class logging.handlers.BaseRotatingHandler(filename, mode, encoding=None, delay=False)
The parameters are as for FileHandler. The attributes are:
namer
If this attribute is set to a callable, the rotation_filename() method delegates to this callable. The parameters passed to the callable are those passed to rotation_filename(). Note The namer function is called quite a few times during rollover, so it should be as simple and as fast as possible. It should also return the same output ever