Add support for KUBECONTEXT environment variable and --kubecontext option into botkube CLI

[mickael-ange]

I will edit later. I'm still testing.

Description

Changes proposed in this pull request:

• Add support for KUBECONTEXT environment variable and --kubecontext option into botkube CLI

Testing

Related issue(s)

Resolves #1456

[pkosiec]

Works well! 🚀

Please see my minor comments and run the following commands to pass the CI checks:

make gen-docs-cli
make lint-fix

Then I'll approve and merge it 👍 Thank you for your contribution!

[pkosiec]

This change is not needed, right? As you pass the &clientcmd.ConfigOverrides{CurrentContext: kubecontext}, it is already properly set? So that means we can revert this to:

func transform(c clientcmd.ClientConfig) (*ConfigWithMeta, error) {
	rawConfig, err := c.RawConfig()
	if err != nil {
		return nil, fmt.Errorf("while getting raw config: %v", err)
	}

	clientConfig, err := c.ClientConfig()
	if err != nil {
		return nil, fmt.Errorf("while getting client config: %v", err)
	}

	return &ConfigWithMeta{
		K8s:            clientConfig,
		CurrentContext: rawConfig.CurrentContext,
	}, nil
}

[mickael-ange]

Yes, I also feel like it was redundant.

I was expecting the same but I don't know why the value of c.RawConfig().CurrentContext is not equal to the value set by configOverrides := &clientcmd.ConfigOverrides{CurrentContext: kubecontext} by the caller of transform.

The value of c.RawConfig().CurrentContext remains the current context in my ~/.kube/config, it is not override yet?!

---

I also tried to configure only ConfigWithMeta.CurrentContext in the transform function and gave up the overrides in LoadRestConfigWithMetaInformation. The ConfigWithMeta.CurrentContext was set correctly but Helm was trying to connect to the cluster which was corresponding to the previously context value.

	return transform(clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, nil))
}

func transform(c clientcmd.ClientConfig) (*ConfigWithMeta, error) {
	rawConfig, err := c.RawConfig()
	if err != nil {
		return nil, fmt.Errorf("while getting raw config: %v", err)
	}

	clientConfig, err := c.ClientConfig()
	if err != nil {
		return nil, fmt.Errorf("while getting client config: %v", err)
	}

	//  1. --kubecontext flag
	if kubecontext == "" {
		// 2. KUBECONTEXT env
		kubecontext = os.Getenv("KUBECONTEXT")
		// 3. load from rawConfig
		if len(kubecontext) == 0 {
			kubecontext = rawConfig.CurrentContext
		}
	}

	return &ConfigWithMeta{
		K8s:            clientConfig,
		CurrentContext: kubecontext,
	}, nil
}

---

I cannot get it work otherwise. I wish to understand but I may not have enough XP with Go. It just let me fell like a pointer issue or I miss understand how overrides work. I'm baffled!

[pkosiec]

Ok, I understand now 👍 Fair enough. I'm also not sure why the behavior is like that but I think we can skip that part to not spend too much time on it.
What do you think about such code then?

       // ...
	configOverrides := &clientcmd.ConfigOverrides{CurrentContext: loadKubecontext("")}
	return transform(clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, configOverrides))
}

func loadKubecontext(fallbackValue string) string {
	//  1. --kubecontext flag
	if kubecontext != "" {
		return kubecontext
	}

	// 2. KUBECONTEXT env
	kubeCtx := os.Getenv("KUBECONTEXT")
	if kubeCtx != "" {
		return kubeCtx
	}

	return fallbackValue
}

func transform(c clientcmd.ClientConfig) (*ConfigWithMeta, error) {
	rawConfig, err := c.RawConfig()
	if err != nil {
		return nil, fmt.Errorf("while getting raw config: %v", err)
	}

	clientConfig, err := c.ClientConfig()
	if err != nil {
		return nil, fmt.Errorf("while getting client config: %v", err)
	}
	
	return &ConfigWithMeta{
		K8s:            clientConfig,
		CurrentContext: loadKubecontext(rawConfig.CurrentContext),
	}, nil
}

Does it look a bit cleaner? If so, then please apply the snippet 👍

[mickael-ange]

Good by me 👍 .

[pkosiec]

What do you think about extracting the kubecontext logic to a separate function? E.g. something like

	configOverrides := &clientcmd.ConfigOverrides{CurrentContext: loadKubecontext()}
	return transform(clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, configOverrides))
}

func loadKubecontext() string {
	//  1. --kubecontext flag
	if kubecontext != "" {
		return kubecontext
	}

	// 2. KUBECONTEXT env
	return os.Getenv("KUBECONTEXT")
}

[mickael-ange]

Sounds reasonable to me.

[mickael-ange]

Works well! 🚀

Please see my minor comments and run the following commands to pass the CI checks:

make gen-docs-cli
make lint-fix

Then I'll approve and merge it 👍 Thank you for your contribution!

I will run the commands once the code logic is approved.
Thanks

[pkosiec]

🚀 Thanks again for such valuable contribution!