Expose Workflow.GetSpanContext API

Author: shijiesheng

internal/context.go

@@ -486,7 +486,7 @@ func (c *valueCtx) Value(key interface{}) interface{} {
 	return c.Context.Value(key)
 }
 
-func spanFromContext(ctx Context) opentracing.SpanContext {
+func GetSpanContext(ctx Context) opentracing.SpanContext {
 	val := ctx.Value(activeSpanContextKey)
 	if sp, ok := val.(opentracing.SpanContext); ok {
 		return sp

internal/tracer.go

@@ -103,7 +103,7 @@ func (t *tracingContextPropagator) InjectFromWorkflow(
 	hw HeaderWriter,
 ) error {
 	// retrieve span from context object
-	spanContext := spanFromContext(ctx)
+	spanContext := GetSpanContext(ctx)
 	if spanContext == nil {
 		return nil
 	}

internal/tracer_test.go

@@ -96,9 +96,9 @@ func TestTracingContextPropagatorWorkflowContext(t *testing.T) {
 	returnCtx2, err := ctxProp.ExtractToWorkflow(Background(), NewHeaderReader(header))
 	require.NoError(t, err)
 
-	newSpanContext := spanFromContext(returnCtx)
+	newSpanContext := GetSpanContext(returnCtx)
 	assert.NotNil(t, newSpanContext)
-	newSpanContext2 := spanFromContext(returnCtx2)
+	newSpanContext2 := GetSpanContext(returnCtx2)
 	assert.NotNil(t, newSpanContext2)
 	assert.Equal(t, newSpanContext2, newSpanContext)
 }
@@ -140,7 +140,7 @@ func TestConsistentInjectionExtraction(t *testing.T) {
 	extractedCtx, err := ctxProp.ExtractToWorkflow(Background(), NewHeaderReader(header))
 	require.NoError(t, err)
 
-	extractedSpanContext := spanFromContext(extractedCtx)
+	extractedSpanContext := GetSpanContext(extractedCtx)
 	extractedSpanContext.ForeachBaggageItem(func(k, v string) bool {
 		if k == "request-tenancy" {
 			assert.Equal(t, v, baggageVal)

workflow/context.go

@@ -21,6 +21,7 @@
 package workflow
 
 import (
+	"github.com/opentracing/opentracing-go"
 	"go.uber.org/cadence/internal"
 )
 
@@ -76,3 +77,19 @@ func WithValue(parent Context, key interface{}, val interface{}) Context {
 func NewDisconnectedContext(parent Context) (ctx Context, cancel CancelFunc) {
 	return internal.NewDisconnectedContext(parent)
 }
+
+// GetSpanContext returns the [opentracing.SpanContext] from [Context].
+// Returns nil if tracer is not set in [go.uber.org/cadence/worker.Options].
+//
+// Note: If tracer is set, we already activate a span for each workflow.
+// This SpanContext will be passed to the activities and child workflows to start new spans.
+//
+// Example Usage:
+//
+//	span := GetSpanContext(ctx)
+//	if span != nil {
+//		span.SetTag("foo", "bar")
+//	}
+func GetSpanContext(ctx Context) opentracing.SpanContext {
+	return internal.GetSpanContext(ctx)
+}