add NewContext

opencensus/opencensus.go

@@ -60,6 +60,14 @@ func (t *Trace) FromContext(ctx context.Context) trace.Spanner {
 	return &Span{span: sp}
 }
 
+// NewContext returns a new context with the given Span attached.
+func (t *Trace) NewContext(ctx context.Context, span trace.Spanner) context.Context {
+	if sp, ok := span.InternalSpan().(*oct.Span); ok {
+		return oct.NewContext(ctx, sp)
+	}
+	return ctx
+}
+
 // AddAttributes sets attributes in the span.
 //
 // Existing attributes whose keys appear in the attributes parameter are overwritten.
@@ -83,6 +91,11 @@ func (s *Span) Inject(carrier trace.Carrier) error {
 	return nil
 }
 
+// InternalSpan returns the real implementation of the Span
+func (s *Span) InternalSpan() interface{} {
+	return s.span
+}
+
 func toOCOption(opts ...interface{}) []oct.StartOption {
 	var ocStartOptions []oct.StartOption
 	for _, opt := range opts {

opentracing/opentracing.go

@@ -52,6 +52,14 @@ func (t *Trace) FromContext(ctx context.Context) trace.Spanner {
 	return &Span{span: sp}
 }
 
+// NewContext returns a new context with the given Span attached.
+func (t *Trace) NewContext(ctx context.Context, span trace.Spanner) context.Context {
+	if sp, ok := span.InternalSpan().(opentracing.Span); ok {
+		return opentracing.ContextWithSpan(ctx, sp)
+	}
+	return ctx
+}
+
 // AddAttributes a tags to the span.
 //
 // If there is a pre-existing tag set for `key`, it is overwritten.
@@ -80,6 +88,11 @@ func (s *Span) Inject(carrier trace.Carrier) error {
 	return opentracing.GlobalTracer().Inject(s.span.Context(), opentracing.TextMap, carrierAdapter{carrier: carrier})
 }
 
+// InternalSpan returns the real implementation of the Span
+func (s *Span) InternalSpan() interface{} {
+	return s.span
+}
+
 // Set a key and value on the carrier
 func (ca *carrierAdapter) Set(key, value string) {
 	ca.carrier.Set(key, value)

trace/trace.go

@@ -69,6 +69,7 @@ type (
 		End()
 		Logger() Logger
 		Inject(carrier Carrier) error
+		InternalSpan() interface{}
 	}
 
 	// Tracer is an abstraction over OpenTracing and OpenCensus trace implementations
@@ -76,6 +77,7 @@ type (
 		StartSpan(ctx context.Context, operationName string, opts ...interface{}) (context.Context, Spanner)
 		StartSpanWithRemoteParent(ctx context.Context, operationName string, carrier Carrier, opts ...interface{}) (context.Context, Spanner)
 		FromContext(ctx context.Context) Spanner
+		NewContext(parent context.Context, span Spanner) context.Context
 	}
 
 	// Logger is a generic interface for logging
@@ -112,6 +114,11 @@ func (ns *noOpSpanner) Inject(carrier Carrier) error {
 	return nil
 }
 
+// InternalSpan returns nil
+func (ns *noOpSpanner) InternalSpan() interface{} {
+	return nil
+}
+
 // For will return a logger for a given context
 func For(ctx context.Context) Logger {
 	if span := tracer.FromContext(ctx); span != nil {