add logError, add timestamp to error logs

statusbar.go

@@ -102,11 +102,10 @@ func (sb *Statusbar) Run() {
  // Keep running until every routine stops.
  for i := 0; i < len(sb.routines); i++ {
  r := <-finished
- msg := fmt.Sprintf("%v: Routine stopped\n", r.rh.Name())
- os.Stderr.WriteString(msg)
+ logError("%v: Routine stopped", r.rh.Name())
  }
 
- os.Stderr.WriteString("All routines have stopped\n")
+ logError("All routines have stopped")
 }
 
 // runRoutine runs a routine in a non-terminating loop.
@@ -125,8 +124,7 @@ func runRoutine(r routine, i int, outputsChan chan []string, finished chan<- rou
  output = handler.String()
  } else {
  output = handler.Error()
- msg := fmt.Sprintf("%v: %v\n", handler.Name(), err.Error())
- os.Stderr.WriteString(msg)
+ logError("%v: %v", handler.Name(), err.Error())
  }
  outputs := <-outputsChan
  outputs[i] = output
@@ -224,6 +222,15 @@ func (sb *Statusbar) Split() {
  sb.split = len(sb.routines) - 1
 }
 
+// logError prints the formatted message to stderr.
+func logError(format string, a ...interface{}) {
+ // Add a timestamp and a newline to our message.
+ format = "(%v) " + format + "\n"
+ items := append([]interface{}{time.Now()}, a...)
+
+ fmt.Fprintf(os.Stderr, format, items...)
+}
+
 // handleSignal clears the statusbar if the program receives an interrupt signal.
 func (sb *Statusbar) handleSignal() {
  c := make(chan os.Signal, 1)
@@ -237,7 +244,7 @@ func (sb *Statusbar) handleSignal() {
 
  // Wait until we receive an interrupt signal.
  <-c
- os.Stderr.WriteString("Received interrupt\n")
+ logError("Received interrupt")
 
  dpy := C.XOpenDisplay(nil)
  root := C.XDefaultRootWindow(dpy)