allow replaceing trace SDK (#1238)

Author: dashpole

go.sum

@@ -48,6 +48,8 @@ golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/text v0.3.3 h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

trace/basetypes.go

@@ -49,6 +49,16 @@ type Attribute struct {
 	value interface{}
 }
 
+// Key returns the attribute's key
+func (a *Attribute) Key() string {
+	return a.key
+}
+
+// Value returns the attribute's value
+func (a *Attribute) Value() interface{} {
+	return a.value
+}
+
 // BoolAttribute returns a bool-valued attribute.
 func BoolAttribute(key string, value bool) Attribute {
 	return Attribute{key: key, value: value}

trace/spanstore.go

@@ -48,8 +48,10 @@ func (i internalOnly) ReportActiveSpans(name string) []*SpanData {
 	var out []*SpanData
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	for span := range s.active {
-		out = append(out, span.makeSpanData())
+	for activeSpan := range s.active {
+		if s, ok := activeSpan.internal.(*span); ok {
+			out = append(out, s.makeSpanData())
+		}
 	}
 	return out
 }

trace/trace.go

@@ -28,12 +28,16 @@ import (
 	"go.opencensus.io/trace/tracestate"
 )
 
+type tracer struct{}
+
+var _ Tracer = &tracer{}
+
 // Span represents a span of a trace.  It has an associated SpanContext, and
 // stores data accumulated while the span is active.
 //
 // Ideally users should interact with Spans by calling the functions in this
 // package that take a Context parameter.
-type Span struct {
+type span struct {
 	// data contains information recorded about the span.
 	//
 	// It will be non-nil if we are exporting the span or recording events for it.
@@ -66,7 +70,7 @@ type Span struct {
 // IsRecordingEvents returns true if events are being recorded for this span.
 // Use this check to avoid computing expensive annotations when they will never
 // be used.
-func (s *Span) IsRecordingEvents() bool {
+func (s *span) IsRecordingEvents() bool {
 	if s == nil {
 		return false
 	}
@@ -109,13 +113,13 @@ type SpanContext struct {
 type contextKey struct{}
 
 // FromContext returns the Span stored in a context, or nil if there isn't one.
-func FromContext(ctx context.Context) *Span {
+func (t *tracer) FromContext(ctx context.Context) *Span {
 	s, _ := ctx.Value(contextKey{}).(*Span)
 	return s
 }
 
 // NewContext returns a new context with the given Span attached.
-func NewContext(parent context.Context, s *Span) context.Context {
+func (t *tracer) NewContext(parent context.Context, s *Span) context.Context {
 	return context.WithValue(parent, contextKey{}, s)
 }
 
@@ -166,12 +170,14 @@ func WithSampler(sampler Sampler) StartOption {
 //
 // Returned context contains the newly created span. You can use it to
 // propagate the returned span in process.
-func StartSpan(ctx context.Context, name string, o ...StartOption) (context.Context, *Span) {
+func (t *tracer) StartSpan(ctx context.Context, name string, o ...StartOption) (context.Context, *Span) {
 	var opts StartOptions
 	var parent SpanContext
-	if p := FromContext(ctx); p != nil {
-		p.addChild()
-		parent = p.spanContext
+	if p := t.FromContext(ctx); p != nil {
+		if ps, ok := p.internal.(*span); ok {
+			ps.addChild()
+		}
+		parent = p.SpanContext()
 	}
 	for _, op := range o {
 		op(&opts)
@@ -180,7 +186,8 @@ func StartSpan(ctx context.Context, name string, o ...StartOption) (context.Cont
 
 	ctx, end := startExecutionTracerTask(ctx, name)
 	span.executionTracerTaskEnd = end
-	return NewContext(ctx, span), span
+	extSpan := NewSpan(span)
+	return t.NewContext(ctx, extSpan), extSpan
 }
 
