Remove context check on stdout exporters (#5189)

CHANGELOG.md

@@ -17,6 +17,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Changed
 
 - `go.opentelemetry.io/otel/exporters/stdout/stdoutlog` won't print timestamps when `WithoutTimestamps` option is set. (#5241)
+- The `Shutdown` method of `Exporter` in `go.opentelemetry.io/otel/exporters/stdout/stdouttrace` ignores the context cancellation and always returns `nil`. (#5189)
+- The `ForceFlush` and `Shutdown` methods of the exporter returned by `New` in `go.opentelemetry.io/otel/exporters/stdout/stdoutmetric` ignore the context cancellation and always return `nil`. (#5189)
 
 ## [1.26.0/0.48.0/0.2.0-alpha] 2024-04-24
 

exporters/stdout/stdoutmetric/exporter.go

@@ -51,12 +51,8 @@ func (e *exporter) Aggregation(k metric.InstrumentKind) metric.Aggregation {
 }
 
 func (e *exporter) Export(ctx context.Context, data *metricdata.ResourceMetrics) error {
-	select {
+	if err := ctx.Err(); err != nil {
-	case <-ctx.Done():
+		return err
-		// Don't do anything if the context has already timed out.
-		return ctx.Err()
-	default:
-		// Context is still valid, continue.
 	}
 	if e.redactTimestamps {
 		redactTimestamps(data)
@@ -67,18 +63,18 @@ func (e *exporter) Export(ctx context.Context, data *metricdata.ResourceMetrics)
 	return e.encVal.Load().(encoderHolder).Encode(data)
 }
 
-func (e *exporter) ForceFlush(ctx context.Context) error {
+func (e *exporter) ForceFlush(context.Context) error {
 	// exporter holds no state, nothing to flush.
-	return ctx.Err()
+	return nil
 }
 
-func (e *exporter) Shutdown(ctx context.Context) error {
+func (e *exporter) Shutdown(context.Context) error {
 	e.shutdownOnce.Do(func() {
 		e.encVal.Store(encoderHolder{
 			encoder: shutdownEncoder{},
 		})
 	})
-	return ctx.Err()
+	return nil
 }
 
 func (e *exporter) MarshalLog() interface{} {

exporters/stdout/stdoutmetric/exporter_test.go

@@ -28,8 +28,7 @@ func testEncoderOption() stdoutmetric.Option {
 func testCtxErrHonored(factory func(*testing.T) func(context.Context) error) func(t *testing.T) {
 	return func(t *testing.T) {
 		t.Helper()
-		ctx, cancel := context.WithCancel(context.Background())
+		ctx := context.Background()
-		t.Cleanup(cancel)
 
 		t.Run("DeadlineExceeded", func(t *testing.T) {
 			innerCtx, innerCancel := context.WithTimeout(ctx, time.Nanosecond)
@@ -55,19 +54,27 @@ func testCtxErrHonored(factory func(*testing.T) func(context.Context) error) fun
 	}
 }
 
-func TestExporterHonorsContextErrors(t *testing.T) {
+func testCtxErrIgnored(factory func(*testing.T) func(context.Context) error) func(t *testing.T) {
-	t.Run("Shutdown", testCtxErrHonored(func(t *testing.T) func(context.Context) error {
+	return func(t *testing.T) {
-		exp, err := stdoutmetric.New(testEncoderOption())
+		t.Helper()
-		require.NoError(t, err)
+		ctx := context.Background()
-		return exp.Shutdown
-	}))
 
-	t.Run("ForceFlush", testCtxErrHonored(func(t *testing.T) func(context.Context) error {
+		t.Run("Canceled Ignored", func(t *testing.T) {
-		exp, err := stdoutmetric.New(testEncoderOption())
+			innerCtx, innerCancel := context.WithCancel(ctx)
-		require.NoError(t, err)
+			innerCancel()
-		return exp.ForceFlush
-	}))
 
+			f := factory(t)
+			assert.NoError(t, f(innerCtx))
+		})
+
+		t.Run("NoError", func(t *testing.T) {
+			f := factory(t)
+			assert.NoError(t, f(ctx))
+		})
+	}
+}
+
+func TestExporterExportHonorsContextErrors(t *testing.T) {
 	t.Run("Export", testCtxErrHonored(func(t *testing.T) func(context.Context) error {
 		exp, err := stdoutmetric.New(testEncoderOption())
 		require.NoError(t, err)
@@ -78,6 +85,22 @@ func TestExporterHonorsContextErrors(t *testing.T) {
 	}))
 }
 
