx)
+	if !ok {
+		t.Fatalf("context does not have logger")
+	}
+
+	l.Info(ctx, "message")
+	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
+}
+
+func TestClone(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	nl := l.Clone(logger.WithLevel(logger.ErrorLevel))
+	if err := nl.Init(); err != nil {
+		t.Fatal(err)
+	}
+	nl.Info(ctx, "info message")
+	if len(buf.Bytes()) != 0 {
+		t.Fatal("message must not be logged")
+	}
+	l.Info(ctx, "info message")
+	if len(buf.Bytes()) == 0 {
+		t.Fatal("message must be logged")
+	}
+}
+
+func TestRedirectStdLogger(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.ErrorLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	fn := logger.RedirectStdLogger(l, logger.ErrorLevel)
+	defer fn()
+	log.Print("test")
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"error"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"test"`))) {
+		t.Fatalf("logger error, buf %s", buf.Bytes())
+	}
+}
+
+func TestStdLogger(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	lg := logger.NewStdLogger(l, logger.ErrorLevel)
+	lg.Print("test")
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"error"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"test"`))) {
+		t.Fatalf("logger error, buf %s", buf.Bytes())
+	}
+}
+
+func TestLogger(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(logger.WithLevel(logger.TraceLevel), logger.WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	l.Trace(ctx, "trace_msg1")
+	l.Warn(ctx, "warn_msg1")
+	l.Fields("error", "test").Info(ctx, "error message")
+	l.Warn(ctx, "first second")
+
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"trace"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"trace_msg1"`))) {
+		t.Fatalf("logger tracer, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"warn"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"warn_msg1"`))) {
+		t.Fatalf("logger warn, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"info"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"error message","error":"test"`))) {
+		t.Fatalf("logger info, buf %s", buf.Bytes())
+	}
+	if !(bytes.Contains(buf.Bytes(), []byte(`"level":"warn"`)) && bytes.Contains(buf.Bytes(), []byte(`"msg":"first second"`))) {
+		t.Fatalf("logger warn, buf %s", buf.Bytes())
+	}
+}

logger/unwrap/unwrap.go

@@ -8,7 +8,7 @@ import (
 	"strconv"
 	"strings"
 
-	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v3/codec"
 )
 
 const sf = "0-+# "

logger/unwrap/unwrap_test.go

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

logger/wrapper/wrapper.go

@@ -5,9 +5,9 @@ import (
 	"context"
 	"fmt"
 
-	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/server"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/server"
 )
 
 var (

metadata/context.go

@@ -39,8 +39,6 @@ func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
 
 // FromContext returns metadata from the given context
 // returned metadata shoud not be modified or race condition happens
-//
-// Deprecated: use FromIncomingContext or FromOutgoingContext
 func FromContext(ctx context.Context) (Metadata, bool) {
 	if ctx == nil {
 		return nil, false
@@ -53,8 +51,6 @@ func FromContext(ctx context.Context) (Metadata, bool) {
 }
 
 // NewContext creates a new context with the given metadata
-//
-// Deprecated: use NewIncomingContext or NewOutgoingContext
 func NewContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()

metadata/metadata.go

@@ -1,5 +1,5 @@
 // Package metadata is a way of defining message headers
-package metadata // import "go.unistack.org/micro/v4/metadata"
+package metadata // import "go.unistack.org/micro/v3/metadata"
 
 import (
 	"net/textproto"
@@ -19,6 +19,8 @@ var (
 	HeaderTimeout = "Micro-Timeout"
 	// HeaderAuthorization specifies Authorization header
 	HeaderAuthorization = "Authorization"
+	// HeaderXRequestID specifies request id
+	HeaderXRequestID = "X-Request-Id"
 )
 
 // Metadata is our way of representing request headers internally.
@@ -96,11 +98,12 @@ func (md Metadata) Del(keys ...string) {
 }
 
 // Copy makes a copy of the metadata
-func Copy(md Metadata) Metadata {
+func Copy(md Metadata, exclude ...string) Metadata {
 	nmd := New(len(md))
 	for key, val := range md {
 		nmd.Set(key, val)
 	}
+	nmd.Del(exclude...)
 	return nmd
 }
 

metadata/metadata_test.go

@@ -190,3 +190,14 @@ func TestMetadataContext(t *testing.T) {
 		t.Errorf("Expected metadata length 1 got %d", i)
 	}
 }
+
+func TestCopy(t *testing.T) {
+	md := New(2)
+	md.Set("key1", "val1", "key2", "val2")
+	nmd := Copy(md, "key2")
+	if len(nmd) != 1 {
+		t.Fatal("Copy exclude not works")
+	} else if nmd["Key1"] != "val1" {
+		t.Fatal("Copy exclude not works")
+	}
+}

meter/meter.go

@@ -1,5 +1,5 @@
 // Package meter is for instrumentation
-package meter // import "go.unistack.org/micro/v4/meter"
+package meter
 
 import (
 	"io"
@@ -11,7 +11,7 @@ import (
 
 var (
 	// DefaultMeter is the default meter
-	DefaultMeter = NewMeter()
+	DefaultMeter Meter = 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/options.go

@@ -3,7 +3,7 @@ package meter
 import (
 	"context"
 
-	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v3/logger"
 )
 
 // Option powers the configuration for metrics implementations:

meter/wrapper/wrapper.go

@@ -1,13 +1,13 @@
-package wrapper // import "go.unistack.org/micro/v4/meter/wrapper"
+package wrapper // import "go.unistack.org/micro/v3/meter/wrapper"
 
 import (
 	"context"
 	"fmt"
 	"time"
 
