Python 日志记录 : propagate messages of level below current logger level

Question

我想将特定记录器名称、特定级别或更高级别(比如 INFO 及以上)的消息记录到特定的日志处理程序，比如文件处理程序，同时仍然获取所有日志消息到控制台。 Python 是 2.7 版。

到目前为止我尝试的是创建两个记录器:

• 根记录器
• 命名记录器

对于根记录器，我附加了一个logging.StreamHandler，并将日志级别设置为logging.DEBUG。

然后我将一个处理程序附加到指定的记录器，并将该记录器的级别设置为 logging.INFO。

当我现在调用使用命名记录器的模块时，我不再将 DEBUG 日志传播到根记录器。

注意:extraLogger 在这里有一个StreamHandler 来演示这个问题。在我的生产代码中，我会使用 FileHandler

import logging

def do_logging(turn):
    logger = logging.getLogger('extra')
    logger.info('some info turn %d' % turn) 
    logger.debug('this is debug fudge turn %d' % turn)

rootLogger = logging.getLogger()
handler = logging.StreamHandler()
rootFormatter = logging.Formatter('root - %(levelname)s: %(msg)s')
handler.setFormatter(rootFormatter)
rootLogger.addHandler(handler)
rootLogger.setLevel(logging.DEBUG)

do_logging(1)

extraLogger = logging.getLogger('extra')
extraHandler = logging.StreamHandler()
extraFormatter = logging.Formatter('extra - %(levelname)s: %(msg)s')
extraHandler.setFormatter(extraFormatter)
extraLogger.addHandler(extraHandler)
extraLogger.setLevel(logging.INFO)

do_logging(2)

实际输出:

root - INFO: some info turn 1
root - DEBUG: this is debug fudge turn 1
extra - INFO: some info turn 2
root - INFO: some info turn 2

我想要的输出:

root - INFO: some info turn 1
root - DEBUG: this is debug fudge turn 1
extra - INFO: some info turn 2
root - INFO: some info turn 2
root - DEBUG: this is debug fudge turn 2

我怀疑自定义 Filter 在这种情况下会有所帮助，但我不知道如何...

Answer 1

你可以使用 robert's LevelFilter像这样:

# Put the Filter on the Handler so only INFO and higher is handled
extraHandler.addFilter(LevelFilter(logging.INFO))

# Let the Logger process everything (so it can propagate records to root)
extraLogger.setLevel(logging.DEBUG)

---

import logging

class LevelFilter(logging.Filter):
    """
    https://stackoverflow.com/a/7447596/190597 (robert)
    """
    def __init__(self, level):
        self.level = level

    def filter(self, record):
        return record.levelno >= self.level

def do_logging(turn):
    logger = logging.getLogger('extra')
    logger.info('some info turn %d' % turn) 
    logger.debug('this is debug fudge turn %d' % turn)

rootLogger = logging.getLogger()
handler = logging.StreamHandler()
rootFormatter = logging.Formatter('root - %(levelname)s: %(msg)s')
handler.setFormatter(rootFormatter)
rootLogger.addHandler(handler)
rootLogger.setLevel(logging.DEBUG)
do_logging(1)

extraLogger = logging.getLogger('extra')
extraHandler = logging.StreamHandler()
extraFormatter = logging.Formatter('extra - %(levelname)s: %(msg)s')
extraHandler.setFormatter(extraFormatter)
extraLogger.addHandler(extraHandler)

# Put the Filter on the Handler so only INFO and higher is handled
extraHandler.addFilter(LevelFilter(logging.INFO))

# Handle everything (so it can propagate to root)
extraLogger.setLevel(logging.DEBUG)
do_logging(2)