Merge branch 'master' into #335

# Conflicts: # logger/options.go
2024-04-15 13:20:28 +03:00 · 2024-04-15 13:20:28 +03:00 · b0879be9f6
commit b0879be9f6
parent a9426dfea5 b8928d3da9
53 changed files with 1481 additions and 589 deletions
--- a/.gitea/workflows/autoupdate.yml
+++ b/.gitea/workflows/autoupdate.yml
@ -5,8 +5,8 @@ on:
    - 'master'
    - 'v3'
  schedule:
-    - cron: '* * * * *'
-    #- cron: '@hourly'
+    #- cron: '* * * * *'
+    - cron: '@hourly'

 jobs:
  autoupdate:
--- a/.gitea/workflows/coverage.yml
+++ b/.gitea/workflows/coverage.yml
@ -0,0 +1,30 @@
+name: Go
+
+on:
+  push:
+    branches: [ master, v3 ]
+  pull_request:
+    branches: [ master, v3 ]
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout
+      uses: actions/checkout@v4
+
+    - name: setup
+      uses: actions/setup-go@v4
+      with:
+        go-version: stable
+
+    - name: coverage
+      run: go test -v -coverprofile coverage.out ./...
+
+    - name: badge
+      uses: ncruces/go-coverage-report@main
+      with:
+        coverage-file: coverage.out
+        reuse-go: true
+        amend: true
--- a/.gitea/workflows/pr.yml
+++ b/.gitea/workflows/pr.yml
@ -20,4 +20,4 @@ jobs:
    - name: test
      env:
        INTEGRATION_TESTS: yes
-      run: go test -mod readonly -v ./...
+      run: go test -v -mod readonly -race -coverprofile=coverage.txt -covermode=atomic ./...
--- a/.gitignore
+++ b/.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]
--- a/.golangci.yml
+++ b/.golangci.yml
@ -1,6 +1,5 @@
 run:
  concurrency: 4
-  deadline: 5m
  issues-exit-code: 1
  tests: true

@ -13,15 +12,13 @@ linters-settings:
 linters:
  enable:
    - govet
-    - deadcode
    - errcheck
    - govet
    - ineffassign
    - staticcheck
-    - structcheck
    - typecheck
    - unused
-    - varcheck
+    - spancheck
    - bodyclose
    - gci
    - goconst
@ -41,4 +38,5 @@ linters:
    - prealloc
    - unconvert
    - unparam
+    - unused
  disable-all: false
--- a/broker/broker.go
+++ b/broker/broker.go
@ -4,6 +4,7 @@ package broker // import "go.unistack.org/micro/v4/broker"
 import (
 	"context"
 	"errors"
+	"time"

 	"go.unistack.org/micro/v4/metadata"
 	"go.unistack.org/micro/v4/options"
@ -19,6 +20,8 @@ var (
 	ErrDisconnected = errors.New("broker disconnected")
 	// ErrInvalidMessage returns when message has nvalid format
 	ErrInvalidMessage = errors.New("broker message has invalid format")
+	// DefaultGracefulTimeout
+	DefaultGracefulTimeout = 5 * time.Second
 )

 // Broker is an interface used for asynchronous messaging.
--- a/broker/memory_test.go
+++ b/broker/memory_test.go
@ -37,10 +37,10 @@ func TestMemoryBatchBroker(t *testing.T) {
 	msgs := make([]Message, 0, count)
 	for i := 0; i < count; i++ {
 		message := &memoryMessage{
-			header: map[string]string{
-				metadata.HeaderTopic: topic,
-				"foo":                "bar",
-				"id":                 fmt.Sprintf("%d", i),
+			header: metadata.Metadata{
+				metadata.HeaderTopic: []string{topic},
+				"foo":                []string{"bar"},
+				"id":                 []string{fmt.Sprintf("%d", i)},
 			},
 			body: []byte(`"hello world"`),
 		}
@ -83,10 +83,10 @@ func TestMemoryBroker(t *testing.T) {
 	msgs := make([]Message, 0, count)
 	for i := 0; i < count; i++ {
 		message := &memoryMessage{
-			header: map[string]string{
-				metadata.HeaderTopic: topic,
-				"foo":                "bar",
-				"id":                 fmt.Sprintf("%d", i),
+			header: metadata.Metadata{
+				metadata.HeaderTopic: []string{topic},
+				"foo":                []string{"bar"},
+				"id":                 []string{fmt.Sprintf("%d", i)},
 			},
 			body: []byte(`"hello world"`),
 		}
--- a/broker/options.go
+++ b/broker/options.go
@ -11,6 +11,7 @@ import (
 	"go.unistack.org/micro/v4/meter"
 	"go.unistack.org/micro/v4/options"
 	"go.unistack.org/micro/v4/register"
+	"go.unistack.org/micro/v4/sync"
 	"go.unistack.org/micro/v4/tracer"
 )

@ -36,36 +37,41 @@ type Options struct {
 	Name string
 	// Address holds the broker address
 	Address []string
+
+	Wait *sync.WaitGroup
+
+	GracefulTimeout time.Duration
 }

 // NewOptions create new Options
 func NewOptions(opts ...options.Option) Options {
-	options := Options{
-		Register: register.DefaultRegister,
-		Logger:   logger.DefaultLogger,
-		Context:  context.Background(),
-		Meter:    meter.DefaultMeter,
-		Codecs:   make(map[string]codec.Codec),
-		Tracer:   tracer.DefaultTracer,
+	newOpts := Options{
+		Register:        register.DefaultRegister,
+		Logger:          logger.DefaultLogger,
+		Context:         context.Background(),
+		Meter:           meter.DefaultMeter,
+		Codecs:          make(map[string]codec.Codec),
+		Tracer:          tracer.DefaultTracer,
+		GracefulTimeout: DefaultGracefulTimeout,
 	}
 	for _, o := range opts {
-		o(&options)
+		o(&newOpts)
 	}
-	return options
+	return newOpts
 }

 // PublishOptions struct
 type PublishOptions struct {
 	// Context holds external options
 	Context context.Context
-	// BodyOnly flag says the message contains raw body bytes
-	BodyOnly bool
 	// Message metadata usually passed as message headers
 	Metadata metadata.Metadata
 	// Content-Type of message for marshal
 	ContentType string
 	// Topic destination
 	Topic string
+	// BodyOnly flag says the message contains raw body bytes
+	BodyOnly bool
 }

 // NewPublishOptions creates PublishOptions struct
--- a/broker/subscriber.go
+++ b/broker/subscriber.go
@ -19,8 +19,8 @@ var typeOfError = reflect.TypeOf((*error)(nil)).Elem()

 // Is this an exported - upper case - name?
 func isExported(name string) bool {
-	rune, _ := utf8.DecodeRuneInString(name)
-	return unicode.IsUpper(rune)
+	r, _ := utf8.DecodeRuneInString(name)
+	return unicode.IsUpper(r)
 }

 // Is this type exported or a builtin?
--- a/database/dsn.go
+++ b/database/dsn.go
@ -75,78 +75,80 @@ func ParseDSN(dsn string) (*Config, error) {
 	// 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
+		if dsn[i] != '/' {
+			continue
+		}

-			// 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]
-					}
+		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
+			// [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.Params = append(cfg.Params, k, v)
 					}
-
+					cfg.Username = dsn[len(cfg.Scheme)+3 : k]
 					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)
+
+			for k = j + 1; k < i; k++ {
+				if dsn[k] == ':' {
+					cfg.Host = dsn[j+1 : k]
+					cfg.Port = dsn[k+1 : i]
+					break
+				}
 			}

-			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 {
--- a/go.mod
+++ b/go.mod
@ -5,17 +5,16 @@ go 1.20
 require (
 	dario.cat/mergo v1.0.0
 	github.com/DATA-DOG/go-sqlmock v1.5.0
-	github.com/google/uuid v1.3.1
+	github.com/google/uuid v1.6.0
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/silas/dag v0.0.0-20220518035006-a7e85ada93c5
-	golang.org/x/sync v0.3.0
-	golang.org/x/sys v0.12.0
-	google.golang.org/grpc v1.58.2
-	google.golang.org/protobuf v1.31.0
+	golang.org/x/sync v0.6.0
+	golang.org/x/sys v0.16.0
+	google.golang.org/grpc v1.62.1
+	google.golang.org/protobuf v1.32.0
 )

 require (
 	github.com/golang/protobuf v1.5.3 // indirect
-	golang.org/x/net v0.15.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80 // indirect
 )
--- a/go.sum
+++ b/go.sum
@ -6,29 +6,28 @@ github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaS
 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 v1.3.1 h1:KjJaJ9iWZ3jOFZIf1Lqf4laDRCasjl0BCmnEGxkdLb4=
-github.com/google/uuid v1.3.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/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 v0.0.0-20220518035006-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 v0.15.0 h1:ugBLEUaxABaB5AJqW9enI0ACdci2RUd4eP51NTBvuJ8=
-golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=
-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 v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
-golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
+golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
+golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
+golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98 h1:bVf09lpb+OJbByTj913DRJioFFAjf/ZGxEz7MajTp2U=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98/go.mod h1:TUfxEVdsvPg18p6AslUXFoLdpED4oBnGwyqk3dV1XzM=
-google.golang.org/grpc v1.58.2 h1:SXUpjxeVF3FKrTYQI4f4KvbGD5u2xccdYdurwowix5I=
-google.golang.org/grpc v1.58.2/go.mod h1:tgX3ZQDlNJGU96V6yHh1T/JeoBQ2TXdr43YbYSsCJk0=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80 h1:AjyfHzEPEFp/NpvfN5g+KDla3EMojjhRVZc1i7cj+oM=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80/go.mod h1:PAREbraiVEVGVdTZsVWjSbbTtSyGbAgIIvni8a8CD5s=
+google.golang.org/grpc v1.62.1 h1:B4n+nfKzOICUXMgyrNd19h/I9oH0L1pizfk1d4zSgTk=
+google.golang.org/grpc v1.62.1/go.mod h1:IWTG0VlJLCh1SkC58F7np9ka9mx/WNkjl4PGJaiq+QE=
 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=
+google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
+google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 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=
--- a/logger/logger.go
+++ b/logger/logger.go
@ -48,8 +48,10 @@ type Logger interface {
 	Fatal(ctx context.Context, msg string, attrs ...interface{})
 	// Log logs message with needed level
 	Log(ctx context.Context, level Level, msg string, attrs ...interface{})
-	// String returns the name of logger
+	// String returns the type name of logger
 	String() string
+	// String returns the name of logger
+	Name() string
 }

