Set maximum AMQP client attempts - spring

Question

I have a case where I might have Java NPE into the listener which accepts queue payload. I get multiple attempts and errors:
18:41:50.549 [processingeContainer-1] WARN o.s.a.r.l.ConditionalRejectingErrorHandler - Execution of Rabbit message listener failed.
2019-09-24 18:41:50,551 INFO [stdout] (processingContainer-1) org.springframework.amqp.rabbit.listener.exception.ListenerExecutionFailedException: Listener method 'transactionProcess' threw exception
Is there some way to limit the AMQP client attempts?

Answer 1

You should really fix the NPE but you can configure the listener container error handler.
The default ConditionalRejectingErrorHandler treats certain exceptions as fatal.
It uses a DefaultExceptionStrategy which has the following code:
private boolean isCauseFatal(Throwable cause) {
return cause instanceof MessageConversionException // NOSONAR boolean complexity
|| cause instanceof org.springframework.messaging.converter.MessageConversionException
|| cause instanceof MethodArgumentResolutionException
|| cause instanceof NoSuchMethodException
|| cause instanceof ClassCastException
|| isUserCauseFatal(cause);
}
/**
* Subclasses can override this to add custom exceptions.
* #param cause the cause
* #return true if the cause is fatal.
*/
protected boolean isUserCauseFatal(Throwable cause) {
return false;
}
So, configure your own ConditionalRejectingErrorHandler with a subclass of DefaultExceptionStrategy which overrides isUserCauseFatal() return true for NullPointerException.
You would then inject your error hander into the listener container or listener container factory.
Another technique would be to add a retry interceptor; by default, the error is just logged after the retries are exhausted. With spring boot, the default recoverer is a RejectAndDontRequeueRecoverer.
EDIT
I just tested it and it worked fine...
#SpringBootApplication
public class So58087354Application {
public static void main(String[] args) {
SpringApplication.run(So58087354Application.class, args);
}
#RabbitListener(queues = "foo")
public void listen(String in) {
System.out.println("here");
throw new NullPointerException("Test");
}
}
spring.rabbitmq.listener.simple.retry.enabled=true
spring.rabbitmq.listener.simple.retry.initial-interval=1000ms
spring.rabbitmq.listener.simple.retry.max-attempts=2
and
here
here
2019-10-01 09:07:11.936 WARN 75435 --- [ntContainer#0-1] o.s.a.r.r.RejectAndDontRequeueRecoverer : Retries exhausted for message (Body:'[B#6d890bbc(byte[3])' MessageProperties [headers={}, contentLength=0, receivedDeliveryMode=NON_PERSISTENT, redelivered=false, receivedExchange=, receivedRoutingKey=foo, deliveryTag=1, consumerTag=amq.ctag-mwYtmPtBplrefsOa05hG0w, consumerQueue=foo])
...
2019-10-01 09:07:11.937 WARN 75435 --- [ntContainer#0-1] s.a.r.l.ConditionalRejectingErrorHandler : Execution of Rabbit message listener failed.
...
Caused by: org.springframework.amqp.AmqpRejectAndDontRequeueException: null
... 19 common frames omitted
EDIT2
To add a retry advice to the container factory manually...
#Component
class ContainerRetryConfigurer {
ContainerRetryConfigurer(AbstractRabbitListenerContainerFactory<?> factory) {
factory.setAdviceChain(RetryInterceptorBuilder.stateless()
.maxAttempts(2)
.backOffOptions(1000, 1.0, 1000)
.build());
}
}