Send configured headers with every request

exporters/otlp/README.md

@@ -92,7 +92,7 @@ Some compressors auto-register on import, such as gzip, which can be registered
 
 ### `WithHeaders(headers map[string]string)`
 
-Headers to send when the gRPC stream connection is instantiated.
+Headers to send with gRPC requests.
 
 ### `WithTLSCredentials(creds "google.golang.org/grpc/credentials".TransportCredentials)`
 

exporters/otlp/mock_collector_test.go

@@ -24,6 +24,7 @@ import (
 	"time"
 
 	"google.golang.org/grpc"
+	metadata "google.golang.org/grpc/metadata"
 
 	colmetricpb "github.com/open-telemetry/opentelemetry-proto/gen/go/collector/metrics/v1"
 	coltracepb "github.com/open-telemetry/opentelemetry-proto/gen/go/collector/trace/v1"
@@ -44,8 +45,13 @@ func makeMockCollector(t *testing.T) *mockCol {
 }
 
 type mockTraceService struct {
-	mu  sync.RWMutex
-	rsm map[string]*tracepb.ResourceSpans
+	mu      sync.RWMutex
+	rsm     map[string]*tracepb.ResourceSpans
+	headers metadata.MD
+}
+
+func (mts *mockTraceService) getHeaders() metadata.MD {
+	return mts.headers
 }
 
 func (mts *mockTraceService) getSpans() []*tracepb.Span {
@@ -70,6 +76,7 @@ func (mts *mockTraceService) getResourceSpans() []*tracepb.ResourceSpans {
 
 func (mts *mockTraceService) Export(ctx context.Context, exp *coltracepb.ExportTraceServiceRequest) (*coltracepb.ExportTraceServiceResponse, error) {
 	mts.mu.Lock()
+	mts.headers, _ = metadata.FromIncomingContext(ctx)
 	defer mts.mu.Unlock()
 	rss := exp.GetResourceSpans()
 	for _, rs := range rss {
@@ -192,6 +199,10 @@ func (mc *mockCol) getResourceSpans() []*tracepb.ResourceSpans {
 	return mc.traceSvc.getResourceSpans()
 }
 
+func (mc *mockCol) getHeaders() metadata.MD {
+	return mc.traceSvc.getHeaders()
+}
+
 func (mc *mockCol) getMetrics() []*metricpb.Metric {
 	return mc.metricSvc.getMetrics()
 }

exporters/otlp/options.go

@@ -122,8 +122,7 @@ func WithCompressor(compressor string) ExporterOption {
 	}
 }
 
-// WithHeaders will send the provided headers when the gRPC stream connection
-// is instantiated.
+// WithHeaders will send the provided headers with gRPC requests
 func WithHeaders(headers map[string]string) ExporterOption {
 	return func(cfg *Config) {
 		cfg.headers = headers

exporters/otlp/otlp.go

@@ -50,7 +50,8 @@ type Exporter struct {
 
 	backgroundConnectionDoneCh chan bool
 
-	c Config
+	c        Config
+	metadata metadata.MD
 }
 
 var _ tracesdk.SpanBatcher = (*Exporter)(nil)
@@ -77,6 +78,9 @@ func NewUnstartedExporter(opts ...ExporterOption) *Exporter {
 		grpcServiceConfig: DefaultGRPCServiceConfig,
 	}
 	configureOptions(&e.c, opts...)
+	if len(e.c.headers) > 0 {
+		e.metadata = metadata.New(e.c.headers)
+	}
 
 	// TODO (rghetia): add resources
 
@@ -178,8 +182,8 @@ func (e *Exporter) dialToCollector() (*grpc.ClientConn, error) {
 	}
 
 	ctx := context.Background()
-	if len(e.c.headers) > 0 {
-		ctx = metadata.NewOutgoingContext(ctx, metadata.New(e.c.headers))
+	if e.metadata.Len() > 0 {
+		ctx = metadata.NewOutgoingContext(ctx, e.metadata)
 	}
 	return grpc.DialContext(ctx, addr, dialOpts...)
 }
@@ -245,6 +249,9 @@ func (e *Exporter) Export(parent context.Context, cps metricsdk.CheckpointSet) e
 	case <-ctx.Done():
 		return errContextCanceled
 	default:
+		if e.metadata.Len() > 0 {
+			ctx = metadata.NewOutgoingContext(ctx, e.metadata)
+		}
 		e.senderMu.Lock()
 		_, err := e.metricExporter.Export(ctx, &colmetricpb.ExportMetricsServiceRequest{
 			ResourceMetrics: rms,
@@ -280,6 +287,9 @@ func (e *Exporter) uploadTraces(ctx context.Context, sdl []*tracesdk.SpanData) {
 			return
 		}
 
+		if e.metadata.Len() > 0 {
+			ctx = metadata.NewOutgoingContext(ctx, e.metadata)
+		}
 		e.senderMu.Lock()
 		_, err := e.traceExporter.Export(ctx, &coltracepb.ExportTraceServiceRequest{
 			ResourceSpans: protoSpans,

exporters/otlp/otlp_integration_test.go

@@ -400,3 +400,27 @@ func TestNewExporter_withAddress(t *testing.T) {
 		t.Fatalf("Unexpected Start error: %v", err)
 	}
 }
+
+func TestNewExporter_withHeaders(t *testing.T) {
+	mc := runMockCol(t)
+	defer func() {
+		_ = mc.stop()
+	}()
+
+	exp, _ := otlp.NewExporter(
+		otlp.WithInsecure(),
+		otlp.WithReconnectionPeriod(50*time.Millisecond),
+		otlp.WithAddress(mc.address),
+		otlp.WithHeaders(map[string]string{"header1": "value1"}),
+	)
+	exp.ExportSpans(context.Background(), []*exporttrace.SpanData{{Name: "in the midst"}})
+
+	defer func() {
+		_ = exp.Stop()
+	}()
+
+	headers := mc.getHeaders()
+	assert.Equal(t, 1, len(headers.Get("header1")))
+	assert.Equal(t, "value1", headers.Get("header1")[0])
+
+}