grpc-ecosystem/grpc-gateway · error

no service %s found

Error message

no service %s found

What it means

Service-level options are checked against the set of fully-qualified service names built from registered files. If opts.Service names a service not found in that set, the registry returns this error rather than dropping the option silently.

Source

Thrown at internal/descriptor/registry.go:797

		qualifiedMethod := "." + opt.Method
		if _, ok := methods[qualifiedMethod]; !ok {
			return fmt.Errorf("no method %s found", opt.Method)
		}
		r.methodOptions[qualifiedMethod] = opt.Option
	}

	for _, opt := range opts.Message {
		qualifiedMessage := "." + opt.Message
		if _, ok := r.msgs[qualifiedMessage]; !ok {
			return fmt.Errorf("no message %s found", opt.Message)
		}
		r.messageOptions[qualifiedMessage] = opt.Option
	}

	for _, opt := range opts.Service {
		qualifiedService := "." + opt.Service
		if _, ok := services[qualifiedService]; !ok {
			return fmt.Errorf("no service %s found", opt.Service)
		}
		r.serviceOptions[qualifiedService] = opt.Option
	}

	// build map of all registered fields
	fields := make(map[string]struct{})
	for _, m := range r.msgs {
		for _, f := range m.Fields {
			fields[f.FQFN()] = struct{}{}
		}
	}
	for _, opt := range opts.Field {
		qualifiedField := "." + opt.Field
		if _, ok := fields[qualifiedField]; !ok {
			return fmt.Errorf("no field %s found", opt.Field)
		}
		r.fieldOptions[qualifiedField] = opt.Option
	}

View on GitHub (pinned to a58a4436a3)

Solutions

1. Use the fully-qualified service name: pkg.ServiceName
2. Ensure the .proto defining the service is in the load set
3. Sync your options file with the current proto definitions
4. Check for typos and correct package prefix

Example fix

// before
Service: "EchoService"
// after
Service: "grpc.gateway.examples.v1.EchoService"

want := "." + opt.Service
if !knownServices[want] {
    return fmt.Errorf("service %q not found; use pkg.Service", opt.Service)
}
err = reg.RegisterOptions(opts)

When it happens

Trigger: Registering options with opts.Service set to a service that is misspelled, lacks its package prefix, was removed/renamed, or whose defining file was not loaded.

Common situations: Options config copied from another API; service renamed in a major-version bump; running the generator only on a subset of protos while the options file still targets services from the full set.

Related errors

• no file %s found
• no method %s found
• no message %s found
• no field %s found
• no target service defined in the file

AI-assisted analysis of grpc-ecosystem/grpc-gateway@a58a4436a3 (2026-09-02). Data as JSON: /api/errors/0d303c8e54352bf0. Report an issue: GitHub.