 // StartSpanWithRemoteParent starts a new child span of the span from the given parent.
@@ -190,20 +197,21 @@ func StartSpan(ctx context.Context, name string, o ...StartOption) (context.Cont
 //
 // Returned context contains the newly created span. You can use it to
 // propagate the returned span in process.
-func StartSpanWithRemoteParent(ctx context.Context, name string, parent SpanContext, o ...StartOption) (context.Context, *Span) {
+func (t *tracer) StartSpanWithRemoteParent(ctx context.Context, name string, parent SpanContext, o ...StartOption) (context.Context, *Span) {
 	var opts StartOptions
 	for _, op := range o {
 		op(&opts)
 	}
 	span := startSpanInternal(name, parent != SpanContext{}, parent, true, opts)
 	ctx, end := startExecutionTracerTask(ctx, name)
 	span.executionTracerTaskEnd = end
-	return NewContext(ctx, span), span
+	extSpan := NewSpan(span)
+	return t.NewContext(ctx, extSpan), extSpan
 }
 
-func startSpanInternal(name string, hasParent bool, parent SpanContext, remoteParent bool, o StartOptions) *Span {
-	span := &Span{}
-	span.spanContext = parent
+func startSpanInternal(name string, hasParent bool, parent SpanContext, remoteParent bool, o StartOptions) *span {
+	s := &span{}
+	s.spanContext = parent
 
 	cfg := config.Load().(*Config)
 	if gen, ok := cfg.IDGenerator.(*defaultIDGenerator); ok {
@@ -212,9 +220,9 @@ func startSpanInternal(name string, hasParent bool, parent SpanContext, remotePa
 	}
 
 	if !hasParent {
-		span.spanContext.TraceID = cfg.IDGenerator.NewTraceID()
+		s.spanContext.TraceID = cfg.IDGenerator.NewTraceID()
 	}
-	span.spanContext.SpanID = cfg.IDGenerator.NewSpanID()
+	s.spanContext.SpanID = cfg.IDGenerator.NewSpanID()
 	sampler := cfg.DefaultSampler
 
 	if !hasParent || remoteParent || o.Sampler != nil {
@@ -226,47 +234,47 @@ func startSpanInternal(name string, hasParent bool, parent SpanContext, remotePa
 		if o.Sampler != nil {
 			sampler = o.Sampler
 		}
-		span.spanContext.setIsSampled(sampler(SamplingParameters{
+		s.spanContext.setIsSampled(sampler(SamplingParameters{
 			ParentContext:   parent,
-			TraceID:         span.spanContext.TraceID,
-			SpanID:          span.spanContext.SpanID,
+			TraceID:         s.spanContext.TraceID,
+			SpanID:          s.spanContext.SpanID,
 			Name:            name,
 			HasRemoteParent: remoteParent}).Sample)
 	}
 
-	if !internal.LocalSpanStoreEnabled && !span.spanContext.IsSampled() {
-		return span
+	if !internal.LocalSpanStoreEnabled && !s.spanContext.IsSampled() {
+		return s
 	}
 
-	span.data = &SpanData{
-		SpanContext:     span.spanContext,
+	s.data = &SpanData{
+		SpanContext:     s.spanContext,
 		StartTime:       time.Now(),
 		SpanKind:        o.SpanKind,
 		Name:            name,
 		HasRemoteParent: remoteParent,
 	}
-	span.lruAttributes = newLruMap(cfg.MaxAttributesPerSpan)
-	span.annotations = newEvictedQueue(cfg.MaxAnnotationEventsPerSpan)
-	span.messageEvents = newEvictedQueue(cfg.MaxMessageEventsPerSpan)
-	span.links = newEvictedQueue(cfg.MaxLinksPerSpan)
+	s.lruAttributes = newLruMap(cfg.MaxAttributesPerSpan)
+	s.annotations = newEvictedQueue(cfg.MaxAnnotationEventsPerSpan)
+	s.messageEvents = newEvictedQueue(cfg.MaxMessageEventsPerSpan)
+	s.links = newEvictedQueue(cfg.MaxLinksPerSpan)
 
