如何删除日志过滤器/格式化程序

Question

我有以下日志过滤器：

class LogFilter:
    """
    Print all messages that do not equal hello."""
    def filter(self, record):
        print ('@@@@@@@ Filter', record)
        if getattr(record, 'msg') == 'Hello':
            return False
        return True
    def __repr__(self):
        return 'LogFilter'

进而：

import logging
handler = logging.StreamHandler()
handler.addFilter(LogFilter())
logger = logging.getLogger(__name__)
logger.addHandler(handler)

我该如何删除这个过滤器？例如当我尝试：

>>> handler.removeFilter(LogFilter())
>>> handler.removeFilter(LogFilter)
>>> handler.removeFilter('LogFilter') # ????
>>> handler.filters
[LogFilter] # filter is still there.

我还有过滤器。删除过滤器（或格式化程序）的正确方法是什么？

Answer 1

如果你查看源代码removeFilter

def removeFilter(self, filter):
    """
    Remove the specified filter from this handler.
    """
    if filter in self.filters:
        self.filters.remove(filter)

您会发现您需要实际的filter对象才能将其删除。一个快速解决办法是

import logging
handler = logging.StreamHandler()
LF = LogFilter()
handler.addFilter(LF)
logger = logging.getLogger(__name__)
logger.addHandler(handler)

然后，当你想删除过滤器时

>>> handler.removeFilter(LF)
>>> handler.filters
[]