-	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/server"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/server"
 )
 
 var (
@@ -27,6 +27,22 @@ var (
 	ServerRequestTotal = "server_request_total"
 	// ServerRequestInflight specifies meter metric name
 	ServerRequestInflight = "server_request_inflight"
+	// PublishMessageDurationSeconds specifies meter metric name
+	PublishMessageDurationSeconds = "publish_message_duration_seconds"
+	// PublishMessageLatencyMicroseconds specifies meter metric name
+	PublishMessageLatencyMicroseconds = "publish_message_latency_microseconds"
+	// PublishMessageTotal specifies meter metric name
+	PublishMessageTotal = "publish_message_total"
+	// PublishMessageInflight specifies meter metric name
+	PublishMessageInflight = "publish_message_inflight"
+	// SubscribeMessageDurationSeconds specifies meter metric name
+	SubscribeMessageDurationSeconds = "subscribe_message_duration_seconds"
+	// SubscribeMessageLatencyMicroseconds specifies meter metric name
+	SubscribeMessageLatencyMicroseconds = "subscribe_message_latency_microseconds"
+	// SubscribeMessageTotal specifies meter metric name
+	SubscribeMessageTotal = "subscribe_message_total"
+	// SubscribeMessageInflight specifies meter metric name
+	SubscribeMessageInflight = "subscribe_message_inflight"
 
 	labelSuccess  = "success"
 	labelFailure  = "failure"
@@ -214,7 +230,37 @@ func (w *wrapper) Stream(ctx context.Context, req client.Request, opts ...client
 }
 
 func (w *wrapper) Publish(ctx context.Context, p client.Message, opts ...client.PublishOption) error {
-	return w.Client.Publish(ctx, p, opts...)
+	endpoint := p.Topic()
+
+	labels := make([]string, 0, 4)
+	labels = append(labels, labelEndpoint, endpoint)
+
+	w.opts.Meter.Counter(PublishMessageInflight, labels...).Inc()
+	ts := time.Now()
+	err := w.Client.Publish(ctx, p, opts...)
+	te := time.Since(ts)
+	w.opts.Meter.Counter(PublishMessageInflight, labels...).Dec()
+
+	w.opts.Meter.Summary(PublishMessageLatencyMicroseconds, labels...).Update(te.Seconds())
+	w.opts.Meter.Histogram(PublishMessageDurationSeconds, labels...).Update(te.Seconds())
+
+	if err == nil {
+		labels = append(labels, labelStatus, labelSuccess)
+	} else {
+		labels = append(labels, labelStatus, labelFailure)
+	}
+	w.opts.Meter.Counter(PublishMessageTotal, labels...).Inc()
+
+	return err
+}
+
+// NewHandlerWrapper create new server handler wrapper
+// deprecated
+func NewHandlerWrapper(opts ...Option) server.HandlerWrapper {
+	handler := &wrapper{
+		opts: NewOptions(opts...),
+	}
+	return handler.HandlerFunc
 }
 
 // NewServerHandlerWrapper create new server handler wrapper
@@ -256,3 +302,46 @@ func (w *wrapper) HandlerFunc(fn server.HandlerFunc) server.HandlerFunc {
 		return err
 	}
 }
+
+// NewSubscriberWrapper create server subscribe wrapper
+// deprecated
+func NewSubscriberWrapper(opts ...Option) server.SubscriberWrapper {
+	handler := &wrapper{
+		opts: NewOptions(opts...),
+	}
+	return handler.SubscriberFunc
+}
+
+func NewServerSubscriberWrapper(opts ...Option) server.SubscriberWrapper {
+	handler := &wrapper{
+		opts: NewOptions(opts...),
+	}
+	return handler.SubscriberFunc
+}
+
+func (w *wrapper) SubscriberFunc(fn server.SubscriberFunc) server.SubscriberFunc {
+	return func(ctx context.Context, msg server.Message) error {
+		endpoint := msg.Topic()
+
+		labels := make([]string, 0, 4)
+		labels = append(labels, labelEndpoint, endpoint)
+
+		w.opts.Meter.Counter(SubscribeMessageInflight, labels...).Inc()
+		ts := time.Now()
+		err := fn(ctx, msg)
+		te := time.Since(ts)
+		w.opts.Meter.Counter(SubscribeMessageInflight, labels...).Dec()
+
+		w.opts.Meter.Summary(SubscribeMessageLatencyMicroseconds, labels...).Update(te.Seconds())
+		w.opts.Meter.Histogram(SubscribeMessageDurationSeconds, labels...).Update(te.Seconds())
+
+		if err == nil {
+			labels = append(labels, labelStatus, labelSuccess)
+		} else {
+			labels = append(labels, labelStatus, labelFailure)
+		}
+		w.opts.Meter.Counter(SubscribeMessageTotal, labels...).Inc()
+
+		return err
+	}
+}

micro.go

@@ -0,0 +1,94 @@
+package micro
+
+import (
+	"reflect"
+
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/flow"
+	"go.unistack.org/micro/v3/fsm"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v3/resolver"
+	"go.unistack.org/micro/v3/router"
+	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v3/server"
+	"go.unistack.org/micro/v3/store"
+	"go.unistack.org/micro/v3/sync"
+	"go.unistack.org/micro/v3/tracer"
+)
+
+func As(b any, target any) bool {
+	if b == nil {
+		return false
+	}
+	if target == nil {
+		return false
+	}
+	val := reflect.ValueOf(target)
+	typ := val.Type()
+	if typ.Kind() != reflect.Ptr || val.IsNil() {
+		return false
+	}
+	targetType := typ.Elem()
+	if targetType.Kind() != reflect.Interface {
+		switch {
+		case targetType.Implements(brokerType):
+			break
+		case targetType.Implements(loggerType):
+			break
+		case targetType.Implements(clientType):
+			break
+		case targetType.Implements(serverType):
+			break
+		case targetType.Implements(codecType):
+			break
+		case targetType.Implements(flowType):
+			break
+		case targetType.Implements(fsmType):
+			break
+		case targetType.Implements(meterType):
+			break
+		case targetType.Implements(registerType):
+			break
+		case targetType.Implements(resolverType):
+			break
+		case targetType.Implements(selectorType):
+			break
+		case targetType.Implements(storeType):
+			break
+		case targetType.Implements(syncType):
+			break
+		case targetType.Implements(serviceType):
+			break
+		case targetType.Implements(routerType):
+			break
+		default:
+			return false
+		}
+	}
+	if reflect.TypeOf(b).AssignableTo(targetType) {
+		val.Elem().Set(reflect.ValueOf(b))
+		return true
+	}
+	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()

