Stackdriver exporter: Allow overriding client options via config

exporter/stackdriverexporter/config.go

@@ -17,6 +17,7 @@ package stackdriverexporter
 import (
 	"go.opentelemetry.io/collector/config/configmodels"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
+	"google.golang.org/api/option"
 )
 
 // Config defines configuration for Stackdriver exporter.
@@ -33,6 +34,11 @@ type Config struct {
 	// Timeout for all API calls. If not set, defaults to 12 seconds.
 	exporterhelper.TimeoutSettings `mapstructure:",squash"` // squash ensures fields are correctly decoded in embedded struct.
 	ResourceMappings               []ResourceMapping        `mapstructure:"resource_mappings"`
+	// GetClientOptions returns additional options to be passed
+	// to the underlying Google Cloud API client.
+	// Must be set programmatically (no support via declarative config).
+	// Optional.
+	GetClientOptions func() []option.ClientOption
 }
 
 // ResourceMapping defines mapping of resources from source (OpenCensus) to target (Stackdriver).

exporter/stackdriverexporter/stackdriver.go

@@ -65,16 +65,29 @@ func (me *metricsExporter) Shutdown(context.Context) error {
 	return nil
 }
 
-func generateClientOptions(cfg *Config, dialOpts ...grpc.DialOption) ([]option.ClientOption, error) {
+func generateClientOptions(cfg *Config, userAgent string) ([]option.ClientOption, error) {
 	var copts []option.ClientOption
-	if cfg.UseInsecure {
-		conn, err := grpc.Dial(cfg.Endpoint, append(dialOpts, grpc.WithInsecure())...)
-		if err != nil {
-			return nil, fmt.Errorf("cannot configure grpc conn: %w", err)
+	if userAgent != "" {
+		copts = append(copts, option.WithUserAgent(userAgent))
+	}
+	if cfg.Endpoint != "" {
+		if cfg.UseInsecure {
+			// WithGRPCConn option takes precedent over all other supplied options so need to provide user agent here as well
+			var dialOpts []grpc.DialOption
+			if userAgent != "" {
+				dialOpts = append(dialOpts, grpc.WithUserAgent(userAgent))
+			}
+			conn, err := grpc.Dial(cfg.Endpoint, append(dialOpts, grpc.WithInsecure())...)
+			if err != nil {
+				return nil, fmt.Errorf("cannot configure grpc conn: %w", err)
+			}
+			copts = append(copts, option.WithGRPCConn(conn))
+		} else {
+			copts = append(copts, option.WithEndpoint(cfg.Endpoint))
 		}
-		copts = append(copts, option.WithGRPCConn(conn))
-	} else {
-		copts = append(copts, option.WithEndpoint(cfg.Endpoint))
+	}
+	if cfg.GetClientOptions != nil {
+		copts = append(copts, cfg.GetClientOptions()...)
 	}
 	return copts, nil
 }
@@ -84,13 +97,11 @@ func newStackdriverTraceExporter(cfg *Config) (component.TraceExporter, error) {
 		cloudtrace.WithProjectID(cfg.ProjectID),
 		cloudtrace.WithTimeout(cfg.Timeout),
 	}
-	if cfg.Endpoint != "" {
-		copts, err := generateClientOptions(cfg)
-		if err != nil {
-			return nil, err
-		}
-		topts = append(topts, cloudtrace.WithTraceClientOptions(copts))
+	copts, err := generateClientOptions(cfg, "")
+	if err != nil {
+		return nil, err
 	}
+	topts = append(topts, cloudtrace.WithTraceClientOptions(copts))
 	if cfg.NumOfWorkers > 0 {
 		topts = append(topts, cloudtrace.WithMaxNumberOfWorkers(cfg.NumOfWorkers))
 	}
@@ -126,21 +137,12 @@ func newStackdriverMetricsExporter(cfg *Config, version string) (component.Metri
 	}
 
 	userAgent := strings.ReplaceAll(cfg.UserAgent, "{{version}}", version)
-	if cfg.Endpoint != "" {
-		// WithGRPCConn option takes precedent over all other supplied options so need to provide user agent here as well
-		dialOpts := []grpc.DialOption{}
-		if userAgent != "" {
-			dialOpts = append(dialOpts, grpc.WithUserAgent(userAgent))
-		}
-
-		copts, err := generateClientOptions(cfg, dialOpts...)
-		if err != nil {
-			return nil, err
-		}
-		options.TraceClientOptions = copts
-		options.MonitoringClientOptions = copts
+	copts, err := generateClientOptions(cfg, userAgent)
+	if err != nil {
+		return nil, err
 	}
-	options.MonitoringClientOptions = append(options.MonitoringClientOptions, option.WithUserAgent(options.UserAgent))
+	options.TraceClientOptions = copts
+	options.MonitoringClientOptions = copts
 
 	if cfg.NumOfWorkers > 0 {
 		options.NumberOfWorkers = cfg.NumOfWorkers

exporter/stackdriverexporter/stackdriver_test.go

@@ -29,6 +29,7 @@ import (
 	"go.opentelemetry.io/collector/consumer/pdata"
 	"go.opentelemetry.io/collector/testutil/metricstestutil"
 	"go.opentelemetry.io/collector/translator/internaldata"
+	"google.golang.org/api/option"
 	cloudmetricpb "google.golang.org/genproto/googleapis/api/metric"
 	cloudtracepb "google.golang.org/genproto/googleapis/devtools/cloudtrace/v2"
 	cloudmonitoringpb "google.golang.org/genproto/googleapis/monitoring/v3"
@@ -144,7 +145,21 @@ func TestStackdriverMetricExport(t *testing.T) {
 
 	go srv.Serve(lis)
 
-	sde, err := newStackdriverMetricsExporter(&Config{ProjectID: "idk", Endpoint: "127.0.0.1:8080", UserAgent: "MyAgent {{version}}", UseInsecure: true}, "v0.0.1")
+	// Example with overridden client options
+	clientOptions := []option.ClientOption{
+		option.WithoutAuthentication(),
+		option.WithTelemetryDisabled(),
+	}
+
+	sde, err := newStackdriverMetricsExporter(&Config{
+		ProjectID: "idk",
+		Endpoint: "127.0.0.1:8080",
+		UserAgent: "MyAgent {{version}}",
+		UseInsecure: true,
+		GetClientOptions: func() []option.ClientOption {
+			 return clientOptions
+		},
+	}, "v0.0.1")
 	require.NoError(t, err)
 	defer func() { require.NoError(t, sde.Shutdown(context.Background())) }()