Update SpanProcessor Shutdown with context and error

CHANGELOG.md

@@ -61,6 +61,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
    They no longer track the gRPC codes. (#1214)
 - The `StatusCode` field of the `SpanData` struct in the `go.opentelemetry.io/otel/sdk/export/trace` package now uses the codes package from this package instead of the gRPC project. (#1214)
 - Move the `go.opentelemetry.io/otel/api/baggage` package into `go.opentelemetry.io/otel/propagators`. (#1217)
+- A `Shutdown` method of `SpanProcessor` and all its implementations receives a context and returns an error. (#1264)
 
 ### Fixed
 

example/basic/main.go

@@ -45,8 +45,10 @@ func main() {
 		log.Fatalf("failed to initialize stdout export pipeline: %v", err)
 	}
 
+	ctx := context.Background()
+
 	bsp := sdktrace.NewBatchSpanProcessor(exporter)
-	defer bsp.Shutdown()
+	defer func() { _ = bsp.Shutdown(ctx) }()
 	tp := sdktrace.NewTracerProvider(sdktrace.WithSpanProcessor(bsp))
 	pusher := push.New(
 		basic.New(
@@ -76,7 +78,6 @@ func main() {
 
 	valuerecorderTwo := otel.Must(meter).NewFloat64ValueRecorder("ex.com.two")
 
-	ctx := context.Background()
 	ctx = otel.ContextWithBaggageValues(ctx, fooKey.String("foo1"), barKey.String("bar1"))
 
 	valuerecorder := valuerecorderTwo.Bind(commonLabels...)

example/namedtracer/main.go

@@ -52,7 +52,9 @@ func initTracer() func() {
 		sdktrace.WithSpanProcessor(bsp),
 	)
 	global.SetTracerProvider(tp)
-	return bsp.Shutdown
+	return func() {
+		_ = bsp.Shutdown(context.Background())
+	}
 }
 
 func main() {

example/otel-collector/main.go

@@ -80,8 +80,9 @@ func initProvider() func() {
 	pusher.Start()
 
 	return func() {
-		bsp.Shutdown() // shutdown the processor
-		handleErr(exp.Shutdown(context.Background()), "failed to stop exporter")
+		ctx := context.Background()
+		_ = bsp.Shutdown(ctx) // shutdown the processor
+		handleErr(exp.Shutdown(ctx), "failed to stop exporter")
 		pusher.Stop() // pushes any last exports to the receiver
 	}
 }

sdk/trace/batch_span_processor.go

@@ -125,11 +125,23 @@ func (bsp *BatchSpanProcessor) OnEnd(sd *export.SpanData) {
 
 // Shutdown flushes the queue and waits until all spans are processed.
 // It only executes once. Subsequent call does nothing.
-func (bsp *BatchSpanProcessor) Shutdown() {
+func (bsp *BatchSpanProcessor) Shutdown(ctx context.Context) error {
+	var err error
 	bsp.stopOnce.Do(func() {
-		close(bsp.stopCh)
-		bsp.stopWait.Wait()
+		wait := make(chan struct{})
+		go func() {
+			close(bsp.stopCh)
+			bsp.stopWait.Wait()
+			close(wait)
+		}()
+		// Wait until the wait group is done or the context is cancelled
+		select {
+		case <-wait:
+		case <-ctx.Done():
+			err = ctx.Err()
+		}
 	})
+	return err
 }
 
 // ForceFlush exports all ended spans that have not yet been exported.

sdk/trace/batch_span_processor_test.go

@@ -65,7 +65,7 @@ func TestNewBatchSpanProcessorWithNilExporter(t *testing.T) {
 	bsp.OnStart(&export.SpanData{})
 	bsp.OnEnd(&export.SpanData{})
 	bsp.ForceFlush()
-	bsp.Shutdown()
+	_ = bsp.Shutdown(context.Background())
 }
 
 type testOption struct {
@@ -222,8 +222,8 @@ func getSpanContext() otel.SpanContext {
 func TestBatchSpanProcessorShutdown(t *testing.T) {
 	bsp := sdktrace.NewBatchSpanProcessor(&testBatchExporter{})
 
-	bsp.Shutdown()
+	_ = bsp.Shutdown(context.Background())
 
 	// Multiple call to Shutdown() should not panic.
-	bsp.Shutdown()
+	_ = bsp.Shutdown(context.Background())
 }

sdk/trace/provider.go

@@ -15,6 +15,7 @@
 package trace
 
 import (
+	"context"
 	"sync"
 	"sync/atomic"
 
