Refactor kubeadm config list-images

In preparation for creating a `kubeadm config images pull`
this commit refactors `kubeadm config list-images` into
`kubeadm config images list`.

Signed-off-by: Chuck Ha <ha.chuck@gmail.com>

cmd/kubeadm/app/cmd/config.go

@@ -66,7 +66,7 @@ func NewCmdConfig(out io.Writer) *cobra.Command {
 
 	cmd.AddCommand(NewCmdConfigUpload(out, &kubeConfigFile))
 	cmd.AddCommand(NewCmdConfigView(out, &kubeConfigFile))
-	cmd.AddCommand(NewCmdConfigListImages(out))
+	cmd.AddCommand(NewCmdConfigImages(out))
 	return cmd
 }
 
@@ -206,50 +206,61 @@ func uploadConfiguration(client clientset.Interface, cfgPath string, defaultcfg
 	return uploadconfig.UploadConfiguration(internalcfg, client)
 }
 
-// NewCmdConfigListImages returns the "kubeadm images" command
-func NewCmdConfigListImages(out io.Writer) *cobra.Command {
+// NewCmdConfigImages returns the "config images" command
+func NewCmdConfigImages(out io.Writer) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "images",
+		Short: "Interact with container images used by kubeadm.",
+		RunE:  cmdutil.SubCmdRunE("images"),
+	}
+	cmd.AddCommand(NewCmdConfigImagesList(out))
+	return cmd
+}
+
+// NewCmdConfigImagesList returns the "config images list" command
+func NewCmdConfigImagesList(out io.Writer) *cobra.Command {
 	cfg := &kubeadmapiv1alpha1.MasterConfiguration{}
 	kubeadmapiv1alpha1.SetDefaults_MasterConfiguration(cfg)
 	var cfgPath, featureGatesString string
 	var err error
 
 	cmd := &cobra.Command{
-		Use:   "list-images",
+		Use:   "list",
 		Short: "Print a list of images kubeadm will use. The configuration file is used in case any images or image repositories are customized.",
 		Run: func(_ *cobra.Command, _ []string) {
 			if cfg.FeatureGates, err = features.NewFeatureGate(&features.InitFeatureGates, featureGatesString); err != nil {
 				kubeadmutil.CheckErr(err)
 			}
-			listImages, err := NewListImages(cfgPath, cfg)
+			imagesList, err := NewImagesList(cfgPath, cfg)
 			kubeadmutil.CheckErr(err)
-			kubeadmutil.CheckErr(listImages.Run(out))
+			kubeadmutil.CheckErr(imagesList.Run(out))
 		},
 	}
-	AddListImagesConfigFlag(cmd.PersistentFlags(), cfg, &featureGatesString)
-	AddListImagesFlags(cmd.PersistentFlags(), &cfgPath)
+	AddImagesListConfigFlags(cmd.PersistentFlags(), cfg, &featureGatesString)
+	AddImagesListFlags(cmd.PersistentFlags(), &cfgPath)
 
 	return cmd
 }
 
-// NewListImages returns a "kubeadm images" command
-func NewListImages(cfgPath string, cfg *kubeadmapiv1alpha1.MasterConfiguration) (*ListImages, error) {
+// NewImagesList returns the underlying struct for the "kubeadm config images list" command
+func NewImagesList(cfgPath string, cfg *kubeadmapiv1alpha1.MasterConfiguration) (*ImagesList, error) {
 	internalcfg, err := configutil.ConfigFileAndDefaultsToInternalConfig(cfgPath, cfg)
 	if err != nil {
 		return nil, fmt.Errorf("could not convert cfg to an internal cfg: %v", err)
 	}
 
-	return &ListImages{
+	return &ImagesList{
 		cfg: internalcfg,
 	}, nil
 }
 
-// ListImages defines the struct used for "kubeadm images"
-type ListImages struct {
+// ImagesList defines the struct used for "kubeadm config images list"
+type ImagesList struct {
 	cfg *kubeadmapi.MasterConfiguration
 }
 
-// Run runs the images command and writes the result to the io.Writer passed in
-func (i *ListImages) Run(out io.Writer) error {
+// Run gets a list of images kubeadm expects to use and writes the result to the io.Writer passed in
+func (i *ImagesList) Run(out io.Writer) error {
 	imgs := images.GetAllImages(i.cfg)
 	for _, img := range imgs {
 		fmt.Fprintln(out, img)
@@ -258,8 +269,8 @@ func (i *ListImages) Run(out io.Writer) error {
 	return nil
 }
 
