Add Support for --kubeconfig flag in skaffold run/dev commands

[sujit-kamireddy]

Skaffold run/dev commands support the --kube-context flag to get the context name, but relies on the KUBECONFIG env variable to get the list of kubeconfig file(s).

The ask is below:
Like the kubectl, support --kubeconfig flag that takes a single kubeconfig file path and prefer this flag over the KUBECONFIG env variable when both are present.

Adding this flag will enable us to specify the exact kubeconfig file and the context name that we want to work with, in a consistent way.

Reference: https://kubernetes.io/docs/concepts/configuration/organize-cluster-access-kubeconfig

[balopat]

this should be relatively easy to implement, it's a medium sized work, we need to make sure we test for these too:

1. kustomize/kubectl: we can pass the value of the flag directly to kubectl, probably here: https://github.com/GoogleContainerTools/skaffold/blob/master/pkg/skaffold/kubectl/cli.go#L83
2. helm: does not support it (add --kubeconfig option helm/helm#2219) so we need to set the env var - probably here: https://github.com/GoogleContainerTools/skaffold/blob/master/pkg/skaffold/deploy/helm.go#L159
3. for client-go, somewhere here: https://github.com/GoogleContainerTools/skaffold/blob/master/pkg/skaffold/kubernetes/context/context.go#L75

[marti1125]

Could I work on this ?

[balopat]

Hi @marti1125, absolutely!

[corneliusweig]

@marti1125 Are you still working on this? If you need input or support feel free to ping me.

[marti1125]

yes please I need help @corneliusweig at slack

[corneliusweig]

yes please I need help @corneliusweig at slack

I found your message in the #skaffold channel and pinged you. If feasible, I would prefer to keep the conversation on github though.

[balopat]

ping @marti1125 @corneliusweig are you looking at this? It would be important for us to move forward with it. Let me know!

[corneliusweig]

@marti1125 Would you be ok if I send a PR and you do a review round on it? Given the priority of the issue this might be a good alternative. WDYT?

[marti1125]

@corneliusweig yes please