Implement force option to protect overwriting file (#14)

README.md

@@ -84,6 +84,7 @@ cluster: karbon_cluster_name
 user: admin
 insecure: true
 verbose: false
+force: false
 kubie: false
 #ssh-agent: false
 #ssh-file: false
@@ -104,6 +105,7 @@ you can also use the following environement variable
 `KARBON_USER`  
 `KARBON_INSECURE`  
 `KARBON_VERBOSE`  
+`KARBON_FORCE`  
 `KARBON_PASSWORD`  
 `KARBON_KUBIE`  
 `KARBON_KUBIE_PATH`  
@@ -115,6 +117,10 @@ precedence is
 
 `FLAGS` => `ENV` => `CONFIG FILE` => `DEFAULT`
 
+## File overwrite
+
+You can use the `--force` option to overwrite any existing file(s) like kubeconfig or ssh key/cert.
+
 ## Password
 
 This tools never stored the password. You can use the `KARBON_PASSWORD` env variable otherwise it should be provided in an interactive way.

cmd/common.go

@@ -95,7 +95,7 @@ func (nutanix *nutanixCluster) listKarbonClusters() ([]map[string]interface{}, e
 	return clusters, nil
 }
 
-func saveKeyFile(cluster string, sshResponseJSON map[string]interface{}) error {
+func saveKeyFile(cluster string, sshResponseJSON map[string]interface{}, force bool) error {
 
 	privateKey := []byte(sshResponseJSON["private_key"].(string))
 	certificate := []byte(sshResponseJSON["certificate"].(string))
@@ -111,11 +111,23 @@ func saveKeyFile(cluster string, sshResponseJSON map[string]interface{}) error {
 
 	// Write the private key
 	privateKeyFile := filepath.Join(sshDir, cluster)
+
+	_, err = os.Stat(privateKeyFile)
+	if err == nil && !force {
+		return fmt.Errorf("file %s already exist, use force option to overwrite it", privateKeyFile)
+	}
+
 	err = ioutil.WriteFile(privateKeyFile, privateKey, 0600)
 	cobra.CheckErr(err)
 
 	// Write the certificate
 	certificateFile := filepath.Join(sshDir, fmt.Sprintf("%s-cert.pub", cluster))
+
+	_, err = os.Stat(certificateFile)
+	if err == nil && !force {
+		return fmt.Errorf("file %s already exist, use force option to overwrite it", certificateFile)
+	}
+
 	err = ioutil.WriteFile(certificateFile, certificate, 0600)
 	cobra.CheckErr(err)
 

cmd/login.go

@@ -47,6 +47,7 @@ If option enabled retrieve SSH key/cert and add them to ssh-agent or in file in
 		viper.BindPFlag("kubie-path", cmd.Flags().Lookup("kubie-path"))
 		viper.BindPFlag("ssh-agent", cmd.Flags().Lookup("ssh-agent"))
 		viper.BindPFlag("ssh-file", cmd.Flags().Lookup("ssh-file"))
+		viper.BindPFlag("force", cmd.Flags().Lookup("force"))
 	},
 	Run: func(cmd *cobra.Command, args []string) {
 
@@ -107,6 +108,11 @@ If option enabled retrieve SSH key/cert and add them to ssh-agent or in file in
 			cobra.CheckErr(err)
 		}
 
+		_, err = os.Stat(kubeconfig)
+		if err == nil && !viper.GetBool("force") {
+			cobra.CheckErr(fmt.Errorf("file %s already exist, use force option to overwrite it", kubeconfig))
+		}
+
 		err = ioutil.WriteFile(kubeconfig, data, 0600)
 		cobra.CheckErr(err)
 
@@ -132,7 +138,7 @@ If option enabled retrieve SSH key/cert and add them to ssh-agent or in file in
 		cobra.CheckErr(err)
 
 		if viper.GetBool("ssh-file") {
-			err = saveKeyFile(karbonCluster, karbonSSH)
+			err = saveKeyFile(karbonCluster, karbonSSH, viper.GetBool("force"))
 			cobra.CheckErr(err)
 		}
 
@@ -164,6 +170,8 @@ func init() {
 
 	loginCmd.Flags().BoolP("insecure", "k", false, "Skip certificate verification (this is insecure)")
 
+	loginCmd.Flags().Bool("force", false, "Overwrite file(s) if already exist")
+
 	loginCmd.Flags().Bool("kubie", false, "Store kubeconfig in independent file in kubie-path directory")
 
 	userHomeDir, err := os.UserHomeDir()