[Hawkular-dev] Moving Nest and Bus to Hawkular Commons git repository

[Peter Palaga]

Hi *,

this was already discussed on several calls. Although I know of no 
objections, I am putting it also here to give you all the last chance to 
protest or discuss.

The plan is to move the Maven modules from Nest [1] and Bus [2] git 
repositories to Commons repository [3].

Details:
* Nest and Bus Maven modules will be moved to Hawkular Commons git
   repository
* Nest and Bus Maven modules will belong to groupId org.hawkular.commons
* All modules of the org.hawkular.commons incl. Nest and Bus will be
   released together
* The new and old subcomponents of Commons (such as Nest, Bus,
   Templates, c* driver, ...) will be allowed to depend on each other,
   but clearly, they may not introduce circular dependencies.
* To help to keep control on which subcomponent depends on which other
   subcomponents, the dependency management will happen on
   the subcomponent level rather than in hawkular-commons-parent

* Components consuming Nest, Bus or any of the other subcomponents of
   Hawkular Commons will have to declare just one version property
   version.org.hawkular.commons to manage all the the artifacts they
   need from commons

* As noted by Stefan, only such subcomponents should be allowed to be
   hosted in Commons that are generic enough -i.e. that do not contain
   any deep and specific domain knowledge. Move of Bus and Nest to
   commons satisfies this.

Pros:
* Decrease the maintenance overhead by decreasing the number of git
   repositories and by decreasing the number of Hawkular components
   having independent release cycles - e.g. after a new release of
   Hawkular Parent there is two component less to upgrade, two componets
   less to release and n components less to upgrade that depend on Bus
   and Nest

Cons:
* Loose some amount of design cleanness - Hawkular Commons hosts Maven
   modules with clean logical borders that could be hosted and released
   independently.
* Esp. the independent release cycle could be seen as an
   advantage when fixing bugs and CVEs

Pseudo-con:
* Note that the new home of Nest and Bus does not prescribe any
   component that consumed Commons so far to consume also Nest and Bus
   from now on. Dependent components can still choose the artifacts to
   depend on with an unchanged granularity: Who dependeded on embedded
   c* so far can stay with it without depending on Bus or Nest.

I am going to work on this change now.

[1] https://github.com/hawkular/hawkular-nest
[2] https://github.com/hawkular/hawkular-bus
[3] https://github.com/hawkular/hawkular-commons

Thanks,

Peter