Merge pull request #132 from docker/login-prompt

Prompt if username is empty on login

internal/commands/login.go

@@ -36,15 +36,19 @@ const (
 
 func newLoginCmd(streams command.Streams, store credentials.Store, hubClient *hub.Client) *cobra.Command {
 	cmd := &cobra.Command{
-		Use:                   loginName + " USERNAME",
+		Use:                   loginName + " [USERNAME]",
 		Short:                 "Login to the Hub",
-		Args:                  cli.ExactArgs(1),
+		Args:                  cli.RequiresMaxArgs(1),
 		DisableFlagsInUseLine: true,
 		PreRun: func(cmd *cobra.Command, args []string) {
 			metrics.Send("root", loginName)
 		},
 		RunE: func(cmd *cobra.Command, args []string) error {
-			if err := login.RunLogin(cmd.Context(), streams, hubClient, store, args[0]); err != nil {
+			username := ""
+			if len(args) > 0 {
+				username = args[0]
+			}
+			if err := login.RunLogin(cmd.Context(), streams, hubClient, store, username); err != nil {
 				return err
 			}
 			fmt.Fprintln(streams.Out(), ansi.Info("Login Succeeded"))

internal/login/login.go

@@ -36,7 +36,14 @@ import (
 )
 
 // RunLogin logs the user and asks for the 2FA code if needed
-func RunLogin(ctx context.Context, streams command.Streams, hubClient *hub.Client, store credentials.Store, username string) error {
+func RunLogin(ctx context.Context, streams command.Streams, hubClient *hub.Client, store credentials.Store, candidateUsername string) error {
+	username := candidateUsername
+	if username == "" {
+		var err error
+		if username, err = readClearText(ctx, streams, "Username: "); err != nil {
+			return err
+		}
+	}
 	password, err := readPassword(streams)
 	if err != nil {
 		return err
@@ -62,24 +69,27 @@ func RunLogin(ctx context.Context, streams command.Streams, hubClient *hub.Clien
 // VerifyTwoFactorCode run 2FA login
 func VerifyTwoFactorCode(ctx context.Context, streams command.Streams, hubClient *hub.Client, username string, password string) (string, string, error) {
 	return hubClient.Login(username, password, func() (string, error) {
-		userIn := make(chan string, 1)
-		go func() {
-			fmt.Fprint(streams.Out(), ansi.Info("2FA required, please provide the 6 digit code: "))
-			reader := bufio.NewReader(streams.In())
-			input, _ := reader.ReadString('\n')
-			userIn <- strings.TrimSpace(input)
-		}()
-		input := ""
-		select {
-		case <-ctx.Done():
-			return "", errors.New("canceled")
-		case input = <-userIn:
-		}
-
-		return input, nil
+		return readClearText(ctx, streams, "2FA required, please provide the 6 digit code: ")
 	})
 }
 
+func readClearText(ctx context.Context, streams command.Streams, prompt string) (string, error) {
+	userIn := make(chan string, 1)
+	go func() {
+		fmt.Fprint(streams.Out(), ansi.Info(prompt))
+		reader := bufio.NewReader(streams.In())
+		input, _ := reader.ReadString('\n')
+		userIn <- strings.TrimSpace(input)
+	}()
+	input := ""
+	select {
+	case <-ctx.Done():
+		return "", errors.New("canceled")
+	case input = <-userIn:
+	}
+	return input, nil
+}
+
 func readPassword(streams command.Streams) (string, error) {
 	in := streams.In()
 	// On Windows, force the use of the regular OS stdin stream. Fixes #14336/#14210