writing temporary kubeconfig files and adding a cleanup command

cmd/switcher/switch.go

@@ -9,10 +9,10 @@ import (
 )
 
 var (
-	kubeconfigDir     string
-	kubeconfigName     string
-	showPreview     bool
-	cmd = &cobra.Command{
+	kubeconfigDir  string
+	kubeconfigName string
+	showPreview    bool
+	rootCommand    = &cobra.Command{
 		Use:   "switch",
 		Short: "Launch the kubeconfig switcher",
 		Long: `Simple tool for switching between kubeconfig files.`,
@@ -22,23 +22,35 @@ var (
 	}
 )
 
+func init() {
+	deleteCmd := &cobra.Command{
+		Use:   "clean",
+		Short: "Cleans all temporary kubeconfig files",
+		Long: `Cleans the temporary kubeconfig files created in the directory $HOME/.kube/switch_tmp`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return pkg.Clean()
+		},
+	}
+	rootCommand.AddCommand(deleteCmd)
+}
+
 func NewCommandStartSwitcher() *cobra.Command {
-	return cmd
+	return rootCommand
 }
 
 func init() {
-	cmd.Flags().StringVar(
+	rootCommand.Flags().StringVar(
 		&kubeconfigDir,
 		"kubeconfig-directory",
-		os.ExpandEnv("$HOME/.kube/switch"),
+		os.ExpandEnv("$HOME/.kube"),
 		"directory containing the kubeconfig files.")
 
-	cmd.Flags().StringVar(
+	rootCommand.Flags().StringVar(
 		&kubeconfigName,
 		"kubeconfig-name",
 		"config",
 		"only shows kubeconfig files with exactly this name.")
-	cmd.Flags().BoolVar(
+	rootCommand.Flags().BoolVar(
 		&showPreview,
 		"show-preview",
 		true,

hack/switch/switch.sh

@@ -3,11 +3,12 @@
 usage()
 {
    echo "Usage:"
-   echo -e "  --kubeconfig-directory directory containing the kubeconfig files. Default is $HOME/.kube/switch"
+   echo -e "  --kubeconfig-directory directory containing the kubeconfig files. Default is $HOME/.kube"
    echo -e "  --kubeconfig-name only shows kubeconfig files with exactly this name. Defaults to 'config'."
    echo -e "  --executable-path path to the 'switch' executable. If unset tries to use 'switch' from the path."
    echo -e "  --show-preview if it should show a preview. Preview is sanitized from credentials. Defaults to true."
    echo -e "  --help shows available flags."
+   echo -e "  clean removes all the temporary kubeconfig files created in the directory $HOME/.kube/switch_tmp."
 }
 
 switch(){
@@ -19,6 +20,7 @@ switch(){
   KUBECONFIG_NAME=''
   EXECUTABLE_PATH=''
   SHOW_PREVIEW=''
+  CLEAN=''
 
   while test $# -gt 0; do
              case "$1" in
@@ -42,6 +44,10 @@ switch(){
                       SHOW_PREVIEW=$1
                       shift
                       ;;
+                  clean)
+                      CLEAN=$1
+                      shift
+                      ;;
                   --help)
                      usage
                      return
@@ -83,6 +89,12 @@ switch(){
      EXECUTABLE_PATH=$DEFAULT_EXECUTABLE_PATH
   fi
 
+  if [ -n "$CLEAN" ]
+  then
+     $EXECUTABLE_PATH clean
+     return
+  fi
+
   # execute golang binary handing over all the flags
   NEW_KUBECONFIG=$($EXECUTABLE_PATH $KUBECONFIG_DIRECTORY_FLAG ${KUBECONFIG_DIRECTORY} $KUBECONFIG_NAME_FLAG ${KUBECONFIG_NAME} $SHOW_PREVIEW_FLAG ${SHOW_PREVIEW})
   if [[ "$?" = "0" ]]; then

pkg/clean.go

@@ -0,0 +1,18 @@
+package pkg
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
+func Clean() error {
+	tempDir := os.ExpandEnv(temporaryKubeconfigDir)
+	files,_ := ioutil.ReadDir(tempDir)
+	err := os.RemoveAll(tempDir)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Cleaned %d files.", len(files))
+	return nil
+}

pkg/main.go

@@ -17,6 +17,7 @@ import (
 
 const separator = "/"
 const kubeconfigCurrentContext = "current-context:"
+const temporaryKubeconfigDir = "$HOME/.kube/.switch_tmp"
 
 func Switcher(kubeconfigDirectory, kubeconfigName string, showPreview bool) error {
 	kubeconfigPaths, err := findFilePathsInDirectory(kubeconfigDirectory, kubeconfigName)
@@ -81,20 +82,21 @@ func Switcher(kubeconfigDirectory, kubeconfigName string, showPreview bool) erro
 		log.Fatal(err)
 	}
 
-	// map selection back to Kubeconfig
+	// map selection back to kubeconfig
 	selectedContext := allKubeconfigContextNames[idx]
 	kubeconfigPath := contextToPathMapping[selectedContext]
 
 	// remove the folder name from the context name
 	split := strings.Split(selectedContext, separator)
 	selectedContext = split[len(split)-1]
 
-	if err := setCurrentContext(kubeconfigPath, selectedContext); err != nil {
+	tempKubeconfigPath, err := setCurrentContext(kubeconfigPath, selectedContext)
+	if err != nil {
 		log.Fatalf("failed to write current context to kubeconfig: %v", err)
 	}
 
 	// print kubeconfig path to std.out -> captured by calling bash script to set KUBECONFIG ENV Variable
-	fmt.Print(kubeconfigPath)
+	fmt.Print(tempKubeconfigPath)
 
 	return nil
 }
@@ -135,7 +137,7 @@ func getContextNames(config *types.KubeConfig, parentFoldername string) []string
 	return contextNames
 }
 
-func setCurrentContext(kubeconfigPath, ctxnName string) error {
+func setCurrentContext(kubeconfigPath string, ctxnName string) (string, error) {
 	currentContext := fmt.Sprintf("%s %s", kubeconfigCurrentContext, ctxnName)
 
 	input, err := ioutil.ReadFile(kubeconfigPath)
@@ -153,16 +155,31 @@ func setCurrentContext(kubeconfigPath, ctxnName string) error {
 		}
 	}
 
-	if !foundCurrentContext {
-		return appendCurrentContext(kubeconfigPath, currentContext)
+	output := strings.Join(lines, "\n")
+	tempDir := os.ExpandEnv(temporaryKubeconfigDir)
+	err = os.Mkdir(tempDir, 0700)
+	if err != nil && !os.IsExist(err) {
+		log.Fatalln(err)
 	}
 
-	output := strings.Join(lines, "\n")
-	err = ioutil.WriteFile(kubeconfigPath, []byte(output), 0644)
+	// write temporary kubeconfig file
+	file, err := ioutil.TempFile(tempDir, "config.*.tmp")
 	if err != nil {
 		log.Fatalln(err)
 	}
-	return nil
+
+	_, err = file.Write([]byte(output))
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	// if written file does not have the current context set,
+	// add the context at the last line of the file
+	if !foundCurrentContext {
+		return file.Name(), appendCurrentContext(file.Name(), currentContext)
+	}
+
+	return file.Name(), nil
 }
 
 func appendCurrentContext(kubeconfigPath, currentContext string) error {