Question

我正在使用“{hello world”教程：http://www.rabbitmq.com/tutorials/tutorial-two-python.html。 worker.py看起来像这样

import pika
import time


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

channel.queue_declare(queue='task_queue', durable=True)
print ' [*] Waiting for messages. To exit press CTRL+C'

def callback(ch, method, properties, body):
    print " [x] Received %r" % (body,)
    time.sleep( body.count('.') )
    print " [x] Done"
    ch.basic_ack(delivery_tag = method.delivery_tag)

channel.basic_qos(prefetch_count=1)
channel.basic_consume(callback,
                      queue='task_queue')

channel.start_consuming()

我已经在我的工作中使用了这段代码。一切都顺利进行，直到队列中有一个点，在打印[x] Done

之后它会引发异常

Traceback (most recent call last):
  File "hullworker2.py", line 242, in <module>
    channel.basic_consume(callback,queue='test_queue2')
  File "/usr/local/lib/python2.7/dist-packages/pika/channel.py", line 211, in basic_consume
    {'consumer_tag': consumer_tag})])
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 904, in _rpc
    self.connection.process_data_events()
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 88, in process_data_events
    if self._handle_read():
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 184, in _handle_read
    super(BlockingConnection, self)._handle_read()
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/base_connection.py", line 300, in _handle_read
    return self._handle_error(error)
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/base_connection.py", line 264, in _handle_error
    self._handle_disconnect()
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 181, in _handle_disconnect
    self._on_connection_closed(None, True)
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 232, in _on_connection_closed
    self._channels[channel]._on_close(method_frame)
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 817, in _on_close
    self._send_method(spec.Channel.CloseOk(), None, False)
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 920, in _send_method
    self.connection.send_method(self.channel_number, method_frame, content)
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 120, in send_method
    self._send_method(channel_number, method_frame, content)
  File "/usr/local/lib/python2.7/dist-packages/pika/connection.py", line 1331, in _send_method
    self._send_frame(frame.Method(channel_number, method_frame))
  File "/usr/local/lib/python2.7/dist-packages/pika/adapters/blocking_connection.py", line 245, in _send_frame
    super(BlockingConnection, self)._send_frame(frame_value)
  File "/usr/local/lib/python2.7/dist-packages/pika/connection.py", line 1312, in _send_frame
    raise exceptions.ConnectionClosed
pika.exceptions.ConnectionClosed

我不明白连接在进程之间是如何自动关闭的。进程在队列中的100条消息中运行正常，然后突然出现此错误。任何帮助表示赞赏。

Answer 1

有heartbeats的概念。它基本上是服务器如何确保客户端仍然连接的方式。

当你做

时

time.sleep( body.count('.') )

您将代码阻隔N秒。这意味着如果服务器想要发送heartbeat帧以检查您的客户端是否还活着，那么它将不会得到响应，因为您的代码被阻止并且不知道心跳是否到达。

您应该使用time.sleep()，而不是使用connection.sleep()，这也会使代码在N秒内“休眠”，但它也会与服务器通信并回复

 sleep(duration)[source]

    A safer way to sleep than calling time.sleep() directly which will keep the adapter from ignoring frames sent from RabbitMQ. The connection will “sleep” or block the number of seconds specified in duration in small intervals.

在python中使用rabbitmq时出现“pika.exceptions.ConnectionClosed”错误

1 个答案: