Allow use of the monitor in non-terminal envs

internal/cli/feedback/terminal.go

@@ -35,21 +35,26 @@ func InteractiveStreams() (io.Reader, io.Writer, error) {
 	if format != Text {
 		return nil, nil, errors.New(tr("interactive terminal not supported for the '%s' output format", format))
 	}
-	if !isTerminal() {
-		return nil, nil, errors.New(tr("not running in a terminal"))
-	}
 	return os.Stdin, stdOut, nil
 }
 
 var oldStateStdin *term.State
 
 // SetRawModeStdin sets the stdin stream in RAW mode (no buffering, echo disabled,
 // no terminal escape codes nor signals interpreted)
-func SetRawModeStdin() {
+func SetRawModeStdin() error {
 	if oldStateStdin != nil {
 		panic("terminal already in RAW mode")
 	}
-	oldStateStdin, _ = term.MakeRaw(int(os.Stdin.Fd()))
+	if !IsTerminal() {
+		return errors.New(tr("not running in a terminal"))
+	}
+	old, err := term.MakeRaw(int(os.Stdin.Fd()))
+	if err != nil {
+		return err
+	}
+	oldStateStdin = old
+	return nil
 }
 
 // RestoreModeStdin restore the terminal settings to the normal non-RAW state. This
@@ -63,7 +68,8 @@ func RestoreModeStdin() {
 	oldStateStdin = nil
 }
 
-func isTerminal() bool {
+// IsTerminal returns true if there is an interactive terminal
+func IsTerminal() bool {
 	return term.IsTerminal(int(os.Stdin.Fd()))
 }
 
@@ -72,7 +78,7 @@ func InputUserField(prompt string, secret bool) (string, error) {
 	if format != Text {
 		return "", errors.New(tr("user input not supported for the '%s' output format", format))
 	}
-	if !isTerminal() {
+	if !IsTerminal() {
 		return "", errors.New(tr("user input not supported in non interactive mode"))
 	}
 

internal/cli/monitor/monitor.go

@@ -169,10 +169,12 @@ func runMonitorCmd(portArgs *arguments.Port, fqbn *arguments.Fqbn, configs []str
 
 	ctx, cancel := cleanup.InterruptableContext(context.Background())
 	if raw {
-		feedback.SetRawModeStdin()
-		defer func() {
-			feedback.RestoreModeStdin()
-		}()
+		if feedback.IsTerminal() {
+			if err := feedback.SetRawModeStdin(); err != nil {
+				feedback.Warning(tr("Error setting raw mode: %s", err.Error()))
+			}
+			defer feedback.RestoreModeStdin()
+		}
 
 		// In RAW mode CTRL-C is not converted into an Interrupt by
 		// the terminal, we must intercept ASCII 3 (CTRL-C) on our own...