Merge pull request #180 from justinsb/delete_cluster_positional_arg

kops delete cluster now recognizes clustername as a positional arg

cmd/kops/delete_cluster.go

@@ -23,11 +23,11 @@ var deleteCluster DeleteClusterCmd
 
 func init() {
 	cmd := &cobra.Command{
-		Use:   "cluster",
+		Use:   "cluster CLUSTERNAME [--yes]",
 		Short: "Delete cluster",
 		Long:  `Deletes a k8s cluster.`,
 		Run: func(cmd *cobra.Command, args []string) {
-			err := deleteCluster.Run()
+			err := deleteCluster.Run(args)
 			if err != nil {
 				glog.Exitf("%v", err)
 			}
@@ -45,9 +45,13 @@ func init() {
 
 type getter func(o interface{}) interface{}
 
-func (c *DeleteClusterCmd) Run() error {
+func (c *DeleteClusterCmd) Run(args []string) error {
 	var clusterRegistry *api.ClusterRegistry
-	var err error
+
+	err := rootCommand.ProcessArgs(args)
+	if err != nil {
+		return err
+	}
 
 	var cloud fi.Cloud
 	clusterName := ""
@@ -55,7 +59,7 @@ func (c *DeleteClusterCmd) Run() error {
 	if c.External {
 		region = c.Region
 		if region == "" {
-			return fmt.Errorf("--region is required")
+			return fmt.Errorf("--region is required (when --external)")
 		}
 		clusterName = rootCommand.clusterName
 		if clusterName == "" {

cmd/kops/root.go

@@ -79,6 +79,26 @@ func (c *RootCmd) AddCommand(cmd *cobra.Command) {
 	c.cobraCommand.AddCommand(cmd)
 }
 
+// ProcessArgs will parse the positional args.  It assumes one of these formats:
+//  * <no arguments at all>
+//  * <clustername> (and --name not specified)
+// Everything else is an error.
+func (c *RootCmd) ProcessArgs(args []string) error {
+	if len(args) == 0 {
+		return nil
+	}
+	if len(args) == 1 {
+		// Assume <clustername>
+		if c.clusterName != "" {
+			return fmt.Errorf("Cannot specify cluster via --name and positional argument")
+		}
+		c.clusterName = args[0]
+		return nil
+	}
+
+	return fmt.Errorf("expected a single <clustername> to be passed as an argument")
+}
+
 func (c *RootCmd) ClusterName() string {
 	if c.clusterName != "" {
 		return c.clusterName