 // Info writes formatted msg to default logger on info level
@ -62,8 +64,8 @@ func Error(ctx context.Context, msg string, attrs ...interface{}) {
 	DefaultLogger.Error(ctx, msg, attrs...)
 }

-// Debugf writes formatted msg to default logger on debug level
-func Debugf(ctx context.Context, msg string, attrs ...interface{}) {
+// Debug writes formatted msg to default logger on debug level
+func Debug(ctx context.Context, msg string, attrs ...interface{}) {
 	DefaultLogger.Debug(ctx, msg, attrs...)
 }

--- a/logger/noop.go
+++ b/logger/noop.go
@ -45,6 +45,10 @@ func (l *noopLogger) Options() Options {
 	return l.opts
 }

+func (l *noopLogger) Name() string {
+	return l.opts.Name
+}
+
 func (l *noopLogger) String() string {
 	return "noop"
 }
--- a/logger/options.go
+++ b/logger/options.go
@ -6,6 +6,7 @@ import (
 	"log/slog"
 	"os"
 	"reflect"
+	"time"

 	"go.unistack.org/micro/v4/options"
 	rutil "go.unistack.org/micro/v4/util/reflect"
@ -17,24 +18,34 @@ type Options struct {
 	Out io.Writer
 	// Context holds exernal options
 	Context context.Context
-	// Attrs holds additional attributes
-	Attrs []interface{}
-	// Name holds the logger name
-	Name string
-	// The logging level the logger should log
-	Level Level
-	// CallerSkipCount number of frmaes to skip
-	CallerSkipCount int
-	// ContextAttrFuncs contains funcs that executed before log func on context
-	ContextAttrFuncs []ContextAttrFunc
+	// TimeFunc used to obtain current time
+	TimeFunc func() time.Time
 	// TimeKey is the key used for the time of the log call
 	TimeKey string
+	// Name holds the logger name
+	Name string
 	// LevelKey is the key used for the level of the log call
 	LevelKey string
 	// MessageKey is the key used for the message of the log call
 	MessageKey string
+	// ErrorKey is the key used for the error info
+	ErrorKey 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
+	// Attrs holds additional attributes
+	Attrs []interface{}
+	// ContextAttrFuncs contains funcs that executed before log func on context
+	ContextAttrFuncs []ContextAttrFunc
+	// CallerSkipCount number of frmaes to skip
+	CallerSkipCount int
+	// The logging level the logger should log
+	Level Level
+	// AddStacktrace controls writing of stacktaces on error
+	AddStacktrace bool
+	// AddSource enabled writing source file and position in log
+	AddSource bool
 }

 // NewOptions creates new options struct
@ -46,12 +57,14 @@ func NewOptions(opts ...options.Option) Options {
 		CallerSkipCount:  DefaultCallerSkipCount,
 		Context:          context.Background(),
 		ContextAttrFuncs: DefaultContextAttrFuncs,
+		AddSource:        true,
+		TimeFunc:         time.Now,
 	}

-	WithMicroKeys()(&options)
+	_ = WithMicroKeys()(&options)

 	for _, o := range opts {
-		o(&options)
+		_ = o(&options)
 	}
 	return options
 }
@ -116,6 +129,12 @@ func WithZapKeys() options.Option {
 		if err = options.Set(src, "caller", ".SourceKey"); err != nil {
 			return err
 		}
+		if err = options.Set(src, "stacktrace", ".StacktraceKey"); err != nil {
+			return err
+		}
+		if err = options.Set(src, "error", ".ErrorKey"); err != nil {
+			return err
+		}
 		return nil
 	}
 }
@ -135,6 +154,12 @@ func WithZerologKeys() options.Option {
 		if err = options.Set(src, "caller", ".SourceKey"); err != nil {
 			return err
 		}
+		if err = options.Set(src, "stacktrace", ".StacktraceKey"); err != nil {
+			return err
+		}
+		if err = options.Set(src, "error", ".ErrorKey"); err != nil {
+			return err
+		}
 		return nil
 	}
 }
@ -154,6 +179,12 @@ func WithSlogKeys() options.Option {
 		if err = options.Set(src, slog.SourceKey, ".SourceKey"); err != nil {
 			return err
 		}
+		if err = options.Set(src, "stacktrace", ".StacktraceKey"); err != nil {
+			return err
+		}
+		if err = options.Set(src, "error", ".ErrorKey"); err != nil {
+			return err
+		}
 		return nil
 	}
 }
@ -173,6 +204,12 @@ func WithMicroKeys() options.Option {
 		if err = options.Set(src, "caller", ".SourceKey"); err != nil {
 			return err
 		}
+		if err = options.Set(src, "stacktrace", ".StacktraceKey"); err != nil {
+			return err
+		}
+		if err = options.Set(src, "error", ".ErrorKey"); err != nil {
+			return err
+		}
 		return nil
 	}
 }
@ -189,3 +226,17 @@ func WithIncCallerSkipCount(n int) options.Option {
 		return nil
 	}
 }
+
+// WithAddStacktrace controls writing stacktrace on error
+func WithAddStacktrace(v bool) options.Option {
+	return func(src interface{}) error {
+		return options.Set(src, v, ".AddStacktrace")
+	}
+}
+
+// WitAddSource controls writing source file and pos in log
+func WithAddSource(v bool) options.Option {
+	return func(src interface{}) error {
+		return options.Set(src, v, ".AddSource")
+	}
+}
--- a/logger/slog/slog.go
+++ b/logger/slog/slog.go
@ -4,15 +4,18 @@ import (
 	"context"
 	"log/slog"
 	"os"
+	"regexp"
 	"runtime"
 	"strconv"
-	"time"
+	"sync"

 	"go.unistack.org/micro/v4/logger"
 	"go.unistack.org/micro/v4/options"
 	"go.unistack.org/micro/v4/tracer"
 )

+var reTrace = regexp.MustCompile(`.*/slog/logger\.go.*\n`)
+
 var (
 	traceValue = slog.StringValue("trace")
 	debugValue = slog.StringValue("debug")
@ -58,38 +61,33 @@ func (s *slogLogger) renameAttr(_ []string, a slog.Attr) slog.Attr {
 }

 type slogLogger struct {
-	slog    *slog.Logger
 	leveler *slog.LevelVar
+	handler slog.Handler
 	opts    logger.Options
+	mu      sync.RWMutex
 }

 func (s *slogLogger) Clone(opts ...options.Option) logger.Logger {
+	s.mu.RLock()
 	options := s.opts
+	s.mu.RUnlock()

 	for _, o := range opts {
-		o(&options)
+		_ = o(&options)
 	}

 	l := &slogLogger{
 		opts: options,
 	}

-	/*
-		if slog, ok := s.opts.Context.Value(loggerKey{}).(*slog.Logger); ok {
-			l.slog = slog
-			return nil
-		}
-	*/
-
 	l.leveler = new(slog.LevelVar)
 	handleOpt := &slog.HandlerOptions{
-		ReplaceAttr: s.renameAttr,
+		ReplaceAttr: l.renameAttr,
 		Level:       l.leveler,
-		AddSource:   true,
+		AddSource:   l.opts.AddSource,
 	}
 	l.leveler.Set(loggerToSlogLevel(l.opts.Level))
-	handler := slog.NewJSONHandler(options.Out, handleOpt)
-	l.slog = slog.New(handler).With(options.Attrs...)
+	l.handler = slog.New(slog.NewJSONHandler(options.Out, handleOpt)).With(options.Attrs...).Handler()

 	return l
 }
@ -107,48 +105,48 @@ func (s *slogLogger) Options() logger.Options {
 }

 func (s *slogLogger) Attrs(attrs ...interface{}) logger.Logger {
-	nl := &slogLogger{opts: s.opts}
-	nl.leveler = new(slog.LevelVar)
-	nl.leveler.Set(s.leveler.Level())
+	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: nl.renameAttr,
-		Level:       s.leveler,
-		AddSource:   true,
+		ReplaceAttr: l.renameAttr,
+		Level:       l.leveler,
+		AddSource:   l.opts.AddSource,
 	}

-	handler := slog.NewJSONHandler(s.opts.Out, handleOpt)
-	nl.slog = slog.New(handler).With(attrs...)
+	l.handler = slog.New(slog.NewJSONHandler(s.opts.Out, handleOpt)).With(attrs...).Handler()

-	return nl
+	return l
 }

 func (s *slogLogger) Init(opts ...options.Option) error {
+	s.mu.Lock()
+
 	if len(s.opts.ContextAttrFuncs) == 0 {
 		s.opts.ContextAttrFuncs = logger.DefaultContextAttrFuncs
 	}
+
 	for _, o := range opts {
 		if err := o(&s.opts); err != nil {
 			return err
 		}
 	}

