Make guest name be an argument and not a flag

README.md

@@ -44,13 +44,13 @@ virgo makes use of the following utilities:
 
 Provision a new VM called "foo":
 ```console
-$ sudo virgo provision --config guest_config.json --provision-script provision.sh --initd-script initd.sh --guest foo
+$ sudo virgo provision foo --config guest_config.json --provision-script provision.sh --initd-script initd.sh
 ```
 "foo" will shutdown after provisioning. 
 
 Edit `guest_config.json` to change VM's parameters (e.g. #vCPUs), and launch "foo":
 ```console
-$ sudo virgo --config guest_config.json --guest foo
+$ sudo virgo launch foo --config guest_config.json
 ```
 
 Usage:

cmd/launch.go

@@ -18,11 +18,9 @@ Any previous specification of the VM is overriden by the new launch options.
 
 The available launch options are presented in detail in virgo's main help message.
 `,
+	Args: cobra.ExactArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
-		guest, err := cmd.Flags().GetString("guest")
-		if err != nil {
-			return fmt.Errorf("failed to parse 'guest' argument: %v", err)
-		}
+		guest := args[0]
 
 		conf, err := cmd.Flags().GetString("config")
 		if err != nil {
@@ -64,7 +62,6 @@ The available launch options are presented in detail in virgo's main help messag
 }
 
 func init() {
-	launchCmd.Flags().StringP("guest", "g", "", "guest to launch")
 	launchCmd.Flags().StringP("config", "c", "", "JSON file containing the launch options")
 	rootCmd.AddCommand(launchCmd)
 }

cmd/provision.go

@@ -18,11 +18,9 @@ var provisionCmd = &cobra.Command{
 The available provisioning options are presented in detail in virgo's main help message. 
 The bash script can be any valid bash script and is executed with root permissions. 
 `,
+	Args: cobra.ExactArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
-		guest, err := cmd.Flags().GetString("guest")
-		if err != nil {
-			return fmt.Errorf("failed to parse 'guest' argument: %v", err)
-		}
+		guest := args[0]
 
 		provisionScript, err := cmd.Flags().GetString("provision-script")
 		if err != nil {
@@ -90,11 +88,9 @@ The bash script can be any valid bash script and is executed with root permissio
 }
 
 func init() {
-	provisionCmd.Flags().StringP("guest", "g", "", "guest to provision")
 	provisionCmd.Flags().StringP("provision-script", "p", "", "bash script to be used for provisioning")
 	provisionCmd.Flags().StringP("initd-script", "i", "", "bash script to be used in init.d")
 	provisionCmd.Flags().StringP("config", "c", "", "JSON file containing the provisioning options")
 	provisionCmd.MarkFlagRequired("config")
-	provisionCmd.MarkFlagRequired("guest")
 	rootCmd.AddCommand(provisionCmd)
 }

cmd/purge.go

@@ -12,11 +12,9 @@ var purgeCmd = &cobra.Command{
 	Use:   "purge",
 	Short: "Fully destroy a VM by undefining it and removing its image",
 	Long:  `Fully destroy a domain by undefining it and removing its image`,
+	Args: cobra.ExactArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
-		guest, err := cmd.Flags().GetString("guest")
-		if err != nil {
-			return fmt.Errorf("failed to parse 'guest' argument: %v", err)
-		}
+		guest := args[0]
 
 		l, err := virgo.NewLibvirtConn()
 		if err != nil {
@@ -40,7 +38,5 @@ var purgeCmd = &cobra.Command{
 }
 
 func init() {
-	purgeCmd.Flags().StringP("guest", "g", "", "guest to purge")
-	purgeCmd.MarkFlagRequired("guest")
 	rootCmd.AddCommand(purgeCmd)
 }

cmd/root.go

@@ -13,6 +13,9 @@ var rootCmd = &cobra.Command{
 	Short: "virgo enables easy provisioning, configuration and management of Libvirt guests",
 	Long: `virgo enables easy provisioning, configuration and management of Libvirt guests. 
 
+All virgo commands accept a single argument, the name of the VM they act upon. Every command
+has its own flags. 
+
 For provisioning a new VM image, you should specify a JSON config file with provisioning
 options, along with a provisioning script to be executed on image's first boot.
 

cmd/ssh.go

@@ -17,7 +17,7 @@ Cobra is a CLI library for Go that empowers applications.
 This application is a tool to generate the needed files
 to quickly create a Cobra application.`,
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("ssh called")
+		fmt.Printf("ssh called, args %+v", args)
 	},
 }
 

cmd/start.go

@@ -14,11 +14,9 @@ var startCmd = &cobra.Command{
 	Long: `Create a new VM instance from an already existing specification.
 This implies that the VM should have been already launched at least once in the past, 
 either via 'provision' or 'launch'`,
+	Args: cobra.ExactArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
-		guest, err := cmd.Flags().GetString("guest")
-		if err != nil {
-			return fmt.Errorf("failed to parse 'guest' argument: %v", err)
-		}
+		guest := args[0]
 
 		l, err := virgo.NewLibvirtConn()
 		if err != nil {
@@ -38,7 +36,5 @@ either via 'provision' or 'launch'`,
 }
 
 func init() {
-	startCmd.Flags().StringP("guest", "g", "", "guest to start")
-	startCmd.MarkFlagRequired("guest")
 	rootCmd.AddCommand(startCmd)
 }

cmd/stop.go

@@ -12,11 +12,9 @@ var stopCmd = &cobra.Command{
 	Use:   "stop",
 	Short: "Shut down a running VM instance",
 	Long:  `Shut down a running VM instance. Keep its current definition intact.`,
+	Args: cobra.ExactArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
-		guest, err := cmd.Flags().GetString("guest")
-		if err != nil {
-			return fmt.Errorf("failed to parse 'guest' argument: %v", err)
-		}
+		guest := args[0]
 
 		l, err := virgo.NewLibvirtConn()
 		if err != nil {
@@ -36,7 +34,5 @@ var stopCmd = &cobra.Command{
 }
 
 func init() {
-	stopCmd.Flags().StringP("guest", "g", "", "guest to stop")
-	stopCmd.MarkFlagRequired("guest")
 	rootCmd.AddCommand(stopCmd)
 }

cmd/undefine.go

@@ -14,11 +14,9 @@ var undefineCmd = &cobra.Command{
 	Short: "Undefine a VM by removing its specification",
 	Long: `Undefine a VM by removing its specification. Its image is not affected.
 If it's running, the domain is first stopped.'`,
+	Args: cobra.ExactArgs(1),
 	RunE: func(cmd *cobra.Command, args []string) error {
-		guest, err := cmd.Flags().GetString("guest")
-		if err != nil {
-			return fmt.Errorf("failed to parse 'guest' argument: %v", err)
-		}
+		guest := args[0]
 
 		l, err := virgo.NewLibvirtConn()
 		if err != nil {
@@ -38,7 +36,5 @@ If it's running, the domain is first stopped.'`,
 }
 
 func init() {
-	undefineCmd.Flags().StringP("guest", "g", "", "guest to undefine")
-	undefineCmd.MarkFlagRequired("guest")
 	rootCmd.AddCommand(undefineCmd)
 }