Shutdown underlying span exporter while shutting down BatchSpanProcessor (open-telemetry#1443)

* Fix BatchSpanProcessor does not shutdown underlying span exporter

* Update CHANGELOG

* Fix tests

* Update CHANGELOG.md

Author: XSAM

CHANGELOG.md

@@ -47,6 +47,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Remove Metric export functionality related to quantiles and summary data points: this is not specified (#1412)
 - Remove DDSketch metric aggregator; our intention is to re-introduce this as an option of the histogram aggregator after [new OTLP histogram data types](https://github.com/open-telemetry/opentelemetry-proto/pull/226) are released (#1412)
 
+### Fixed
+
+- `BatchSpanProcessor.Shutdown()` will now shutdown underlying `export.SpanExporter`. (#1443)
+
 ## [0.15.0] - 2020-12-10
 
 ### Added

sdk/trace/batch_span_processor.go

@@ -132,6 +132,11 @@ func (bsp *BatchSpanProcessor) Shutdown(ctx context.Context) error {
 		go func() {
 			close(bsp.stopCh)
 			bsp.stopWait.Wait()
+			if bsp.e != nil {
+				if err := bsp.e.Shutdown(ctx); err != nil {
+					otel.Handle(err)
+				}
+			}
 			close(wait)
 		}()
 		// Wait until the wait group is done or the context is cancelled

sdk/trace/batch_span_processor_test.go

@@ -21,17 +21,20 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
+
 	"go.opentelemetry.io/otel/trace"
 
 	export "go.opentelemetry.io/otel/sdk/export/trace"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 )
 
 type testBatchExporter struct {
-	mu         sync.Mutex
-	spans      []*export.SpanSnapshot
-	sizes      []int
-	batchCount int
+	mu            sync.Mutex
+	spans         []*export.SpanSnapshot
+	sizes         []int
+	batchCount    int
+	shutdownCount int
 }
 
 func (t *testBatchExporter) ExportSpans(ctx context.Context, ss []*export.SpanSnapshot) error {
@@ -44,7 +47,10 @@ func (t *testBatchExporter) ExportSpans(ctx context.Context, ss []*export.SpanSn
 	return nil
 }
 
-func (t *testBatchExporter) Shutdown(context.Context) error { return nil }
+func (t *testBatchExporter) Shutdown(context.Context) error {
+	t.shutdownCount++
+	return nil
+}
 
 func (t *testBatchExporter) len() int {
 	t.mu.Lock()
@@ -231,16 +237,19 @@ func getSpanContext() trace.SpanContext {
 }
 
 func TestBatchSpanProcessorShutdown(t *testing.T) {
-	bsp := sdktrace.NewBatchSpanProcessor(&testBatchExporter{})
+	var bp testBatchExporter
+	bsp := sdktrace.NewBatchSpanProcessor(&bp)
 
 	err := bsp.Shutdown(context.Background())
 	if err != nil {
 		t.Error("Error shutting the BatchSpanProcessor down\n")
 	}
+	assert.Equal(t, 1, bp.shutdownCount, "shutdown from span exporter not called")
 
 	// Multiple call to Shutdown() should not panic.
 	err = bsp.Shutdown(context.Background())
 	if err != nil {
 		t.Error("Error shutting the BatchSpanProcessor down\n")
 	}
+	assert.Equal(t, 1, bp.shutdownCount)
 }