Function AddService

micro/service.go:325–401

AddService adds a microservice. It will enable internal common services (PING, STATS and INFO). Request handlers have to be registered separately using Service.AddEndpoint. A service name, version and Endpoint configuration are required to add a service. AddService returns a [Service] interface, all

(nc *nats.Conn, config Config)

// AddService returns a [Service] interface, allowing service management.
// Each service is assigned a unique ID.
func AddService(nc *nats.Conn, config Config) (Service, error) {
	if err := config.valid(); err != nil {
		return nil, err
	}

	if config.Metadata == nil {
		config.Metadata = map[string]string{}
	}

	id := nuid.Next()
	svc := &service{
		Config: config,
		nc:     nc,
		id:     id,
		asyncDispatcher: asyncCallbacksHandler{
			cbQueue: make(chan func(), 100),
		},
		verbSubs:  make(map[string]*nats.Subscription),
		endpoints: make([]*Endpoint, 0),
	}

	// Add connection event (closed, error) wrapper handlers. If the service has
	// custom callbacks, the events are queued and invoked by the same
	// goroutine, starting now.
	go svc.asyncDispatcher.run()
	svc.wrapConnectionEventCallbacks()

	if config.Endpoint != nil {
		opts := []EndpointOpt{WithEndpointSubject(config.Endpoint.Subject)}
		if config.Endpoint.Metadata != nil {
			opts = append(opts, WithEndpointMetadata(config.Endpoint.Metadata))
		}
		if config.Endpoint.QueueGroup != "" {
			opts = append(opts, WithEndpointQueueGroup(config.Endpoint.QueueGroup))
		} else if config.QueueGroup != "" {
			opts = append(opts, WithEndpointQueueGroup(config.QueueGroup))
		}
		if err := svc.AddEndpoint("default", config.Endpoint.Handler, opts...); err != nil {
			svc.asyncDispatcher.close()
			return nil, err
		}
	}

	// Setup internal subscriptions.
	pingResponse := Ping{
		ServiceIdentity: svc.serviceIdentity(),
		Type:            PingResponseType,
	}

	handleVerb := func(verb Verb, valuef func() any) func(req Request) {
		return func(req Request) {
			response, _ := json.Marshal(valuef())
			if err := req.Respond(response); err != nil {
				if err := req.Error("500", fmt.Sprintf("Error handling %s request: %s", verb, err), nil); err != nil && config.ErrorHandler != nil {
					svc.asyncDispatcher.push(func() {
						config.ErrorHandler(svc, &NATSError{Subject: req.Subject(), Description: err.Error(), err: err})
					})
				}