Can't override Kubernetes config in Kubernetes Go client

Question

I want to use Kubernetes Go client to execute various actions in a cluster. I am loading my local kubeconfig which contains multiple clusters and contexts. The default context is prod and one of the config values I want to override is the CurrentContext

    clientConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
        &clientcmd.ClientConfigLoadingRules{ExplicitPath: "/Users/me/.kube/config"},
        &clientcmd.ConfigOverrides{
            CurrentContext: "stage",
        })

    rawConfig, _ := clientConfig.RawConfig()
    log.Printf(rawConfig.CurrentContext) // outputs "prod" instead of "stage"

When I inspect RawConfig() the current context is still "prod" instead of "stage". Why does the config override not work?

Also how does the override for AuthInfo etc. work? The override accepts only a single AuthInfo whereas the configuration contains a map of AuthInfo etc.

GitHub related issue https://github.com/kubernetes/client-go/issues/735

Answer 1

Why does the config override not work?

according to

https://github.com/kubernetes/client-go/blob/a432bd9ba7da427ae0a38a6889d72136bce4c4ea/tools/clientcmd/client_config.go#L57-L58

// ClientConfig is used to make it easy to get an api server client
type ClientConfig interface {
    // RawConfig returns the merged result of all overrides
    RawConfig() (clientcmdapi.Config, error)

RawConfig should return config with overrides, but it really doesn't

https://github.com/kubernetes/client-go/blob/a432bd9ba7da427ae0a38a6889d72136bce4c4ea/tools/clientcmd/client_config.go#L122-L124

func (config *DirectClientConfig) RawConfig() (clientcmdapi.Config, error) {
    return config.config, nil
}

just return config without overrides. You could see a possible solution here in my patch

https://github.com/vvelikodny/kubernetes-client-go/pull/1/files

Also how does the override for AuthInfo etc. work? The override accepts only a single AuthInfo whereas the configuration contains a map of AuthInfo etc.

override only AuthInfo with the key of username which presented in context.AuthInfo (string).

https://github.com/kubernetes/client-go/blob/a432bd9ba7da427ae0a38a6889d72136bce4c4ea/tools/clientcmd/client_config.go#L424-L437

https://github.com/kubernetes/client-go/blob/a432bd9ba7da427ae0a38a6889d72136bce4c4ea/tools/clientcmd/client_config.go#L388-L394

// getAuthInfoName returns a string containing the current authinfo name for the current context,
// and a boolean indicating  whether the default authInfo name is overwritten by a user-set flag, or
// left as its default value
func (config *DirectClientConfig) getAuthInfoName() (string, bool) {
    if len(config.overrides.Context.AuthInfo) != 0 {
        return config.overrides.Context.AuthInfo, true
    }
    context, _ := config.getContext()
    return context.AuthInfo, false
}