rabbitmq ReturnCallback在NO_ROUTE上声明队列时卡住了

Question

如果没有可用的路由，我试图使用发布者返回回调来声明队列和绑定，以便消息不会再次被丢弃。这是因为我的队列是自动删除的，如果我的消费者下线，它将被删除。

但是ReturnCallback线程在admin.declareQueue(queue)的return dmessage()中卡住了。

在进一步的调试中，我看到它卡在RabbitAdmin.declareQueue()中:DeclareOk[] declare = declareQueues(channel, queue);

虽然这个调用卡住了，但我看到了队列声明(通过控制台检查)。另外，后续的send调用不会调用returnedMessage，因为可能第一个return message 调用还没有返回。

我在这里做错了什么?在返回回调中声明队列/绑定是否正确?

任何帮助都将非常感激。谢谢。

下面是我的ReturnCallback:

public class MyReturnCallback implements ReturnCallback {
    // constructor, member initialization goes here
    @Override
    public void returnedMessage(Message message, int replyCode,
            String replyText, String exchangeName, String routingKey) {
        if (replyCode == 312) {
            if (this.exchangeName.equals(exchangeName) && this.routingKey.equals(routingKey)) {
                RabbitAdmin admin = new RabbitAdmin(connectionFactory);
                Exchange exchange = new DirectExchange(exchangeName, true, false);
                Queue queue = new Queue(queueName, true, false, true);
                admin.declareQueue(queue);
                Binding binding = BindingBuilder.bind(queue).to((DirectExchange)exchange).with(routingKey); 
                admin.declareBinding(binding);
                if (null != binding) {
                    RabbitTemplate rabbitmqTemplate = new RabbitTemplate(connectionFactory);
                    logger.debug("Sending to [exchange:" + exchange.getName() + ", routing-key:" + routingKey + "]:" + message.toString());
                    rabbitmqTemplate.send(exchangeName, routingKey, message);
                }
            }
        }
    }
}

我的测试制作人是这样的:

public class TestProducer {
    // constructor, member initialization goes here
    void initialize()
        rabbitAdmin = new RabbitAdmin(connectionFactory);
        rabbitTemplate = new RabbitTemplate(connectionFactory);
        rabbitTemplate.setExchange(exchangeName);
        rabbitTemplate.setMessageConverter(messageConverter);
        rabbitTemplate.setRoutingKey(routingKey);
        rabbitTemplate.setMandatory(true);
        rabbitTemplate.setReturnCallback(new RabbitReturnCallback());
        Exchange exchange = new DirectExchange(exchangeName, true, false);
        rabbitAdmin.declareExchange(exchange);
        Queue queue = new Queue(queueName, true, false, true);
        rabbitAdmin.declareQueue(queue);
        Binding binding = BindingBuilder.bind(queue).to((DirectExchange)exchange).with(routingKey); 
        rabbitAdmin.declareBinding(binding);
    }
    void send() {
        rabbitTemplate.convertAndSend(message);
    }
}

ConnectionFactory bean is:

<rabbit:connection-factory id="rabbitmqConnectionFactory"
    host="${rabbitmq.host:localhost}"
    port="${rabbitmq.port:5672}"
    username="${rabbitmq.username}"
    password="${rabbitmq.password}"
    virtual-host="${rabbitmq.vhost:/}"
    cache-mode="CHANNEL"
    channel-cache-size="${rabbitmq.channel-cache-size:25}" 
    publisher-returns="true"/>

附加调试日志供参考:

