I'm thinking if Spring Cloud Stream can be a good fit for a specific system we're thinking to build ground up. There's currently a Monolith (ESB) which is currently in use but we are looking to get benefitted by the goodness of microservices (spring cloud ecosystem especially).
We receive request from the input source (JMS Queue, ActiveMQ to be specific) at the rate of 5 requests/second.
We will need to have different routing rules (based on the payload or some derived logic) and route the message to different output destinations (say A, B, C). The output destinations are JMS queues.
Finally, we'll have to receive the 3 responses from A,B,C (by listening to different set of queues) and mash up the final response. This response is finally dispatched to another output channel (which is anther JMS queue).
There are a few corner cases such as when the response for A takes more than '5' seconds, then we'll want to mash up the responses of 'B' and 'C' and an error object for 'A'. Same goes for 'B' and 'C' too.
Also, the destinations 'A','B' and 'C' are dynamic. We could have more target systems 'D', 'E' etc in the future. We're looking at not having to change the main orchestration layer if a new system is introduced.
Is Spring Cloud Stream the right choice? I'm looking for more specific pointers in case of Aggregating the responses from multiple JMS queues (with timeouts) and mashing up the response.
What you are talking about is fully sufficient for the Aggregator EIP or its more powerful friend Scatter-Gather .
Both of them are available in Spring Integration:
So, you will need to have some correlationKey to be able to gather all the responses to the same group to aggregate in the end.
Also there is group-timeout option which allows you to release group when there is no all replies after some time.