-	/*
-		if slog, ok := s.opts.Context.Value(loggerKey{}).(*slog.Logger); ok {
-			s.slog = slog
-			return nil
-		}
-	*/
-
 	s.leveler = new(slog.LevelVar)
 	handleOpt := &slog.HandlerOptions{
 		ReplaceAttr: s.renameAttr,
 		Level:       s.leveler,
-		AddSource:   true,
+		AddSource:   s.opts.AddSource,
 	}
 	s.leveler.Set(loggerToSlogLevel(s.opts.Level))
-	handler := slog.NewJSONHandler(s.opts.Out, handleOpt)
-	s.slog = slog.New(handler).With(s.opts.Attrs...)
+	s.handler = slog.New(slog.NewJSONHandler(s.opts.Out, handleOpt)).With(s.opts.Attrs...).Handler()
+	s.mu.Unlock()

 	return nil
 }
@ -159,12 +157,36 @@ func (s *slogLogger) Log(ctx context.Context, lvl logger.Level, msg string, attr
 	}
 	var pcs [1]uintptr
 	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
-	r := slog.NewRecord(time.Now(), loggerToSlogLevel(lvl), msg, pcs[0])
+	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...)
-	_ = s.slog.Handler().Handle(ctx, r)
+	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, msg string, attrs ...interface{}) {
@ -173,12 +195,18 @@ func (s *slogLogger) Info(ctx context.Context, msg string, attrs ...interface{})
 	}
 	var pcs [1]uintptr
 	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
-	r := slog.NewRecord(time.Now(), slog.LevelInfo, msg, pcs[0])
+	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.slog.Handler().Handle(ctx, r)
+	_ = s.handler.Handle(ctx, r)
 }

 func (s *slogLogger) Debug(ctx context.Context, msg string, attrs ...interface{}) {
@ -187,12 +215,18 @@ func (s *slogLogger) Debug(ctx context.Context, msg string, attrs ...interface{}
 	}
 	var pcs [1]uintptr
 	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
-	r := slog.NewRecord(time.Now(), slog.LevelDebug, msg, pcs[0])
+	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.slog.Handler().Handle(ctx, r)
+	_ = s.handler.Handle(ctx, r)
 }

 func (s *slogLogger) Trace(ctx context.Context, msg string, attrs ...interface{}) {
@ -201,12 +235,18 @@ func (s *slogLogger) Trace(ctx context.Context, msg string, attrs ...interface{}
 	}
 	var pcs [1]uintptr
 	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
-	r := slog.NewRecord(time.Now(), slog.LevelDebug-1, msg, pcs[0])
+	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...)
-	_ = s.slog.Handler().Handle(ctx, r)
+	_ = s.handler.Handle(ctx, r)
 }

 func (s *slogLogger) Error(ctx context.Context, msg string, attrs ...interface{}) {
@ -215,13 +255,28 @@ func (s *slogLogger) Error(ctx context.Context, msg string, attrs ...interface{}
 	}
 	var pcs [1]uintptr
 	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
-	r := slog.NewRecord(time.Now(), slog.LevelError, msg, pcs[0])
+	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(s.opts.StacktraceKey, traceLines[len(traceLines)-1]))
+			}
+		}
+	}
 	r.Add(attrs...)
 	r.Attrs(func(a slog.Attr) bool {
-		if a.Key == "error" {
+		if a.Key == s.opts.ErrorKey {
 			if span, ok := tracer.SpanFromContext(ctx); ok {
 				span.SetStatus(tracer.SpanStatusError, a.Value.String())
 				return false
@ -229,7 +284,7 @@ func (s *slogLogger) Error(ctx context.Context, msg string, attrs ...interface{}
 		}
 		return true
 	})
-	_ = s.slog.Handler().Handle(ctx, r)
+	_ = s.handler.Handle(ctx, r)
 }

 func (s *slogLogger) Fatal(ctx context.Context, msg string, attrs ...interface{}) {
@ -238,12 +293,18 @@ func (s *slogLogger) Fatal(ctx context.Context, msg string, attrs ...interface{}
 	}
 	var pcs [1]uintptr
 	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
-	r := slog.NewRecord(time.Now(), slog.LevelError+1, msg, pcs[0])
+	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.slog.Handler().Handle(ctx, r)
+	_ = s.handler.Handle(ctx, r)
 	os.Exit(1)
 }

@ -253,12 +314,22 @@ func (s *slogLogger) Warn(ctx context.Context, msg string, attrs ...interface{})
 	}
 	var pcs [1]uintptr
 	runtime.Callers(s.opts.CallerSkipCount, pcs[:]) // skip [Callers, Infof]
-	r := slog.NewRecord(time.Now(), slog.LevelWarn, msg, pcs[0])
+	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...)
-	_ = s.slog.Handler().Handle(ctx, r)
+	_ = s.handler.Handle(ctx, r)
+}
+
+func (s *slogLogger) Name() string {
+	return s.opts.Name
 }

 func (s *slogLogger) String() string {
--- a/logger/slog/slog_test.go
+++ b/logger/slog/slog_test.go
@ -3,12 +3,26 @@ package slog
 import (
 	"bytes"
 	"context"
+	"fmt"
 	"log"
 	"testing"

 	"go.unistack.org/micro/v4/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, "msg", fmt.Errorf("message"))
+	if !bytes.Contains(buf.Bytes(), []byte(`"stacktrace":"`)) {
+		t.Fatalf("logger stacktrace not works, buf contains: %s", buf.Bytes())
+	}
+}
+
 func TestContext(t *testing.T) {
 	ctx := context.TODO()
 	buf := bytes.NewBuffer(nil)
--- a/logger/unwrap/unwrap.go
+++ b/logger/unwrap/unwrap.go
@ -56,9 +56,9 @@ type Wrapper struct {
 	s                fmt.State
 	pointers         map[uintptr]int
 	opts             *Options
+	takeMap          map[int]bool
 	depth            int
 	ignoreNextType   bool
-	takeMap          map[int]bool
 	protoWrapperType bool
 	sqlWrapperType   bool
 }
--- a/metadata/context.go
+++ b/metadata/context.go
@ -17,11 +17,11 @@ func FromIncomingContext(ctx context.Context) (Metadata, bool) {
 	if ctx == nil {
 		return nil, false
 	}
-	md, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata)
-	if !ok || md.md == nil {
+	md, ok := ctx.Value(mdIncomingKey{}).(Metadata)
+	if !ok || md == nil {
 		return nil, false
 	}
-	return md.md, ok
+	return md, ok
 }

 // FromOutgoingContext returns metadata from outgoing ctx
@ -30,11 +30,11 @@ func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
 	if ctx == nil {
 		return nil, false
 	}
-	md, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata)
-	if !ok || md.md == nil {
+	md, ok := ctx.Value(mdOutgoingKey{}).(Metadata)
+	if !ok || md == nil {
 		return nil, false
 	}
-	return md.md, ok
+	return md, ok
 }

 // FromContext returns metadata from the given context
@ -43,11 +43,11 @@ func FromContext(ctx context.Context) (Metadata, bool) {
 	if ctx == nil {
 		return nil, false
 	}
-	md, ok := ctx.Value(mdKey{}).(*rawMetadata)
-	if !ok || md.md == nil {
+	md, ok := ctx.Value(mdKey{}).(Metadata)
+	if !ok || md == nil {
 		return nil, false
 	}
-	return md.md, ok
+	return md, ok
 }

 // NewContext creates a new context with the given metadata
@ -55,45 +55,16 @@ func NewContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	ctx = context.WithValue(ctx, mdKey{}, &rawMetadata{md})
-	ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{})
-	ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{})
+	ctx = context.WithValue(ctx, mdKey{}, md)
 	return ctx
 }

-// SetOutgoingContext modify outgoing context with given metadata
-func SetOutgoingContext(ctx context.Context, md Metadata) bool {
-	if ctx == nil {
-		return false
-	}
-	if omd, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata); ok {
-		omd.md = md
-		return true
-	}
-	return false
-}
-
-// SetIncomingContext modify incoming context with given metadata
-func SetIncomingContext(ctx context.Context, md Metadata) bool {
-	if ctx == nil {
-		return false
-	}
-	if omd, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata); ok {
-		omd.md = md
-		return true
-	}
-	return false
-}
-
 // NewIncomingContext creates a new context with incoming metadata attached
 func NewIncomingContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{md})
-	if v, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata); !ok || v == nil {
-		ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{})
-	}
+	ctx = context.WithValue(ctx, mdIncomingKey{}, md)
 	return ctx
 }

@ -102,41 +73,28 @@ func NewOutgoingContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
 		ctx = context.Background()
 	}
-	ctx = context.WithValue(ctx, mdOutgoingKey{}, &rawMetadata{md})
-	if v, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata); !ok || v == nil {
-		ctx = context.WithValue(ctx, mdIncomingKey{}, &rawMetadata{})
-	}
+	ctx = context.WithValue(ctx, mdOutgoingKey{}, md)
 	return ctx
 }

 // AppendOutgoingContext apends new md to context
 func AppendOutgoingContext(ctx context.Context, kv ...string) context.Context {
-	md, ok := Pairs(kv...)
-	if !ok {
-		return ctx
-	}
+	md := Pairs(kv...)
 	omd, ok := FromOutgoingContext(ctx)
 	if !ok {
 		return NewOutgoingContext(ctx, md)
 	}
-	for k, v := range md {
-		omd.Set(k, v)
-	}
-	return NewOutgoingContext(ctx, omd)
+	nmd := Merge(omd, md, true)
+	return NewOutgoingContext(ctx, nmd)
 }

 // AppendIncomingContext apends new md to context
 func AppendIncomingContext(ctx context.Context, kv ...string) context.Context {
-	md, ok := Pairs(kv...)
-	if !ok {
-		return ctx
-	}
+	md := Pairs(kv...)
 	omd, ok := FromIncomingContext(ctx)
 	if !ok {
 		return NewIncomingContext(ctx, md)
 	}
-	for k, v := range md {
-		omd.Set(k, v)
-	}
-	return NewIncomingContext(ctx, omd)
+	nmd := Merge(omd, md, true)
+	return NewIncomingContext(ctx, nmd)
 }
--- a/metadata/context_test.go
+++ b/metadata/context_test.go
@ -24,7 +24,7 @@ func TestNewNilContext(t *testing.T) {
 }

 func TestFromContext(t *testing.T) {
-	ctx := context.WithValue(context.TODO(), mdKey{}, &rawMetadata{New(0)})
+	ctx := context.WithValue(context.TODO(), mdKey{}, New(0))

 	c, ok := FromContext(ctx)
 	if c == nil || !ok {
@ -42,7 +42,7 @@ func TestNewContext(t *testing.T) {
 }

 func TestFromIncomingContext(t *testing.T) {
-	ctx := context.WithValue(context.TODO(), mdIncomingKey{}, &rawMetadata{New(0)})
+	ctx := context.WithValue(context.TODO(), mdIncomingKey{}, New(0))

 	c, ok := FromIncomingContext(ctx)
 	if c == nil || !ok {
@ -51,7 +51,7 @@ func TestFromIncomingContext(t *testing.T) {
 }

 func TestFromOutgoingContext(t *testing.T) {
-	ctx := context.WithValue(context.TODO(), mdOutgoingKey{}, &rawMetadata{New(0)})
+	ctx := context.WithValue(context.TODO(), mdOutgoingKey{}, New(0))

 	c, ok := FromOutgoingContext(ctx)
 	if c == nil || !ok {
@ -59,36 +59,6 @@ func TestFromOutgoingContext(t *testing.T) {
 	}
 }