micro_test.go

@@ -0,0 +1,115 @@
+package micro
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/fsm"
+)
+
+func TestAs(t *testing.T) {
+	var b *bro
+	broTarget := &bro{name: "kafka"}
+	fsmTarget := &fsmT{name: "fsm"}
+
+	testCases := []struct {
+		b      any
+		target any
+		match  bool
+		want   any
+	}{
+		{
+			broTarget,
+			&b,
+			true,
+			broTarget,
+		},
+		{
+			nil,
+			&b,
+			false,
+			nil,
+		},
+		{
+			fsmTarget,
+			&b,
+			false,
+			nil,
+		},
+	}
+	for i, tc := range testCases {
+		name := fmt.Sprintf("%d:As(Errorf(..., %v), %v)", i, tc.b, tc.target)
+		// Clear the target pointer, in case it was set in a previous test.
+		rtarget := reflect.ValueOf(tc.target)
+		rtarget.Elem().Set(reflect.Zero(reflect.TypeOf(tc.target).Elem()))
+		t.Run(name, func(t *testing.T) {
+			match := As(tc.b, tc.target)
+			if match != tc.match {
+				t.Fatalf("match: got %v; want %v", match, tc.match)
+			}
+			if !match {
+				return
+			}
+			if got := rtarget.Elem().Interface(); got != tc.want {
+				t.Fatalf("got %#v, want %#v", got, tc.want)
+			}
+		})
+	}
+}
+
+type bro struct {
+	name string
+}
+
+func (p *bro) Name() string { return p.name }
+
+func (p *bro) Init(opts ...broker.Option) error { return nil }
+
+// Options returns broker options
+func (p *bro) Options() broker.Options { return broker.Options{} }
+
+// Address return configured address
+func (p *bro) Address() string { return "" }
+
+// Connect connects to broker
+func (p *bro) Connect(ctx context.Context) error { return nil }
+
+// Disconnect disconnect from broker
+func (p *bro) Disconnect(ctx 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 {
+	return nil
+}
+
+// BatchPublish messages to broker with multiple topics
+func (p *bro) BatchPublish(ctx context.Context, msgs []*broker.Message, opts ...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) {
+	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) {
+	return nil, nil
+}
+
+// String type of broker
+func (p *bro) String() string { return p.name }
+
+type fsmT struct {
+	name string
+}
+
+func (f *fsmT) Start(ctx context.Context, a interface{}, o ...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) {}

mtls/mtls.go

@@ -1,4 +1,4 @@
-package mtls // import "go.unistack.org/micro/v4/mtls"
+package mtls // import "go.unistack.org/micro/v3/mtls"
 
 import (
 	"bytes"

network/network.go

@@ -1,9 +1,9 @@
 // Package network is for creating internetworks
-package network // import "go.unistack.org/micro/v4/network"
+package network // import "go.unistack.org/micro/v3/network"
 
 import (
-	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v4/server"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/server"
 )
 
 // Error is network node errors

network/options.go

@@ -1,13 +1,13 @@
 package network
 
 import (
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/network/tunnel"
-	"go.unistack.org/micro/v4/proxy"
-	"go.unistack.org/micro/v4/router"
-	"go.unistack.org/micro/v4/tracer"
-	"go.unistack.org/micro/v4/util/id"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/network/tunnel"
+	"go.unistack.org/micro/v3/proxy"
+	"go.unistack.org/micro/v3/router"
+	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v3/util/id"
 )
 
 // Option func

network/transport/memory.go

@@ -8,9 +8,9 @@ import (
 	"sync"
 	"time"
 
-	maddr "go.unistack.org/micro/v4/util/addr"
-	mnet "go.unistack.org/micro/v4/util/net"
-	"go.unistack.org/micro/v4/util/rand"
+	maddr "go.unistack.org/micro/v3/util/addr"
+	mnet "go.unistack.org/micro/v3/util/net"
+	"go.unistack.org/micro/v3/util/rand"
 )
 
 type memorySocket struct {

network/transport/options.go

@@ -5,10 +5,10 @@ import (
 	"crypto/tls"
 	"time"
 
-	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/codec"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Options struct holds the transport options

network/transport/transport.go

@@ -1,11 +1,11 @@
 // Package transport is an interface for synchronous connection based communication
-package transport // import "go.unistack.org/micro/v4/network/transport"
+package transport // import "go.unistack.org/micro/v3/network/transport"
 
 import (
 	"context"
 	"time"
 
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 var (

network/tunnel/broker/broker.go

@@ -1,15 +1,15 @@
 // Package broker is a tunnel broker
-package broker // import "go.unistack.org/micro/v4/network/tunnel/broker"
+package broker // import "go.unistack.org/micro/v3/network/tunnel/broker"
 
 import (
 	"context"
 	"fmt"
 
-	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v4/network/transport"
-	"go.unistack.org/micro/v4/network/tunnel"
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v3/network/transport"
+	"go.unistack.org/micro/v3/network/tunnel"
 )
 
 type tunBroker struct {

network/tunnel/options.go

@@ -3,11 +3,11 @@ package tunnel
 import (
 	"time"
 
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/network/transport"
-	"go.unistack.org/micro/v4/tracer"
-	"go.unistack.org/micro/v4/util/id"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/network/transport"
+	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v3/util/id"
 )
 
 var (

network/tunnel/transport/listener.go

@@ -1,8 +1,8 @@
 package transport
 
 import (
-	"go.unistack.org/micro/v4/network/transport"
-	"go.unistack.org/micro/v4/network/tunnel"
+	"go.unistack.org/micro/v3/network/transport"
+	"go.unistack.org/micro/v3/network/tunnel"
 )
 
 type tunListener struct {

network/tunnel/transport/transport.go

@@ -1,12 +1,12 @@
 // Package transport provides a tunnel transport
-package transport // import "go.unistack.org/micro/v4/network/tunnel/transport"
+package transport // import "go.unistack.org/micro/v3/network/tunnel/transport"
 
 import (
 	"context"
 	"fmt"
 
-	"go.unistack.org/micro/v4/network/transport"
-	"go.unistack.org/micro/v4/network/tunnel"
+	"go.unistack.org/micro/v3/network/transport"
+	"go.unistack.org/micro/v3/network/tunnel"
 )
 
 type tunTransport struct {

network/tunnel/tunnel.go

@@ -1,12 +1,12 @@
 // Package tunnel provides gre network tunnelling
-package tunnel // import "go.unistack.org/micro/v4/network/transport/tunnel"
+package tunnel // import "go.unistack.org/micro/v3/network/transport/tunnel"
 
 import (
 	"context"
 	"errors"
 	"time"
 
-	"go.unistack.org/micro/v4/network/transport"
+	"go.unistack.org/micro/v3/network/transport"
 )
 
 // DefaultTunnel contains default tunnel implementation

options.go

@@ -5,17 +5,17 @@ import (
 	"fmt"
 	"time"
 
-	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v4/config"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/register"
-	"go.unistack.org/micro/v4/router"
-	"go.unistack.org/micro/v4/server"
-	"go.unistack.org/micro/v4/store"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/config"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v3/router"
+	"go.unistack.org/micro/v3/server"
+	"go.unistack.org/micro/v3/store"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Options for micro service

options/hooks.go

@@ -1,4 +1,4 @@
-package options // import "go.unistack.org/micro/v4/options"
+package options
 