 	if hasParent {
-		span.data.ParentSpanID = parent.SpanID
+		s.data.ParentSpanID = parent.SpanID
 	}
 	if internal.LocalSpanStoreEnabled {
 		var ss *spanStore
 		ss = spanStoreForNameCreateIfNew(name)
 		if ss != nil {
-			span.spanStore = ss
-			ss.add(span)
+			s.spanStore = ss
+			ss.add(NewSpan(s))
 		}
 	}
 
-	return span
+	return s
 }
 
 // End ends the span.
-func (s *Span) End() {
+func (s *span) End() {
 	if s == nil {
 		return
 	}
@@ -283,7 +291,7 @@ func (s *Span) End() {
 			sd := s.makeSpanData()
 			sd.EndTime = internal.MonotonicEndTime(sd.StartTime)
 			if s.spanStore != nil {
-				s.spanStore.finished(s, sd)
+				s.spanStore.finished(NewSpan(s), sd)
 			}
 			if mustExport {
 				for e := range exp {
@@ -296,7 +304,7 @@ func (s *Span) End() {
 
 // makeSpanData produces a SpanData representing the current state of the Span.
 // It requires that s.data is non-nil.
-func (s *Span) makeSpanData() *SpanData {
+func (s *span) makeSpanData() *SpanData {
 	var sd SpanData
 	s.mu.Lock()
 	sd = *s.data
@@ -321,15 +329,15 @@ func (s *Span) makeSpanData() *SpanData {
 }
 
 // SpanContext returns the SpanContext of the span.
-func (s *Span) SpanContext() SpanContext {
+func (s *span) SpanContext() SpanContext {
 	if s == nil {
 		return SpanContext{}
 	}
 	return s.spanContext
 }
 
 // SetName sets the name of the span, if it is recording events.
-func (s *Span) SetName(name string) {
+func (s *span) SetName(name string) {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -339,7 +347,7 @@ func (s *Span) SetName(name string) {
 }
 
 // SetStatus sets the status of the span, if it is recording events.
-func (s *Span) SetStatus(status Status) {
+func (s *span) SetStatus(status Status) {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -348,31 +356,31 @@ func (s *Span) SetStatus(status Status) {
 	s.mu.Unlock()
 }
 
-func (s *Span) interfaceArrayToLinksArray() []Link {
+func (s *span) interfaceArrayToLinksArray() []Link {
 	linksArr := make([]Link, 0, len(s.links.queue))
 	for _, value := range s.links.queue {
 		linksArr = append(linksArr, value.(Link))
 	}
 	return linksArr
 }
 
-func (s *Span) interfaceArrayToMessageEventArray() []MessageEvent {
+func (s *span) interfaceArrayToMessageEventArray() []MessageEvent {
 	messageEventArr := make([]MessageEvent, 0, len(s.messageEvents.queue))
 	for _, value := range s.messageEvents.queue {
 		messageEventArr = append(messageEventArr, value.(MessageEvent))
 	}
 	return messageEventArr
 }
 
-func (s *Span) interfaceArrayToAnnotationArray() []Annotation {
+func (s *span) interfaceArrayToAnnotationArray() []Annotation {
 	annotationArr := make([]Annotation, 0, len(s.annotations.queue))
 	for _, value := range s.annotations.queue {
 		annotationArr = append(annotationArr, value.(Annotation))
 	}
 	return annotationArr
 }
 
-func (s *Span) lruAttributesToAttributeMap() map[string]interface{} {
+func (s *span) lruAttributesToAttributeMap() map[string]interface{} {
 	attributes := make(map[string]interface{}, s.lruAttributes.len())
 	for _, key := range s.lruAttributes.keys() {
 		value, ok := s.lruAttributes.get(key)
@@ -384,13 +392,13 @@ func (s *Span) lruAttributesToAttributeMap() map[string]interface{} {
 	return attributes
 }
 