-func TestSetIncomingContext(t *testing.T) {
-	md := New(1)
-	md.Set("key", "val")
-	ctx := context.WithValue(context.TODO(), mdIncomingKey{}, &rawMetadata{})
-	if !SetIncomingContext(ctx, md) {
-		t.Fatal("SetIncomingContext not works")
-	}
-	md, ok := FromIncomingContext(ctx)
-	if md == nil || !ok {
-		t.Fatal("SetIncomingContext not works")
-	} else if v, ok := md.Get("key"); !ok || v != "val" {
-		t.Fatal("SetIncomingContext not works")
-	}
-}
-
-func TestSetOutgoingContext(t *testing.T) {
-	md := New(1)
-	md.Set("key", "val")
-	ctx := context.WithValue(context.TODO(), mdOutgoingKey{}, &rawMetadata{})
-	if !SetOutgoingContext(ctx, md) {
-		t.Fatal("SetOutgoingContext not works")
-	}
-	md, ok := FromOutgoingContext(ctx)
-	if md == nil || !ok {
-		t.Fatal("SetOutgoingContext not works")
-	} else if v, ok := md.Get("key"); !ok || v != "val" {
-		t.Fatal("SetOutgoingContext not works")
-	}
-}
-
 func TestNewIncomingContext(t *testing.T) {
 	md := New(1)
 	md.Set("key", "val")
--- a/metadata/metadata.go
+++ b/metadata/metadata.go
@ -1,9 +1,9 @@
 // Package metadata is a way of defining message headers
-package metadata // import "go.unistack.org/micro/v4/metadata"
+package metadata

 import (
 	"net/textproto"
-	"sort"
+	"strings"
 )

 var (
@ -24,47 +24,7 @@ var (
 )

 // Metadata is our way of representing request headers internally.
-// They're used at the RPC level and translate back and forth
-// from Transport headers.
-type Metadata map[string]string
-
-type rawMetadata struct {
-	md Metadata
-}
-
-// defaultMetadataSize used when need to init new Metadata
-var defaultMetadataSize = 2
-
-// Iterator used to iterate over metadata with order
-type Iterator struct {
-	md   Metadata
-	keys []string
-	cur  int
-	cnt  int
-}
-
-// Next advance iterator to next element
-func (iter *Iterator) Next(k, v *string) bool {
-	if iter.cur+1 > iter.cnt {
-		return false
-	}
-
-	*k = iter.keys[iter.cur]
-	*v = iter.md[*k]
-	iter.cur++
-	return true
-}
-
-// Iterator returns the itarator for metadata in sorted order
-func (md Metadata) Iterator() *Iterator {
-	iter := &Iterator{md: md, cnt: len(md)}
-	iter.keys = make([]string, 0, iter.cnt)
-	for k := range md {
-		iter.keys = append(iter.keys, k)
-	}
-	sort.Strings(iter.keys)
-	return iter
-}
+type Metadata map[string][]string

 // Get returns value from metadata by key
 func (md Metadata) Get(key string) (string, bool) {
@ -74,7 +34,7 @@ func (md Metadata) Get(key string) (string, bool) {
 		// slow path
 		val, ok = md[textproto.CanonicalMIMEHeaderKey(key)]
 	}
-	return val, ok
+	return strings.Join(val, ","), ok
 }

 // Set is used to store value in metadata
@ -83,10 +43,19 @@ func (md Metadata) Set(kv ...string) {
 		kv = kv[:len(kv)-1]
 	}
 	for idx := 0; idx < len(kv); idx += 2 {
-		md[textproto.CanonicalMIMEHeaderKey(kv[idx])] = kv[idx+1]
+		md[textproto.CanonicalMIMEHeaderKey(kv[idx])] = []string{kv[idx+1]}
 	}
 }

+// Append is used to append value in metadata
+func (md Metadata) Append(k string, v ...string) {
+	if len(v) == 0 {
+		return
+	}
+	k = textproto.CanonicalMIMEHeaderKey(k)
+	md[k] = append(md[k], v...)
+}
+
 // Del is used to remove value from metadata
 func (md Metadata) Del(keys ...string) {
 	for _, key := range keys {
@ -98,46 +67,52 @@ func (md Metadata) Del(keys ...string) {
 }

 // Copy makes a copy of the metadata
-func Copy(md Metadata) Metadata {
-	nmd := New(len(md))
-	for key, val := range md {
-		nmd.Set(key, val)
+func Copy(md Metadata, exclude ...string) Metadata {
+	nmd := make(Metadata, len(md))
+	for k, v := range md {
+		nmd[k] = v
 	}
+	nmd.Del(exclude...)
 	return nmd
 }

 // New return new sized metadata
 func New(size int) Metadata {
 	if size == 0 {
-		size = defaultMetadataSize
+		size = 2
 	}
 	return make(Metadata, size)
 }

 // Merge merges metadata to existing metadata, overwriting if specified
 func Merge(omd Metadata, mmd Metadata, overwrite bool) Metadata {
-	var ok bool
 	nmd := Copy(omd)
 	for key, val := range mmd {
-		_, ok = nmd[key]
+		nval, ok := nmd[key]
 		switch {
+		case ok && overwrite:
+			nmd[key] = nval
+			continue
 		case ok && !overwrite:
 			continue
-		case val != "":
-			nmd.Set(key, val)
-		case ok && val == "":
-			nmd.Del(key)
+		case !ok:
+			for _, v := range val {
+				if v != "" {
+					nval = append(nval, v)
+				}
+			}
+			nmd[key] = nval
 		}
 	}
 	return nmd
 }

 // Pairs from which metadata created
-func Pairs(kv ...string) (Metadata, bool) {
+func Pairs(kv ...string) Metadata {
 	if len(kv)%2 == 1 {
-		return nil, false
+		kv = kv[:len(kv)-1]
 	}
-	md := New(len(kv) / 2)
+	md := make(Metadata, len(kv)/2)
 	md.Set(kv...)
-	return md, true
+	return md
 }
--- a/metadata/metadata_test.go
+++ b/metadata/metadata_test.go
@ -33,30 +33,52 @@ func TestAppend(t *testing.T) {
 }

 func TestPairs(t *testing.T) {
-	md, ok := Pairs("key1", "val1", "key2", "val2")
-	if !ok {
-		t.Fatal("odd number of kv")
-	}
-	if _, ok = md.Get("key1"); !ok {
+	md := Pairs("key1", "val1", "key2", "val2")
+
+	if _, ok := md.Get("key1"); !ok {
 		t.Fatal("key1 not found")
 	}
 }

-func testCtx(ctx context.Context) {
-	md := New(2)
-	md.Set("Key1", "Val1_new")
-	md.Set("Key3", "Val3")
-	SetOutgoingContext(ctx, md)
+func testIncomingCtx(ctx context.Context) {
+	if md, ok := FromIncomingContext(ctx); ok && md != nil {
+		md.Set("Key1", "Val1_new")
+		md.Set("Key3", "Val3")
+	}
 }

-func TestPassing(t *testing.T) {
+func testOutgoingCtx(ctx context.Context) {
+	if md, ok := FromOutgoingContext(ctx); ok && md != nil {
+		md.Set("Key1", "Val1_new")
+		md.Set("Key3", "Val3")
+	}
+}
+
+func TestIncoming(t *testing.T) {
 	ctx := context.TODO()
 	md1 := New(2)
 	md1.Set("Key1", "Val1")
 	md1.Set("Key2", "Val2")

 	ctx = NewIncomingContext(ctx, md1)
-	testCtx(ctx)
+	testIncomingCtx(ctx)
+	md, ok := FromIncomingContext(ctx)
+	if !ok {
+		t.Fatalf("missing metadata from incoming context")
+	}
+	if v, ok := md.Get("Key1"); !ok || v != "Val1_new" {
+		t.Fatalf("invalid metadata value %#+v", md)
+	}
+}
+
+func TestOutgoing(t *testing.T) {
+	ctx := context.TODO()
+	md1 := New(2)
+	md1.Set("Key1", "Val1")
+	md1.Set("Key2", "Val2")
+
+	ctx = NewOutgoingContext(ctx, md1)
+	testOutgoingCtx(ctx)
 	md, ok := FromOutgoingContext(ctx)
 	if !ok {
 		t.Fatalf("missing metadata from outgoing context")
@ -68,10 +90,10 @@ func TestPassing(t *testing.T) {

 func TestMerge(t *testing.T) {
 	omd := Metadata{
-		"key1": "val1",
+		"key1": []string{"val1"},
 	}
 	mmd := Metadata{
-		"key2": "val2",
+		"key2": []string{"val2"},
 	}

 	nmd := Merge(omd, mmd, true)
@ -80,21 +102,6 @@ func TestMerge(t *testing.T) {
 	}
 }

-func TestIterator(t *testing.T) {
-	md := Metadata{
-		"1Last":   "last",
-		"2First":  "first",
-		"3Second": "second",
-	}
-
-	iter := md.Iterator()
-	var k, v string
-
-	for iter.Next(&k, &v) {
-		// fmt.Printf("k: %s, v: %s\n", k, v)
-	}
-}
-
 func TestMedataCanonicalKey(t *testing.T) {
 	md := New(1)
 	md.Set("x-request-id", "12345")
@ -134,10 +141,7 @@ func TestMetadataSet(t *testing.T) {
 }

 func TestMetadataDelete(t *testing.T) {
-	md := Metadata{
-		"Foo": "bar",
-		"Baz": "empty",
-	}
+	md := Pairs("Foo", "bar", "Baz", "empty")

 	md.Del("Baz")
 	_, ok := md.Get("Baz")
@ -156,24 +160,19 @@ func TestNilContext(t *testing.T) {
 }

 func TestMetadataCopy(t *testing.T) {
-	md := Metadata{
-		"Foo": "bar",
-		"Bar": "baz",
-	}
+	md := Pairs("Foo", "bar", "Bar", "baz")

 	cp := Copy(md)

 	for k, v := range md {
-		if cv := cp[k]; cv != v {
+		if cv := cp[k]; len(cv) != len(v) {
 			t.Fatalf("Got %s:%s for %s:%s", k, cv, k, v)
 		}
 	}
 }

 func TestMetadataContext(t *testing.T) {
-	md := Metadata{
-		"Foo": "bar",
-	}
+	md := Pairs("Foo", "bar")

 	ctx := NewContext(context.TODO(), md)

