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

Reviewed-on: #381

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
 }

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"
+)

tracer/context.go

@@ -37,6 +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{}) {