Method rotate

lumberjack.go:195–204

rotate closes the current file, moves it aside with a timestamp in the name, (if it exists), opens a new file with the original filename, and then runs post-rotation processing and removal.

()

// (if it exists), opens a new file with the original filename, and then runs
// post-rotation processing and removal.
func (l *Logger) rotate() error {
	if err := l.close(); err != nil {
		return err
	}
	if err := l.openNew(); err != nil {
		return err
	}
	l.mill()
	return nil
}

// openNew opens a new log file for writing, moving any old log file out of the
// way.  This methods assumes the file has already been closed.