cluster: add significant warning when --force is set for scale-in

pkg/cluster/manager/scale_in.go

@@ -49,11 +49,15 @@ func (m *Manager) ScaleIn(
 	)
 	if !skipConfirm {
 		if force {
-			if err := tui.PromptForConfirmOrAbortError(
+			log.Warnf(color.HiRedString(tui.ASCIIArtWarning))
+			if err := tui.PromptForAnswerOrAbortError(
+				"Yes, I know my data might be lost.",
 				color.HiRedString("Forcing scale in is unsafe and may result in data loss for stateful components.\n"+
-					"The process is irreversible and could NOT be cancelled.\n") +
-					"Only use `--force` when some of the servers are already permanently offline.\n" +
-					"Are you sure to continue? [y/N]:",
+					"DO NOT use `--force` if you have any component in ")+
+					color.YellowString("Pending Offline")+color.HiRedString(" status.\n")+
+					color.HiRedString("The process is irreversible and could NOT be cancelled.\n")+
+					"Only use `--force` when some of the servers are already permanently offline.\n"+
+					"Are you sure to continue?",
 			); err != nil {
 				return err
 			}

pkg/tui/tui.go

@@ -21,6 +21,7 @@ import (
 	"syscall"
 
 	"github.com/AstroProfundis/tabby"
+	"github.com/fatih/color"
 	"github.com/pingcap/tiup/pkg/utils/mock"
 	"golang.org/x/term"
 )
@@ -59,6 +60,17 @@ func addRow(t *tabby.Tabby, rawLine []string, header bool) {
 	}
 }
 
+// pre-defined ascii art strings
+const (
+	ASCIIArtWarning = `
+  ██     ██  █████  ██████  ███    ██ ██ ███    ██  ██████
+  ██     ██ ██   ██ ██   ██ ████   ██ ██ ████   ██ ██
+  ██  █  ██ ███████ ██████  ██ ██  ██ ██ ██ ██  ██ ██   ███
+  ██ ███ ██ ██   ██ ██   ██ ██  ██ ██ ██ ██  ██ ██ ██    ██
+   ███ ███  ██   ██ ██   ██ ██   ████ ██ ██   ████  ██████
+`
+)
+
 // Prompt accepts input from console by user
 func Prompt(prompt string) string {
 	if prompt != "" {
@@ -106,6 +118,25 @@ func PromptForConfirmOrAbortError(format string, a ...interface{}) error {
 	return nil
 }
 
+// PromptForConfirmAnswer accepts string from console by user, default to empty and only return
+// true if the user input is exactly the same as pre-defined answer.
+func PromptForConfirmAnswer(answer string, format string, a ...interface{}) (bool, string) {
+	ans := Prompt(fmt.Sprintf(format, a...) + fmt.Sprintf("\n(Type \"%s\" to continue)\n:", color.CyanString(answer)))
+	if ans == answer {
+		return true, ans
+	}
+	return false, ans
+}
+
+// PromptForAnswerOrAbortError accepts string from console by user, generates AbortError if user does
+// not input the pre-defined answer.
+func PromptForAnswerOrAbortError(answer string, format string, a ...interface{}) error {
+	if pass, ans := PromptForConfirmAnswer(answer, format, a...); !pass {
+		return errOperationAbort.New("Operation aborted by user (with incorrect answer '%s')", ans)
+	}
+	return nil
+}
+
 // PromptForPassword reads a password input from console
 func PromptForPassword(format string, a ...interface{}) string {
 	defer fmt.Println("")