@ -182,7 +181,7 @@ func TestMetadataContext(t *testing.T) {
 		t.Errorf("Unexpected error retrieving metadata, got %t", ok)
 	}

-	if emd["Foo"] != md["Foo"] {
+	if len(emd["Foo"]) != len(md["Foo"]) {
 		t.Errorf("Expected key: %s val: %s, got key: %s val: %s", "Foo", md["Foo"], "Foo", emd["Foo"])
 	}

@ -190,3 +189,14 @@ 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"][0] != "val1" {
+		t.Fatal("Copy exclude not works")
+	}
+}
--- a/micro.go
+++ b/micro.go
@ -0,0 +1,98 @@
+package micro
+
+import (
+	"reflect"
+
+	"go.unistack.org/micro/v4/broker"
+	"go.unistack.org/micro/v4/client"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/flow"
+	"go.unistack.org/micro/v4/fsm"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/meter"
+	"go.unistack.org/micro/v4/register"
+	"go.unistack.org/micro/v4/resolver"
+	"go.unistack.org/micro/v4/router"
+	"go.unistack.org/micro/v4/selector"
+	"go.unistack.org/micro/v4/server"
+	"go.unistack.org/micro/v4/store"
+	"go.unistack.org/micro/v4/sync"
+	"go.unistack.org/micro/v4/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
+		case targetType.Implements(tracerType):
+			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()
+	loggerType   = reflect.TypeOf((*logger.Logger)(nil)).Elem()
+	clientType   = reflect.TypeOf((*client.Client)(nil)).Elem()
+	serverType   = reflect.TypeOf((*server.Server)(nil)).Elem()
+	codecType    = reflect.TypeOf((*codec.Codec)(nil)).Elem()
+	flowType     = reflect.TypeOf((*flow.Flow)(nil)).Elem()
+	fsmType      = reflect.TypeOf((*fsm.FSM)(nil)).Elem()
+	meterType    = reflect.TypeOf((*meter.Meter)(nil)).Elem()
+	registerType = reflect.TypeOf((*register.Register)(nil)).Elem()
+	resolverType = reflect.TypeOf((*resolver.Resolver)(nil)).Elem()
+	routerType   = reflect.TypeOf((*router.Router)(nil)).Elem()
+	selectorType = reflect.TypeOf((*selector.Selector)(nil)).Elem()
+	storeType    = reflect.TypeOf((*store.Store)(nil)).Elem()
+	syncType     = reflect.TypeOf((*sync.Sync)(nil)).Elem()
+	tracerType   = reflect.TypeOf((*tracer.Tracer)(nil)).Elem()
+	serviceType  = reflect.TypeOf((*Service)(nil)).Elem()
+)
--- a/micro_test.go
+++ b/micro_test.go
@ -0,0 +1,103 @@
+package micro
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"go.unistack.org/micro/v4/broker"
+	"go.unistack.org/micro/v4/fsm"
+	"go.unistack.org/micro/v4/options"
+)
+
+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 ...options.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, msg interface{}, opts ...options.Option) error { return nil }
+
+// Subscribe subscribes to topic message via handler
+func (p *bro) Subscribe(ctx context.Context, topic string, handler interface{}, opts ...options.Option) (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) {}
--- a/options/options.go
+++ b/options/options.go
@ -151,9 +151,41 @@ func ContentType(ct string) Option {
 }

 // Metadata pass additional metadata
-func Metadata(md metadata.Metadata) Option {
+func Metadata(md ...any) Option {
+	var result metadata.Metadata
+	if len(md) == 1 {
+		switch vt := md[0].(type) {
+		case metadata.Metadata:
+			result = metadata.Copy(vt)
+		case map[string]string:
+			result = make(metadata.Metadata, len(vt))
+			for k, v := range vt {
+				result.Set(k, v)
+			}
+		case map[string][]string:
+			result = metadata.Copy(vt)
+		default:
+			result = metadata.New(0)
+		}
+	} else {
+		result = metadata.New(len(md) / 2)
+		for idx := 0; idx <= len(md)/2; idx += 2 {
+			k, ok := md[idx].(string)
+			switch vt := md[idx+1].(type) {
+			case string:
+				if ok {
+					result.Set(k, vt)
+				}
+			case []string:
+				if ok {
+					result.Append(k, vt...)
+				}
+			}
+		}
+	}
+
 	return func(src interface{}) error {
-		return Set(src, metadata.Copy(md), ".Metadata")
+		return Set(src, result, ".Metadata")
 	}
 }

--- a/options/options_test.go
+++ b/options/options_test.go
@ -4,7 +4,9 @@ import (
 	"testing"

 	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
 	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/util/reflect"
 )

 func TestAddress(t *testing.T) {
@ -84,3 +86,64 @@ func TestLabels(t *testing.T) {
 		t.Fatal("failed to set labels")
 	}
 }
+
+func TestMetadataAny(t *testing.T) {
+	type s struct {
+		Metadata metadata.Metadata
+	}
+
+	testCases := []struct {
+		Name     string
+		Data     any
+		Expected metadata.Metadata
+	}{
+		{
+			"strings_even",
+			[]any{"Strkey1", []string{"val1"}, "Strkey2", []string{"val2"}},
+			metadata.Pairs("Strkey1", "val1", "Strkey2", "val2"),
+		},
+		{
+			"strings_odd",
+			[]any{"key1", "val1", "key2"},
+			metadata.Pairs("Key1", "val1"),
+		},
+		{
+			Name: "map",
+			Data: map[string][]string{
+				"Mapkey1": {"val1"},
+				"Mapkey2": {"val2"},
+			},
+			Expected: metadata.Metadata{
+				"Mapkey1": []string{"val1"},
+				"Mapkey2": []string{"val2"},
+			},
+		},
+		{
+			"metadata.Metadata",
+			metadata.Pairs("key1", "val1", "key2", "val2"),
+			metadata.Pairs("Key1", "val1", "Key2", "val2"),
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.Name, func(t *testing.T) {
+			src := &s{}
+			var opts []options.Option
+			switch valData := tt.Data.(type) {
+			case []any:
+				opts = append(opts, options.Metadata(valData...))
+			case map[string]string, map[string][]string, metadata.Metadata:
+				opts = append(opts, options.Metadata(valData))
+			}
+
+			for _, o := range opts {
+				if err := o(src); err != nil {
+					t.Fatal(err)
+				}
+				if !reflect.Equal(tt.Expected, src.Metadata) {
+					t.Fatalf("expected: %v, actual: %v", tt.Expected, src.Metadata)
+				}
+			}
+		})
+	}
+}
--- a/register/memory/memory.go
+++ b/register/memory/memory.go
@ -1,10 +1,13 @@
-package register
+package memory

 import (
 	"context"
 	"sync"
 	"time"

+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/register"
+
 	"go.unistack.org/micro/v4/logger"
 	"go.unistack.org/micro/v4/util/id"
 )
@ -16,32 +19,32 @@ var (

 type node struct {
 	LastSeen time.Time
-	*Node
+	*register.Node
 	TTL time.Duration
 }

 type record struct {
 	Name      string
 	Version   string
-	Metadata  map[string]string
+	Metadata  metadata.Metadata
 	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
+	sync.RWMutex
 }

 // 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 +78,7 @@ 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 {
@ -99,14 +102,24 @@ func (m *memory) sendEvent(r *Result) {
 }

 func (m *memory) Connect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
 	return nil
 }

 func (m *memory) Disconnect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
 	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 +131,20 @@ 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 {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
 	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]
@ -136,11 +154,11 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio

 	// domain is set in metadata so it can be passed to watchers
 	if s.Metadata == nil {
-		s.Metadata = map[string]string{"domain": options.Domain}
-	} else {
-		s.Metadata["domain"] = options.Domain
+		s.Metadata = metadata.New(0)
 	}

+	s.Metadata.Set("domain", options.Domain)
+
 	// ensure the service name exists
 	r := serviceToRecord(s, options.TTL)
 	if _, ok := srvs[s.Name]; !ok {
@ -153,7 +171,7 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio
 			m.opts.Logger.Debug(m.opts.Context, "register added new service: "+s.Name+", version "+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
@ -164,19 +182,12 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio
 			continue
 		}

-		metadata := make(map[string]string, len(n.Metadata))
-
-		// make copy of metadata
-		for k, v := range n.Metadata {
-			metadata[k] = v
-		}
-
-		// set the domain
-		metadata["domain"] = options.Domain
+		metadata := metadata.Copy(n.Metadata)
+		metadata.Set("domain", options.Domain)

 		// 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 +203,7 @@ func (m *memory) Register(ctx context.Context, s *Service, opts ...RegisterOptio
 		if m.opts.Logger.V(logger.DebugLevel) {
 			m.opts.Logger.Debug(m.opts.Context, "register added new node to service: "+s.Name+", version "+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 {
@ -208,18 +219,17 @@ 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 {
-		s.Metadata = map[string]string{"domain": options.Domain}
-	} else {
-		s.Metadata["domain"] = options.Domain
+		s.Metadata = metadata.New(0)
 	}
+	s.Metadata.Set("domain", options.Domain)

 	// if the domain doesn't exist, there is nothing to deregister
 	services, ok := m.records[options.Domain]
@ -252,7 +262,7 @@ 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 +270,7 @@ 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.Debug(m.opts.Context, "register removed service: "+s.Name)
@ -270,7 +280,7 @@ 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.Debug(m.opts.Context, "register removed service: "+s.Name+", version "+s.Version)
 	}
@ -278,20 +288,20 @@ 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 +310,7 @@ 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 +321,17 @@ 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 +343,19 @@ 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 +371,11 @@ 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 +386,16 @@ 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 +416,13 @@ 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:
@ -424,20 +434,28 @@ func (m *watcher) Next() (*Result, error) {
 				continue
 			}

