[plugin] kubectl plugin env variable is not incorrect

[tamalsaha]

I am experimenting with writing plugins for kubectl. One issue I found is that KUBECTL_PLUGINS_GLOBAL_FLAG_AS_GROUP flag is set to [] when this flag is not set.

KUBECTL_PLUGINS_GLOBAL_FLAG_AS_GROUP=[]

When I try to set this env value back via pflag.Set(), it is considered as []string{"[]"}. .This causes DefaultClientConfig(flags) to throw error. You can find my demo code here: https://github.com/tamalsaha/kubectl-plugin-demo/blob/master/root.go#L79

The real problem seems to be that String() and Set(val string) methods of stringArrayValue in pflag library does not properly handle "empty" value for flags.

[carolynvs]

I hit a similar (maybe the same?) bug in spf13/viper. Here's a related open PR: spf13/viper#398.

I was able to work around the problem by switching to StringSlice instead of StringArray. https://github.com/kubernetes-incubator/service-catalog/pull/1700/files#diff-bac754e10d86591646bb672b9577e16bR74

[fejta-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
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/lifecycle stale

[fejta-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

Send feedback to sig-testing, kubernetes/test-infra and/or fejta.
/lifecycle rotten
/remove-lifecycle stale

[nikhita]

/remove-lifecycle rotten

[seans3]

/sig cli
/kind kubectl
/assign @juanvallejo

[seans3]

/area kubectl

[seans3]

/priority P2

[seans3]

Is this still relevant with the new plugin mechanism? Please close if this is obsolete.

[juanvallejo]

This should no longer be an issue with the updated plugin mechanism. Environment variables are now passed as-is, and user-defined command flags and parameters are now passed straight through to a plugin executable.

/close

[k8s-ci-robot]

@juanvallejo: Closing this issue.

In response to this:

This should no longer be an issue with the updated plugin mechanism. Environment variables are now passed as-is, and user-defined command flags and parameters are now passed straight through to a plugin executable.

/close

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