[Hawkular-dev] Eliminating Alerts -> Command Gateway dependency

[Peter Palaga]

Hi Jay, Lucas and *,

I was looking into the possibility to move all message classes [1] from 
Command Gateway to Commons. My primary motivation was to eliminate the 
dependency of Alerts on Command Gateway. After thinking about the impact 
I basically abandoned that idea.

Initially, I thought, the move can be justified by the fact that those 
classes define a public API that can be hosted separately from the 
implementation. However, we have not done anything like that for any 
other component. I think that such a split would make the development of 
the command gateway (or any other component) unnecessarily complicated.

Moreover, there is another option [2] you (Alerts guys) seem to foresee 
already:

CommandEventListener can be moved to a new deployment in Hawkular. 
Hawkular Alerts should not really have knowledge about Hawkular-level 
decisions, like which possible Events to filter out or various special 
handling that needs to be performed.

Hence I vote for moving CommandEventListener to Hawkular. Do you (Alerts 
guys) already have a Jira for that?

Thanks,

Peter

[1] The message classes are generated from these schemas: 
https://github.com/hawkular/hawkular-command-gateway/tree/master/hawkular-command-gateway-api/src/main/resources/schema 
plus some interfaces etc. in 
https://github.com/hawkular/hawkular-command-gateway/tree/master/hawkular-command-gateway-api/src/main/java/org/hawkular/cmdgw/api

[2] 
https://github.com/hawkular/hawkular-alerts/blob/master/hawkular-alerts-bus/src/main/java/org/hawkular/alerts/bus/listener/CommandEventListener.java#L39-L41