config: fix using the KUBECONFIG to build the client

[rphillips]

Fix passing the kubeconfig to the client factory.

[sjenning]

/lgtm

[k8s-ci-robot]

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In response to this:

/lgtm

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[DirectXMan12]

/lgtm
/approve

[DirectXMan12]

approve bot might be borked right now, need to check.

[DirectXMan12]

/approve

[migueleliasweb]

There appears to be a regression error here. In the master branch the code seem to have been changed back to exactly what this PR fixed initially. Is that right?

Master branch: https://github.com/rphillips/controller-runtime/blob/master/pkg/client/config/config.go

func GetConfig() (*rest.Config, error) {
	if len(kubeconfig) > 0 {
		return clientcmd.BuildConfigFromFlags(masterURL, kubeconfig)
	}
	if len(os.Getenv("KUBECONFIG")) > 0 {
                 // HERE we have kubeconfig instead of os.Getenv("KUBECONFIG") again
		return clientcmd.BuildConfigFromFlags(masterURL, kubeconfig)
	}
	if c, err := rest.InClusterConfig(); err == nil {
		return c, nil
	}
	if usr, err := user.Current(); err == nil {
		if c, err := clientcmd.BuildConfigFromFlags(
			"", filepath.Join(usr.HomeDir, ".kube", "config")); err == nil {
			return c, nil
		}
	}

	return nil, fmt.Errorf("could not locate a kubeconfig")
}

Also, does it make sense to call rest.InClusterConfig() directly since clientcmd.BuildConfigFromFlags does it for us if the first and second params are set to empty string?

[sbueringer]

There is no master branch anymore on the upstream repository. And the code on the main branch looks different

(looks like what you linked is 5 years old)

[migueleliasweb]

Oh my god, I'm so sorry. I swear to god I was looking at the upstream kubernetes-sigs repo. My bad. Too many tabs open!

[sbueringer]

No problem. IIRC GitHub also has some magic feature that sometimes redirects you to a fork if something doesn't exist on the main repo (I don't remember when exactly)