我正在编写一个终端应用程序，通过传递-v选项后，可以得到详细信息。我希望在终端中可用输出，以便进行简单的测试（无论如何，在作为cron运行时，它都会被重定向到日志文件中）。
然而，当使用格式化程序时，Python logging模块不允许我写出具有相应级别的消息。（格式化程序直接从Python Logging Cookbok复制）
这种行为不仅限于Python3。在给定条件下，Python2.7也会引发相同的异常。
one.py
from sys import stdout
import logging
if __name__ == '__main__':
level = 20
log = logging.getLogger()
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
handler = logging.StreamHandler(stdout).setFormatter(formatter)
log.addHandler(handler)
log.setLevel(level)
log.info("Blah")
one.py 输出
Traceback (most recent call last):
File "/home/tlevi/PycharmProjects/untitled/main.py", line 14, in <module>
log.info("Blah")
File "/usr/lib/python3.4/logging/__init__.py", line 1279, in info
self._log(INFO, msg, args, **kwargs)
File "/usr/lib/python3.4/logging/__init__.py", line 1414, in _log
self.handle(record)
File "/usr/lib/python3.4/logging/__init__.py", line 1424, in handle
self.callHandlers(record)
File "/usr/lib/python3.4/logging/__init__.py", line 1485, in callHandlers
if record.levelno >= hdlr.level:
AttributeError: 'NoneType' object has no attribute 'level'
two.py（运行良好）
from sys import stdout
import logging
if __name__ == '__main__':
level = 20
log = logging.getLogger()
handler = logging.StreamHandler(stdout)
log.addHandler(handler)
log.setLevel(level)
log.info("Blah")
two.py 输出
Blah