Switch from arguments to an input structure for kubectl command

[soltysh]

What type of PR is this?

/kind cleanup
/priority backlog
/sig cli

What this PR does / why we need it:

This PR:

1. introduces new WithWrapConfigFn function allowing to provider a wrapper for client config
2. switches kubectl from using multiple arguments to using a structure when constructing kubectl command.

This is alternative to #104926

Special notes for your reviewer:

/assign @eddiezane
/cc @dovholuknf

Does this PR introduce a user-facing change?

NONE

[soltysh]

/triage accepted

[soltysh]

/assign @dims
for cmd approval

[dovholuknf]

I am happy to confirm that these changes, from the outside consumer point of view, are exactly what's needed by me. works perfectly and simplifies our code too as well as making the api cleaner.

[soltysh]

/hold
it looks like this PR breaks -v6 I'll dig into it

[eddiezane]

Do we want to allow chaining of these functions? This is really what I meant when I said this should be a slice.

func main() {
	flags := genericclioptions.NewConfigFlags(false)
	flags = flags.WithWrapConfigFn(func(config *rest.Config) *rest.Config {
		fmt.Println("wrap 1")
		return config
	})
	flags = flags.WithWrapConfigFn(func(config *rest.Config) *rest.Config {
		fmt.Println("wrap 2")
		return config
	})
	flags.ToRESTConfig()
}

// wrap 2
// wrap 1
// Unsure of the order we'd want here.

Or am I missing something here?

Suggested change

	func (f *ConfigFlags) WithWrapConfigFn(wrapConfigFn func(*rest.Config) *rest.Config) *ConfigFlags {
	f.WrapConfigFn = wrapConfigFn
	return f
	}
	func (f *ConfigFlags) WithWrapConfigFn(wrapConfigFn func(*rest.Config) *rest.Config) *ConfigFlags {
	if f.WrapConfigFn == nil {
	f.WrapConfigFn = wrapConfigFn
	} else {
	old := f.WrapConfigFn
	f.WrapConfigFn = func(config *rest.Config) *rest.Config {
	return old(wrapConfigFn(config))
	}
	}
	return f
	}

[soltysh]

Since WrapConfigFn both accepts and returns *rest.Config you can chain then together on your own, and pass that into WithWrapConfigFn that's why I don't think we need or want to make this a slice.

[dovholuknf]

fwiw, for me the change that broke the -v6 flag was due to how the command is executed. prior it was simply created from the factory and then executed. now for -v6 to function one needs to to invoke the command using cli.Run. the default kubectl.go file was updated already and works fine.

I adapted my code to use cli.Run and I can confirm -v6 works for me.

[soltysh]

/hold cancel
the problem was elsewhere

[eddiezane]

/lgtm

[dims]

the cmd/ changes are straight forward and LGTM

/approve
/lgtm

[eddiezane]

/assign @lavalamp

[dims]

/assign @thockin @liggitt

for /cmd approval (looks like we are light on approvers, gonna add myself)

[dims]

/approve
/lgtm

(for the record)

[smarterclayton]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dims, eddiezane, smarterclayton, soltysh

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• cmd/OWNERS [smarterclayton]
• staging/src/k8s.io/cli-runtime/OWNERS [eddiezane,smarterclayton,soltysh]
• staging/src/k8s.io/kubectl/OWNERS [eddiezane,smarterclayton,soltysh]

Approvers can indicate their approval by writing /approve in a comment
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[soltysh]

for /cmd approval (looks like we are light on approvers, gonna add myself)

I've went ahead and added cli-maintaners for the missing bits in #106451