Implement Simple Pipeline Controller with tests

[tejal29]

Addresses 1 pat of #61

This PR, implements simple pipeline controller which records events when a pipelinerun points to right pipeline reference.
This implementation, for now does nothing and logs errors if there the pipeline run refers to invalid ref.

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[tejal29]

Just noticed, Bulk of changes are in vendor directory.
I think previous PR did not clean up all the vendor directories.
I will create a PR to dep prune on master and then submit that first.

[bobcatfish]

Niiiiiice! Very cool!

I think you've done a lot of work here that is going to be super valuable for everyone implementing controllers going forward! My biggest piece of feedback is that if I was to have to do the same thing (e.g. for a different controller/type), looking at the tests that you've added for guidance, I'd be a bit confused about what I needed to do, so it would be great to have some kind of docs or guidance for future unit test authors.

[bobcatfish]

what is an agent in this context? is that a kubernetes term?

[tejal29]

This is the logging agent. The Log line will dump logs with this agent name.

[bobcatfish]

I'm just wondering what "agent" means specifically, is it a kubernetes thing or golang thing?

[tejal29]

nope. this more of logging thing. Its used when logging.
I can rename this to loggerName if that helps.

[bobcatfish]

Note: this syntax will actually CLOSE #61, which I think is not quite what we want b/c I think we still need a few more follow-up PRs to finish #61, so maybe you just want something in the commit and PR description like part of #61 or first step in #61 instead?

[vdemeester]

This could also done with one NewController that takes functional arguments (à-la-builder in a way). That would allow to setup sane defaults, easily overridable (and future-proof).

type ControllerConfig {
    lister func // …
    // …
}

func Lister(f func …) func(*ControllerConfig) {
    return func(c *ControllerConfig) {
        c.lister = f
    }
}

// Any non-required function can have a sane default and thus be written as a "function operator"
func NewController(
	k kubernetes.Interface,
	c clientset.Interface,
	l *zap.SugaredLogger,
        ops ...func(*ControllerConfig)
) controller.Interface { 
    c := &ControllerConfig{
        // … with sane defaults
    }

    for _, op := range ops {
        op(c)
    }
// […]

[tejal29]

@bobcatfish , @pivotal-nader-ziada and @vdemeester This is ready for review with reconciler and documentations on how to test controller.

[nader-ziada]

A good reconciler start, I think it would be good to merge this in and then add the functionality of creating pipelineRun and taskRun along with more tests

@tejal29
small changes we can hopefully change before merging this in:

• Fix the Gopkg.lock diff so it doesn't cause conflicts later
• Add the newController in cmd/controller/main.go

[nader-ziada]

neat!

[nader-ziada]

Thanks @tejal29

/lgtm