packer: Don't output up to \r with remote command, lost anyways

packer/communicator.go

@@ -116,9 +116,9 @@ OutputLoop:
 	for {
 		select {
 		case output := <-stderrCh:
-			ui.Message(strings.TrimSpace(output))
+			ui.Message(r.cleanOutputLine(output))
 		case output := <-stdoutCh:
-			ui.Message(strings.TrimSpace(output))
+			ui.Message(r.cleanOutputLine(output))
 		case <-exitCh:
 			break OutputLoop
 		}
@@ -164,3 +164,19 @@ func (r *RemoteCmd) Wait() {
 
 	<-r.exitCh
 }
+
+// cleanOutputLine cleans up a line so that '\r' don't muck up the
+// UI output when we're reading from a remote command.
+func (r *RemoteCmd) cleanOutputLine(line string) string {
+	// Trim surrounding whitespace
+	line = strings.TrimSpace(line)
+
+	// Trim up to the first carriage return, since that text would be
+	// lost anyways.
+	idx := strings.LastIndex(line, "\r")
+	if idx > -1 {
+		line = line[idx+1:]
+	}
+
+	return line
+}