如何在rabbitmq,pika python中优雅地暂停和恢复消费

我正在使用basic_consume()来接收消息,使用basic_cancel来取消消费,但是有一个问题.

这是pika.channel的代码

 def basic_consume(self, consumer_callback, queue='', no_ack=False,
                      exclusive=False, consumer_tag=None):
        """Sends the AMQP command Basic.Consume to the broker and binds messages
        for the consumer_tag to the consumer callback. If you do not pass in
        a consumer_tag, one will be automatically generated for you. Returns
        the consumer tag.

        For more information on basic_consume, see:
        http://www.rabbitmq.com/amqp-0-9-1-reference.html#basic.consume

        :param method consumer_callback: The method to callback when consuming
        :param queue: The queue to consume from
        :type queue: str or unicode
        :param bool no_ack: Tell the broker to not expect a response
        :param bool exclusive: Don't allow other consumers on the queue
        :param consumer_tag: Specify your own consumer tag
        :type consumer_tag: str or unicode
        :rtype: str

        """
        self._validate_channel_and_callback(consumer_callback)

        # If a consumer tag was not passed, create one
        consumer_tag = consumer_tag or 'ctag%i.%s' % (self.channel_number,
                                                      uuid.uuid4().get_hex())

        if consumer_tag in self._consumers or consumer_tag in self._cancelled:
            raise exceptions.DuplicateConsumerTag(consumer_tag)

        self._consumers[consumer_tag] = consumer_callback
        self._pending[consumer_tag] = list()
        self._rpc(spec.Basic.Consume(queue=queue,
                                     consumer_tag=consumer_tag,
                                     no_ack=no_ack,
                                     exclusive=exclusive),
                           self._on_eventok,
                           [(spec.Basic.ConsumeOk,
                             {'consumer_tag': consumer_tag})])

        return consumer_tag

def basic_cancel(self, callback=None, consumer_tag='', nowait=False):
        """This method cancels a consumer. This does not affect already
        delivered messages, but it does mean the server will not send any more
        messages for that consumer. The client may receive an arbitrary number
        of messages in between sending the cancel method and receiving the
        cancel-ok reply. It may also be sent from the server to the client in
        the event of the consumer being unexpectedly cancelled (i.e. cancelled
        for any reason other than the server receiving the corresponding
        basic.cancel from the client). This allows clients to be notified of
        the loss of consumers due to events such as queue deletion.

        :param method callback: Method to call for a Basic.CancelOk response
        :param str consumer_tag: Identifier for the consumer
        :param bool nowait: Do not expect a Basic.CancelOk response
        :raises: ValueError

        """
        self._validate_channel_and_callback(callback)
        if consumer_tag not in self.consumer_tags:
            return
        if callback:
            if nowait is True:
                raise ValueError('Can not pass a callback if nowait is True')
            self.callbacks.add(self.channel_number,
                               spec.Basic.CancelOk,
                               callback)
        self._cancelled.append(consumer_tag)
        self._rpc(spec.Basic.Cancel(consumer_tag=consumer_tag,
                                    nowait=nowait),
                  self._on_cancelok,
                  [(spec.Basic.CancelOk,
                    {'consumer_tag': consumer_tag})] if nowait is False else [])

正如您在每次取消消费时所看到的那样,consumer_tag被添加到_canceled列表中.如果我再次在basic_consume中使用此标记,则会引发duplicateConsumer异常.好吧,我每次都可以使用一个新的consumer_tag,但实际上我不是.因为迟早生成的标签将与之前的标签完全匹配.

我该如何在鼠兔中优雅地暂停和恢复消费？