Add error returning to writeln

logs/conn.go

@@ -63,7 +63,10 @@ func (c *connWriter) WriteMsg(when time.Time, msg string, level int) error {
 		defer c.innerWriter.Close()
 	}
 
-	c.lg.writeln(when, msg)
+	_, err := c.lg.writeln(when, msg)
+	if err != nil {
+		return err
+	}
 	return nil
 }
 

logs/logger.go

@@ -30,11 +30,12 @@ func newLogWriter(wr io.Writer) *logWriter {
 	return &logWriter{writer: wr}
 }
 
-func (lg *logWriter) writeln(when time.Time, msg string) {
+func (lg *logWriter) writeln(when time.Time, msg string) (int, error) {
 	lg.Lock()
 	h, _, _ := formatTimeHeader(when)
-	lg.writer.Write(append(append(h, msg...), '\n'))
+	n, err := lg.writer.Write(append(append(h, msg...), '\n'))
 	lg.Unlock()
+	return n, err
 }
 
 const (