在简单的 python 日志记录配置中重复输出

Question

我正在按如下方式设置 python 日志记录：

 def setup_logging():
    loggers = (logging.getLogger("amcat"), logging.getLogger("scrapers"),logging.getLogger(__name__))
    filename = "somefile.txt"
    sys.stderr = open(filename, 'a')
    handlers = (logging.StreamHandler(sys.stdout),logging.FileHandler(filename))
    formatter = AmcatFormatter(date = True)

    for handler in handlers:
        handler.setLevel(logging.INFO)
        handler.setFormatter(formatter)

    for logger in loggers:
        logger.propagate = False
        logger.setLevel(logging.INFO)
        for handler in handlers:
            logger.addHandler(handler)
    logging.getLogger().handlers = []

启用了 2 个主要模块记录器，它们都应该记录到控制台和文件。错误被重定向到文件（理想情况下，错误也会显示在控制台中，但我还没有实现这个）

紧接着，我检查事情是否正确：

 should_work = [
    "amcat.scraping.scraper",
    "amcat.scraping.htmltools",
    "amcat.scraping.controller",
    "__main__"]

loggerdict = logging.Logger.manager.loggerDict #all loggers
for name, logger in loggerdict.items():
    if name in should_work:
        print("\nlogger: "+name)
        #iterate through parents see if effective handlers are set correctly
        print(effectivehandlers(logger))
        #test logger
        logger.info("test for {name}".format(**locals()))

def effectivehandlers(logger):
    handlers = logger.handlers
    while True:
        logger = logger.parent
        handlers.extend(logger.handlers)
        if not (logger.parent and logger.propagate):
            break
    return handlers

控制台输出：

 logger: __main__
[<logging.StreamHandler object at 0x3425d50>, <logging.FileHandler object at 0x3425dd0>]
[2013-10-24 10:27:30 daily.py:133 INFO] test for __main__

logger: amcat.scraping.controller
[<logging.StreamHandler object at 0x3425d50>, <logging.FileHandler object at 0x3425dd0>]
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.controller
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.controller

logger: amcat.scraping.htmltools
[<logging.StreamHandler object at 0x3425d50>, <logging.FileHandler object at 0x3425dd0>]
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.htmltools
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.htmltools

logger: amcat.scraping.scraper
[<logging.StreamHandler object at 0x3425d50>, <logging.FileHandler object at 0x3425dd0>]
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.scraper
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.scraper

这是文件输出：

 [2013-10-24 10:27:30 daily.py:133 INFO] test for __main__
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.controller
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.controller
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.htmltools
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.htmltools
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.scraper
[2013-10-24 10:27:30 daily.py:133 INFO] test for amcat.scraping.scraper

如您所见，输出是双倍的，尽管已禁用传播并确保不存在重复的处理程序。这哪里出错了？

原文由 ToonAlfrink 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

我想通了，感谢 Paco 为我指明了正确的方向

事实证明，当 getLogger 被调用时，处理程序被添加到它：

 >>> print(effectivehandlers(logger))
[<logging.StreamHandler object at 0x305ad90>, <logging.FileHandler object at 0x305ae10>]
>>> logging.getLogger(name) #the same logger
<logging.Logger object at 0x7fa08fb9b2d0>
>>> print(effectivehandlers(logger))
[<logging.StreamHandler object at 0x305ad90>, <logging.FileHandler object at 0x305ae10>, <logging.StreamHandler object at 0x305ad90>, <logging.FileHandler object at 0x305ae10>]

现在，孩子和父母都有相同的处理程序。因此重复输出。

原文由 ToonAlfrink 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

基本上，当您的一个子记录器显示一条消息时，它会在层次结构中倒退，并且父记录器也会记录相同的内容。

要取消该行为，您可以添加以下内容：

 logger.propagate = False

注意：您的记录器必须有一个使用非空字符串的名称，getLogger(‘my name’)

当它击中孩子时，它不会再击中父母。

这是有关此行为的一些 文档。

原文由 Paco 发布，翻译遵循 CC BY-SA 4.0 许可协议