enhance login prompt

Signed-off-by: fahed dorgaa <fahed.dorgaa@gmail.com>

Author: fahedouch

cmd/nerdctl/login.go

@@ -308,6 +308,15 @@ func ConfigureAuthentification(authConfig *types.AuthConfig, options *loginOptio
 		options.username = authConfig.Username
 	}
 
+	if options.username == "" {
+		fmt.Print("Enter Username: ")
+		username, err := readUsername()
+		if err != nil {
+			return err
+		}
+		options.username = username
+	}
+
 	if options.username == "" {
 		return fmt.Errorf("error: Username is Required")
 	}
@@ -324,7 +333,7 @@ func ConfigureAuthentification(authConfig *types.AuthConfig, options *loginOptio
 	}
 
 	if options.password == "" {
-		return fmt.Errorf("password is Required")
+		return fmt.Errorf("error: Password is Required")
 	}
 
 	authConfig.Username = options.username

cmd/nerdctl/login_unix.go

@@ -20,8 +20,10 @@
 package main
 
 import (
+	"bufio"
 	"fmt"
 	"os"
+	"strings"
 	"syscall"
 
 	"golang.org/x/term"
@@ -46,3 +48,26 @@ func readPassword() (string, error) {
 
 	return string(bytePassword), nil
 }
+
+func readUsername() (string, error) {
+	var fd *os.File
+	if term.IsTerminal(syscall.Stdin) {
+		fd = os.Stdin
+	} else {
+		tty, err := os.Open("/dev/tty")
+		if err != nil {
+			return "", fmt.Errorf("error allocating terminal: %w", err)
+		}
+		defer tty.Close()
+		fd = tty
+	}
+
+	reader := bufio.NewReader(fd)
+	username, err := reader.ReadString('\n')
+	if err != nil {
+		return "", fmt.Errorf("error reading username: %w", err)
+	}
+	username = strings.TrimSpace(username)
+
+	return username, nil
+}

cmd/nerdctl/login_windows.go

@@ -17,7 +17,10 @@
 package main
 
 import (
+	"bufio"
 	"fmt"
+	"os"
+	"strings"
 	"syscall"
 
 	"golang.org/x/term"
@@ -37,3 +40,21 @@ func readPassword() (string, error) {
 
 	return string(bytePassword), nil
 }
+
+func readUsername() (string, error) {
+	var fd *os.File
+	if term.IsTerminal(int(syscall.Stdin)) {
+		fd = os.Stdin
+	} else {
+		return "", fmt.Errorf("error allocating terminal")
+	}
+
+	reader := bufio.NewReader(fd)
+	username, err := reader.ReadString('\n')
+	if err != nil {
+		return "", fmt.Errorf("error reading username: %w", err)
+	}
+	username = strings.TrimSpace(username)
+
+	return username, nil
+}