 // Hook func interface
 type Hook interface{}

profiler/http/http.go

@@ -1,5 +1,5 @@
 // Package http enables the http profiler
-package http // import "go.unistack.org/micro/v4/profiler/http"
+package http // import "go.unistack.org/micro/v3/profiler/http"
 
 import (
 	"context"
@@ -7,7 +7,7 @@ import (
 	"net/http/pprof"
 	"sync"
 
-	profile "go.unistack.org/micro/v4/profiler"
+	profile "go.unistack.org/micro/v3/profiler"
 )
 
 type httpProfile struct {

profiler/pprof/pprof.go

@@ -1,5 +1,5 @@
 // Package pprof provides a pprof profiler which writes output to /tmp/[name].{cpu,mem}.pprof
-package pprof // import "go.unistack.org/micro/v4/profiler/pprof"
+package pprof // import "go.unistack.org/micro/v3/profiler/pprof"
 
 import (
 	"os"
@@ -9,7 +9,7 @@ import (
 	"sync"
 	"time"
 
-	profile "go.unistack.org/micro/v4/profiler"
+	profile "go.unistack.org/micro/v3/profiler"
 )
 
 type profiler struct {

profiler/profile.go

@@ -1,5 +1,5 @@
 // Package profiler is for profilers
-package profiler // import "go.unistack.org/micro/v4/profiler"
+package profiler // import "go.unistack.org/micro/v3/profiler"
 
 // Profiler interface
 type Profiler interface {

proxy/options.go

@@ -2,11 +2,11 @@
 package proxy
 
 import (
-	"go.unistack.org/micro/v4/client"
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/router"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/client"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/router"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Options for proxy

proxy/proxy.go

@@ -1,10 +1,10 @@
 // Package proxy is a transparent proxy built on the micro/server
-package proxy // import "go.unistack.org/micro/v4/proxy"
+package proxy // import "go.unistack.org/micro/v3/proxy"
 
 import (
 	"context"
 
-	"go.unistack.org/micro/v4/server"
+	"go.unistack.org/micro/v3/server"
 )
 
 // DefaultEndpoint holds default proxy address

register/extractor.go

@@ -6,7 +6,7 @@ import (
 	"unicode"
 	"unicode/utf8"
 
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 // ExtractValue from reflect.Type from specified depth

register/memory/memory.go

@@ -5,8 +5,9 @@ import (
 	"sync"
 	"time"
 
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/util/id"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v3/util/id"
 )
 
 var (
@@ -16,7 +17,7 @@ var (
 
 type node struct {
 	LastSeen time.Time
-	*Node
+	*register.Node
 	TTL time.Duration
 }
 
@@ -25,23 +26,23 @@ type record struct {
 	Version   string
 	Metadata  map[string]string
 	Nodes     map[string]*node
-	Endpoints []*Endpoint
+	Endpoints []*register.Endpoint
 }
 
 type memory struct {
 	sync.RWMutex
 	records  map[string]services
 	watchers map[string]*watcher
-	opts     Options
+	opts     register.Options
 }
 
 // services is a KV map with service name as the key and a map of records as the value
 type services map[string]map[string]*record
 
 // NewRegister returns an initialized in-memory register
-func NewRegister(opts ...Option) Register {
+func NewRegister(opts ...register.Option) register.Register {
 	r := &memory{
-		opts:     NewOptions(opts...),
+		opts:     register.NewOptions(opts...),
 		records:  make(map[string]services),
 		watchers: make(map[string]*watcher),
 	}
@@ -75,7 +76,7 @@ func (m *memory) ttlPrune() {
 	}
 }
 
-func (m *memory) sendEvent(r *Result) {
+func (m *memory) sendEvent(r *register.Result) {
 	m.RLock()
 	watchers := make([]*watcher, 0, len(m.watchers))
 	for _, w := range m.watchers {
@@ -106,7 +107,7 @@ func (m *memory) Disconnect(ctx context.Context) error {
 	return nil
 }
 
-func (m *memory) Init(opts ...Option) error {
+func (m *memory) Init(opts ...register.Option) error {
 	for _, o := range opts {
 		o(&m.opts)
 	}
@@ -118,15 +119,15 @@ func (m *memory) Init(opts ...Option) error {
 	return nil
 }
 
-func (m *memory) Options() Options {
+func (m *memory) Options() register.Options {
 	return m.opts
 }
 
-func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOption) error {
+func (m *memory) Register(ctx context.Context, s *register.Service, opts ...register.RegisterOption) error {
 	m.Lock()
 	defer m.Unlock()
 
-	options := NewRegisterOptions(opts...)
+	options := register.NewRegisterOptions(opts...)
 
 	// get the services for this domain from the register
 	srvs, ok := m.records[options.Domain]
@@ -153,7 +154,7 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio
 			m.opts.Logger.Debugf(m.opts.Context, "Register added new service: %s, version: %s", s.Name, s.Version)
 		}
 		m.records[options.Domain] = srvs
-		go m.sendEvent(&Result{Action: "create", Service: s})
+		go m.sendEvent(&register.Result{Action: "create", Service: s})
 	}
 
 	var addedNodes bool
@@ -176,7 +177,7 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio
 
 		// add the node
 		srvs[s.Name][s.Version].Nodes[n.ID] = &node{
-			Node: &Node{
+			Node: &register.Node{
 				ID:       n.ID,
 				Address:  n.Address,
 				Metadata: metadata,
@@ -192,7 +193,7 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio
 		if m.opts.Logger.V(logger.DebugLevel) {
 			m.opts.Logger.Debugf(m.opts.Context, "Register added new node to service: %s, version: %s", s.Name, s.Version)
 		}
-		go m.sendEvent(&Result{Action: "update", Service: s})
+		go m.sendEvent(&register.Result{Action: "update", Service: s})
 	} else {
 		// refresh TTL and timestamp
 		for _, n := range s.Nodes {
@@ -208,11 +209,11 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio
 	return nil
 }
 
-func (m *memory) Deregister(ctx context.Context, s *Service, opts ...DeregisterOption) error {
+func (m *memory) Deregister(ctx context.Context, s *register.Service, opts ...register.DeregisterOption) error {
 	m.Lock()
 	defer m.Unlock()
 
-	options := NewDeregisterOptions(opts...)
+	options := register.NewDeregisterOptions(opts...)
 