2016-10-04 17:58:58,881 [main] INFO  CachingConnectionFactory:291 - Created new connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:58,883 [main] DEBUG RabbitAdmin:399 - Initializing declarations
2016-10-04 17:58:58,883 [main] DEBUG DefaultListableBeanFactory:250 - Returning cached instance of singleton bean 'org.springframework.context.annotation.ConfigurationClassPostProcessor.importRegistry'
2016-10-04 17:58:58,935 [main] DEBUG CachingConnectionFactory:453 - Creating cached Rabbit Channel from PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1)
2016-10-04 17:58:58,975 [main] DEBUG PublisherCallbackChannelImpl:694 - Added listener org.springframework.amqp.rabbit.core.RabbitTemplate@67f639d3
2016-10-04 17:58:58,976 [main] DEBUG RabbitTemplate:1451 - Added pending confirms for Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/] to map, size now 1
2016-10-04 17:58:58,976 [main] DEBUG RabbitTemplate:1296 - Executing callback on RabbitMQ Channel: Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:58,979 [main] TRACE CachingConnectionFactory:906 - Returning cached Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1)
2016-10-04 17:58:58,979 [main] DEBUG RabbitAdmin:460 - Declarations finished
2016-10-04 17:58:58,980 [main] TRACE CachingConnectionFactory:402 - Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/] retrieved from cache
2016-10-04 17:58:58,981 [main] TRACE CachingConnectionFactory:439 - Found cached Rabbit Channel: Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:58,981 [main] DEBUG PublisherCallbackChannelImpl:694 - Added listener org.springframework.amqp.rabbit.core.RabbitTemplate@82de64a
2016-10-04 17:58:58,982 [main] DEBUG RabbitTemplate:1451 - Added pending confirms for Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/] to map, size now 1
2016-10-04 17:58:58,982 [main] DEBUG RabbitTemplate:1296 - Executing callback on RabbitMQ Channel: Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:58,982 [main] DEBUG RabbitAdmin:487 - declaring Exchange 'myexchange'
2016-10-04 17:58:59,006 [main] TRACE CachingConnectionFactory:906 - Returning cached Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1)
2016-10-04 17:58:59,007 [main] INFO  TestProducer:59 - Declared/Declare-confirmed for direct exchange: myexchange
2016-10-04 17:58:59,009 [main] DEBUG TestProducer:74 - Sending to [exchange:myexchange, routing-key:mykey]:[testpayload]
2016-10-04 17:58:59,090 [main] TRACE CachingConnectionFactory:402 - Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/] retrieved from cache
2016-10-04 17:58:59,091 [main] TRACE CachingConnectionFactory:439 - Found cached Rabbit Channel: Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:59,091 [main] DEBUG PublisherCallbackChannelImpl:694 - Added listener org.springframework.amqp.rabbit.core.RabbitTemplate@793f29ff
2016-10-04 17:58:59,091 [main] DEBUG RabbitTemplate:1451 - Added pending confirms for Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/] to map, size now 1
2016-10-04 17:58:59,091 [main] DEBUG RabbitTemplate:1296 - Executing callback on RabbitMQ Channel: Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:59,098 [main] DEBUG RabbitTemplate:1325 - Publishing message on exchange [myexchange], routingKey = [mykey]
2016-10-04 17:58:59,104 [main] TRACE CachingConnectionFactory:906 - Returning cached Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1)
2016-10-04 17:58:59,134 [AMQP Connection ip-address:5672] DEBUG TestProducer:103 - returnedMessage, replyCode: 312, replyText: NO_ROUTE
2016-10-04 17:58:59,135 [AMQP Connection ip-address:5672] TRACE CachingConnectionFactory:402 - Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/] retrieved from cache
2016-10-04 17:58:59,136 [AMQP Connection ip-address:5672] TRACE CachingConnectionFactory:439 - Found cached Rabbit Channel: Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:59,163 [AMQP Connection ip-address:5672] DEBUG PublisherCallbackChannelImpl:694 - Added listener org.springframework.amqp.rabbit.core.RabbitTemplate@7ec6c641
2016-10-04 17:58:59,163 [AMQP Connection ip-address:5672] DEBUG RabbitTemplate:1451 - Added pending confirms for Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/] to map, size now 1
2016-10-04 17:58:59,163 [AMQP Connection ip-address:5672] DEBUG RabbitTemplate:1296 - Executing callback on RabbitMQ Channel: Cached Rabbit Channel: PublisherCallbackChannelImpl: AMQChannel(amqp://test@ip-address:5672/,1), conn: Proxy@bae7dc0 Shared Rabbit Connection: SimpleConnection@4f2b503c [delegate=amqp://test@ip-address:5672/]
2016-10-04 17:58:59,164 [AMQP Connection ip-address:5672] DEBUG RabbitAdmin:515 - declaring Queue 'myqueue'
2016-10-04 17:59:29,104 [main] DEBUG TestProducer:74 - Sending to [exchange:myexchange, routing-key:mykey]:[testpayload]
Nothing happens after this.

Answer 1

有趣的问题—由于通道在初始发送后被放回缓存中，当在该通道上传递返回时，回调中的发送会获得相同的通道，这会导致通道内的死锁—在我们仍在处理返回时执行声明。

在得到返回值之前，我们真的不能把通道放回缓存中，因为我们不知道是否会得到返回值。

我会考虑是否有任何方法可以检测到这种情况并避免它，但与此同时，对您来说最安全的事情是处理声明并在不同的线程上重新发布…

private final Executor executor = Executors.newCachedThreadPool();
@Override
public void returnedMessage(Message message, int replyCode, String replyText, String exchangeName,
        String routingKey) {
    if (replyCode == 312) {
        executor.execute(() -> {
            RabbitAdmin admin = new RabbitAdmin(connectionFactory);
            Exchange exchange = new DirectExchange(exchangeName, true, false);
            Queue queue = new Queue("foo", true, false, true);
            admin.declareQueue(queue);
            Binding binding = BindingBuilder.bind(queue).to((DirectExchange) exchange).with(routingKey);
            admin.declareBinding(binding);
            if (null != binding) {
                RabbitTemplate rabbitmqTemplate = new RabbitTemplate(connectionFactory);
                System.out.println("Sending to [exchange:" + exchange.getName() + ", routing-key:" + routingKey
                        + "]:" + message.toString());
                rabbitmqTemplate.send(exchangeName, routingKey, message);
            }
        });
    }
}