Sending message to start a procces and wait for a reply message


I am trying to test process communication between processes and encounters a problem that i do not understand:
I have modeled 2 process: a producer and a consumer.
In the producer, i send a message to the consumer.
In the consumer, i receive the message and sends a message back to the producer.

My problem is that the sending of the message and consuming in the comsumer is a blocking operation.
So i cant send a message back to the producer because the producer is still sending and not listening

i’ve solved the problem by sending the message in a new thread in the java delegate code, but i think this is not the way bpmn and camunda works.

So how can i send a message that do not block my process until the consumer of the message is finished?

I tried all combinations of Async Continuations, but then nothing works.

Hint: I started one in-memory process engine in a spring boot app, then i deployed both processes and starting an instance of the producer-process.

I think you have to change the consumer so that it sends the synchronous reply immediately. And then does the real “consuming” work asynchronously.

I try to send the message immediatly, but this fails because no one is listening…
Both consumer and producer are running in the same thread (i dont not know why a process that is started by sending a message is in the same thread). I did not start the comsumer-process by myself, i just sending the message to the consumer
within the consumer, i cannot send (correlate) the answer-message because the producer is not listening. The producer does not continue its work in his own process and so the intermediate message catch is not active.

Have you tried something like this - where the yellow highlight is async before

In this case it will be waiting for the response before the message is sent so the reply wont be missed.

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thank you very much for the help!

My small example now works like a charm with the async-before enabled.


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