 	// domain is set in metadata so it can be passed to watchers
 	if s.Metadata == nil {
@@ -252,7 +253,7 @@ func (m *memory) Deregister(ctx context.Context, s *Service, opts ...DeregisterO
 	// is cleanup
 	if len(version.Nodes) > 0 {
 		m.records[options.Domain][s.Name][s.Version] = version
-		go m.sendEvent(&Result{Action: "update", Service: s})
+		go m.sendEvent(&register.Result{Action: "update", Service: s})
 		return nil
 	}
 
@@ -260,7 +261,7 @@ func (m *memory) Deregister(ctx context.Context, s *Service, opts ...DeregisterO
 	// register and exit
 	if len(versions) == 1 {
 		delete(m.records[options.Domain], s.Name)
-		go m.sendEvent(&Result{Action: "delete", Service: s})
+		go m.sendEvent(&register.Result{Action: "delete", Service: s})
 
 		if m.opts.Logger.V(logger.DebugLevel) {
 			m.opts.Logger.Debugf(m.opts.Context, "Register removed service: %s", s.Name)
@@ -270,7 +271,7 @@ func (m *memory) Deregister(ctx context.Context, s *Service, opts ...DeregisterO
 
 	// there are other versions of the service running, so only remove this version of it
 	delete(m.records[options.Domain][s.Name], s.Version)
-	go m.sendEvent(&Result{Action: "delete", Service: s})
+	go m.sendEvent(&register.Result{Action: "delete", Service: s})
 	if m.opts.Logger.V(logger.DebugLevel) {
 		m.opts.Logger.Debugf(m.opts.Context, "Register removed service: %s, version: %s", s.Name, s.Version)
 	}
@@ -278,20 +279,20 @@ func (m *memory) Deregister(ctx context.Context, s *Service, opts ...DeregisterO
 	return nil
 }
 
-func (m *memory) LookupService(ctx context.Context, name string, opts ...LookupOption) ([]*Service, error) {
-	options := NewLookupOptions(opts...)
+func (m *memory) LookupService(ctx context.Context, name string, opts ...register.LookupOption) ([]*register.Service, error) {
+	options := register.NewLookupOptions(opts...)
 
 	// if it's a wildcard domain, return from all domains
-	if options.Domain == WildcardDomain {
+	if options.Domain == register.WildcardDomain {
 		m.RLock()
 		recs := m.records
 		m.RUnlock()
 
-		var services []*Service
+		var services []*register.Service
 
 		for domain := range recs {
-			srvs, err := m.LookupService(ctx, name, append(opts, LookupDomain(domain))...)
-			if err == ErrNotFound {
+			srvs, err := m.LookupService(ctx, name, append(opts, register.LookupDomain(domain))...)
+			if err == register.ErrNotFound {
 				continue
 			} else if err != nil {
 				return nil, err
@@ -300,7 +301,7 @@ func (m *memory) LookupService(ctx context.Context, name string, opts ...LookupO
 		}
 
 		if len(services) == 0 {
-			return nil, ErrNotFound
+			return nil, register.ErrNotFound
 		}
 		return services, nil
 	}
@@ -311,17 +312,17 @@ func (m *memory) LookupService(ctx context.Context, name string, opts ...LookupO
 	// check the domain exists
 	services, ok := m.records[options.Domain]
 	if !ok {
-		return nil, ErrNotFound
+		return nil, register.ErrNotFound
 	}
 
 	// check the service exists
 	versions, ok := services[name]
 	if !ok || len(versions) == 0 {
-		return nil, ErrNotFound
+		return nil, register.ErrNotFound
 	}
 
 	// serialize the response
-	result := make([]*Service, len(versions))
+	result := make([]*register.Service, len(versions))
 
 	var i int
 
@@ -333,19 +334,19 @@ func (m *memory) LookupService(ctx context.Context, name string, opts ...LookupO
 	return result, nil
 }
 
-func (m *memory) ListServices(ctx context.Context, opts ...ListOption) ([]*Service, error) {
-	options := NewListOptions(opts...)
+func (m *memory) ListServices(ctx context.Context, opts ...register.ListOption) ([]*register.Service, error) {
+	options := register.NewListOptions(opts...)
 
 	// if it's a wildcard domain, list from all domains
-	if options.Domain == WildcardDomain {
+	if options.Domain == register.WildcardDomain {
 		m.RLock()
 		recs := m.records
 		m.RUnlock()
 
-		var services []*Service
+		var services []*register.Service
 
 		for domain := range recs {
-			srvs, err := m.ListServices(ctx, append(opts, ListDomain(domain))...)
+			srvs, err := m.ListServices(ctx, append(opts, register.ListDomain(domain))...)
 			if err != nil {
 				return nil, err
 			}
@@ -361,11 +362,11 @@ func (m *memory) ListServices(ctx context.Context, opts ...ListOption) ([]*Servi
 	// ensure the domain exists
 	services, ok := m.records[options.Domain]
 	if !ok {
-		return make([]*Service, 0), nil
+		return make([]*register.Service, 0), nil
 	}
 
 	// serialize the result, each version counts as an individual service
-	var result []*Service
+	var result []*register.Service
 
 	for _, service := range services {
 		for _, version := range service {
@@ -376,16 +377,16 @@ func (m *memory) ListServices(ctx context.Context, opts ...ListOption) ([]*Servi
 	return result, nil
 }
 
-func (m *memory) Watch(ctx context.Context, opts ...WatchOption) (Watcher, error) {
+func (m *memory) Watch(ctx context.Context, opts ...register.WatchOption) (register.Watcher, error) {
 	id, err := id.New()
 	if err != nil {
 		return nil, err
 	}
-	wo := NewWatchOptions(opts...)
+	wo := register.NewWatchOptions(opts...)
 	// construct the watcher
 	w := &watcher{
 		exit: make(chan bool),
-		res:  make(chan *Result),
+		res:  make(chan *register.Result),
 		id:   id,
 		wo:   wo,
 	}
@@ -406,13 +407,13 @@ func (m *memory) String() string {
 }
 
 type watcher struct {
-	res  chan *Result
+	res  chan *register.Result
 	exit chan bool
-	wo   WatchOptions
+	wo   register.WatchOptions
 	id   string
 }
 
-func (m *watcher) Next() (*Result, error) {
+func (m *watcher) Next() (*register.Result, error) {
 	for {
 		select {
 		case r := <-m.res:
@@ -429,15 +430,15 @@ func (m *watcher) Next() (*Result, error) {
 			if r.Service.Metadata != nil && len(r.Service.Metadata["domain"]) > 0 {
 				domain = r.Service.Metadata["domain"]
 			} else {
-				domain = DefaultDomain
+				domain = register.DefaultDomain
 			}
 
