兔子MQ重新启动后，使用者不重新连接

Question

Sometimes our rabbit messaging server requires a restart. After which however some consumers which are listening via basic consume blocking call do not consume any messages until they are restarted themselves and neither do they raise any exception.

What is the reason for this and how might I fix?

Answer 1

In the connectionFactory, please ensure the following property is set to true:

 factory.setAutomaticRecoveryEnabled(true); 

For more details, please refer the document here

Answer 2

As I mentioned in my comment, every AMQP client library has a different way to recover connections, and some depend on the developer to do that. There is NO canonical method.

Pika has this example as a starting point for connection recovery. Note that the code is for the unreleased version of Pika ( 1.0.0 ). If you're on 0.12.0 you will have to adjust the parameters to the method calls.

The best way to test and implement connection recovery is to simulate failure conditions and then code for them. Run your application, then kill the beam.smp process (RabbitMQ) to see what happens. If you have a RabbitMQ cluster, use firewall rules to simulate a network partition. Can your application handle that? What happens when you run rabbitmqctl stop_app; sleep 10; rabbitmqctl start_app rabbitmqctl stop_app; sleep 10; rabbitmqctl start_app rabbitmqctl stop_app; sleep 10; rabbitmqctl start_app ? Can your app handle that?

Run your application through a TCP proxy like toxiproxy and introduce latency and other non-optimal conditions. Shut down the proxy to simulate a sudden TCP connection close. In each case, code for that failure condition and log the event so that someone can later diagnose what has happened.

I have seen too many developers code for the "happy path" only to have their applications fail spectacularly in production with zero ability to determine the source of the failure.