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

Reviewed-on: #381

broker/context.go

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

broker/memory/memory.go

@@ -109,7 +109,7 @@ func (m *memoryBroker) Init(opts ...broker.Option) error {
 	m.funcSubscribe = m.fnSubscribe
 	m.funcBatchSubscribe = m.fnBatchSubscribe
 
-	m.opts.Hooks.EachNext(func(hook options.Hook) {
+	m.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case broker.HookPublish:
 			m.funcPublish = h(m.funcPublish)

broker/noop.go

@@ -59,7 +59,7 @@ func (b *NoopBroker) Init(opts ...Option) error {
 	b.funcSubscribe = b.fnSubscribe
 	b.funcBatchSubscribe = b.fnBatchSubscribe
 
-	b.opts.Hooks.EachNext(func(hook options.Hook) {
+	b.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case HookPublish:
 			b.funcPublish = h(b.funcPublish)

client/context.go

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

client/noop.go

@@ -194,7 +194,7 @@ func (n *noopClient) Init(opts ...Option) error {
 	n.funcPublish = n.fnPublish
 	n.funcBatchPublish = n.fnBatchPublish
 
-	n.opts.Hooks.EachNext(func(hook options.Hook) {
+	n.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case HookCall:
 			n.funcCall = h(n.funcCall)

codec/context.go

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

config/context.go

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

config/default.go

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

flow/context.go

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

go.mod

@@ -31,6 +31,7 @@ require (
 	github.com/opencontainers/runtime-spec v1.2.0 // indirect
 	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/rogpeppe/go-internal v1.13.1 // indirect
 	github.com/sirupsen/logrus v1.9.3 // indirect
 	github.com/stretchr/testify v1.10.0 // indirect
 	go.uber.org/goleak v1.3.0 // indirect

go.sum

@@ -57,8 +57,7 @@ github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRI
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prashantv/gostub v1.1.0 h1:BTyx3RfQjRHnUWaGF9oQos79AlQ5k8WNktv7VGvVH4g=
 github.com/prashantv/gostub v1.1.0/go.mod h1:A5zLQHz7ieHGG7is6LLXLz7I8+3LZzsrV0P1IAHhP5U=
-github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDNXVBh4M=
+github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
-github.com/rogpeppe/go-internal v1.11.0/go.mod h1:ddIwULY96R17DhadqLgMfk9H9tvdUzkipdSkR5nkCZA=
 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=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=

logger/context.go

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

metadata/context.go

@@ -11,34 +11,6 @@ type (
 	mdKey         struct{}
 )
 
-// MustIncomingContext returns metadata from incoming ctx
-// returned metadata shoud not be modified or race condition happens.
-// If metadata not exists panics.
-func MustIncomingContext(ctx context.Context) Metadata {
-	if ctx == nil {
-		panic("missing metadata")
-	}
-	md, ok := ctx.Value(mdIncomingKey{}).(*rawMetadata)
-	if !ok {
-		panic("missing metadata")
-	}
-	return md.md
-}
-
-// MustOutgoingContext returns metadata from outgoing ctx
-// returned metadata shoud not be modified or race condition happens.
-// If metadata not exists panics.
-func MustOutgoingContext(ctx context.Context) Metadata {
-	if ctx == nil {
-		panic("missing metadata")
-	}
-	md, ok := ctx.Value(mdOutgoingKey{}).(*rawMetadata)
-	if !ok {
-		panic("missing metadata")
-	}
-	return md.md
-}
-
 // FromIncomingContext returns metadata from incoming ctx
 // returned metadata shoud not be modified or race condition happens
 func FromIncomingContext(ctx context.Context) (Metadata, bool) {
@@ -52,6 +24,17 @@ func FromIncomingContext(ctx context.Context) (Metadata, bool) {
 	return md.md, ok
 }
 
+// MustIncomingContext returns metadata from incoming ctx
+// returned metadata shoud not be modified or race condition happens.
+// If metadata not exists panics.
+func MustIncomingContext(ctx context.Context) Metadata {
+	md, ok := FromIncomingContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
 // FromOutgoingContext returns metadata from outgoing ctx
 // returned metadata shoud not be modified or race condition happens
 func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
@@ -65,6 +48,17 @@ func FromOutgoingContext(ctx context.Context) (Metadata, bool) {
 	return md.md, ok
 }
 
+// MustOutgoingContext returns metadata from outgoing ctx
+// returned metadata shoud not be modified or race condition happens.
+// If metadata not exists panics.
+func MustOutgoingContext(ctx context.Context) Metadata {
+	md, ok := FromOutgoingContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
 // FromContext returns metadata from the given context
 // returned metadata shoud not be modified or race condition happens
 func FromContext(ctx context.Context) (Metadata, bool) {
@@ -78,6 +72,16 @@ func FromContext(ctx context.Context) (Metadata, bool) {
 	return md.md, ok
 }
 
+// MustContext returns metadata from the given context
+// returned metadata shoud not be modified or race condition happens
+func MustContext(ctx context.Context) Metadata {
+	md, ok := FromContext(ctx)
+	if !ok {
+		panic("missing metadata")
+	}
+	return md
+}
+
 // NewContext creates a new context with the given metadata
 func NewContext(ctx context.Context, md Metadata) context.Context {
 	if ctx == nil {
@@ -139,7 +143,7 @@ func AppendOutgoingContext(ctx context.Context, kv ...string) context.Context {
 	for k, v := range md {
 		omd.Set(k, v)
 	}
-	return NewOutgoingContext(ctx, omd)
+	return ctx
 }
 
