Esempio n. 1
0
// StartConsuming enters a loop and waits for incoming messages
func (amqpBroker *AMQPBroker) StartConsuming(consumerTag string, taskProcessor TaskProcessor) (bool, error) {
	if amqpBroker.retryFunc == nil {
		amqpBroker.retryFunc = utils.RetryClosure()
	}

	conn, channel, queue, _, err := amqpBroker.open()
	if err != nil {
		amqpBroker.retryFunc()
		return amqpBroker.retry, err // retry true
	}

	defer amqpBroker.close(channel, conn)

	amqpBroker.retryFunc = utils.RetryClosure()

	amqpBroker.stopChan = make(chan int)

	if err := channel.Qos(
		3,     // prefetch count
		0,     // prefetch size
		false, // global
	); err != nil {
		return amqpBroker.retry, fmt.Errorf("Channel Qos: %s", err)
	}

	deliveries, err := channel.Consume(
		queue.Name,  // queue
		consumerTag, // consumer tag
		false,       // auto-ack
		false,       // exclusive
		false,       // no-local
		false,       // no-wait
		nil,         // arguments
	)
	if err != nil {
		return amqpBroker.retry, fmt.Errorf("Queue Consume: %s", err)
	}

	log.Print("[*] Waiting for messages. To exit press CTRL+C")

	if err := amqpBroker.consume(deliveries, taskProcessor); err != nil {
		return amqpBroker.retry, err // retry true
	}

	return amqpBroker.retry, nil
}
Esempio n. 2
0
// StartConsuming enters a loop and waits for incoming messages
func (redisBroker *RedisBroker) StartConsuming(consumerTag string, taskProcessor TaskProcessor) (bool, error) {
	if redisBroker.retryFunc == nil {
		redisBroker.retryFunc = utils.RetryClosure()
	}

	redisBroker.pool = redisBroker.newPool()
	defer redisBroker.pool.Close()

	_, err := redisBroker.pool.Get().Do("PING")
	if err != nil {
		redisBroker.retryFunc()
		return redisBroker.retry, err // retry true
	}

	redisBroker.retryFunc = utils.RetryClosure()
	redisBroker.stopChan = make(chan int)
	redisBroker.stopReceivingChan = make(chan int)
	redisBroker.errorsChan = make(chan error)
	deliveries := make(chan []byte)

	redisBroker.wg.Add(1)

	go func() {
		defer redisBroker.wg.Done()

		log.Print("[*] Waiting for messages. To exit press CTRL+C")

		conn := redisBroker.pool.Get()

		for {
			select {
			// A way to stop this goroutine from redisBroker.StopConsuming
			case <-redisBroker.stopReceivingChan:
				return
			default:
				itemBytes, err := conn.Do("BLPOP", redisBroker.config.DefaultQueue, "1")
				if err != nil {
					redisBroker.errorsChan <- err
					return
				}
				// Unline BLPOP, LPOP is non blocking so nil means we can keep iterating
				if itemBytes == nil {
					continue
				}

				items, err := redis.ByteSlices(itemBytes, nil)
				if err != nil {
					redisBroker.errorsChan <- err
					return
				}

				if len(items) != 2 {
					log.Println("Got unexpected amount of byte arrays, ignoring")
					continue
				}
				// items[0] - queue name (key), items[1] - value
				item := items[1]
				signature := new(signatures.TaskSignature)
				if err := json.Unmarshal(item, signature); err != nil {
					redisBroker.errorsChan <- err
					return
				}

				// If the task is not registered, we requeue it,
				// there might be different workers for processing specific tasks
				if !redisBroker.IsTaskRegistered(signature.Name) {
					_, err := conn.Do("RPUSH", redisBroker.config.DefaultQueue, item)

					if err != nil {
						redisBroker.errorsChan <- err
						return
					}

					continue
				}

				deliveries <- item
			}
		}
	}()

	if err := redisBroker.consume(deliveries, taskProcessor); err != nil {
		return redisBroker.retry, err // retry true
	}
	return redisBroker.retry, nil
}