+			if m.wo.Domain == register.WildcardDomain {
+				return r, nil
+			}
+
+			if r.Service.Metadata == nil {
+				continue
+			}
+
 			// extract domain from service metadata
 			var domain string
-			if r.Service.Metadata != nil && len(r.Service.Metadata["domain"]) > 0 {
-				domain = r.Service.Metadata["domain"]
+			if v, ok := r.Service.Metadata.Get("domain"); ok && v != "" {
+				domain = v
 			} 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 == domain {
 				return r, nil
 			}
 		case <-m.exit:
-			return nil, ErrWatcherStopped
+			return nil, register.ErrWatcherStopped
 		}
 	}
 }
@ -451,11 +469,8 @@ func (m *watcher) Stop() {
 	}
 }

-func serviceToRecord(s *Service, ttl time.Duration) *record {
-	metadata := make(map[string]string, len(s.Metadata))
-	for k, v := range s.Metadata {
-		metadata[k] = v
-	}
+func serviceToRecord(s *register.Service, ttl time.Duration) *record {
+	metadata := metadata.Copy(s.Metadata)

 	nodes := make(map[string]*node, len(s.Nodes))
 	for _, n := range s.Nodes {
@ -466,10 +481,8 @@ func serviceToRecord(s *Service, ttl time.Duration) *record {
 		}
 	}

-	endpoints := make([]*Endpoint, len(s.Endpoints))
-	for i, e := range s.Endpoints { // TODO: vtolstov use copy
-		endpoints[i] = e
-	}
+	endpoints := make([]*register.Endpoint, len(s.Endpoints))
+	copy(endpoints, s.Endpoints)

 	return &record{
 		Name:      s.Name,
@ -480,23 +493,14 @@ func serviceToRecord(s *Service, ttl time.Duration) *record {
 	}
 }

-func recordToService(r *record, domain string) *Service {
-	metadata := make(map[string]string, len(r.Metadata))
-	for k, v := range r.Metadata {
-		metadata[k] = v
-	}
-
-	// 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))
+func recordToService(r *record, domain string) *register.Service {
+	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
-		}
+		md := metadata.Copy(e.Metadata)
+		// set the domain in metadata so it can be determined when a wildcard query is performed
+		md.Set("domain", domain)

-		endpoints[i] = &Endpoint{
+		endpoints[i] = &register.Endpoint{
 			Name:     e.Name,
 			Request:  e.Request,
 			Response: e.Response,
@ -504,26 +508,21 @@ 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))
-		for k, v := range n.Metadata {
-			md[k] = v
-		}
-
-		nodes[i] = &Node{
+		nodes[i] = &register.Node{
 			ID:       n.ID,
 			Address:  n.Address,
-			Metadata: md,
+			Metadata: metadata.Copy(n.Metadata),
 		}
 		i++
 	}

-	return &Service{
+	return &register.Service{
 		Name:      r.Name,
 		Version:   r.Version,
-		Metadata:  metadata,
+		Metadata:  metadata.Copy(r.Metadata),
 		Endpoints: endpoints,
 		Nodes:     nodes,
 	}
--- a/register/memory/memory_test.go
+++ b/register/memory/memory_test.go
@ -1,19 +1,23 @@
-package register
+package memory

 import (
 	"context"
 	"fmt"
+	"reflect"
 	"sync"
 	"testing"
 	"time"
+
+	"go.unistack.org/micro/v4"
+	"go.unistack.org/micro/v4/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 +31,7 @@ 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 +41,7 @@ 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 +53,7 @@ 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 +67,7 @@ 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 +82,7 @@ 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 +159,8 @@ 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 +175,7 @@ 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)
 			}
 		}
@ -200,15 +204,15 @@ 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)
 			}
 		}
 	}

-	//if len(os.Getenv("IN_TRAVIS_CI")) == 0 {
+	// if len(os.Getenv("IN_TRAVIS_CI")) == 0 {
 	//	t.Logf("test will wait %v, then check TTL timeouts", waitTime)
-	//}
+	// }

 	errChan := make(chan error, concurrency)
 	syncChan := make(chan struct{})
@ -249,34 +253,41 @@ func TestMemoryWildcard(t *testing.T) {
 	m := NewRegister()
 	ctx := context.TODO()

-	testSrv := &Service{Name: "foo", Version: "1.0.0"}
+	if err := m.Init(); err != nil {
+		t.Fatal(err)
+	}

-	if err := m.Register(ctx, testSrv, RegisterDomain("one")); err != nil {
+	if err := m.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
+	testSrv := &register.Service{Name: "foo", Version: "1.0.0"}
+
+	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))
@ -284,12 +295,16 @@ 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()
-	m.Init()
-	m.Connect(ctx)
+	if err := m.Init(); err != nil {
+		t.Fatal(err)
+	}
+	if err := m.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
 	wc, err := m.Watch(ctx)
 	if err != nil {
 		t.Fatalf("cant watch: %v", err)
@ -320,3 +335,37 @@ func TestWatcher(t *testing.T) {
 		t.Fatal("expected error on Next()")
 	}
 }
+
+func Test_service_Register(t *testing.T) {
+	t.Skip()
+	r := NewRegister()
+
+	type args struct {
+		names []string
+	}
+	tests := []struct {
+		name string
+		opts []micro.Option
+		args args
+		want register.Register
+	}{
+		{
+			name: "service.Register",
+			opts: []micro.Option{micro.Register(r)},
+			args: args{
+				names: []string{"memory"},
+			},
+			want: r,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := micro.NewService(tt.opts...)
+
+			if got := s.Register(tt.args.names...); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("service.Register() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
--- a/register/noop.go
+++ b/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() {}
--- a/register/register.go
+++ b/register/register.go
@ -4,7 +4,6 @@ package register // import "go.unistack.org/micro/v4/register"
 import (
 	"context"
 	"errors"
-
 	"go.unistack.org/micro/v4/metadata"
 )

--- a/semconv/broker.go
+++ b/semconv/broker.go
@ -17,4 +17,6 @@ var (
 	SubscribeMessageTotal = "subscribe_message_total"
 	// SubscribeMessageInflight specifies meter metric name
 	SubscribeMessageInflight = "subscribe_message_inflight"
+	// BrokerGroupLag specifies broker lag
+	BrokerGroupLag = "broker_lag"
 )
--- a/semconv/cache.go
+++ b/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"
+)
--- a/server/noop.go
+++ b/server/noop.go
@ -112,8 +112,8 @@ func (n *noopServer) Register() error {
 	}
 	n.RUnlock()

-	service.Nodes[0].Metadata["protocol"] = "noop"
-	service.Nodes[0].Metadata["transport"] = service.Nodes[0].Metadata["protocol"]
+	service.Nodes[0].Metadata.Set("protocol", "noop")
+	service.Nodes[0].Metadata.Set("transport", "noop")
 	service.Endpoints = endpoints

 	n.RLock()
--- a/server/options.go
+++ b/server/options.go
@ -13,6 +13,7 @@ import (
 	"go.unistack.org/micro/v4/meter"
 	"go.unistack.org/micro/v4/options"
 	"go.unistack.org/micro/v4/register"
+	msync "go.unistack.org/micro/v4/sync"
 	"go.unistack.org/micro/v4/tracer"
 	"go.unistack.org/micro/v4/util/id"
 )
@ -32,7 +33,7 @@ type Options struct {
 	// Listener may be passed if already created
 	Listener net.Listener
 	// Wait group
-	Wait *sync.WaitGroup
+	Wait *msync.WaitGroup
 	// TLSConfig specifies tls.Config for secure serving
 	TLSConfig *tls.Config
 	// Metadata holds the server metadata
@ -65,6 +66,8 @@ type Options struct {
 	DeregisterAttempts int
 	// Hooks may contains HandleWrapper or Server func wrapper
 	Hooks options.Hooks
+	// GracefulTimeout timeout for graceful stop server
+	GracefulTimeout time.Duration
 }

 // NewOptions returns new options struct with default or passed values
@ -84,6 +87,7 @@ func NewOptions(opts ...options.Option) Options {
 		Name:             DefaultName,
 		Version:          DefaultVersion,
 		ID:               id.Must(),
+		GracefulTimeout:  DefaultGracefulTimeout,
 	}

 	for _, o := range opts {
@ -143,8 +147,11 @@ func Wait(wg *sync.WaitGroup) options.Option {
 	if wg == nil {
 		wg = new(sync.WaitGroup)
 	}
+
+	wrap := msync.WrapWaitGroup(wg)
+
 	return func(src interface{}) error {
-		return options.Set(src, wg, ".Wait")
+		return options.Set(src, wrap, ".Wait")
 	}
 }

@ -162,6 +169,12 @@ func Listener(nl net.Listener) options.Option {
 	}
 }

+func GracefulTimeout(td time.Duration) options.Option {
+	return func(src interface{}) error {
+		return options.Set(src, td, ".GracefulTimeout")
+	}
+}
+
 // HandleOptions struct
 type HandleOptions struct {
 	// Context holds external options
--- a/server/registry.go
+++ b/server/registry.go
@ -77,8 +77,8 @@ func NewRegisterService(s Server) (*register.Service, error) {
 	}
 	node.Metadata = metadata.Copy(opts.Metadata)

-	node.Metadata["server"] = s.String()
-	node.Metadata["register"] = opts.Register.String()
+	node.Metadata.Set("server", s.String())
+	node.Metadata.Set("register", opts.Register.String())

 	return &register.Service{
 		Name:     opts.Name,
--- a/server/server.go
+++ b/server/server.go
@ -32,6 +32,8 @@ var (
 	DefaultMaxMsgRecvSize = 1024 * 1024 * 4 // 4Mb
 	// DefaultMaxMsgSendSize holds default max send size
 	DefaultMaxMsgSendSize = 1024 * 1024 * 4 // 4Mb
+	// DefaultGracefulTimeout default time for graceful stop
+	DefaultGracefulTimeout = 5 * time.Second
 )

 // Server is a simple micro server abstraction
--- a/service_test.go
+++ b/service_test.go
@ -1,6 +1,7 @@
 package micro

 import (
+	"go.unistack.org/micro/v4/register/memory"
 	"reflect"
 	"testing"

