Ability to require variable correlation on a Message Event Catch?

[StephenOTT]

Is it possible to require a Message Catching event to require correlation using specific variables?

Example:

Message: “myMessageName”.
I could POST a message to camunda Rest API with that specific message name with and without a correlation key(s).

Thanks

[thorben]

Hi @StephenOTT,

I’m not sure entirely sure I get the question. So you’d like to define that a message event requires foo and bar to be present in the set of correlation keys or else an expcetion should be raised?

Cheers,
Thorben

[StephenOTT]

@thorben

So you’d like to define that a message event requires foo and bar to be present in the set of correlation keys or else an expcetion should be raised?

Yes. Is this currently possible?

[thorben]

I am afraid not. You could implement CorrelationHandler or extend the default implementation and plug it into the engine via property correlationHandler.

[StephenOTT]

Could this be done with an Execution Listener? (Event Type: Start)

[thorben]

I don’t think so: A listener on start is invoked before the event subscription is persisted and the message is correlated. A listener on end is invoked in the transaction that correlates the message, so throwing an exception there would do the trick. But I think there is no sane way of accessing the correlation keys from within the listener.

[StephenOTT]

@thorben

But I think there is no sane way of accessing the correlation keys from within the listener.

^ This was my guess

This would be a great feature (IMO), as would allow using generic message names for broad Message correlation and specific message correlation at the same time.

[JoHeinem]

Hi @StephenOTT,

@StephenOTT

This would be a great feature (IMO), as would allow using generic message names for broad Message correlation and specific message correlation at the same time.

Maybe I misunderstood you, but can’t you just use expressions in the message name in order to achieve that? See the documentation for more information.

Best,
Johannes

[StephenOTT]

Yes thats been my fallback. But was looking at ways to be able to use the same message name to deliver targeted and broad correlated messages. If i use the dynamic message name, I have hyper-targeted delivery (single message for a single message event), but i lose the broad messaging (one message correlating to many message events).

[kontrag]

Hi,

I’d be interested to use a dynamic name of a Message Start Event of a an Event Sub Process but how would this work with the REST /message API?
Let’s say I define the following message start event:

If another systems wants to call the API to trigger this message, for example call:

{
“messageName” : “TypeA_Msg_arrived”,
“processInstanceId” : “671ec874-6979-11e8-ad76-589920524153”,
“resultEnabled”: “true”
}

then he needs to put a specific name in the messageName field. How can this be resolved to my dynamic name?

Thanks!