kubeadm: move getClientSet to cmd utils

`getClientSet` is used by both cmd `token` and `reset`, move this
method to cmd utils to decouple it from one specific cmd.

Signed-off-by: Dave Chen <dave.chen@arm.com>

cmd/kubeadm/app/cmd/reset.go

@@ -95,7 +95,7 @@ func newResetOptions() *resetOptions {
 func newResetData(cmd *cobra.Command, options *resetOptions, in io.Reader, out io.Writer) (*resetData, error) {
 	var cfg *kubeadmapi.InitConfiguration
 
-	client, err := getClientset(options.kubeconfigPath, false)
+	client, err := cmdutil.GetClientset(options.kubeconfigPath, false)
 	if err == nil {
 		klog.V(1).Infof("[reset] Loaded client set from kubeconfig file: %s", options.kubeconfigPath)
 		cfg, err = configutil.FetchInitConfigurationFromCluster(client, nil, "reset", false, false)

cmd/kubeadm/app/cmd/token.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"os"
 	"strings"
 	"text/tabwriter"
 	"time"
@@ -49,9 +48,7 @@ import (
 	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	tokenphase "k8s.io/kubernetes/cmd/kubeadm/app/phases/bootstraptoken/node"
-	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 	configutil "k8s.io/kubernetes/cmd/kubeadm/app/util/config"
-	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/output"
 )
 
@@ -130,7 +127,7 @@ func newCmdToken(out io.Writer, errW io.Writer) *cobra.Command {
 
 			klog.V(1).Infoln("[token] getting Clientsets from kubeconfig file")
 			kubeConfigFile = cmdutil.GetKubeConfigPath(kubeConfigFile)
-			client, err := getClientset(kubeConfigFile, dryRun)
+			client, err := cmdutil.GetClientset(kubeConfigFile, dryRun)
 			if err != nil {
 				return err
 			}
@@ -162,7 +159,7 @@ func newCmdToken(out io.Writer, errW io.Writer) *cobra.Command {
 		`),
 		RunE: func(tokenCmd *cobra.Command, args []string) error {
 			kubeConfigFile = cmdutil.GetKubeConfigPath(kubeConfigFile)
-			client, err := getClientset(kubeConfigFile, dryRun)
+			client, err := cmdutil.GetClientset(kubeConfigFile, dryRun)
 			if err != nil {
 				return err
 			}
@@ -196,7 +193,7 @@ func newCmdToken(out io.Writer, errW io.Writer) *cobra.Command {
 				return errors.Errorf("missing subcommand; 'token delete' is missing token of form %q", bootstrapapi.BootstrapTokenIDPattern)
 			}
 			kubeConfigFile = cmdutil.GetKubeConfigPath(kubeConfigFile)
-			client, err := getClientset(kubeConfigFile, dryRun)
+			client, err := cmdutil.GetClientset(kubeConfigFile, dryRun)
 			if err != nil {
 				return err
 			}
@@ -433,14 +430,3 @@ func RunDeleteTokens(out io.Writer, client clientset.Interface, tokenIDsOrTokens
 	}
 	return nil
 }
-
-func getClientset(file string, dryRun bool) (clientset.Interface, error) {
-	if dryRun {
-		dryRunGetter, err := apiclient.NewClientBackedDryRunGetterFromKubeconfig(file)
-		if err != nil {
-			return nil, err
-		}
-		return apiclient.NewDryRunClient(dryRunGetter, os.Stdout), nil
-	}
-	return kubeconfigutil.ClientSetFromFile(file)
-}

cmd/kubeadm/app/cmd/token_test.go

@@ -35,6 +35,7 @@ import (
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
 	outputapischeme "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/scheme"
 	outputapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha2"
+	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/output"
 )
 
@@ -275,12 +276,12 @@ func TestGetClientset(t *testing.T) {
 	fullPath := filepath.Join(tmpDir, testConfigTokenFile)
 
 	// test dryRun = false on a non-exisiting file
-	if _, err = getClientset(fullPath, false); err == nil {
+	if _, err = cmdutil.GetClientset(fullPath, false); err == nil {
 		t.Errorf("getClientset(); dry-run: false; did no fail for test file %q: %v", fullPath, err)
 	}
 
 	// test dryRun = true on a non-exisiting file
-	if _, err = getClientset(fullPath, true); err == nil {
+	if _, err = cmdutil.GetClientset(fullPath, true); err == nil {
 		t.Errorf("getClientset(); dry-run: true; did no fail for test file %q: %v", fullPath, err)
 	}
 
@@ -295,7 +296,7 @@ func TestGetClientset(t *testing.T) {
 	}
 
 	// test dryRun = true on an exisiting file
-	if _, err = getClientset(fullPath, true); err != nil {
+	if _, err = cmdutil.GetClientset(fullPath, true); err != nil {
 		t.Errorf("getClientset(); dry-run: true; failed for test file %q: %v", fullPath, err)
 	}
 }
@@ -320,7 +321,7 @@ func TestRunDeleteTokens(t *testing.T) {
 		t.Errorf("Unable to write test file %q: %v", fullPath, err)
 	}
 
-	client, err := getClientset(fullPath, true)
+	client, err := cmdutil.GetClientset(fullPath, true)
 	if err != nil {
 		t.Errorf("Unable to run getClientset() for test file %q: %v", fullPath, err)
 	}

cmd/kubeadm/app/cmd/util/cmdutil.go

@@ -20,18 +20,22 @@ import (
 	"bufio"
 	"fmt"
 	"io"
+	"os"
 	"strings"
 
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 
+	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/klog/v2"
 
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
+	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
+	kubeconfigutil "k8s.io/kubernetes/cmd/kubeadm/app/util/kubeconfig"
 )
 
 // SubCmdRunE returns a function that handles a case where a subcommand must be specified
@@ -121,3 +125,15 @@ func InteractivelyConfirmAction(action, question string, r io.Reader) error {
 
 	return errors.New("won't proceed; the user didn't answer (Y|y) in order to continue")
 }
+
+// GetClientSet gets a real or fake client depending on whether the user is dry-running or not
+func GetClientset(file string, dryRun bool) (clientset.Interface, error) {
+	if dryRun {
+		dryRunGetter, err := apiclient.NewClientBackedDryRunGetterFromKubeconfig(file)
+		if err != nil {
+			return nil, err
+		}
+		return apiclient.NewDryRunClient(dryRunGetter, os.Stdout), nil
+	}
+	return kubeconfigutil.ClientSetFromFile(file)
+}