Add ExportTimeout option to batch span processor (#1755)

* Add ExportTimeout option

* Adjust tests

* Update CHANGELOG

* Beef up the exporter timeout test

* Beef up exporter test - attempt #2

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Added
 
+- Option `ExportTimeout` was added to batch span processor. (#1755)
 - Adds semantic conventions for exceptions. (#1492)
 - Added support for configuring OTLP/HTTP Endpoints, Headers, Compression and Timeout via the Environment Variables. (#1758)
   - `OTEL_EXPORTER_OTLP_ENDPOINT`

sdk/trace/batch_span_processor.go

@@ -28,6 +28,7 @@ import (
 const (
 	DefaultMaxQueueSize       = 2048
 	DefaultBatchTimeout       = 5000 * time.Millisecond
+	DefaultExportTimeout      = 30000 * time.Millisecond
 	DefaultMaxExportBatchSize = 512
 )
 
@@ -44,6 +45,11 @@ type BatchSpanProcessorOptions struct {
 	// The default value of BatchTimeout is 5000 msec.
 	BatchTimeout time.Duration
 
+	// ExportTimeout specifies the maximum duration for exporting spans. If the timeout
+	// is reached, the export will be cancelled.
+	// The default value of ExportTimeout is 30000 msec.
+	ExportTimeout time.Duration
+
 	// MaxExportBatchSize is the maximum number of spans to process in a single batch.
 	// If there are more than one batch worth of spans then it processes multiple batches
 	// of spans one batch after the other without any delay.
@@ -83,6 +89,7 @@ var _ SpanProcessor = (*batchSpanProcessor)(nil)
 func NewBatchSpanProcessor(exporter export.SpanExporter, options ...BatchSpanProcessorOption) SpanProcessor {
 	o := BatchSpanProcessorOptions{
 		BatchTimeout:       DefaultBatchTimeout,
+		ExportTimeout:      DefaultExportTimeout,
 		MaxQueueSize:       DefaultMaxQueueSize,
 		MaxExportBatchSize: DefaultMaxExportBatchSize,
 	}
@@ -185,6 +192,12 @@ func WithBatchTimeout(delay time.Duration) BatchSpanProcessorOption {
 	}
 }
 
+func WithExportTimeout(timeout time.Duration) BatchSpanProcessorOption {
+	return func(o *BatchSpanProcessorOptions) {
+		o.ExportTimeout = timeout
+	}
+}
+
 func WithBlocking() BatchSpanProcessorOption {
 	return func(o *BatchSpanProcessorOptions) {
 		o.BlockOnQueueFull = true
@@ -198,6 +211,12 @@ func (bsp *batchSpanProcessor) exportSpans(ctx context.Context) error {
 	bsp.batchMutex.Lock()
 	defer bsp.batchMutex.Unlock()
 
+	if bsp.o.ExportTimeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, bsp.o.ExportTimeout)
+		defer cancel()
+	}
+
 	if len(bsp.batch) > 0 {
 		if err := bsp.e.ExportSpans(ctx, bsp.batch); err != nil {
 			return err

sdk/trace/batch_span_processor_test.go

@@ -36,12 +36,23 @@ type testBatchExporter struct {
 	sizes         []int
 	batchCount    int
 	shutdownCount int
+	delay         time.Duration
+	err           error
 }
 
 func (t *testBatchExporter) ExportSpans(ctx context.Context, ss []*export.SpanSnapshot) error {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 
+	time.Sleep(t.delay)
+
+	select {
+	case <-ctx.Done():
+		t.err = ctx.Err()
+		return ctx.Err()
+	default:
+	}
+
 	t.spans = append(t.spans, ss...)
 	t.sizes = append(t.sizes, len(ss))
 	t.batchCount++
@@ -88,16 +99,19 @@ func TestNewBatchSpanProcessorWithNilExporter(t *testing.T) {
 }
 
 type testOption struct {
-	name           string
-	o              []sdktrace.BatchSpanProcessorOption
-	wantNumSpans   int
-	wantBatchCount int
-	genNumSpans    int
-	parallel       bool
+	name              string
+	o                 []sdktrace.BatchSpanProcessorOption
+	wantNumSpans      int
+	wantBatchCount    int
+	wantExportTimeout bool
+	genNumSpans       int
+	delayExportBy     time.Duration
+	parallel          bool
 }
 
 func TestNewBatchSpanProcessorWithOptions(t *testing.T) {
 	schDelay := 200 * time.Millisecond
+	exportTimeout := time.Millisecond
 	options := []testOption{
 		{
 			name:           "default BatchSpanProcessorOptions",
@@ -105,6 +119,15 @@ func TestNewBatchSpanProcessorWithOptions(t *testing.T) {
 			wantBatchCount: 4,
 			genNumSpans:    2053,
 		},
+		{
+			name: "non-default ExportTimeout",
+			o: []sdktrace.BatchSpanProcessorOption{
+				sdktrace.WithExportTimeout(exportTimeout),
+			},
+			wantExportTimeout: true,
+			genNumSpans:       2053,
+			delayExportBy:     2 * exportTimeout, // to ensure export timeout
+		},
 		{
 			name: "non-default BatchTimeout",
 			o: []sdktrace.BatchSpanProcessorOption{
@@ -171,7 +194,9 @@ func TestNewBatchSpanProcessorWithOptions(t *testing.T) {
 	}
 	for _, option := range options {
 		t.Run(option.name, func(t *testing.T) {
-			te := testBatchExporter{}
+			te := testBatchExporter{
+				delay: option.delayExportBy,
+			}
 			tp := basicTracerProvider(t)
 			ssp := createAndRegisterBatchSP(option, &te)
 			if ssp == nil {
@@ -185,17 +210,22 @@ func TestNewBatchSpanProcessorWithOptions(t *testing.T) {
 			tp.UnregisterSpanProcessor(ssp)
 
 			gotNumOfSpans := te.len()
-			if option.wantNumSpans != gotNumOfSpans {
+			if option.wantNumSpans > 0 && option.wantNumSpans != gotNumOfSpans {
 				t.Errorf("number of exported span: got %+v, want %+v\n",
 					gotNumOfSpans, option.wantNumSpans)
 			}
 
 			gotBatchCount := te.getBatchCount()
-			if gotBatchCount < option.wantBatchCount {
+			if option.wantBatchCount > 0 && gotBatchCount < option.wantBatchCount {
 				t.Errorf("number batches: got %+v, want >= %+v\n",
 					gotBatchCount, option.wantBatchCount)
 				t.Errorf("Batches %v\n", te.sizes)
 			}
+
+			if option.wantExportTimeout && te.err != context.DeadlineExceeded {
+				t.Errorf("context deadline: got err %+v, want %+v\n",
+					te.err, context.DeadlineExceeded)
+			}
 		})
 	}
 }