 // AppendIncomingContext apends new md to context
@@ -155,5 +159,21 @@ func AppendIncomingContext(ctx context.Context, kv ...string) context.Context {
 	for k, v := range md {
 		omd.Set(k, v)
 	}
-	return NewIncomingContext(ctx, omd)
+	return ctx
+}
+
+// AppendContext apends new md to context
+func AppendContext(ctx context.Context, kv ...string) context.Context {
+	md, ok := Pairs(kv...)
+	if !ok {
+		return ctx
+	}
+	omd, ok := FromContext(ctx)
+	if !ok {
+		return NewContext(ctx, md)
+	}
+	for k, v := range md {
+		omd.Set(k, v)
+	}
+	return ctx
 }

metadata/metadata.go

@@ -68,15 +68,7 @@ func (md Metadata) Iterator() *Iterator {
 }
 
 func (md Metadata) MustGet(key string) string {
-	// fast path
+	val, ok := md.Get(key)
-	val, ok := md[key]
-	if !ok {
-		// slow path
-		val, ok = md[textproto.CanonicalMIMEHeaderKey(key)]
-		if !ok {
-			val, ok = md[strings.ToLower(key)]
-		}
-	}
 	if !ok {
 		panic("missing metadata key")
 	}
@@ -119,11 +111,18 @@ func (md Metadata) Del(keys ...string) {
 	}
 }
 
+// Copy makes a copy of the metadata
+func (md Metadata) CopyTo(dst Metadata) {
+	for k, v := range md {
+		dst[k] = v
+	}
+}
+
 // Copy makes a copy of the metadata
 func Copy(md Metadata, exclude ...string) Metadata {
 	nmd := New(len(md))
-	for key, val := range md {
+	for k, v := range md {
-		nmd.Set(key, val)
+		nmd[k] = v
 	}
 	nmd.Del(exclude...)
 	return nmd
@@ -147,7 +146,7 @@ func Merge(omd Metadata, mmd Metadata, overwrite bool) Metadata {
 		case ok && !overwrite:
 			continue
 		case val != "":
-			nmd.Set(key, val)
+			nmd[key] = val
 		case ok && val == "":
 			nmd.Del(key)
 		}
@@ -161,6 +160,8 @@ func Pairs(kv ...string) (Metadata, bool) {
 		return nil, false
 	}
 	md := New(len(kv) / 2)
-	md.Set(kv...)
+	for idx := 0; idx < len(kv); idx += 2 {
+		md[kv[idx]] = kv[idx+1]
+	}
 	return md, true
 }

metadata/metadata_test.go

@@ -32,8 +32,8 @@ func TestMultipleUsage(t *testing.T) {
 		m.Del("key1_3")
 		return ctx
 	}(ctx)
-	t.Logf("imd %#+v", imd)
+	_ = imd
-	t.Logf("omd %#+v", omd)
+	_ = omd
 }
 
 func TestMetadataSetMultiple(t *testing.T) {

meter/context.go

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

register/context.go

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

router/context.go

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

semconv/metadata.go

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

server/context.go

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

server/noop.go

@@ -723,7 +723,7 @@ func (n *noopServer) createSubHandler(sb *subscriber, opts Options) broker.Handl
 				return nil
 			}
 
-			opts.Hooks.EachNext(func(hook options.Hook) {
+			opts.Hooks.EachPrev(func(hook options.Hook) {
 				if h, ok := hook.(HookSubHandler); ok {
 					fn = h(fn)
 				}

server/noop_test.go

@@ -9,6 +9,7 @@ import (
 	"go.unistack.org/micro/v3/client"
 	"go.unistack.org/micro/v3/codec"
 	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v3/options"
 	"go.unistack.org/micro/v3/server"
 )
 
@@ -84,3 +85,40 @@ func TestNoopSub(t *testing.T) {
 		}
 	}()
 }
+
+func TestHooks_Wrap(t *testing.T) {
+	n := 5
+	fn1 := func(next server.FuncSubHandler) server.FuncSubHandler {
+		return func(ctx context.Context, msg server.Message) (err error) {
+			n *= 2
+			return next(ctx, msg)
+		}
+	}
+	fn2 := func(next server.FuncSubHandler) server.FuncSubHandler {
+		return func(ctx context.Context, msg server.Message) (err error) {
+			n -= 10
+			return next(ctx, msg)
+		}
+	}
+
+	hs := &options.Hooks{}
+	hs.Append(server.HookSubHandler(fn1), server.HookSubHandler(fn2))
+
+	var fn = func(ctx context.Context, msg server.Message) error {
+		return nil
+	}
+
+	hs.EachPrev(func(hook options.Hook) {
+		if h, ok := hook.(server.HookSubHandler); ok {
+			fn = h(fn)
+		}
+	})
+
+	if err := fn(nil, nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if n != 0 {
+		t.Fatalf("uncorrected hooks call")
+	}
+}

store/context.go

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

store/memory/memory.go

@@ -123,7 +123,7 @@ func (m *memoryStore) Init(opts ...store.Option) error {
 	m.funcList = m.fnList
 	m.funcDelete = m.fnDelete
 
-	m.opts.Hooks.EachNext(func(hook options.Hook) {
+	m.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case store.HookRead:
 			m.funcRead = h(m.funcRead)

store/noop.go

@@ -54,7 +54,7 @@ func (n *noopStore) Init(opts ...Option) error {
 	n.funcList = n.fnList
 	n.funcDelete = n.fnDelete
 
-	n.opts.Hooks.EachNext(func(hook options.Hook) {
+	n.opts.Hooks.EachPrev(func(hook options.Hook) {
 		switch h := hook.(type) {
 		case HookRead:
 			n.funcRead = h(n.funcRead)

tracer/context.go

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

tracer/memory/memory.go

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

tracer/noop.go

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