kubeadm: De-dup the confirmation on the interactive cmds

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

cmd/kubeadm/app/cmd/phases/reset/preflight.go

@@ -17,15 +17,14 @@ limitations under the License.
 package phases
 
 import (
-	"bufio"
 	"errors"
 	"fmt"
-	"strings"
 
 	"k8s.io/klog/v2"
 
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
+	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
 )
 
@@ -53,15 +52,7 @@ func runPreflight(c workflow.RunData) error {
 
 	if !r.ForceReset() && !r.DryRun() {
 		klog.Warning("[reset] WARNING: Changes made to this host by 'kubeadm init' or 'kubeadm join' will be reverted.")
-		fmt.Print("[reset] Are you sure you want to proceed? [y/N]: ")
+		return util.InteractivelyConfirmAction("reset", "Are you sure you want to proceed?", r.InputReader())
-		s := bufio.NewScanner(r.InputReader())
-		s.Scan()
-		if err := s.Err(); err != nil {
-			return err
-		}
-		if strings.ToLower(s.Text()) != "y" {
-			return errors.New("aborted reset operation")
-		}
 	}
 
 	fmt.Println("[preflight] Running pre-flight checks")

cmd/kubeadm/app/cmd/upgrade/apply.go

@@ -18,6 +18,7 @@ package upgrade
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
@@ -30,6 +31,7 @@ import (
 
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
+	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/features"
 	"k8s.io/kubernetes/cmd/kubeadm/app/phases/upgrade"
@@ -133,7 +135,7 @@ func runApply(flags *applyFlags, args []string) error {
 
 	// If the current session is interactive, ask the user whether they really want to upgrade.
 	if flags.sessionIsInteractive() {
-		if err := InteractivelyConfirmUpgrade("Are you sure you want to proceed with the upgrade?"); err != nil {
+		if err := cmdutil.InteractivelyConfirmAction("upgrade", "Are you sure you want to proceed?", os.Stdin); err != nil {
 			return err
 		}
 	}

cmd/kubeadm/app/cmd/upgrade/common.go

@@ -19,7 +19,6 @@ package upgrade
 import (
 	"bufio"
 	"bytes"
-	"fmt"
 	"io"
 	"os"
 	"strings"
@@ -321,21 +320,3 @@ func getWaiter(dryRun bool, client clientset.Interface, timeout time.Duration) a
 	}
 	return apiclient.NewKubeWaiter(client, timeout, os.Stdout)
 }
-
-// InteractivelyConfirmUpgrade asks the user whether they _really_ want to upgrade.
-func InteractivelyConfirmUpgrade(question string) error {
-
-	fmt.Printf("[upgrade/confirm] %s [y/N]: ", question)
-
-	scanner := bufio.NewScanner(os.Stdin)
-	scanner.Scan()
-	if err := scanner.Err(); err != nil {
-		return errors.Wrap(err, "couldn't read from standard input")
-	}
-	answer := scanner.Text()
-	if strings.ToLower(answer) == "y" || strings.ToLower(answer) == "yes" {
-		return nil
-	}
-
-	return errors.New("won't proceed; the user didn't answer (Y|y) in order to continue")
-}

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

@@ -17,6 +17,11 @@ limitations under the License.
 package util
 
 import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
@@ -100,3 +105,19 @@ func DefaultInitConfiguration() *kubeadmapiv1.InitConfiguration {
 	}
 	return initCfg
 }
+
+// InteractivelyConfirmAction asks the user whether they _really_ want to take the action.
+func InteractivelyConfirmAction(action, question string, r io.Reader) error {
+	fmt.Printf("[%s] %s [y/N]: ", action, question)
+	scanner := bufio.NewScanner(r)
+	scanner.Scan()
+	if err := scanner.Err(); err != nil {
+		return errors.Wrap(err, "couldn't read from standard input")
+	}
+	answer := scanner.Text()
+	if strings.ToLower(answer) == "y" || strings.ToLower(answer) == "yes" {
+		return nil
+	}
+
+	return errors.New("won't proceed; the user didn't answer (Y|y) in order to continue")
+}