@ -425,7 +426,7 @@ func Test_service_Store(t *testing.T) {
 }

 func Test_service_Register(t *testing.T) {
-	r := register.NewRegister()
+	r := memory.NewRegister()
 	type fields struct {
 		opts Options
 	}
@ -444,7 +445,7 @@ func Test_service_Register(t *testing.T) {
 				opts: Options{Registers: []register.Register{r}},
 			},
 			args: args{
-				names: []string{"noop"},
+				names: []string{"memory"},
 			},
 			want: r,
 		},
--- a/sync/waitgroup.go
+++ b/sync/waitgroup.go
@ -0,0 +1,69 @@
+package sync
+
+import (
+	"context"
+	"sync"
+)
+
+type WaitGroup struct {
+	wg *sync.WaitGroup
+	c  int
+	mu sync.Mutex
+}
+
+func WrapWaitGroup(wg *sync.WaitGroup) *WaitGroup {
+	g := &WaitGroup{
+		wg: wg,
+	}
+	return g
+}
+
+func NewWaitGroup() *WaitGroup {
+	var wg sync.WaitGroup
+	return WrapWaitGroup(&wg)
+}
+
+func (g *WaitGroup) Add(n int) {
+	g.mu.Lock()
+	g.c += n
+	g.wg.Add(n)
+	g.mu.Unlock()
+}
+
+func (g *WaitGroup) Done() {
+	g.mu.Lock()
+	g.c += -1
+	g.wg.Add(-1)
+	g.mu.Unlock()
+}
+
+func (g *WaitGroup) Wait() {
+	g.wg.Wait()
+}
+
+func (g *WaitGroup) WaitContext(ctx context.Context) {
+	done := make(chan struct{})
+	go func() {
+		g.wg.Wait()
+		close(done)
+	}()
+
+	select {
+	case <-ctx.Done():
+		g.mu.Lock()
+		g.wg.Add(-g.c)
+		<-done
+		g.wg.Add(g.c)
+		g.mu.Unlock()
+		return
+	case <-done:
+		return
+	}
+}
+
+func (g *WaitGroup) Waiters() int {
+	g.mu.Lock()
+	c := g.c
+	g.mu.Unlock()
+	return c
+}
--- a/sync/waitgroup_test.go
+++ b/sync/waitgroup_test.go
@ -0,0 +1,37 @@
+package sync
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+func TestWaitGroupContext(t *testing.T) {
+	wg := NewWaitGroup()
+	_ = t
+	wg.Add(1)
+	ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+}
+
+func TestWaitGroupReuse(t *testing.T) {
+	wg := NewWaitGroup()
+	defer func() {
+		if wg.Waiters() != 0 {
+			t.Fatal("lost goroutines")
+		}
+	}()
+
+	wg.Add(1)
+	defer wg.Done()
+	ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+
+	wg.Add(1)
+	defer wg.Done()
+	ctx, cancel = context.WithTimeout(context.TODO(), 1*time.Second)
+	defer cancel()
+	wg.WaitContext(ctx)
+}
--- a/tracer/memory/memory.go
+++ b/tracer/memory/memory.go
@ -0,0 +1,143 @@
+package memory
+
+import (
+	"context"
+	"time"
+
+	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v4/util/id"
+)
+
+var _ tracer.Tracer = (*Tracer)(nil)
+
+type Tracer struct {
+	opts  tracer.Options
+	spans []tracer.Span
+}
+
+func (t *Tracer) Spans() []tracer.Span {
+	return t.spans
+}
+
+func (t *Tracer) Start(ctx context.Context, name string, opts ...options.Option) (context.Context, tracer.Span) {
+	options := tracer.NewSpanOptions(opts...)
+	span := &Span{
+		name:      name,
+		ctx:       ctx,
+		tracer:    t,
+		kind:      options.Kind,
+		startTime: time.Now(),
+	}
+	span.spanID.s, _ = id.New()
+	span.traceID.s, _ = id.New()
+	if span.ctx == nil {
+		span.ctx = context.Background()
+	}
+	t.spans = append(t.spans, span)
+	return tracer.NewSpanContext(ctx, span), span
+}
+
+func (t *Tracer) Flush(_ context.Context) error {
+	return nil
+}
+
+func (t *Tracer) Init(opts ...options.Option) error {
+	var err error
+	for _, o := range opts {
+		if err = o(&t.opts); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (t *Tracer) Name() string {
+	return t.opts.Name
+}
+
+type noopStringer struct {
+	s string
+}
+
+func (s noopStringer) String() string {
+	return s.s
+}
+
+type Span struct {
+	ctx        context.Context
+	tracer     tracer.Tracer
+	name       string
+	statusMsg  string
+	startTime  time.Time
+	finishTime time.Time
+	traceID    noopStringer
+	spanID     noopStringer
+	events     []*Event
+	labels     []interface{}
+	logs       []interface{}
+	kind       tracer.SpanKind
+	status     tracer.SpanStatus
+}
+
+func (s *Span) Finish(opts ...options.Option) {
+	s.finishTime = time.Now()
+}
+
+func (s *Span) Context() context.Context {
+	return s.ctx
+}
+
+func (s *Span) Tracer() tracer.Tracer {
+	return s.tracer
+}
+
+type Event struct {
+	name   string
+	labels []interface{}
+}
+
+func (s *Span) AddEvent(name string, opts ...options.Option) {
+	options := tracer.NewEventOptions(opts...)
+	s.events = append(s.events, &Event{name: name, labels: options.Labels})
+}
+
+func (s *Span) SetName(name string) {
+	s.name = name
+}
+
+func (s *Span) AddLogs(kv ...interface{}) {
+	s.logs = append(s.logs, kv...)
+}
+
+func (s *Span) AddLabels(kv ...interface{}) {
+	s.labels = append(s.labels, kv...)
+}
+
+func (s *Span) Kind() tracer.SpanKind {
+	return s.kind
+}
+
+func (s *Span) TraceID() string {
+	return s.traceID.String()
+}
+
+func (s *Span) SpanID() string {
+	return s.spanID.String()
+}
+
+func (s *Span) Status() (tracer.SpanStatus, string) {
+	return s.status, s.statusMsg
+}
+
+func (s *Span) SetStatus(st tracer.SpanStatus, msg string) {
+	s.status = st
+	s.statusMsg = msg
+}
+
+// NewTracer returns new memory tracer
+func NewTracer(opts ...options.Option) *Tracer {
+	return &Tracer{
+		opts: tracer.NewOptions(opts...),
+	}
+}
--- a/tracer/memory/memory_test.go
+++ b/tracer/memory/memory_test.go
@ -0,0 +1,38 @@
+package memory
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"strings"
+	"testing"
+
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/logger/slog"
+	"go.unistack.org/micro/v4/tracer"
+)
+
+func TestLoggerWithTracer(t *testing.T) {
+	ctx := context.TODO()
+	buf := bytes.NewBuffer(nil)
+	logger.DefaultLogger = slog.NewLogger(logger.WithOutput(buf))
+
+	if err := logger.Init(); err != nil {
+		t.Fatal(err)
+	}
+	var span tracer.Span
+	tr := NewTracer()
+	ctx, span = tr.Start(ctx, "test1")
+
+	logger.Error(ctx, "my test error", fmt.Errorf("error"))
+
+	if !strings.Contains(buf.String(), span.TraceID()) {
+		t.Fatalf("log does not contains trace id: %s", buf.Bytes())
+	}
+
+	_, _ = tr.Start(ctx, "test2")
+
+	for _, s := range tr.Spans() {
+		_ = s
+	}
+}
--- a/tracer/noop.go
+++ b/tracer/noop.go
@ -24,7 +24,6 @@ func (t *noopTracer) Start(ctx context.Context, name string, opts ...options.Opt
 		name:   name,
 		ctx:    ctx,
 		tracer: t,
-		labels: options.Labels,
 		kind:   options.Kind,
 	}
 	span.spanID.s, _ = id.New()
@ -36,7 +35,7 @@ func (t *noopTracer) Start(ctx context.Context, name string, opts ...options.Opt
 	return NewSpanContext(ctx, span), span
 }

-func (t *noopTracer) Flush(ctx context.Context) error {
+func (t *noopTracer) Flush(_ context.Context) error {
 	return nil
 }

@ -51,11 +50,6 @@ func (t *noopTracer) Name() string {
 	return t.opts.Name
 }

-type noopEvent struct {
-	name   string
-	labels []interface{}
-}
-
 type noopStringer struct {
 	s string
 }
@ -71,14 +65,11 @@ type noopSpan struct {
 	statusMsg string
 	traceID   noopStringer
 	spanID    noopStringer
-	events    []*noopEvent
-	labels    []interface{}
-	logs      []interface{}
 	kind      SpanKind
 	status    SpanStatus
 }

-func (s *noopSpan) Finish(opts ...options.Option) {
+func (s *noopSpan) Finish(_ ...options.Option) {
 }

 func (s *noopSpan) Context() context.Context {
@ -89,21 +80,17 @@ func (s *noopSpan) Tracer() Tracer {
 	return s.tracer
 }

-func (s *noopSpan) AddEvent(name string, opts ...options.Option) {
-	options := NewEventOptions(opts...)
-	s.events = append(s.events, &noopEvent{name: name, labels: options.Labels})
+func (s *noopSpan) AddEvent(_ string, _ ...options.Option) {
 }

 func (s *noopSpan) SetName(name string) {
 	s.name = name
 }

-func (s *noopSpan) AddLogs(kv ...interface{}) {
-	s.logs = append(s.logs, kv...)
+func (s *noopSpan) AddLogs(_ ...interface{}) {
 }

-func (s *noopSpan) AddLabels(kv ...interface{}) {
-	s.labels = append(s.labels, kv...)
+func (s *noopSpan) AddLabels(_ ...interface{}) {
 }

 func (s *noopSpan) Kind() SpanKind {
--- a/tracer/options.go
+++ b/tracer/options.go
@ -171,7 +171,8 @@ func NewEventOptions(opts ...options.Option) EventOptions {
 // NewOptions returns default options
 func NewOptions(opts ...options.Option) Options {
 	options := Options{
-		Logger: logger.DefaultLogger,
+		Logger:  logger.DefaultLogger,
+		Context: context.Background(),
 	}
 	for _, o := range opts {
 		o(&options)
--- a/tracer/tracer.go
+++ b/tracer/tracer.go
@ -1,10 +1,8 @@
 // Package tracer provides an interface for distributed tracing
-package tracer // import "go.unistack.org/micro/v4/tracer"
+package tracer

 import (
 	"context"
-	"fmt"
-	"sort"

