Disable alpha kustomize commands by default.

- enable alpha commands with env KUSTOMIZE_SHOW_ALPHA_COMMANDS=true

cmd/config/cmds/cmds.go

@@ -12,6 +12,7 @@ import (
 	"sigs.k8s.io/kustomize/cmd/config/cmd"
 	"sigs.k8s.io/kustomize/cmd/config/cmddocs/api"
 	"sigs.k8s.io/kustomize/cmd/config/cmddocs/tutorials"
+	"sigs.k8s.io/kustomize/kyaml/commandutil"
 )
 
 var root = &cobra.Command{
@@ -40,7 +41,6 @@ Advanced Documentation Topics:
 	$ kustomize help config docs-fn
 	$ kustomize help config docs-io-annotations
 `,
-	Version: "v0.0.1",
 }
 
 // NewConfigCommand returns a new *cobra.Command for the config command group.  This may
@@ -52,6 +52,18 @@ Advanced Documentation Topics:
 // "kustomize" and the built-in docs will display "kustomize config" in the examples.
 //
 func NewConfigCommand(name string) *cobra.Command {
+	// config command is alpha
+	root.Version = "v0.0.0"
+
+	// Only populate the command if Alpha commands are enabled.
+	if !commandutil.GetAlphaEnabled() {
+		// return the command because other subcommands are added to it
+		root.Short = "[Alpha] To enable set KUSTOMIZE_ENABLE_ALPHA_COMMANDS=true"
+		root.Long = "[Alpha] To enable set KUSTOMIZE_ENABLE_ALPHA_COMMANDS=true"
+		root.Example = ""
+		return root
+	}
+
 	root.PersistentFlags().BoolVar(&cmd.StackOnError, "stack-trace", false,
 		"print a stack-trace on failure")
 

cmd/config/cmds/example_test.go

@@ -4,13 +4,18 @@
 package cmds_test
 
 import (
+	"os"
+
 	"github.com/spf13/cobra"
 	"sigs.k8s.io/kustomize/cmd/config/cmds"
+	"sigs.k8s.io/kustomize/kyaml/commandutil"
 )
 
 // ExampleNewConfigCommand demonstrates how to embed the config command as a command inside
 // another group.
 func ExampleNewConfigCommand() {
+	// enable the config commands
+	os.Setenv(commandutil.EnableAlphaCommmandsEnvName, "true")
 	var root = &cobra.Command{
 		Use:   "my-cmd",
 		Short: "My command.",

cmd/config/main.go

@@ -10,9 +10,12 @@ import (
 	"os"
 
 	"sigs.k8s.io/kustomize/cmd/config/cmds"
+	"sigs.k8s.io/kustomize/kyaml/commandutil"
 )
 
 func main() {
+	// enable the config commands
+	os.Setenv(commandutil.EnableAlphaCommmandsEnvName, "true")
 	if err := cmds.NewConfigCommand("").Execute(); err != nil {
 		os.Exit(1)
 	}

kustomize/go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/spf13/pflag v1.0.5
 	sigs.k8s.io/kustomize/api v0.2.0
 	sigs.k8s.io/kustomize/cmd/config v0.0.0
+	sigs.k8s.io/kustomize/kyaml v0.0.0
 	sigs.k8s.io/yaml v1.1.0
 )
 

kustomize/internal/commands/config/config.go

@@ -11,6 +11,7 @@ import (
 	"sigs.k8s.io/kustomize/api/filesys"
 	"sigs.k8s.io/kustomize/api/konfig/builtinpluginconsts"
 	"sigs.k8s.io/kustomize/cmd/config/cmds"
+	"sigs.k8s.io/kustomize/kyaml/commandutil"
 )
 
 // NewCmdConfig returns an instance of 'config' subcommand.
@@ -50,7 +51,9 @@ func newCmdSave(fSys filesys.FileSystem) *cobra.Command {
 			}
 			return o.RunSave(fSys)
 		},
-		Hidden: true, // Don't display this command, but keep it for backwards compatibility.
+		// Alpha version of config is very different than the current version.
+		// If alpha is enabled, don't display this command, but keep it for backwards compatibility.
+		Hidden: commandutil.GetAlphaEnabled(),
 		Deprecated: `The save command is deprecated and will be removed in a future release.
 
 If you require this command file an issue at https://github.com/kubernetes-sigs/kustomize/issues

kyaml/commandutil/commandutil.go

@@ -0,0 +1,14 @@
+package commandutil
+
+import (
+	"os"
+)
+
+// EnabkeAlphaCommmandsEnvName is the environment variable used to enable Alpha kustomize commands.
+//If set to "true" alpha commands will be enabled.
+const EnableAlphaCommmandsEnvName = "KUSTOMIZE_ENABLE_ALPHA_COMMANDS"
+
+// GetAlphaEnabled returns true if alpha commands should be enabled.
+func GetAlphaEnabled() bool {
+	return os.Getenv(EnableAlphaCommmandsEnvName) == "true"
+}