-// AddListImagesConfigFlag adds the flags that configure kubeadm
-func AddListImagesConfigFlag(flagSet *flag.FlagSet, cfg *kubeadmapiv1alpha1.MasterConfiguration, featureGatesString *string) {
+// AddImagesListConfigFlags adds the flags that configure kubeadm (and affect the images kubeadm will use)
+func AddImagesListConfigFlags(flagSet *flag.FlagSet, cfg *kubeadmapiv1alpha1.MasterConfiguration, featureGatesString *string) {
 	flagSet.StringVar(
 		&cfg.KubernetesVersion, "kubernetes-version", cfg.KubernetesVersion,
 		`Choose a specific Kubernetes version for the control plane.`,
@@ -268,7 +279,7 @@ func AddListImagesConfigFlag(flagSet *flag.FlagSet, cfg *kubeadmapiv1alpha1.Mast
 		"Options are:\n"+strings.Join(features.KnownFeatures(&features.InitFeatureGates), "\n"))
 }
 
-// AddListImagesFlags adds the flag that defines the location of the config file
-func AddListImagesFlags(flagSet *flag.FlagSet, cfgPath *string) {
+// AddImagesListFlags adds the flag that defines the location of the config file
+func AddImagesListFlags(flagSet *flag.FlagSet, cfgPath *string) {
 	flagSet.StringVar(cfgPath, "config", *cfgPath, "Path to kubeadm config file.")
 }

cmd/kubeadm/app/cmd/config_test.go

@@ -37,7 +37,7 @@ const (
 
 func TestNewCmdConfigListImages(t *testing.T) {
 	var output bytes.Buffer
-	images := cmd.NewCmdConfigListImages(&output)
+	images := cmd.NewCmdConfigImagesList(&output)
 	images.Run(nil, nil)
 	actual := strings.Split(output.String(), "\n")
 	if len(actual) != defaultNumberOfImages {
@@ -45,7 +45,7 @@ func TestNewCmdConfigListImages(t *testing.T) {
 	}
 }
 
-func TestListImagesRunWithCustomConfigPath(t *testing.T) {
+func TestImagesListRunWithCustomConfigPath(t *testing.T) {
 	testcases := []struct {
 		name               string
 		expectedImageCount int
@@ -99,7 +99,7 @@ func TestListImagesRunWithCustomConfigPath(t *testing.T) {
 				t.Fatalf("Failed writing a config file: %v", err)
 			}
 
-			i, err := cmd.NewListImages(configFilePath, &kubeadmapiv1alpha1.MasterConfiguration{})
+			i, err := cmd.NewImagesList(configFilePath, &kubeadmapiv1alpha1.MasterConfiguration{})
 			if err != nil {
 				t.Fatalf("Failed getting the kubeadm images command: %v", err)
 			}
@@ -121,7 +121,7 @@ func TestListImagesRunWithCustomConfigPath(t *testing.T) {
 	}
 }
 
-func TestConfigListImagesRunWithoutPath(t *testing.T) {
+func TestConfigImagesListRunWithoutPath(t *testing.T) {
 	testcases := []struct {
 		name           string
 		cfg            kubeadmapiv1alpha1.MasterConfiguration
@@ -153,7 +153,7 @@ func TestConfigListImagesRunWithoutPath(t *testing.T) {
 
 	for _, tc := range testcases {
 		t.Run(tc.name, func(t *testing.T) {
-			i, err := cmd.NewListImages("", &tc.cfg)
+			i, err := cmd.NewImagesList("", &tc.cfg)
 			if err != nil {
 				t.Fatalf("did not expect an error while creating the Images command: %v", err)
 			}

docs/.generated_docs

@@ -58,7 +58,8 @@ docs/admin/kubeadm_alpha_phase_selfhosting_convert-from-staticpods.md
 docs/admin/kubeadm_alpha_phase_upload-config.md
 docs/admin/kubeadm_completion.md
 docs/admin/kubeadm_config.md
-docs/admin/kubeadm_config_list-images.md
+docs/admin/kubeadm_config_images.md
+docs/admin/kubeadm_config_images_list.md
 docs/admin/kubeadm_config_upload.md
 docs/admin/kubeadm_config_upload_from-file.md
 docs/admin/kubeadm_config_upload_from-flags.md
@@ -133,7 +134,8 @@ docs/man/man1/kubeadm-alpha-phase-upload-config.1
 docs/man/man1/kubeadm-alpha-phase.1
 docs/man/man1/kubeadm-alpha.1
 docs/man/man1/kubeadm-completion.1
-docs/man/man1/kubeadm-config-list-images.1
+docs/man/man1/kubeadm-config-images-list.1
+docs/man/man1/kubeadm-config-images.1
 docs/man/man1/kubeadm-config-upload-from-file.1
 docs/man/man1/kubeadm-config-upload-from-flags.1
 docs/man/man1/kubeadm-config-upload.1

docs/man/man1/kubeadm-config-images-list.1

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

docs/man/man1/kubeadm-config-images.1

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.