Apache Camel JMS/AMQP component create destination queue only if required

Question

I am currently working on an Integration application that uses Camel with Spring Boot. There is a camel route in integration application that receive messages from source Artemis broker that is transformed and sent to another Artemis broker. The camel route looks like this:

from(sourceQueue).process(transformProcessor).to(destinationQueue)

When the camel route starts, it recreates the queue names mentioned in the from and to and the previous messages are lost. We do not expect this to happen.

One way I found to do this is in the Artemis ActiveMQ broker.xml, disable the queue and topic auto creation and create the queue(s) using Artemis API.

My question is, can we configure camel JMS / AMQP component to create the queue only if it is not present and if present use the existing ones?

Answer 1

By default Camel will use DynamicDestinationResolver. You can create your own custom DestinationResolver and plug it in your endpoint (or into your component)

.to("jms:queue:myQueue?destinationResolver=MyCustomDestinationResolver");

You can also use JndiDestinationResolver, which by default does not fallback into creating a dynamic destination.

Answer 2

I don't know Artemis but it sounds weird for a broker to delete a queue with its messages. At least its "brother" ActiveMQ has by default the behavior you expect: queues are automatically created if they do not exist, but they just stay if they already exist.

Are you sure the queues are recreated on route start? Are these queues persistent? Could it be that a consumer just drains the queue? I also found a queue attribute of Artemis named auto-delete-queues that would delete the queue if it was drained by a consumer.

auto-delete-queues Whether or not to the broker should automatically delete auto-created JMS queues when they have both 0 consumers and 0 messages.