Add *_labels metrics for custom resource configurations

[chrischdi]

What would you like to be added:

Allow to expose *_labels for Custom Resource configuration which behaves the same as kube_*_labels metrics.
This means it would also use the configured value for the flag --metric-labels-allowlist for filtering the exposed labels.

Why is this needed:

To have the same kind of features for custom resource metrics.

Describe the solution you'd like

One option would be to add a boolean for enabling the labels for a custom resource configuration, e.g. at the Resource struct level https://github.com/kubernetes/kube-state-metrics/blob/master/pkg/customresourcestate/config.go#L42

Additional context

As of today it would require some custom configuration to expose something like that for a custom resource.

kind: CustomResourceStateMetrics
spec:
  resources:
    - groupVersionKind:
        group: myteam.io
        kind: "Foo"
        version: "v1"
      metrics:
        - name: "labels"
          each:
            type: Info
            info:
              labelsFromPath:
                label_foo: [metadata, labels, foo]
                label_bar: [metadata, labels, bar]

[dgrisonnet]

I wonder if this is really something we want. I am personally quite pleased by the fact that users have to define which label they want to use themself since it prevents any unwanted scenarios to occur.

Also, we will have to do the same for annotations at some point if we have an option to enable label metrics, and I'd rather keep the configuration format simple with metrics having to be defined manually rather than have some magic mechanisms for some of them.

[chrischdi]

Totally fair point, also there is the above example how it could be done using an Allowlist approach 👍

[k8s-triage-robot]

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/lifecycle stale

[chrischdi]

I'll leave this up to get staled / rotten / closed. There were no comments from others requiring this feature.

[k8s-triage-robot]

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/lifecycle rotten

[k8s-triage-robot]

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/close not-planned

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue, marking it as "Not Planned".

In response to this:

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Reopen this issue with /reopen
• Mark this issue as fresh with /remove-lifecycle rotten
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/close not-planned

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