是否有方法更改未使用basicConfig配置的记录器对象的文件模式？

Question

如果使用logger=logging.getLogger（“Name”）创建logger对象，则无法将filemode从append（'a'）更改为write（'w'）。如果我将根日志与basicConfig一起使用，我可以这样做，但是当我只需要从调试级别开始的自己的消息时，就会得到很多系统调试消息。

我希望（1）将我自己的logger对象的filemode更改为'w' 或者（2）向根记录器添加筛选器。甚至可以从根日志中筛选出这些调试消息吗？

def create_log():
    # create logger for "Sample App"
    logger = logging.getLogger('automated_testing')
    logger.setLevel(logging.DEBUG)

    # create file handler which logs even debug messages
    fh = logging.FileHandler('results.log')
    fh.setLevel(logging.DEBUG)
    # create console handler with a higher log level
    ch = logging.StreamHandler(stream=sys.stdout)
    ch.setLevel(logging.DEBUG)
    # create formatter and add it to the handlers
    formatter = logging.Formatter('[%(asctime)s] %(levelname)8s --- %(message)s ' +
                                  '(%(filename)s:%(lineno)s)',datefmt='%Y-%m-%d %H:%M:%S')
    fh.setFormatter(formatter)
    ch.setFormatter(formatter)
    # add the handlers to the logger
    logger.addHandler(ch)
    logger.addHandler(fh)

    return logger

Answer 1

类似于：

import sys
import logging

def create_logger():
    # create logger for "Sample App"
    logger = logging.getLogger('automated_testing')
    logger.setLevel(logging.DEBUG)

    # create file handler which logs even debug messages
    fh = logging.FileHandler('results.log', mode='w')
    fh.setLevel(logging.DEBUG)

    # create console handler with a higher log level
    ch = logging.StreamHandler(stream=sys.stdout)
    ch.setLevel(logging.INFO)

    # create formatter and add it to the handlers
    formatter = logging.Formatter('[%(asctime)s] %(levelname)8s --- %(message)s ' +
                                  '(%(filename)s:%(lineno)s)',datefmt='%Y-%m-%d %H:%M:%S')
    fh.setFormatter(formatter)
    ch.setFormatter(formatter)

    # add the handlers to the logger
    logger.addHandler(ch)
    logger.addHandler(fh)

    return logger

logger = create_logger()


logger.log(logging.NOTSET,   "NOTSET   Message - 0")
logger.log(logging.DEBUG,    "DEBUG    Message - 10")
logger.log(logging.INFO,     "INFO     Message - 20")
logger.log(logging.WARNING,  "WARNING  Message - 30")
logger.log(logging.CRITICAL, "CRITICAL Message - 40")

打印到标准输出：

[2015-03-16 17:51:08]     INFO --- INFO     Message - 20 (temp3.py:34)
[2015-03-16 17:51:08]  WARNING --- WARNING  Message - 30 (temp3.py:35)
[2015-03-16 17:51:08] CRITICAL --- CRITICAL Message - 40 (temp3.py:36)

写入（不追加）results.log：

[2015-03-16 17:51:08]    DEBUG --- DEBUG    Message - 10 (temp3.py:33)
[2015-03-16 17:51:08]     INFO --- INFO     Message - 20 (temp3.py:34)
[2015-03-16 17:51:08]  WARNING --- WARNING  Message - 30 (temp3.py:35)
[2015-03-16 17:51:08] CRITICAL --- CRITICAL Message - 40 (temp3.py:36)

DEBUG+记录在results.txt中，而只有INFO+发送到stdout。

请注意，NOTSET日志条目会被传递到根日志记录器，然后，由于根日志记录器上没有任何处理程序，因此会被丢弃。