Adjust the way {pipeline,task}run metrics are surfaced.

[mattmoor]

It's been bugging me that NewController methods for the TaskRun and PipelineRun controllers launch a go routine to harvest metrics, and it occurred to me that there might be a better way.

Borrowing from the CloudEvent client's use of hand-crafted injection logic:

pipeline/pkg/reconciler/events/cloudevent/cloudeventclient.go

Line 29 in 7297c48

func init() {

This change takes a similar approach, creating pkg/{task,pipeline}runmetrics packages, which surface their *Recorder via .Get(ctx) methods. Rather than the controller spinning off go routine, this piggybacks on informer injection to "Start()" that process after the dependent informers have been started.

/kind cleanup

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Docs included if any changes are user facing
• Tests included if any functionality added or changed
• Follows the commit message standard
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  functionality, content, code)
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Release Notes

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[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/pipelinerunmetrics/injection.go	Do not exist	18.2%
pkg/pipelinerunmetrics/metrics.go	Do not exist	75.4%
pkg/reconciler/taskrun/controller.go	95.8%	95.0%	-0.8
pkg/taskrunmetrics/injection.go	Do not exist	18.2%
pkg/taskrunmetrics/metrics.go	Do not exist	81.7%

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/pipelinerunmetrics/injection.go	Do not exist	18.2%
pkg/pipelinerunmetrics/metrics.go	Do not exist	75.4%
pkg/reconciler/taskrun/controller.go	95.8%	95.0%	-0.8
pkg/taskrunmetrics/injection.go	Do not exist	18.2%
pkg/taskrunmetrics/metrics.go	Do not exist	81.7%

[mattmoor]

/retest

the alpha tests are very flaky 😞

[vdemeester]

/cc @khrm as it affects #4201

[tekton-robot]

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[dlorenc]

/lgtm

[mattmoor]

Hmm, the race detector blew up, gonna take a quick look at where

[mattmoor]

    testing.go:1092: race detected during execution of test
FAIL
FAIL	github.com/tektoncd/pipeline/pkg/reconciler/taskrun	6.991s

I don't see the usual stack trace in the blended -v output, so I'm going to try and repro this locally with -race -count=10 🤞

[mattmoor]

Nothing at 10, going for 100 while I walk the dog :)

[mattmoor]

Well all I got was:

race: limit on 8128 simultaneously alive goroutines is exceeded, dying

Let's see if prow can repro it.

/retest

[mattmoor]

I guess not.