unsupported exporter protocol %q, only %q and %q are support

Error message

unsupported exporter protocol %q, only %q and %q are supported

What it means

Validate's exporter-protocol subcheck found K6_OTEL_EXPORTER_PROTOCOL set to a value other than the two supported protocols ("grpc" and "http/protobuf"). This is a sentinel-style guard on the protocol string.

Source

Thrown at internal/output/opentelemetry/config.go:226

func (cfg Config) Validate() error {
	if cfg.ServiceName.String == "" {
		return errors.New("providing service name is required")
	}
	// TODO: it's not actually required, but we should probably have a default
	// check if it works without it
	if cfg.ServiceVersion.String == "" {
		return errors.New("providing service version is required")
	}
	if err := cfg.validateExporterProtocol(); err != nil {
		return err
	}
	return nil
}

func (cfg Config) validateExporterProtocol() error {
	if cfg.ExporterProtocol.String != "" {
		if cfg.ExporterProtocol.String != grpcExporterProtocol && cfg.ExporterProtocol.String != httpExporterProtocol {
			return fmt.Errorf(
				"unsupported exporter protocol %q, only %q and %q are supported",
				cfg.ExporterProtocol.String,
				grpcExporterProtocol,
				httpExporterProtocol,
			)
		}
		switch cfg.ExporterProtocol.String {
		case grpcExporterProtocol:
			if cfg.GRPCExporterEndpoint.String == "" {
				return errors.New("gRPC exporter endpoint is required")
			}
		case httpExporterProtocol:
			endpoint := cfg.HTTPExporterEndpoint.String
			if endpoint == "" {
				return errors.New("HTTP exporter endpoint is required")
			}

			if strings.HasPrefix(endpoint, "http://") ||

View on GitHub (pinned to 01ffac6f24)

Solutions

Set K6_OTEL_EXPORTER_PROTOCOL=grpc or K6_OTEL_EXPORTER_PROTOCOL=http/protobuf
Unset the variable to use the default protocol

Defensive patterns

Strategy: validation

When it happens

Trigger: Thrown at internal/output/opentelemetry/config.go:226 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/5969d5c3898cfcee. Report an issue: GitHub.