Golang Queue Examples

Example #1

File: consumer.go Project: ZhuJingfa/go-micro

// Example of a shared subscription which receives a subset of messages
func sharedSub() {
	_, err := broker.Subscribe(topic, func(p broker.Publication) error {
		fmt.Println("[sub] received message:", string(p.Message().Body), "header", p.Message().Header)
		return nil
	}, broker.Queue("consumer"))
	if err != nil {
		fmt.Println(err)
	}
}

Example #2

File: broker.go Project: Zerak/micro

func (c *conn) writeLoop() {
	ticker := time.NewTicker(pingTime)

	var opts []broker.SubscribeOption

	if len(c.queue) > 0 {
		opts = append(opts, broker.Queue(c.queue))
	}

	subscriber, err := (*cmd.DefaultOptions().Broker).Subscribe(c.topic, func(p broker.Publication) error {
		b, err := json.Marshal(p.Message())
		if err != nil {
			return nil
		}
		return c.write(websocket.TextMessage, b)
	}, opts...)

	defer func() {
		subscriber.Unsubscribe()
		ticker.Stop()
		c.ws.Close()
	}()

	if err != nil {
		log.Print(err.Error())
		return
	}

	for {
		select {
		case <-ticker.C:
			if err := c.write(websocket.PingMessage, []byte{}); err != nil {
				return
			}
		case <-c.exit:
			return
		}
	}
}

Example #3

File: rpc_server.go Project: ZhuJingfa/go-micro

func (s *rpcServer) Register() error {
	// parse address for host, port
	config := s.Options()
	var advt, host string
	var port int

	// check the advertise address first
	// if it exists then use it, otherwise
	// use the address
	if len(config.Advertise) > 0 {
		advt = config.Advertise
	} else {
		advt = config.Address
	}

	parts := strings.Split(advt, ":")
	if len(parts) > 1 {
		host = strings.Join(parts[:len(parts)-1], ":")
		port, _ = strconv.Atoi(parts[len(parts)-1])
	} else {
		host = parts[0]
	}

	addr, err := extractAddress(host)
	if err != nil {
		return err
	}

	// register service
	node := &registry.Node{
		Id:       config.Name + "-" + config.Id,
		Address:  addr,
		Port:     port,
		Metadata: config.Metadata,
	}

	node.Metadata["transport"] = config.Transport.String()
	node.Metadata["broker"] = config.Broker.String()
	node.Metadata["server"] = s.String()
	node.Metadata["registry"] = config.Registry.String()

	s.RLock()
	var endpoints []*registry.Endpoint
	for _, e := range s.handlers {
		// Only advertise non internal handlers
		if !e.Options().Internal {
			endpoints = append(endpoints, e.Endpoints()...)
		}
	}
	for e, _ := range s.subscribers {
		// Only advertise non internal subscribers
		if !e.Options().Internal {
			endpoints = append(endpoints, e.Endpoints()...)
		}
	}
	s.RUnlock()

	service := &registry.Service{
		Name:      config.Name,
		Version:   config.Version,
		Nodes:     []*registry.Node{node},
		Endpoints: endpoints,
	}

	s.Lock()
	registered := s.registered
	s.Unlock()

	if !registered {
		log.Printf("Registering node: %s", node.Id)
	}

	// create registry options
	rOpts := []registry.RegisterOption{registry.RegisterTTL(config.RegisterTTL)}

	if err := config.Registry.Register(service, rOpts...); err != nil {
		return err
	}

	// already registered? don't need to register subscribers
	if registered {
		return nil
	}

	s.Lock()
	defer s.Unlock()

	s.registered = true

	for sb, _ := range s.subscribers {
		handler := s.createSubHandler(sb, s.opts)
		var opts []broker.SubscribeOption
		if queue := sb.Options().Queue; len(queue) > 0 {
			opts = append(opts, broker.Queue(queue))
		}
		sub, err := config.Broker.Subscribe(sb.Topic(), handler, opts...)
		if err != nil {
			return err
		}
		s.subscribers[sb] = []broker.Subscriber{sub}
	}

	return nil
}