[Hawkular-dev] Extra back-end for our front-end

[Viliam Rockai]

Hey all,

As we put more and more functionality into Hawkular, the more and more
logic is put into the front-end itself, too. From my perspective, we're
dealing with too much stuff that doesn't even belong to the front-end
anyway. I believe we should create a new back-end module, which would
connect all the existing modules with the front-end. This module may
even be maintained by the front-end team, since it'll evolve and mutate
very fast - to suit the UI needs. There are several use-cases which call
for such module. For example to create all the alert entities needed for
alerting you need to create a:
* Trigger (per alerting "entity")
* Dampening (one or more)
* Condition (one or more)

Each of those has its separate endpoint and creation of each may fail.
So basically we should (we don't do that yet, we just assume everything
went all right) even deal with transactions in the front-end right now.
>From the UI perspective, this is just a single entity "Alert
definition". Another question is - when should those objects be created?
Once you add an URL - that's pretty easy (for URLS). But, in my opinion,
for JVMs they should be created once the resource is discovered, not the
1st time the resource is accessed by UI. And the situation will be more
complicated with new resources. Being able to get some predefined sets
of metrics would be another nice feature. I.e., right now, we do 3
requests (User, maximum, committed) to get the data for the "JVM Heap
Usage" graph (and other graphs, too). Being able to process those data
on a server and send it the the front-end in one bulk would be pretty
neat.

I believe adding a new module to the back-end, which role would be to
connect the UI to the rest of Hawkular services would be beneficial for
performance, testability and robustness of the whole app.

WDYT?

Viliam