Add logs when tracing information is not propagated (#765)

Author: shreyassrivatsan

internal/client.go

@@ -31,6 +31,7 @@ import (
 	s "go.uber.org/cadence/.gen/go/shared"
 	"go.uber.org/cadence/encoded"
 	"go.uber.org/cadence/internal/common/metrics"
+	"go.uber.org/zap"
 )
 
 const (
@@ -477,7 +478,7 @@ func NewClient(service workflowserviceclient.Interface, domain string, options *
 	var tracer opentracing.Tracer
 	if options != nil && options.Tracer != nil {
 		tracer = options.Tracer
-		contextPropagators = append(contextPropagators, NewTracingContextPropagator(tracer))
+		contextPropagators = append(contextPropagators, NewTracingContextPropagator(zap.NewNop(), tracer))
 	} else {
 		tracer = opentracing.NoopTracer{}
 	}

internal/internal_worker.go

@@ -1399,7 +1399,7 @@ func augmentWorkerOptions(options WorkerOptions) WorkerOptions {
 
 	// if the user passes in a tracer then add a tracing context propagator
 	if options.Tracer != nil {
-		options.ContextPropagators = append(options.ContextPropagators, NewTracingContextPropagator(options.Tracer))
+		options.ContextPropagators = append(options.ContextPropagators, NewTracingContextPropagator(options.Logger, options.Tracer))
 	} else {
 		options.Tracer = opentracing.NoopTracer{}
 	}

internal/tracer.go

@@ -24,13 +24,9 @@ import (
 	"context"
 
 	"github.com/opentracing/opentracing-go"
+	"go.uber.org/zap"
 )
 
-// NewTracingContextPropagator returns new tracing context propagator object
-func NewTracingContextPropagator(tracer opentracing.Tracer) ContextPropagator {
-	return &tracingContextPropagator{tracer}
-}
-
 type tracingReader struct {
 	reader HeaderReader
 }
@@ -62,16 +58,23 @@ func (t tracingWriter) Set(key, val string) {
 //		the header and puts it in the Context object. Does not start a new span
 //		as that is started outside when the workflow is actually executed
 type tracingContextPropagator struct {
+	logger *zap.Logger
 	tracer opentracing.Tracer
 }
 
+// NewTracingContextPropagator returns new tracing context propagator object
+func NewTracingContextPropagator(logger *zap.Logger, tracer opentracing.Tracer) ContextPropagator {
+	return &tracingContextPropagator{logger, tracer}
+}
+
 func (t *tracingContextPropagator) Inject(
 	ctx context.Context,
 	hw HeaderWriter,
 ) error {
 	// retrieve span from context object
 	span := opentracing.SpanFromContext(ctx)
 	if span == nil {
+		t.logger.Info("could not retrieve span from context")
 		return nil
 	}
 	return t.tracer.Inject(span.Context(), opentracing.TextMap, tracingWriter{hw})
@@ -84,6 +87,7 @@ func (t *tracingContextPropagator) Extract(
 	spanContext, err := t.tracer.Extract(opentracing.TextMap, tracingReader{hr})
 	if err != nil {
 		// did not find a tracing span, just return the current context
+		t.logger.Info("could not extract span information", zap.Error(err))
 		return ctx, nil
 	}
 	return context.WithValue(ctx, activeSpanContextKey, spanContext), nil
@@ -96,6 +100,7 @@ func (t *tracingContextPropagator) InjectFromWorkflow(
 	// retrieve span from context object
 	spanContext := spanFromContext(ctx)
 	if spanContext == nil {
+		t.logger.Info("could not retrieve span from context")
 		return nil
 	}
 	return t.tracer.Inject(spanContext, opentracing.HTTPHeaders, tracingWriter{hw})
@@ -108,6 +113,7 @@ func (t *tracingContextPropagator) ExtractToWorkflow(
 	spanContext, err := t.tracer.Extract(opentracing.TextMap, tracingReader{hr})
 	if err != nil {
 		// did not find a tracing span, just return the current context
+		t.logger.Info("could not extract span information", zap.Error(err))
 		return ctx, nil
 	}
 	return contextWithSpan(ctx, spanContext), nil

internal/tracer_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	jaeger_config "github.com/uber/jaeger-client-go/config"
 	"go.uber.org/cadence/.gen/go/shared"
+	"go.uber.org/zap"
 )
 
 func TestTracingContextPropagator(t *testing.T) {
@@ -36,7 +37,7 @@ func TestTracingContextPropagator(t *testing.T) {
 	assert.NoError(t, err)
 	defer closer.Close()
 	tracer := opentracing.GlobalTracer()
-	ctxProp := NewTracingContextPropagator(tracer)
+	ctxProp := NewTracingContextPropagator(zap.NewNop(), tracer)
 
 	span := tracer.StartSpan("test-operation")
 	ctx := context.Background()
@@ -57,7 +58,7 @@ func TestTracingContextPropagator(t *testing.T) {
 }
 
 func TestTracingContextPropagatorNoSpan(t *testing.T) {
-	ctxProp := NewTracingContextPropagator(opentracing.NoopTracer{})
+	ctxProp := NewTracingContextPropagator(zap.NewNop(), opentracing.NoopTracer{})
 
 	header := &shared.Header{
 		Fields: map[string][]byte{},
@@ -76,7 +77,7 @@ func TestTracingContextPropagatorWorkflowContext(t *testing.T) {
 	assert.NoError(t, err)
 	defer closer.Close()
 	tracer := opentracing.GlobalTracer()
-	ctxProp := NewTracingContextPropagator(tracer)
+	ctxProp := NewTracingContextPropagator(zap.NewNop(), tracer)
 
 	span := tracer.StartSpan("test-operation")
 	ctx := contextWithSpan(Background(), span.Context())
@@ -97,7 +98,7 @@ func TestTracingContextPropagatorWorkflowContext(t *testing.T) {
 }
 
 func TestTracingContextPropagatorWorkflowContextNoSpan(t *testing.T) {
-	ctxProp := NewTracingContextPropagator(opentracing.NoopTracer{})
+	ctxProp := NewTracingContextPropagator(zap.NewNop(), opentracing.NoopTracer{})
 
 	header := &shared.Header{
 		Fields: map[string][]byte{},