困惑：定义的日志级别是NOSET，实际是WANING ？求解释

Question

log_file = "log/log"
datetime_format = "%Y-%m-%d %H:%M:%S"
per_log_file_max_size = 10240
backup_count = 3

log_format = "%(asctime)s %(filename)s[line:%(lineno)d][%(levelname)s] %(message)s"

rotate_file_handler = RotatingFileHandler(log_file, maxBytes=per_log_file_max_size,
backupCount=backup_count)

rotate_file_handler.setLevel(logging.NOTSET)
formatter = logging.Formatter(log_format)
rotate_file_handler.setFormatter(formatter)
logging.getLogger('').addHandler(rotate_file_handler)

logging.debug('This is debug message')
logging.info('This is info message')
logging.warning('This is warning message')
logging.error('error')
logging.critical('critical')

输出：
2017-02-10 17:43:29,055 test.py[line:31][WARNING] This is warning message
2017-02-10 17:43:29,055 test.py[line:32][ERROR] error
2017-02-10 17:43:29,055 test.py[line:33][CRITICAL] critical

Answer 1

log_format = "%(asctime)s %(filename)s[line:%(lineno)d][%(levelname)s] %(message)s"logging.basicConfig(format=log_format,level='ERROR')logging.debug('This is debug message')logging.info('This is info message')logging.warning('This is warning message')logging.error('error')logging.critical('critical')