 	"go.unistack.org/micro/v4/logger"
 	"go.unistack.org/micro/v4/options"
@ -13,6 +11,26 @@ import (
 // DefaultTracer is the global default tracer
 var DefaultTracer = NewTracer()

+var (
+	// TraceIDKey is the key used for the trace id in the log call
+	TraceIDKey = "trace-id"
+	// SpanIDKey is the key used for the span id in the log call
+	SpanIDKey = "span-id"
+)
+
+func init() {
+	logger.DefaultContextAttrFuncs = append(logger.DefaultContextAttrFuncs,
+		func(ctx context.Context) []interface{} {
+			if span, ok := SpanFromContext(ctx); ok {
+				return []interface{}{
+					TraceIDKey, span.TraceID(),
+					SpanIDKey, span.SpanID(),
+				}
+			}
+			return nil
+		})
+}
+
 // Tracer is an interface for distributed tracing
 type Tracer interface {
 	// Name return tracer name
@ -51,46 +69,3 @@ type Span interface {
 	// SpanID returns span id
 	SpanID() string
 }
-
-func init() {
-	logger.DefaultContextAttrFuncs = append(logger.DefaultContextAttrFuncs, func(ctx context.Context) []interface{} {
-		span, ok := SpanFromContext(ctx)
-		if !ok || span == nil {
-			return nil
-		}
-		return []interface{}{"trace", span.TraceID(), "span", span.SpanID()}
-	})
-}
-
-// sort labels alphabeticaly by label name
-type byKey []interface{}
-
-func (k byKey) Len() int           { return len(k) / 2 }
-func (k byKey) Less(i, j int) bool { return fmt.Sprintf("%s", k[i*2]) < fmt.Sprintf("%s", k[j*2]) }
-func (k byKey) Swap(i, j int) {
-	k[i*2], k[j*2] = k[j*2], k[i*2]
-	k[i*2+1], k[j*2+1] = k[j*2+1], k[i*2+1]
-}
-
-func UniqLabels(labels []interface{}) []interface{} {
-	if len(labels)%2 == 1 {
-		labels = labels[:len(labels)-1]
-	}
-	if len(labels) > 2 {
-		sort.Sort(byKey(labels))
-
-		idx := 0
-		for {
-			if labels[idx] == labels[idx+2] {
-				copy(labels[idx:], labels[idx+2:])
-				labels = labels[:len(labels)-2]
-			} else {
-				idx += 2
-			}
-			if idx+2 >= len(labels) {
-				break
-			}
-		}
-	}
-	return labels
-}
--- a/util/reflect/reflect.go
+++ b/util/reflect/reflect.go
@ -1,6 +1,7 @@
-package reflect // import "go.unistack.org/micro/v4/util/reflect"
+package reflect

 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"reflect"
@ -45,15 +46,23 @@ func SliceAppend(b bool) Option {

 // Merge merges map[string]interface{} to destination struct
 func Merge(dst interface{}, mp map[string]interface{}, opts ...Option) error {
-	var err error
-	var sval reflect.Value
-	var fname string
-
 	options := Options{}
 	for _, o := range opts {
 		o(&options)
 	}

+	if unmarshaler, ok := dst.(json.Unmarshaler); ok {
+		buf, err := json.Marshal(mp)
+		if err == nil {
+			err = unmarshaler.UnmarshalJSON(buf)
+		}
+		return err
+	}
+
+	var err error
+	var sval reflect.Value
+	var fname string
+
 	dviface := reflect.ValueOf(dst)
 	if dviface.Kind() == reflect.Ptr {
 		dviface = dviface.Elem()
@ -532,6 +541,9 @@ func Equal(src interface{}, dst interface{}, excptFields ...string) bool {
 			}
 			s := srcVal.MapIndex(key)
 			d := dstVal.MapIndex(key)
+			if !s.IsValid() || !d.IsValid() {
+				return false
+			}
 			if !Equal(s.Interface(), d.Interface(), excptFields...) {
 				return false
 			}
--- a/util/register/util.go
+++ b/util/register/util.go
@ -109,12 +109,11 @@ func Merge(olist []*register.Service, nlist []*register.Service) []*register.Ser
 				seen = true
 				srv = append(srv, sp)
 				break
-			} else {
-				sp := &register.Service{}
-				// make copy
-				*sp = *o
-				srv = append(srv, sp)
 			}
+			sp := &register.Service{}
+			// make copy
+			*sp = *o
+			srv = append(srv, sp)
 		}
 		if !seen {
 			srv = append(srv, Copy([]*register.Service{n})...)
--- a/util/sort/sort.go
+++ b/util/sort/sort.go
@ -0,0 +1,40 @@
+package sort
+
+import (
+	"fmt"
+	"sort"
+)
+
+// sort labels alphabeticaly by label name
+type byKey []interface{}
+
+func (k byKey) Len() int           { return len(k) / 2 }
+func (k byKey) Less(i, j int) bool { return fmt.Sprintf("%s", k[i*2]) < fmt.Sprintf("%s", k[j*2]) }
+func (k byKey) Swap(i, j int) {
+	k[i*2], k[j*2] = k[j*2], k[i*2]
+	k[i*2+1], k[j*2+1] = k[j*2+1], k[i*2+1]
+}
+
+func Uniq(labels []interface{}) []interface{} {
+	if len(labels)%2 == 1 {
+		labels = labels[:len(labels)-1]
+	}
+
+	if len(labels) > 2 {
+		sort.Sort(byKey(labels))
+
+		idx := 0
+		for {
+			if labels[idx] == labels[idx+2] {
+				copy(labels[idx:], labels[idx+2:])
+				labels = labels[:len(labels)-2]
+			} else {
+				idx += 2
+			}
+			if idx+2 >= len(labels) {
+				break
+			}
+		}
+	}
+	return labels
+}
--- a/util/structfs/metadata_ec2.go
+++ b/util/structfs/metadata_ec2.go
@ -12,7 +12,7 @@ type EC2Metadata struct {
 			InstanceType       string   `json:"instance-type"`
 			LocalHostname      string   `json:"local-hostname"`
 			LocalIPv4          string   `json:"local-ipv4"`
-			kernelID           int      `json:"kernel-id"`
+			KernelID           int      `json:"kernel-id"`
 			Placement          string   `json:"placement"`
 			AvailabilityZone   string   `json:"availability-zone"`
 			ProductCodes       string   `json:"product-codes"`
--- a/util/structfs/structfs.go
+++ b/util/structfs/structfs.go
@ -67,9 +67,9 @@ func (fi *fileInfo) Name() string {

 func (fi *fileInfo) Mode() os.FileMode {
 	if strings.HasSuffix(fi.name, "/") {
-		return os.FileMode(0755) | os.ModeDir
+		return os.FileMode(0o755) | os.ModeDir
 	}
-	return os.FileMode(0644)
+	return os.FileMode(0o644)
 }

 func (fi *fileInfo) IsDir() bool {
@ -112,15 +112,14 @@ func (f *file) Readdir(count int) ([]os.FileInfo, error) {
 func (f *file) Seek(offset int64, whence int) (int64, error) {
 	//	log.Printf("seek %d %d %s\n", offset, whence, f.name)
 	switch whence {
-	case os.SEEK_SET:
+	case io.SeekStart:
 		f.offset = offset
-	case os.SEEK_CUR:
+	case io.SeekCurrent:
 		f.offset += offset
-	case os.SEEK_END:
+	case io.SeekEnd:
 		f.offset = int64(len(f.data)) + offset
 	}
 	return f.offset, nil
-
 }

 func (f *file) Stat() (os.FileInfo, error) {
--- a/util/structfs/structfs_test.go
+++ b/util/structfs/structfs_test.go
@ -2,7 +2,7 @@ package structfs

 import (
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"reflect"
 	"testing"
@ -82,7 +82,7 @@ func get(path string) ([]byte, error) {
 		return nil, err
 	}
 	defer res.Body.Close()
-	return ioutil.ReadAll(res.Body)
+	return io.ReadAll(res.Body)
 }

 func TestAll(t *testing.T) {
--- a/util/time/duration_test.go
+++ b/util/time/duration_test.go
@ -35,7 +35,7 @@ func TestUnmarshalJSON(t *testing.T) {
 	err = json.Unmarshal([]byte(`{"ttl":"1y"}`), v)
 	if err != nil {
 		t.Fatal(err)
-	} else if v.TTL != 31536000000000000 {
+	} else if v.TTL != 31622400000000000 {
 		t.Fatalf("invalid duration %v != 31536000000000000", v.TTL)
 	}
 }
@ -55,7 +55,7 @@ func TestParseDuration(t *testing.T) {
 	if err != nil {
 		t.Fatalf("ParseDuration error: %v", err)
 	}
-	if td.String() != "8760h0m0s" {
+	if td.String() != "8784h0m0s" {
 		t.Fatalf("ParseDuration 1y != 8760h0m0s : %s", td.String())
 	}
 }
--- a/util/xpool/pool.go
+++ b/util/xpool/pool.go
@ -0,0 +1,25 @@
+package pool
+
+import "sync"
+
+type Pool[T any] struct {
+	p *sync.Pool
+}
+
+func NewPool[T any](fn func() T) Pool[T] {
+	return Pool[T]{
+		p: &sync.Pool{
+			New: func() interface{} {
+				return fn()
+			},
+		},
+	}
+}
+
+func (p Pool[T]) Get() T {
+	return p.p.Get().(T)
+}
+
+func (p Pool[T]) Put(t T) {
+	p.p.Put(t)
+}
--- a/util/xpool/pool_test.go
+++ b/util/xpool/pool_test.go
@ -0,0 +1,27 @@
+package pool
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestBytes(t *testing.T) {
+	p := NewPool(func() *bytes.Buffer { return bytes.NewBuffer(nil) })
+	b := p.Get()
+	b.Write([]byte(`test`))
+	if b.String() != "test" {
+		t.Fatal("pool not works")
+	}
+	p.Put(b)
+}
+
+func TestStrings(t *testing.T) {
+	p := NewPool(func() *strings.Builder { return &strings.Builder{} })
+	b := p.Get()
+	b.Write([]byte(`test`))
+	if b.String() != "test" {
+		t.Fatal("pool not works")
+	}
+	p.Put(b)
+}