🌱 Register kubeconfig flag variable via RegisterFlags func

[johannesfrey]

There have been reported issues (flag redefined) because CR registers the kubeconfig flag to the default command line FlagSet via init function. See:

• Import of controller-runtime calls flag for "kubeconfig" #1396
• flag redefined: kubeconfig: allow double vendoring this library but still register flags on behalf of users #878

This PR provides an exported func to register flags that defensively tries to register the kubeconfig flag if not already defined. It does only change the current behaviour by previously checking if has already been defined.

As a follow up the registration via init should probably removed in conjunction with a ⚠️ release note, as it would be a breaking change for the user.

NOTE: I am not entirely sure if this really is the desired way to go and to start a discussion regarding the topic.

_{Johannes Frey <johannes.frey@mercedes-benz.com>, Mercedes-Benz Tech Innovation GmbH (Provider Information)}

[johannesfrey]

/test pull-controller-runtime-test-master

[johannesfrey]

/retest

[johannesfrey]

/label do-not-merge/work-in-progress

[k8s-ci-robot]

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[sbueringer]

/label do-not-merge/work-in-progress

I think if you move [WIP] to be a prefix it should work automatically

[sbueringer]

/retitle [WIP] 🌱 Register kubeconfig flag variable via RegisterFlags func

[johannesfrey]

/label do-not-merge/work-in-progress

I think if you move [WIP] to be a prefix it should work automatically

Yeah, I had it like that but then workflow complains 😅

[sbueringer]

/label do-not-merge/work-in-progress

I think if you move [WIP] to be a prefix it should work automatically

Yeah, I had it like that but then workflow complains sweat_smile

This can be fixed/changed by bumping kubebuilder-release-tools to v0.2.0: https://github.com/kubernetes-sigs/controller-runtime/blob/master/.github/workflows/verify.yml#L12

[johannesfrey]

/retest

[johannesfrey]

/retest

[alvaroaleman]

thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alvaroaleman, johannesfrey

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