-func (s *Span) copyToCappedAttributes(attributes []Attribute) {
+func (s *span) copyToCappedAttributes(attributes []Attribute) {
 	for _, a := range attributes {
 		s.lruAttributes.add(a.key, a.value)
 	}
 }
 
-func (s *Span) addChild() {
+func (s *span) addChild() {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -402,7 +410,7 @@ func (s *Span) addChild() {
 // AddAttributes sets attributes in the span.
 //
 // Existing attributes whose keys appear in the attributes parameter are overwritten.
-func (s *Span) AddAttributes(attributes ...Attribute) {
+func (s *span) AddAttributes(attributes ...Attribute) {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -418,7 +426,7 @@ func copyAttributes(m map[string]interface{}, attributes []Attribute) {
 	}
 }
 
-func (s *Span) lazyPrintfInternal(attributes []Attribute, format string, a ...interface{}) {
+func (s *span) lazyPrintfInternal(attributes []Attribute, format string, a ...interface{}) {
 	now := time.Now()
 	msg := fmt.Sprintf(format, a...)
 	var m map[string]interface{}
@@ -435,7 +443,7 @@ func (s *Span) lazyPrintfInternal(attributes []Attribute, format string, a ...in
 	s.mu.Unlock()
 }
 
-func (s *Span) printStringInternal(attributes []Attribute, str string) {
+func (s *span) printStringInternal(attributes []Attribute, str string) {
 	now := time.Now()
 	var a map[string]interface{}
 	s.mu.Lock()
@@ -453,15 +461,15 @@ func (s *Span) printStringInternal(attributes []Attribute, str string) {
 
 // Annotate adds an annotation with attributes.
 // Attributes can be nil.
-func (s *Span) Annotate(attributes []Attribute, str string) {
+func (s *span) Annotate(attributes []Attribute, str string) {
 	if !s.IsRecordingEvents() {
 		return
 	}
 	s.printStringInternal(attributes, str)
 }
 
 // Annotatef adds an annotation with attributes.
-func (s *Span) Annotatef(attributes []Attribute, format string, a ...interface{}) {
+func (s *span) Annotatef(attributes []Attribute, format string, a ...interface{}) {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -474,7 +482,7 @@ func (s *Span) Annotatef(attributes []Attribute, format string, a ...interface{}
 // unique in this span and the same between the send event and the receive
 // event (this allows to identify a message between the sender and receiver).
 // For example, this could be a sequence id.
-func (s *Span) AddMessageSendEvent(messageID, uncompressedByteSize, compressedByteSize int64) {
+func (s *span) AddMessageSendEvent(messageID, uncompressedByteSize, compressedByteSize int64) {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -496,7 +504,7 @@ func (s *Span) AddMessageSendEvent(messageID, uncompressedByteSize, compressedBy
 // unique in this span and the same between the send event and the receive
 // event (this allows to identify a message between the sender and receiver).
 // For example, this could be a sequence id.
-func (s *Span) AddMessageReceiveEvent(messageID, uncompressedByteSize, compressedByteSize int64) {
+func (s *span) AddMessageReceiveEvent(messageID, uncompressedByteSize, compressedByteSize int64) {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -513,7 +521,7 @@ func (s *Span) AddMessageReceiveEvent(messageID, uncompressedByteSize, compresse
 }
 
 // AddLink adds a link to the span.
-func (s *Span) AddLink(l Link) {
+func (s *span) AddLink(l Link) {
 	if !s.IsRecordingEvents() {
 		return
 	}
@@ -522,7 +530,7 @@ func (s *Span) AddLink(l Link) {
 	s.mu.Unlock()
 }
 
-func (s *Span) String() string {
+func (s *span) String() string {
 	if s == nil {
 		return "<nil>"
 	}