 			// only send the event if watching the wildcard or this specific domain
-			if m.wo.Domain == WildcardDomain || m.wo.Domain == domain {
+			if m.wo.Domain == register.WildcardDomain || m.wo.Domain == domain {
 				return r, nil
 			}
 		case <-m.exit:
-			return nil, ErrWatcherStopped
+			return nil, register.ErrWatcherStopped
 		}
 	}
 }
@@ -451,7 +452,7 @@ func (m *watcher) Stop() {
 	}
 }
 
-func serviceToRecord(s *Service, ttl time.Duration) *record {
+func serviceToRecord(s *register.Service, ttl time.Duration) *record {
 	metadata := make(map[string]string, len(s.Metadata))
 	for k, v := range s.Metadata {
 		metadata[k] = v
@@ -466,7 +467,7 @@ func serviceToRecord(s *Service, ttl time.Duration) *record {
 		}
 	}
 
-	endpoints := make([]*Endpoint, len(s.Endpoints))
+	endpoints := make([]*register.Endpoint, len(s.Endpoints))
 	for i, e := range s.Endpoints {
 		endpoints[i] = e
 	}
@@ -480,7 +481,7 @@ func serviceToRecord(s *Service, ttl time.Duration) *record {
 	}
 }
 
-func recordToService(r *record, domain string) *Service {
+func recordToService(r *record, domain string) *register.Service {
 	metadata := make(map[string]string, len(r.Metadata))
 	for k, v := range r.Metadata {
 		metadata[k] = v
@@ -489,14 +490,14 @@ func recordToService(r *record, domain string) *Service {
 	// set the domain in metadata so it can be determined when a wildcard query is performed
 	metadata["domain"] = domain
 
-	endpoints := make([]*Endpoint, len(r.Endpoints))
+	endpoints := make([]*register.Endpoint, len(r.Endpoints))
 	for i, e := range r.Endpoints {
 		md := make(map[string]string, len(e.Metadata))
 		for k, v := range e.Metadata {
 			md[k] = v
 		}
 
-		endpoints[i] = &Endpoint{
+		endpoints[i] = &register.Endpoint{
 			Name:     e.Name,
 			Request:  e.Request,
 			Response: e.Response,
@@ -504,7 +505,7 @@ func recordToService(r *record, domain string) *Service {
 		}
 	}
 
-	nodes := make([]*Node, len(r.Nodes))
+	nodes := make([]*register.Node, len(r.Nodes))
 	i := 0
 	for _, n := range r.Nodes {
 		md := make(map[string]string, len(n.Metadata))
@@ -512,7 +513,7 @@ func recordToService(r *record, domain string) *Service {
 			md[k] = v
 		}
 
-		nodes[i] = &Node{
+		nodes[i] = &register.Node{
 			ID:       n.ID,
 			Address:  n.Address,
 			Metadata: md,
@@ -520,7 +521,7 @@ func recordToService(r *record, domain string) *Service {
 		i++
 	}
 
-	return &Service{
+	return &register.Service{
 		Name:      r.Name,
 		Version:   r.Version,
 		Metadata:  metadata,

register/memory/memory_test.go

@@ -6,14 +6,16 @@ import (
 	"sync"
 	"testing"
 	"time"
+
+	"go.unistack.org/micro/v3/register"
 )
 
-var testData = map[string][]*Service{
+var testData = map[string][]*register.Service{
 	"foo": {
 		{
 			Name:    "foo",
 			Version: "1.0.0",
-			Nodes: []*Node{
+			Nodes: []*register.Node{
 				{
 					ID:      "foo-1.0.0-123",
 					Address: "localhost:9999",
@@ -27,7 +29,7 @@ var testData = map[string][]*Service{
 		{
 			Name:    "foo",
 			Version: "1.0.1",
-			Nodes: []*Node{
+			Nodes: []*register.Node{
 				{
 					ID:      "foo-1.0.1-321",
 					Address: "localhost:6666",
@@ -37,7 +39,7 @@ var testData = map[string][]*Service{
 		{
 			Name:    "foo",
 			Version: "1.0.3",
-			Nodes: []*Node{
+			Nodes: []*register.Node{
 				{
 					ID:      "foo-1.0.3-345",
 					Address: "localhost:8888",
@@ -49,7 +51,7 @@ var testData = map[string][]*Service{
 		{
 			Name:    "bar",
 			Version: "default",
-			Nodes: []*Node{
+			Nodes: []*register.Node{
 				{
 					ID:      "bar-1.0.0-123",
 					Address: "localhost:9999",
@@ -63,7 +65,7 @@ var testData = map[string][]*Service{
 		{
 			Name:    "bar",
 			Version: "latest",
-			Nodes: []*Node{
+			Nodes: []*register.Node{
 				{
 					ID:      "bar-1.0.1-321",
 					Address: "localhost:6666",
@@ -78,7 +80,7 @@ func TestMemoryRegistry(t *testing.T) {
 	ctx := context.TODO()
 	m := NewRegister()
 
-	fn := func(k string, v []*Service) {
+	fn := func(k string, v []*register.Service) {
 		services, err := m.LookupService(ctx, k)
 		if err != nil {
 			t.Errorf("Unexpected error getting service %s: %v", k, err)
@@ -155,8 +157,8 @@ func TestMemoryRegistry(t *testing.T) {
 	for _, v := range testData {
 		for _, service := range v {
 			services, err := m.LookupService(ctx, service.Name)
-			if err != ErrNotFound {
-				t.Errorf("Expected error: %v, got: %v", ErrNotFound, err)
+			if err != register.ErrNotFound {
+				t.Errorf("Expected error: %v, got: %v", register.ErrNotFound, err)
 			}
 			if len(services) != 0 {
 				t.Errorf("Expected %d services for %s, got %d", 0, service.Name, len(services))
@@ -171,7 +173,7 @@ func TestMemoryRegistryTTL(t *testing.T) {
 
 	for _, v := range testData {
 		for _, service := range v {
-			if err := m.Register(ctx, service, RegisterTTL(time.Millisecond)); err != nil {
+			if err := m.Register(ctx, service, register.RegisterTTL(time.Millisecond)); err != nil {
 				t.Fatal(err)
 			}
 		}
@@ -200,7 +202,7 @@ func TestMemoryRegistryTTLConcurrent(t *testing.T) {
 	ctx := context.TODO()
 	for _, v := range testData {
 		for _, service := range v {
-			if err := m.Register(ctx, service, RegisterTTL(waitTime/2)); err != nil {
+			if err := m.Register(ctx, service, register.RegisterTTL(waitTime/2)); err != nil {
 				t.Fatal(err)
 			}
 		}
@@ -249,34 +251,34 @@ func TestMemoryWildcard(t *testing.T) {
 	m := NewRegister()
 	ctx := context.TODO()
 
