python - Pika basic_publish 在多个队列上发布时挂起

Question

我需要在一个交换器上设置多个队列。我想创建一个连接，然后声明多个队列(这行得通)，然后在多个队列上发布消息(这行不通)。

我设置了一些测试代码来执行此操作，但它每次都在第二次发布时挂起。我认为它不喜欢在不关闭连接的情况下在多个队列上发布，因为当我在单个队列上发布时这段代码有效(甚至在一个队列上有多个消息)。

我需要添加什么才能使这项工作正常进行吗？我真的不想关闭发布之间的连接。此外，当我让我的消费者启动时，当我在多个队列上发送到 basic_publish() 时，他们看不到任何东西。当我在单个队列上发布时，我确实看到消息几乎立即出现。

#!/usr/bin/env python
import pika


queue_names = ['1a', '2b', '3c', '4d']


# Variables to hold our connection and channel
connection = None
channel = None


# Called when our connection to RabbitMQ is closed
def on_closed(frame):
    global connection
    # connection.ioloop is blocking, this will stop and exit the app
    connection.ioloop.stop()



def on_connected(connection):
    """
    Called when we have connected to RabbitMQ
    This creates a channel on the connection
    """
    global channel #TODO: Test removing this global call

    connection.add_on_close_callback(on_closed)

    # Create a channel on our connection passing the on_channel_open callback
    connection.channel(on_channel_open)



def on_channel_open(channel_):
    """
    Called when channel opened
    Declare a queue on the channel
    """
    global channel

    # Our usable channel has been passed to us, assign it for future use
    channel = channel_


    # Declare a set of queues on this channel
    for queue_name in reversed(queue_names):
        channel.queue_declare(queue=queue_name, durable=True,
                              exclusive=False, auto_delete=False,
                              callback=on_queue_declared)
        #print "done making hash"

def on_queue_declared(frame):
    """
    Called when a queue is declared
    """
    global channel

    print "Sending 'Hello World!' on ", frame.method.queue

    # Send a message
    channel.basic_publish(exchange='',
                          routing_key=frame.method.queue,
                          body='Hello World!')


# Create our connection parameters and connect to RabbitMQ
connection = pika.SelectConnection(pika.ConnectionParameters('localhost'), \
                                   on_connected)

# Start our IO/Event loop
try:
    connection.ioloop.start()
except KeyboardInterrupt:
    print "interrupt"
    # Gracefully close the connection
    connection.close()
    # Loop until we're fully closed, will stop on its own
    #connection.ioloop.start()

Answer 1

我的解决方案是让一个变量跟踪我的所有队列是否已声明。

在 on_queue_declared() 中，我会检查这个变量，如果我所有的队列都已声明，那么我就开始发布消息。我认为在取回所有 Queue.DeclareOks 之前尝试发布消息是导致问题的原因。