Use the otel ErrorHandler for handling errors.

exporter/trace/cloudtrace.go

@@ -19,9 +19,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"log"
 	"time"
 
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 
@@ -45,11 +45,21 @@ type options struct {
 	// project, e.g. on-premise resource like k8s_container or generic_task.
 	ProjectID string
 
+	// Location is the identifier of the GCP or AWS cloud region/zone in which
+	// the data for a resource is stored.
+	// If not set, it will default to the location provided by the metadata server.
+	//
+	// It will be used in the location label of a Stackdriver monitored resource
+	// if the resource does not inherently belong to a specific project, e.g.
+	// on-premise resource like k8s_container or generic_task.
+	Location string
+
 	// OnError is the hook to be called when there is
 	// an error uploading the stats or tracing data.
-	// If no custom hook is set, errors are logged.
+	// If no custom hook is set, errors are handled with the
+	// OpenTelemetry global handler, which defaults to logging.
 	// Optional.
-	OnError func(err error)
+	errorHandler otel.ErrorHandler
 
 	// TraceClientOptions are additional options to be passed
 	// to the underlying Stackdriver Trace API client.
@@ -86,12 +96,12 @@ func WithProjectID(projectID string) func(o *options) {
 	}
 }
 
-// WithOnError sets the hook to be called when there is an error
+// WithErrorHandler sets the hook to be called when there is an error
 // occurred on uploading the span data to Stackdriver.
 // If no custom hook is set, errors are logged.
-func WithOnError(onError func(err error)) func(o *options) {
+func WithErrorHandler(handler otel.ErrorHandler) func(o *options) {
 	return func(o *options) {
-		o.OnError = onError
+		o.errorHandler = handler
 	}
 }
 
@@ -118,11 +128,11 @@ func WithTimeout(t time.Duration) func(o *options) {
 }
 
 func (o *options) handleError(err error) {
-	if o.OnError != nil {
-		o.OnError(err)
+	if o.errorHandler != nil {
+		o.errorHandler.Handle(err)
 		return
 	}
-	log.Printf("Failed to export to Stackdriver: %v", err)
+	otel.Handle(err)
 }
 
 // defaultTimeout is used as default when timeout is not set in newContextWithTimout.

exporter/trace/cloudtrace_test.go

@@ -82,22 +82,29 @@ func TestExporter_ExportSpan(t *testing.T) {
 	assert.Len(t, mock.GetSpan(1).Links.Link, 1)
 }
 
+type errorHandler struct {
+	errs []error
+}
+
+func (e *errorHandler) Handle(err error) {
+	e.errs = append(e.errs, err)
+}
+
 func TestExporter_Timeout(t *testing.T) {
 	// Initial test precondition
 	mock := cloudmock.NewCloudMock()
 	mock.SetDelay(20 * time.Millisecond)
 	clientOpt := []option.ClientOption{option.WithGRPCConn(mock.ClientConn())}
-	var exportErrors []error
+	handler := &errorHandler{}
 
 	// Create Google Cloud Trace Exporter
 	exporter, err := New(
 		WithProjectID("PROJECT_ID_NOT_REAL"),
 		WithTraceClientOptions(clientOpt),
 		WithTimeout(1*time.Millisecond),
 		// handle bundle as soon as span is received
-		WithOnError(func(err error) {
-			exportErrors = append(exportErrors, err)
-		}))
+		WithErrorHandler(handler),
+	)
 	assert.NoError(t, err)
 	tp := sdktrace.NewTracerProvider(
 		sdktrace.WithSampler(sdktrace.AlwaysSample()),
@@ -113,10 +120,10 @@ func TestExporter_Timeout(t *testing.T) {
 	// wait for error to be handled
 	shutdown() // closed grpc connection
 	assert.EqualValues(t, 0, mock.GetNumSpans())
-	if got, want := len(exportErrors), 1; got != want {
+	if got, want := len(handler.errs), 1; got != want {
 		t.Fatalf("len(exportErrors) = %q; want %q", got, want)
 	}
-	got, want := exportErrors[0].Error(), "rpc error: code = (DeadlineExceeded|Unknown) desc = context deadline exceeded"
+	got, want := handler.errs[0].Error(), "rpc error: code = (DeadlineExceeded|Unknown) desc = context deadline exceeded"
 	if match, _ := regexp.MatchString(want, got); !match {
 		t.Fatalf("err.Error() = %q; want %q", got, want)
 	}

exporter/trace/trace.go

@@ -98,7 +98,7 @@ func (e *traceExporter) uploadSpans(ctx context.Context, spans []*tracepb.Span)
 	if err != nil {
 		// TODO(ymotongpoo): handle detailed error categories
 		// span.SetStatus(codes.Unknown)
-		e.o.handleError(err)
+		e.o.handleError(fmt.Errorf("failed to export to Google Cloud Monitoring: %w", err))
 	}
 	return err
 }