Use direct streams where appropiate

Author: cmaglie

internal/cli/completion/completion.go

@@ -47,8 +47,11 @@ func NewCommand() *cobra.Command {
 }
 
 func runCompletionCommand(cmd *cobra.Command, args []string) {
-	stdOut, _, res := feedback.OutputStreams()
 	logrus.Info("Executing `arduino-cli completion`")
+	stdOut, _, err := feedback.DirectStreams()
+	if err != nil {
+		feedback.Fatal(err.Error(), feedback.ErrGeneric)
+	}
 	if completionNoDesc && (args[0] == "powershell") {
 		feedback.Fatal(tr("Error: command description is not supported by %v", args[0]), feedback.ErrGeneric)
 	}
@@ -66,5 +69,4 @@ func runCompletionCommand(cmd *cobra.Command, args []string) {
 	case "powershell":
 		cmd.Root().GenPowerShellCompletion(stdOut)
 	}
-	feedback.PrintResult(res())
 }

internal/cli/daemon/daemon.go

@@ -89,12 +89,11 @@ func runDaemonCommand(cmd *cobra.Command, args []string) {
 			defer f.Close()
 			debugStdOut = f
 		} else {
-			// Attach to os.Stdout only if we are in Text mode
-			if feedback.GetFormat() != feedback.Text {
-				feedback.Fatal(tr("Debug log is only available in text format"), feedback.ErrBadArgument)
+			if out, _, err := feedback.DirectStreams(); err != nil {
+				feedback.Fatal(tr("Can't write debug log: %s", err), feedback.ErrBadArgument)
+			} else {
+				debugStdOut = out
 			}
-			out, _, _ := feedback.OutputStreams()
-			debugStdOut = out
 		}
 		gRPCOptions = append(gRPCOptions,
 			grpc.UnaryInterceptor(unaryLoggerInterceptor),

internal/cli/feedback/stdio.go

@@ -16,17 +16,37 @@
 package feedback
 
 import (
+	"errors"
 	"io"
 )
 
-// OutputStreams returns the underlying io.Writer to directly stream to
+// DirectStreams returns the underlying io.Writer to directly stream to
 // stdout and stderr.
-// If the selected output format is not Text, the returned writers will
-// accumulate the output until command execution is completed.
+// If the selected output format is not Text, the function will error.
+// Using this function will allow usage of the PrintResult anymore.
+func DirectStreams() (io.Writer, io.Writer, error) {
+	if !formatSelected {
+		panic("output format not yet selected")
+	}
+	if format != Text {
+		return nil, nil, errors.New(tr("available only in text format"))
+	}
+	return stdOut, stdErr, nil
+}
+
+// OutputStreams returns a pair of io.Writer to write the command output.
+// The returned writers will accumulate the output until the command
+// execution is completed, so they are not suitable for printing an unbounded
+// stream like a debug logger or an event watcher (use DirectStreams for
+// that purpose).
+//
+// If the output format is Text the output will be directly streamed to the
+// underlying stdio streams in real time.
+//
 // This function returns also a callback that must be called when the
-// command execution is completed, it will return a *OutputStreamsResult
-// object that can be used as a Result or to retrieve the output to embed
-// it in another object.
+// command execution is completed, it will return an *OutputStreamsResult
+// object that can be used as a Result or to retrieve the accumulated output
+// to embed it in another object.
 func OutputStreams() (io.Writer, io.Writer, func() *OutputStreamsResult) {
 	if !formatSelected {
 		panic("output format not yet selected")