Fix flaky test TestSimpleSpanProcessorShutdownHonorsContextCancel

CHANGELOG.md

@@ -23,6 +23,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Adds `otlptracegrpc.WithGRPCConn` and `otlpmetricgrpc.WithGRPCConn` for reusing existing gRPC connection. (#2002)
 - Added a new `schema` module to help parse Schema Files in OTEP 0152 format. (#2267)
 
+### Fixed
+
+- The simple span processor shutdown method deterministically returns the exporter error status if it simultaneously finishes when the deadline is reached. (#2290, #2289)
+
 ## [1.0.1] - 2021-10-01
 
 ### Fixed

sdk/trace/simple_span_processor.go

@@ -91,7 +91,17 @@ func (ssp *simpleSpanProcessor) Shutdown(ctx context.Context) error {
 		select {
 		case err = <-done:
 		case <-ctx.Done():
-			err = ctx.Err()
+			// It is possible for the exporter to have immediately shut down
+			// and the context to already be done. In that case this select
+			// statement will randomly choose a case. This could result in a
+			// different response for similar scenarios. Instead, double check
+			// if the exporter shut down at the same time and return that
+			// error if so.
+			if expErr, ok := <-done; ok {
+				err = expErr
+			} else {
+				err = ctx.Err()
+			}
 		}
 	})
 	return err

sdk/trace/simple_span_processor_test.go

@@ -40,9 +40,15 @@ func (t *testExporter) ExportSpans(ctx context.Context, spans []sdktrace.ReadOnl
 	return nil
 }
 
-func (t *testExporter) Shutdown(context.Context) error {
+func (t *testExporter) Shutdown(ctx context.Context) error {
 	t.shutdown = true
-	return nil
+	select {
+	case <-ctx.Done():
+		// Ensure context deadline tests receive the expected error.
+		return ctx.Err()
+	default:
+		return nil
+	}
 }
 
 var _ sdktrace.SpanExporter = (*testExporter)(nil)