k8s client-go rest.Config api.Config

I am trying to run a tool(Tekton cli) in a container.

It could be any tool using kubeconfig, as long I can give it a parameter of kubeconfig.

In code I can use InClusterConfig, but I am using a tool that do not use InClusterConfig, so I was thinking maybe I can write out the kubeconfig file from client-go InClusterConfig and use it as a parameter to the tool(Tekton cli)

I found some usage of clientcmd.WriteToFile but I can not figure out how to convert rest.Config to api.Config - and why are there so many Config types.

Anyways do you know how to write out restclient.InClusterConfig to a file, so it can be used as kubeconfig file?

if clusterConfig, err := restclient.InClusterConfig(); err == nil {
    if tempFile, err := ioutil.TempFile(os.TempDir(), "kubeconfig-"); err == nil {
        // problem >> kubeConfig := createKubeConfig(clusterConfig)
        clientcmd.WriteToFile(*kubeConfig, tempFile.Name())
    }
}

A ClientConfig may be instantiated based on a KubeConfig. The ClientConfig has a method ClientConfig() which returns *rest.Config; it also has a method RawConfig() which may be used to get an api.Config.

The KubeConfig may then be written back to a file using the clientCmd.WriteToFile() method and passing the api.Config returned from RawConfig().

package main

import (
   "k8s.io/client-go/rest"
   "k8s.io/client-go/tools/clientcmd"
   "k8s.io/client-go/tools/clientcmd/api"
   "log"
)   

var clientCfg clientcmd.ClientConfig

clientCfg, err = clientcmd.NewClientConfigFromBytes(kubeConfig)
if err != nil {
   log.Fatal(err)
}

var restCfg *rest.Config

restCfg, err = clientCfg.ClientConfig()
if err != nil {
   log.Fatal(err)
}

var apiCfg api.Config

apiCfg, err = clientCfg.RawConfig()
if err != nil {
   log.Fatal(err)
}

err = clientcmd.WriteToFile(apiCfg, filename)
if err != nil {
   log.Fatal(err)
}