-	testSrv := &Service{Name: "foo", Version: "1.0.0"}
+	testSrv := &register.Service{Name: "foo", Version: "1.0.0"}
 
-	if err := m.Register(ctx, testSrv, RegisterDomain("one")); err != nil {
+	if err := m.Register(ctx, testSrv, register.RegisterDomain("one")); err != nil {
 		t.Fatalf("Register err: %v", err)
 	}
-	if err := m.Register(ctx, testSrv, RegisterDomain("two")); err != nil {
+	if err := m.Register(ctx, testSrv, register.RegisterDomain("two")); err != nil {
 		t.Fatalf("Register err: %v", err)
 	}
 
-	if recs, err := m.ListServices(ctx, ListDomain("one")); err != nil {
+	if recs, err := m.ListServices(ctx, register.ListDomain("one")); err != nil {
 		t.Errorf("List err: %v", err)
 	} else if len(recs) != 1 {
 		t.Errorf("Expected 1 record, got %v", len(recs))
 	}
 
-	if recs, err := m.ListServices(ctx, ListDomain("*")); err != nil {
+	if recs, err := m.ListServices(ctx, register.ListDomain("*")); err != nil {
 		t.Errorf("List err: %v", err)
 	} else if len(recs) != 2 {
 		t.Errorf("Expected 2 records, got %v", len(recs))
 	}
 
-	if recs, err := m.LookupService(ctx, testSrv.Name, LookupDomain("one")); err != nil {
+	if recs, err := m.LookupService(ctx, testSrv.Name, register.LookupDomain("one")); err != nil {
 		t.Errorf("Lookup err: %v", err)
 	} else if len(recs) != 1 {
 		t.Errorf("Expected 1 record, got %v", len(recs))
 	}
 
-	if recs, err := m.LookupService(ctx, testSrv.Name, LookupDomain("*")); err != nil {
+	if recs, err := m.LookupService(ctx, testSrv.Name, register.LookupDomain("*")); err != nil {
 		t.Errorf("Lookup err: %v", err)
 	} else if len(recs) != 2 {
 		t.Errorf("Expected 2 records, got %v", len(recs))
@@ -284,7 +286,7 @@ func TestMemoryWildcard(t *testing.T) {
 }
 
 func TestWatcher(t *testing.T) {
-	testSrv := &Service{Name: "foo", Version: "1.0.0"}
+	testSrv := &register.Service{Name: "foo", Version: "1.0.0"}
 
 	ctx := context.TODO()
 	m := NewRegister()

register/noop.go

@@ -0,0 +1,72 @@
+package register
+
+import "context"
+
+type noop struct {
+	opts Options
+}
+
+func NewRegister(opts ...Option) Register {
+	return &noop{
+		opts: NewOptions(opts...),
+	}
+}
+
+func (n *noop) Name() string {
+	return n.opts.Name
+}
+
+func (n *noop) Init(opts ...Option) error {
+	for _, o := range opts {
+		o(&n.opts)
+	}
+	return nil
+}
+
+func (n *noop) Options() Options {
+	return n.opts
+}
+
+func (n *noop) Connect(ctx context.Context) error {
+	return nil
+}
+
+func (n *noop) Disconnect(ctx context.Context) error {
+	return nil
+}
+
+func (n *noop) Register(ctx context.Context, service *Service, option ...RegisterOption) error {
+	return nil
+}
+
+func (n *noop) Deregister(ctx context.Context, service *Service, option ...DeregisterOption) error {
+	return nil
+}
+
+func (n *noop) LookupService(ctx context.Context, s string, option ...LookupOption) ([]*Service, error) {
+	return nil, nil
+}
+
+func (n *noop) ListServices(ctx context.Context, option ...ListOption) ([]*Service, error) {
+	return nil, nil
+}
+
+func (n *noop) Watch(ctx context.Context, opts ...WatchOption) (Watcher, error) {
+	wOpts := NewWatchOptions(opts...)
+
+	return &watcher{wo: wOpts}, nil
+}
+
+func (n *noop) String() string {
+	return "noop"
+}
+
+type watcher struct {
+	wo WatchOptions
+}
+
+func (m *watcher) Next() (*Result, error) {
+	return nil, nil
+}
+
+func (m *watcher) Stop() {}

register/options.go

@@ -5,9 +5,9 @@ import (
 	"crypto/tls"
 	"time"
 
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/meter"
-	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v3/tracer"
 )
 
 // Options holds options for register

register/register.go

@@ -1,11 +1,11 @@
 // Package register is an interface for service discovery
-package register // import "go.unistack.org/micro/v4/register"
+package register // import "go.unistack.org/micro/v3/register"
 
 import (
 	"context"
 	"errors"
 
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 const (
@@ -18,7 +18,7 @@ var DefaultDomain = "micro"
 
 var (
 	// DefaultRegister is the global default register
-	DefaultRegister = NewRegister()
+	DefaultRegister Register = NewRegister()
 	// ErrNotFound returned when LookupService is called and no services found
 	ErrNotFound = errors.New("service not found")
 	// ErrWatcherStopped returned when when watcher is stopped

resolver/dns/dns.go

@@ -1,5 +1,5 @@
 // Package dns resolves names to dns records
-package dns // import "go.unistack.org/micro/v4/resolver/dns"
+package dns // import "go.unistack.org/micro/v3/resolver/dns"
 
 import (
 	"context"
@@ -7,7 +7,7 @@ import (
 	"sync"
 	"time"
 
-	"go.unistack.org/micro/v4/resolver"
+	"go.unistack.org/micro/v3/resolver"
 )
 
 // Resolver is a DNS network resolve

resolver/dnssrv/dnssrv.go

@@ -1,11 +1,11 @@
 // Package dnssrv resolves names to dns srv records
-package dnssrv // import "go.unistack.org/micro/v4/resolver/dnssrv"
+package dnssrv // import "go.unistack.org/micro/v3/resolver/dnssrv"
 
 import (
 	"fmt"
 	"net"
 
-	"go.unistack.org/micro/v4/resolver"
+	"go.unistack.org/micro/v3/resolver"
 )
 
 // Resolver is a DNS network resolve

resolver/http/http.go

@@ -1,5 +1,5 @@
 // Package http resolves names to network addresses using a http request
-package http // import "go.unistack.org/micro/v4/resolver/http"
+package http // import "go.unistack.org/micro/v3/resolver/http"
 
 import (
 	"encoding/json"
@@ -8,7 +8,7 @@ import (
 	"net/http"
 	"net/url"
 
