Merge pull request #2283 from lonelyCZ/pr-options-cmd

karmadactl: Introduce options subcmd to list global command-line options

pkg/karmadactl/cmdinit/cmdinit.go

@@ -76,7 +76,7 @@ func NewCmdInit(parentCommand string) *cobra.Command {
 			return nil
 		},
 	}
-	flags := cmd.PersistentFlags()
+	flags := cmd.Flags()
 
 	releaseVer, err := version.ParseGitVersion(version.Get().GitVersion)
 	if err != nil {

pkg/karmadactl/karmadactl.go

@@ -14,6 +14,7 @@ import (
 	"k8s.io/kubectl/pkg/util/templates"
 
 	"github.com/karmada-io/karmada/pkg/karmadactl/cmdinit"
+	"github.com/karmada-io/karmada/pkg/karmadactl/options"
 	"github.com/karmada-io/karmada/pkg/version/sharedcommand"
 )
 
@@ -95,6 +96,7 @@ func NewKarmadaCtlCommand(cmdUse, parentCommand string) *cobra.Command {
 	filters := []string{"options"}
 
 	rootCmd.AddCommand(sharedcommand.NewCmdVersion(parentCommand))
+	rootCmd.AddCommand(options.NewCmdOptions(parentCommand, ioStreams.Out))
 
 	templates.ActsAsRootCommand(rootCmd, filters, groups...)
 

pkg/karmadactl/options/options.go

@@ -0,0 +1,41 @@
+package options
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/spf13/cobra"
+	"k8s.io/kubectl/pkg/util/templates"
+)
+
+var (
+	optionsExample = templates.Examples(`
+		# Print flags inherited by all commands
+		%[1]s options`)
+)
+
+// NewCmdOptions implements the options command
+func NewCmdOptions(parentCommand string, out io.Writer) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:     "options",
+		Short:   "Print the list of flags inherited by all commands",
+		Long:    "Print the list of flags inherited by all commands",
+		Example: fmt.Sprintf(optionsExample, parentCommand),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if err := cmd.Usage(); err != nil {
+				return err
+			}
+			return nil
+		},
+	}
+
+	// The `options` command needs write its output to the `out` stream
+	// (typically stdout). Without calling SetOutput here, the Usage()
+	// function call will fall back to stderr.
+	//
+	// See https://github.com/kubernetes/kubernetes/pull/46394 for details.
+	cmd.SetOutput(out)
+
+	templates.UseOptionsTemplates(cmd)
+	return cmd
+}