Search code examples
springrabbitmqspring-amqpspring-rabbit

Spring AMQP multiple threads calling into message listener

I have a DirectRabbitListenerContainer (created through a DirectRabbitListenerContainerFactory) where I have a MessageListener setup through a MessageListenerAdapter.

The issue I am have is that sometimes the same message from RabbitMQ will arrive at the MessageListener multiple times by different threads.

[2020-06-16 11:12:45,910] INFO com.something.MyMsgListener [pool-1-thread-3] Message ID:bca8cdcc-385a-4847-bd15-50e8936 [2020-06-16 11:12:45,910] INFO com.something.MyMsgListener [pool-1-thread-8] Message ID:bca8cdcc-385a-4847-bd15-50e8936

This is causing a lot of problems for the application I am writing. I am wondering if someone can point out which configuration item is causing this (or can prevent this). On the message producer side, I know only 1 message was produced and sent to RabbitMQ. Sometimes up to 6 threads will process the same message. Sometimes the problem goes away. I don't have a good grasp of why this is happening... any help would be greatly appreciated.

Thanks!

Solution

  • It's not possible, unless the listener called by pool-1-thread-3 throws an exception and the message is redelivered.

    There is no guarantee that a redelivery will arrive on the same thread since it uses the thread pool managed by the amqp-client.

    With the SimpleMessageListenerContainer and concurrency=1, the redeliveries will always occur on the same thread.