+func TestExporterForceFlushIgnoresContextErrors(t *testing.T) {
+	t.Run("ForceFlush", testCtxErrIgnored(func(t *testing.T) func(context.Context) error {
+		exp, err := stdoutmetric.New(testEncoderOption())
+		require.NoError(t, err)
+		return exp.ForceFlush
+	}))
+}
+
+func TestExporterShutdownIgnoresContextErrors(t *testing.T) {
+	t.Run("Shutdown", testCtxErrIgnored(func(t *testing.T) func(context.Context) error {
+		exp, err := stdoutmetric.New(testEncoderOption())
+		require.NoError(t, err)
+		return exp.Shutdown
+	}))
+}
+
 func TestShutdownExporterReturnsShutdownErrorOnExport(t *testing.T) {
 	var (
 		data     = new(metricdata.ResourceMetrics)

exporters/stdout/stdouttrace/trace.go

@@ -47,6 +47,9 @@ type Exporter struct {
 
 // ExportSpans writes spans in json format to stdout.
 func (e *Exporter) ExportSpans(ctx context.Context, spans []trace.ReadOnlySpan) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
 	e.stoppedMu.RLock()
 	stopped := e.stopped
 	e.stoppedMu.RUnlock()
@@ -88,11 +91,6 @@ func (e *Exporter) Shutdown(ctx context.Context) error {
 	e.stopped = true
 	e.stoppedMu.Unlock()
 
-	select {
-	case <-ctx.Done():
-		return ctx.Err()
-	default:
-	}
 	return nil
 }
 

exporters/stdout/stdouttrace/trace_test.go

@@ -60,30 +60,44 @@ func TestExporterExportSpan(t *testing.T) {
 	tests := []struct {
 		opts      []stdouttrace.Option
 		expectNow time.Time
+		ctx       context.Context
+		wantErr   error
 	}{
 		{
 			opts:      []stdouttrace.Option{stdouttrace.WithPrettyPrint()},
 			expectNow: now,
+			ctx:       context.Background(),
 		},
 		{
 			opts: []stdouttrace.Option{stdouttrace.WithPrettyPrint(), stdouttrace.WithoutTimestamps()},
 			// expectNow is an empty time.Time
+			ctx: context.Background(),
+		},
+		{
+			opts: []stdouttrace.Option{},
+			ctx: func() context.Context {
+				ctx, cancel := context.WithCancel(context.Background())
+				cancel()
+				return ctx
+			}(),
+			wantErr: context.Canceled,
 		},
 	}
 
-	ctx := context.Background()
 	for _, tt := range tests {
 		// write to buffer for testing
 		var b bytes.Buffer
 		ex, err := stdouttrace.New(append(tt.opts, stdouttrace.WithWriter(&b))...)
 		require.Nil(t, err)
 
-		err = ex.ExportSpans(ctx, tracetest.SpanStubs{ss, ss}.Snapshots())
+		err = ex.ExportSpans(tt.ctx, tracetest.SpanStubs{ss, ss}.Snapshots())
-		require.Nil(t, err)
+		assert.Equal(t, tt.wantErr, err)
 
-		got := b.String()
+		if tt.wantErr == nil {
-		wantone := expectedJSON(tt.expectNow)
+			got := b.String()
-		assert.Equal(t, wantone+wantone, got)
+			wantone := expectedJSON(tt.expectNow)
+			assert.Equal(t, wantone+wantone, got)
+		}
 	}
 }
 
@@ -181,23 +195,7 @@ func expectedJSON(now time.Time) string {
 `
 }
 
-func TestExporterShutdownHonorsTimeout(t *testing.T) {
+func TestExporterShutdownIgnoresContext(t *testing.T) {
-	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
-	defer cancel()
-
-	e, err := stdouttrace.New()
-	if err != nil {
-		t.Fatalf("failed to create exporter: %v", err)
-	}
-
-	innerCtx, innerCancel := context.WithTimeout(ctx, time.Nanosecond)
-	defer innerCancel()
-	<-innerCtx.Done()
-	err = e.Shutdown(innerCtx)
-	assert.ErrorIs(t, err, context.DeadlineExceeded)
-}
-
-func TestExporterShutdownHonorsCancel(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
 	defer cancel()
 
@@ -209,7 +207,7 @@ func TestExporterShutdownHonorsCancel(t *testing.T) {
 	innerCtx, innerCancel := context.WithCancel(ctx)
 	innerCancel()
 	err = e.Shutdown(innerCtx)
-	assert.ErrorIs(t, err, context.Canceled)
+	assert.NoError(t, err)
 }
 
 func TestExporterShutdownNoError(t *testing.T) {