Originally Posted by DomainExpertDoug
good day ! We are in the throes of a project that unfortunately is more R&D than implementation. I have a concept of a process manager service that has its own event stream and communicates with the services it manages by events appended to their own event streams.
below is what I posted to the DDD/CQRS google group: no discussion yet.
I have a process manager that "wakes up" at a certain time and polls a feed (more confusion on that later). NOW it has something to do with some stuff ....
Should this process manager service append a "Command Given (aka Request)" to a "downstream called service"s input stream OR should the "called service" subscribe to the event the process manager documents for itself OR to some sort of projection OR do I have my terminology all screwed up (likely).
NOTE: I expect that the "called service" would append a "Result Returned (aka Response)" to the upstream process manager service input stream OR the upstream process manager service would subscribe to the event the "called service" documents for itself OR do I have my terminology all screwed up (again most likely).
Help - I'm a domain expert stuck in a communication do loop with developers.
Interesting scenario. From what I can tell I would probably have the downstream service poll the upstream service like we did in the REST example. I think there are few reasons why my initial reaction is to go this way:
1. the downstream service may want to do some processing of before events are added to its stream.
2. in future there may be other subscribers of the data. Having to update a service each time a new subscriber is added may cross team boundaries.
Does that sound reasonable? If you want to share more details I'd be happy to have another take.