获取“pika.exceptions.ConnectionClosed"在python中使用rabbitmq时出错 [英] Getting "pika.exceptions.ConnectionClosed" error while using rabbitmq in python

问题描述

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

I am using "hello world" tutorial in :http://www.rabbitmq.com/tutorials/tutorial-two-python.html . worker.py looks like this

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()

我已使用此代码在我的工作中实现.一切都很顺利，直到队列中有一个点在打印 [x] Done

I have used this code to implement in my work. Everything works smoothly untill there comes a point in a queue for which it raises an exception after printing [x] Done

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

我不明白连接是如何在进程之间自动关闭的.对于队列中的 100 条消息，进程运行良好，然后突然出现此错误.任何帮助表示赞赏.

I don't understand how the connection is closing automatically in between the process. Process runs fine for 100's of messages in the queue then suddenly this error comes up. Any help appreciated.

推荐答案

有一个heartbeats 的概念.这基本上是服务器如何确保客户端仍然连接的一种方式.

There is a concept of heartbeats. It's basically a way how the server can make sure that the client is still connected.

什么时候做

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

您阻止代码 N 秒.这意味着如果服务器想发送一个 heartbeat 帧来检查您的客户端是否还活着，那么它不会得到响应，因为您的代码被阻止并且不知道心跳是否到达.

You blocking the code by N number of seconds. It means that if server would like to send a heartbeat frame to check if your client is still alive, then it will not get a response back, because your code is blocked and doesn't know if heartbeat arrived.

你应该使用 connection.sleep() 而不是使用 time.sleep() 这也会使 N 秒数，但它也会与服务器通信并作出响应.

Instead of using time.sleep() you should use connection.sleep() this will also make the code "sleep" for N number of seconds, but it will also communicate with the server and will respond back.

 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.

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