@@ -141,7 +142,7 @@ func (p *TracerProvider) UnregisterSpanProcessor(s SpanProcessor) {
 	}
 	if stopOnce != nil {
 		stopOnce.state.Do(func() {
-			s.Shutdown()
+			_ = s.Shutdown(context.Background())
 		})
 	}
 	if len(new) > 1 {

sdk/trace/simple_span_processor.go

@@ -52,7 +52,8 @@ func (ssp *SimpleSpanProcessor) OnEnd(sd *export.SpanData) {
 }
 
 // Shutdown method does nothing. There is no data to cleanup.
-func (ssp *SimpleSpanProcessor) Shutdown() {
+func (ssp *SimpleSpanProcessor) Shutdown(_ context.Context) error {
+	return nil
 }
 
 // ForceFlush does nothing as there is no data to flush.

sdk/trace/simple_span_processor_test.go

@@ -84,5 +84,5 @@ func TestSimpleSpanProcessorShutdown(t *testing.T) {
 		t.Errorf("Error creating new instance of SimpleSpanProcessor\n")
 	}
 
-	ssp.Shutdown()
+	_ = ssp.Shutdown(context.Background())
 }

sdk/trace/span_processor.go

@@ -15,6 +15,7 @@
 package trace
 
 import (
+	"context"
 	"sync"
 
 	export "go.opentelemetry.io/otel/sdk/export/trace"
@@ -31,10 +32,10 @@ type SpanProcessor interface {
 	// and hence should not block.
 	OnEnd(sd *export.SpanData)
 
-	// Shutdown is invoked when SDK shutsdown. Use this call to cleanup any processor
+	// Shutdown is invoked when SDK shuts down. Use this call to cleanup any processor
 	// data. No calls to OnStart and OnEnd method is invoked after Shutdown call is
 	// made. It should not be blocked indefinitely.
-	Shutdown()
+	Shutdown(ctx context.Context) error
 
 	// ForceFlush exports all ended spans to the configured Exporter that have not yet
 	// been exported.  It should only be called when absolutely necessary, such as when

sdk/trace/span_processor_example_test.go

@@ -15,6 +15,7 @@
 package trace
 
 import (
+	"context"
 	"time"
 
 	export "go.opentelemetry.io/otel/sdk/export/trace"
@@ -33,9 +34,9 @@ type DurationFilter struct {
 	Max time.Duration
 }
 
-func (f DurationFilter) OnStart(sd *export.SpanData) { f.Next.OnStart(sd) }
-func (f DurationFilter) Shutdown()                   { f.Next.Shutdown() }
-func (f DurationFilter) ForceFlush()                 { f.Next.ForceFlush() }
+func (f DurationFilter) OnStart(sd *export.SpanData)        { f.Next.OnStart(sd) }
+func (f DurationFilter) Shutdown(ctx context.Context) error { return f.Next.Shutdown(ctx) }
+func (f DurationFilter) ForceFlush()                        { f.Next.ForceFlush() }
 func (f DurationFilter) OnEnd(sd *export.SpanData) {
 	if f.Min > 0 && sd.EndTime.Sub(sd.StartTime) < f.Min {
 		// Drop short lived spans.
@@ -59,9 +60,9 @@ type InstrumentationBlacklist struct {
 	Blacklist map[string]bool
 }
 
-func (f InstrumentationBlacklist) OnStart(sd *export.SpanData) { f.Next.OnStart(sd) }
-func (f InstrumentationBlacklist) Shutdown()                   { f.Next.Shutdown() }
-func (f InstrumentationBlacklist) ForceFlush()                 { f.Next.ForceFlush() }
+func (f InstrumentationBlacklist) OnStart(sd *export.SpanData)        { f.Next.OnStart(sd) }
+func (f InstrumentationBlacklist) Shutdown(ctx context.Context) error { return f.Next.Shutdown(ctx) }
+func (f InstrumentationBlacklist) ForceFlush()                        { f.Next.ForceFlush() }
 func (f InstrumentationBlacklist) OnEnd(sd *export.SpanData) {
 	if f.Blacklist != nil && f.Blacklist[sd.InstrumentationLibrary.Name] {
 		// Drop spans from this instrumentation

sdk/trace/span_processor_test.go

@@ -47,8 +47,9 @@ func (t *testSpanProcesor) OnEnd(s *export.SpanData) {
 	t.spansEnded = append(t.spansEnded, s)
 }
 
-func (t *testSpanProcesor) Shutdown() {
+func (t *testSpanProcesor) Shutdown(_ context.Context) error {
 	t.shutdownCount++
+	return nil
 }
 
 func (t *testSpanProcesor) ForceFlush() {
@@ -181,7 +182,7 @@ func TestSpanProcessorShutdown(t *testing.T) {
 	tp.RegisterSpanProcessor(sp)
 
 	wantCount := 1
-	sp.Shutdown()
+	_ = sp.Shutdown(context.Background())
 
 	gotCount := sp.shutdownCount
 	if wantCount != gotCount {