RabbitMQ報錯(406, "PRECONDITION_FAILED - parameters for queue 'test_queue' in vhost '/test' not equivalent")

 

1. 報錯信息如下：

File "C:\projects\project_name\mq\rabbitclient.py", line 26, in __init__
self.channel.queue_declare(queue=conf.queue_name)
File "C:\env\project_name\lib\site-packages\pika\adapters\blocking_connection.py", line 2507, in queue_declare
self._flush_output(declare_ok_result.is_ready)
File "C:\env\project_name\lib\site-packages\pika\adapters\blocking_connection.py", line 1340, in _flush_output
raise self._closing_reason # pylint: disable=E0702

pika.exceptions.ChannelClosedByBroker: (406, "PRECONDITION_FAILED - parameters for queue 'test_queue' in vhost '/test' not equivalent")

2. 代碼如下：

# -*- coding: utf-8 -*-

import json
import pika
import Config


class RabbitMQClient(object):
    """
    RabbitMQ Client
    """
    def __init__(self):
        conf = Config()
        credentials = pika.PlainCredentials(conf.rabbit_user, conf.rabbit_password)
        self.conn = pika.BlockingConnection(pika.ConnectionParameters(
            host=conf.rabbit_ip,
            port=conf.rabbit_port,
            virtual_host=conf.vhost,
            credentials=credentials
        ))

        self.channel = self.conn.channel()
        self.exchange = conf.exchange
        self.routing_key = conf.routing_key
        self.channel.exchange_declare(exchange=self.exchange, exchange_type='direct', durable=True)
        self.channel.queue_declare(queue=conf.queue_name)
        self.channel.queue_bind(
            queue=conf.queue_name,
            exchange=self.exchange,
            routing_key=self.routing_key
        )

    def send(self, msg):
        try:
            self.channel.basic_publish(
                exchange=self.exchange,
                routing_key=self.routing_key,
                body=json.dumps(msg),
                properties=pika.BasicProperties(
                    delivery_mode=2
                )
            )
        except Exception as e:
            raise e

    def close(self):
        self.conn.close()


if __name__ == '__main__':
        client = RabbitMQClient()
        client.send(exec_info)
        client.close()

3. 定位問題

我們在聲明exchange的時候加了如下參數：durable=True，代表持久化；
發布信息的時候加了如下參數：delivery_mode=2，代表持久化消息；
我們再看聲明queue的時候如何？
在rabbitmq中，想要重啟后不丟失消息，要為信息加delivery_mode=2參數，只為消息加持久化限制，MQ重啟之后，exchange和queue全部丟失，也是不行的，所以也要為exchange和queue做持久化，都是由durable=True控制。

所以，修改上述代碼第26行如下：
self.channel.queue_declare(queue=conf.queue_name, durable=True)
再次測試便不報錯了。