-	"go.unistack.org/micro/v4/resolver"
+	"go.unistack.org/micro/v3/resolver"
 )
 
 // nolint: golint,revive

resolver/noop/noop.go

@@ -1,8 +1,8 @@
 // Package noop is a noop resolver
-package noop // import "go.unistack.org/micro/v4/resolver/noop"
+package noop // import "go.unistack.org/micro/v3/resolver/noop"
 
 import (
-	"go.unistack.org/micro/v4/resolver"
+	"go.unistack.org/micro/v3/resolver"
 )
 
 // Resolver contains noop resolver

resolver/registry/registry.go

@@ -1,11 +1,11 @@
 // Package register resolves names using the micro register
-package register // import "go.unistack.org/micro/v4/resolver/registry"
+package register // import "go.unistack.org/micro/v3/resolver/registry"
 
 import (
 	"context"
 
-	"go.unistack.org/micro/v4/register"
-	"go.unistack.org/micro/v4/resolver"
+	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v3/resolver"
 )
 
 // Resolver is a register network resolver

resolver/resolver.go

@@ -1,5 +1,5 @@
 // Package resolver resolves network names to addresses
-package resolver // import "go.unistack.org/micro/v4/resolver"
+package resolver
 
 // Resolver is network resolver. It's used to find network nodes
 // via the name to connect to. This is done based on Network.Name().

resolver/static/static.go

@@ -1,8 +1,8 @@
 // Package static is a static resolver
-package static // import "go.unistack.org/micro/v4/resolver/static"
+package static // import "go.unistack.org/micro/v3/resolver/static"
 
 import (
-	"go.unistack.org/micro/v4/resolver"
+	"go.unistack.org/micro/v3/resolver"
 )
 
 // Resolver returns a static list of nodes. In the event the node list

router/options.go

@@ -3,9 +3,9 @@ package router
 import (
 	"context"
 
-	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v4/register"
-	"go.unistack.org/micro/v4/util/id"
+	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/register"
+	"go.unistack.org/micro/v3/util/id"
 )
 
 // Options are router options

router/route.go

@@ -3,7 +3,7 @@ package router
 import (
 	"hash/fnv"
 
-	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v3/metadata"
 )
 
 var (

router/router.go

@@ -1,5 +1,5 @@
 // Package router provides a network routing control plane
-package router // import "go.unistack.org/micro/v4/router"
+package router // import "go.unistack.org/micro/v3/router"
 
 import (
 	"errors"
@@ -7,7 +7,7 @@ import (
 
 var (
 	// DefaultRouter is the global default router
-	DefaultRouter = NewRouter()
+	DefaultRouter Router = NewRouter()
 	// DefaultNetwork is default micro network
 	DefaultNetwork = "micro"
 	// ErrRouteNotFound is returned when no route was found in the routing table

selector/random/random.go

@@ -1,8 +1,8 @@
-package random // import "go.unistack.org/micro/v4/selector/random"
+package random // import "go.unistack.org/micro/v3/selector/random"
 
 import (
-	"go.unistack.org/micro/v4/selector"
-	"go.unistack.org/micro/v4/util/rand"
+	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v3/util/rand"
 )
 
 type random struct{}

selector/random/random_test.go

@@ -3,7 +3,7 @@ package random
 import (
 	"testing"
 
-	"go.unistack.org/micro/v4/selector"
+	"go.unistack.org/micro/v3/selector"
 )
 
 func TestRandom(t *testing.T) {

selector/roundrobin/roundrobin.go

@@ -1,8 +1,8 @@
-package roundrobin // import "go.unistack.org/micro/v4/selector/roundrobin"
+package roundrobin // import "go.unistack.org/micro/v3/selector/roundrobin"
 
 import (
-	"go.unistack.org/micro/v4/selector"
-	"go.unistack.org/micro/v4/util/rand"
+	"go.unistack.org/micro/v3/selector"
+	"go.unistack.org/micro/v3/util/rand"
 )
 
 // NewSelector returns an initialised round robin selector

selector/roundrobin/roundrobin_test.go

@@ -3,7 +3,7 @@ package roundrobin
 import (
 	"testing"
 
-	"go.unistack.org/micro/v4/selector"
+	"go.unistack.org/micro/v3/selector"
 )
 
 func TestRoundRobin(t *testing.T) {

selector/selector.go

@@ -1,5 +1,5 @@
 // Package selector is for node selection and load balancing
-package selector // import "go.unistack.org/micro/v4/selector"
+package selector // import "go.unistack.org/micro/v3/selector"
 
 import (
 	"errors"

semconv/broker.go

@@ -0,0 +1,22 @@
+package semconv
+
+var (
+	// PublishMessageDurationSeconds specifies meter metric name
+	PublishMessageDurationSeconds = "publish_message_duration_seconds"
+	// PublishMessageLatencyMicroseconds specifies meter metric name
+	PublishMessageLatencyMicroseconds = "publish_message_latency_microseconds"
+	// PublishMessageTotal specifies meter metric name
+	PublishMessageTotal = "publish_message_total"
+	// PublishMessageInflight specifies meter metric name
+	PublishMessageInflight = "publish_message_inflight"
+	// SubscribeMessageDurationSeconds specifies meter metric name
+	SubscribeMessageDurationSeconds = "subscribe_message_duration_seconds"
+	// SubscribeMessageLatencyMicroseconds specifies meter metric name
+	SubscribeMessageLatencyMicroseconds = "subscribe_message_latency_microseconds"
+	// SubscribeMessageTotal specifies meter metric name
+	SubscribeMessageTotal = "subscribe_message_total"
+	// SubscribeMessageInflight specifies meter metric name
+	SubscribeMessageInflight = "subscribe_message_inflight"
+	// BrokerGroupLag specifies broker lag
+	BrokerGroupLag = "broker_group_lag"
+)

semconv/cache.go

@@ -0,0 +1,12 @@
+package semconv
+
+var (
+	// CacheRequestDurationSeconds specifies meter metric name
+	CacheRequestDurationSeconds = "cache_request_duration_seconds"
+	// ClientRequestLatencyMicroseconds specifies meter metric name
+	CacheRequestLatencyMicroseconds = "cache_request_latency_microseconds"
+	// CacheRequestTotal specifies meter metric name
+	CacheRequestTotal = "cache_request_total"
+	// CacheRequestInflight specifies meter metric name
+	CacheRequestInflight = "cache_request_inflight"
+)