First prototype for config splitter

main.go

@@ -7,23 +7,149 @@ import (
 	"path/filepath"
 
 	clientcmd "k8s.io/client-go/tools/clientcmd"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
+)
+
+const (
+	kubeConfigFlagKey = "kubeconfig"
+
+	homeEnvVar = "HOME"
+	homeEnvVarDefault = "~/"
+
+	kubeConfigFolderDefault = ".kube"
+	kubeConfigFilenameDefault = "config"
+
+	kubeConfigOutputFolderName = ".kube/configs"
+	kubeConfigOutputFolderPerm = 0755
+
+	//kubeConfigEnvVar = "KUBECONFIG"
+	kubeConfigEnvVar = "NEW_KUBECONFIG"
 )
 
 func main() {
+	fmt.Println("📚 Get Kubernetes configuration file")
+	kubeConfigFilePath := getKubeConfigFlagValue(kubeConfigFlagKey)
+	srcConfig := getKubeConfig(*kubeConfigFilePath)
+
+	fmt.Println("✂️ Split Kubernetes configuration file")
+	tgConfigs := splitKubeConfig(srcConfig)
 
-	var kubeconfig *string
-	if home := homeDir(); home != "" {
-		kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeconfig file")
-	} else {
-		kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
+	fmt.Println(" Save single Kubernetes configuration files")
+	configsPath, saveErr := saveKubeConfigs(tgConfigs)
+	if saveErr != nil {
+		fmt.Println("❌ ERROR: " + saveErr.Error())
+		os.Exit(1)
 	}
-	config := clientcmd.GetConfigFromFileOrDie(*kubeconfig)
-	fmt.Println(*config)
+	fmt.Printf("✅ Completed, files stored in '%s'\n", configsPath)
+
+	envErr := setKubeConfigEnvVar(configsPath)
+	if envErr != nil {
+		fmt.Println("❌ ERROR: " + envErr.Error())
+		os.Exit(1)
+	}
+	fmt.Printf( "👀 New '%s' env var: '%s'\n", kubeConfigEnvVar, getKubeConfigEnvVar())
+
+	fmt.Println("")
 }
 
-func homeDir() string {
-	if h := os.Getenv("HOME"); h != "" {
-		return h
+func getKubeConfigFlagValue(flagKey string) *string {
+	home := getHomeDir()
+	//if home != "" {
+		return flag.String(flagKey, filepath.Join(home, kubeConfigFolderDefault, kubeConfigFilenameDefault), "(optional) absolute path to the kubeconfig file")
+	//} else {
+	//	return flag.String(flagKey, "", "absolute path to the kubeconfig file")
+	//}
+}
+
+func getKubeConfig(kubeConfigFilePath string) *clientcmdapi.Config {
+	return clientcmd.GetConfigFromFileOrDie(kubeConfigFilePath)
+}
+
+func splitKubeConfig(srcConfig *clientcmdapi.Config) map[string]*clientcmdapi.Config {
+	tgConfigs := make(map[string]*clientcmdapi.Config, len(srcConfig.Contexts))
+	for ctxKey, ctxValue := range srcConfig.Contexts {
+		contexts := make(map[string]*clientcmdapi.Context, 1)
+		contexts[ctxKey] = ctxValue
+		clusters := make(map[string]*clientcmdapi.Cluster, 1)
+		clusters[ctxValue.Cluster] = srcConfig.Clusters[ctxValue.Cluster]
+		authInfos := make(map[string]*clientcmdapi.AuthInfo, 1)
+		authInfos[ctxValue.AuthInfo] = srcConfig.AuthInfos[ctxValue.AuthInfo]
+		tgConfigs[ctxKey] = &clientcmdapi.Config{
+			APIVersion: srcConfig.APIVersion,
+			Kind: srcConfig.Kind,
+			CurrentContext: ctxKey,
+			Contexts: contexts,
+			Clusters: clusters,
+			AuthInfos: authInfos,
+		}
+	}
+	return tgConfigs
+}
+
+func saveKubeConfigs(configs map[string]*clientcmdapi.Config) (string, error) {
+	configsPath := buildKubeConfigsPath(getHomeDir(), kubeConfigOutputFolderName)
+
+	fmt.Printf("Check '%s' configs folder\n", configsPath)
+	checkErr := checkKubeConfigsFolder(configsPath, kubeConfigOutputFolderPerm)
+	if checkErr != nil {
+		return "", checkErr
+	}
+
+	for cfgKey, cfg := range configs {
+		fmt.Printf("Validate config '%s'\n", cfgKey)
+		valErr := validateKubeConfig(cfg)
+		if valErr != nil {
+			return "", valErr
+		}
+		fmt.Printf("Write config '%s' to file\n", cfgKey)
+		writeErr := writeKubeConfig(cfg, filepath.Join(configsPath, cfgKey))
+		if writeErr != nil {
+			return "", writeErr
+		}
 	}
-	return "~/"
+
+	return configsPath, nil
+}
+
+func checkKubeConfigsFolder(path string, mode os.FileMode) error {
+	_, statErr := os.Stat(path)
+	if statErr != nil {
+		if os.IsNotExist(statErr) {
+			return os.Mkdir(path, mode)
+		}
+		return statErr
+	}
+	return nil
+}
+
+func validateKubeConfig(config *clientcmdapi.Config) error {
+	validateErr := clientcmd.Validate(*config)
+	if clientcmd.IsConfigurationInvalid(validateErr) {
+		return validateErr
+	}
+	return nil
+}
+
+func writeKubeConfig(config *clientcmdapi.Config, filepath string) error {
+	return clientcmd.WriteToFile(*config, filepath)
+}
+
+func getHomeDir() string {
+	home := os.Getenv(homeEnvVar)
+	if home != "" {
+		return home
+	}
+	return homeEnvVarDefault
+}
+
+func buildKubeConfigsPath(home, path string) string {
+	return filepath.Join(home, path)
+}
+
+func setKubeConfigEnvVar(kubeConfigsPath string) error {
+	return os.Setenv(kubeConfigEnvVar, kubeConfigsPath)
+}
+
+func getKubeConfigEnvVar() string {
+	return os.Getenv(kubeConfigEnvVar)
 }