Modify ExecCommand to always cache stdout/stderr

By adding a new Stream type we can address programs like uploaders which show a progress bar or other long running tools

Author: facchinm

utils/utils.go

@@ -30,7 +30,6 @@
 package utils
 
 import (
-	"bufio"
 	"bytes"
 	"crypto/md5"
 	"encoding/hex"
@@ -282,72 +281,53 @@ func PrintableCommand(parts []string) string {
 
 const (
 	Ignore        = 0 // Redirect to null
-	Show          = 1 // Show on stdout/stderr as normal
-	ShowIfVerbose = 2 // Show if verbose is set, Ignore otherwise
-	Capture       = 3 // Capture into buffer
+	Show          = 1 // Print the stream
+	ShowIfVerbose = 2 // Print the stream only if verbose
+	Capture       = 3 // Capture into buffer and don't print
+	Stream        = 4 // Stream data as it comes in, no capture
 )
 
 func ExecCommand(ctx *types.Context, command *exec.Cmd, stdout int, stderr int) ([]byte, []byte, error) {
 	if ctx.Verbose {
 		ctx.GetLogger().UnformattedFprintln(os.Stdout, PrintableCommand(command.Args))
 	}
 
-	var stdoutCopy io.ReadCloser
-	var stderrCopy io.ReadCloser
-
-	if stdout == Capture {
+	if stdout != Stream {
 		buffer := &bytes.Buffer{}
 		command.Stdout = buffer
-	} else if stdout == Show || stdout == ShowIfVerbose && ctx.Verbose {
-		stdoutCopy, _ = command.StdoutPipe()
+	} else {
+		command.Stdout = os.Stdout
 	}
 
-	if stderr == Capture {
+	if stderr != Stream {
 		buffer := &bytes.Buffer{}
 		command.Stderr = buffer
-	} else if stderr == Show || stderr == ShowIfVerbose && ctx.Verbose {
-		stderrCopy, _ = command.StderrPipe()
+	} else {
+		command.Stderr = os.Stderr
 	}
 
 	err := command.Start()
 	if err != nil {
 		return nil, nil, i18n.WrapError(err)
 	}
 
-	var outbytes, errbytes []byte
-
-	if stdoutCopy != nil && stderrCopy != nil {
-		stdOut := bufio.NewScanner(stdoutCopy)
-		stdErr := bufio.NewScanner(stderrCopy)
-		stdOut.Split(bufio.ScanLines)
-		stdErr.Split(bufio.ScanLines)
-
-		go func() {
-			for stdOut.Scan() {
-				txt := stdOut.Text() + "\n"
-				fmt.Fprint(os.Stderr, txt)
-				outbytes = append(outbytes, txt...)
-			}
-		}()
+	err = command.Wait()
 
-		go func() {
-			for stdErr.Scan() {
-				txt := stdErr.Text() + "\n"
-				fmt.Fprint(os.Stderr, txt)
-				errbytes = append(errbytes, txt...)
-			}
-		}()
+	var outbytes, errbytes []byte
+	// this operation is a no-op in case of streaming
+	if buf, ok := command.Stdout.(*bytes.Buffer); ok {
+		outbytes = buf.Bytes()
+	}
+	if buf, ok := command.Stderr.(*bytes.Buffer); ok {
+		errbytes = buf.Bytes()
 	}
 
-	err = command.Wait()
+	if stdout == Show || (stdout == ShowIfVerbose && ctx.Verbose) {
+		ctx.GetLogger().UnformattedWrite(os.Stdout, outbytes)
+	}
 
-	if stdoutCopy == nil || stderrCopy == nil {
-		if buf, ok := command.Stdout.(*bytes.Buffer); ok {
-			outbytes = buf.Bytes()
-		}
-		if buf, ok := command.Stderr.(*bytes.Buffer); ok {
-			errbytes = buf.Bytes()
-		}
+	if stderr == Show || (stderr == ShowIfVerbose && ctx.Verbose) {
+		ctx.GetLogger().UnformattedWrite(os.Stderr, errbytes)
 	}
 
 	return outbytes, errbytes, i18n.WrapError(err)