Logs: modify StartLogger to private

@@ -97,12 +97,12 @@ func (w *FileLogWriter) Init(jsonconfig string) error {
 	if len(w.Filename) == 0 {
 		return errors.New("jsonconfig must have filename")
 	}
-	err = w.StartLogger()
+	err = w.startLogger()
 	return err
 }
 
 // start file logger. create log file and set to locker-inside file writer.
-func (w *FileLogWriter) StartLogger() error {
+func (w *FileLogWriter) startLogger() error {
 	fd, err := w.createLogFile()
 	if err != nil {
 		return err
@@ -199,7 +199,7 @@ func (w *FileLogWriter) DoRotate() error {
 		}
 
 		// re-start logger
-		err = w.StartLogger()
+		err = w.startLogger()
 		if err != nil {
 			return fmt.Errorf("Rotate StartLogger: %s\n", err)
 		}

@@ -67,7 +67,7 @@ func NewLogger(channellen int64) *BeeLogger {
 	bl.msg = make(chan *logMsg, channellen)
 	bl.outputs = make(map[string]LoggerInterface)
 	//bl.SetLogger("console", "") // default output to console
-	go bl.StartLogger()
+	go bl.startLogger()
 	return bl
 }
 
@@ -78,7 +78,10 @@ func (bl *BeeLogger) SetLogger(adaptername string, config string) error {
 	defer bl.lock.Unlock()
 	if log, ok := adapters[adaptername]; ok {
 		lg := log()
-		lg.Init(config)
+		err := lg.Init(config)
+		if err != nil {
+			return err
+		}
 		bl.outputs[adaptername] = lg
 		return nil
 	} else {
@@ -138,7 +141,7 @@ func (bl *BeeLogger) EnableFuncCallDepth(b bool) {
 
 // start logger chan reading.
 // when chan is full, write logs.
-func (bl *BeeLogger) StartLogger() {
+func (bl *BeeLogger) startLogger() {
 	for {
 		select {
 		case bm := <-bl.msg: