Python RabbitMQ - 消费者只能看到每秒的消息

Question

我正在使用 Pika 0.98 测试 RabbitMQ 的生产者消费者示例。我的生产者在我的本地 PC 上运行，消费者在亚马逊的 EC2 实例上运行。

我的生产者坐在一个循环中，每秒发送一些系统属性。问题是我只看到消费者阅读了每 2 条消息，就好像每 2 条消息都没有被阅读一样。例如，我的生产者打印出这个(时间戳，使用的 cpu pct，使用的 RAM):

    2014-08-16 14:36:17.576000 -0700,16.0,8050806784    2014-08-16 14:36:18.578000 -0700,15.5,8064458752    2014-08-16 14:36:19.579000 -0700,15.0,8075313152    2014-08-16 14:36:20.580000 -0700,12.1,8074121216    2014-08-16 14:36:21.581000 -0700,16.0,8077778944    2014-08-16 14:36:22.582000 -0700,14.2,8075038720

but my consumer is printing out this:

    Received '2014-08-16 14:36:17.576000 -0700,16.0,8050806784'    Received '2014-08-16 14:36:19.579000 -0700,15.0,8075313152'    Received '2014-08-16 14:36:21.581000 -0700,16.0,8077778944'

The code for the producer is:

    import pika
    import psutil
    import time
    import datetime
    from dateutil.tz import tzlocal
    import logging
    logging.getLogger('pika').setLevel(logging.DEBUG)

    connection = pika.BlockingConnection(pika.ConnectionParameters(
            host='54.191.161.213'))
    channel = connection.channel()

    channel.queue_declare(queue='ems.data')

    while True:
        now = datetime.datetime.now(tzlocal())
        timestamp = now.strftime('%Y-%m-%d %H:%M:%S.%f %z')
        msg="%s,%.1f,%d" % (timestamp, psutil.cpu_percent(),psutil.virtual_memory().used)
        channel.basic_publish(exchange='', 
                          routing_key='ems.data',
                          body=msg)
        print msg
        time.sleep(1)
    connection.close()





消费者的代码是:

    connection = pika.BlockingConnection(pika.ConnectionParameters(
            host='0.0.0.0'))
    channel = connection.channel()


    channel.queue_declare(queue='hello')

    print ' [*] Waiting for messages. To exit press CTRL+C'

    def callback(ch, method, properties, body):
        print " [x] Received %r" % (body,)

    channel.basic_consume(callback,
                          queue='hello',
                          no_ack=True)

    channel.start_consuming()





Answer 1

您的代码在逻辑上没有问题，并且在我的机器上运行没有问题。您看到的行为表明您可能不小心启动了两个消费者，每个消费者以循环方式从队列中抓取一条消息。尝试杀死额外的消费者(如果你能找到它)，或者重新启动。