将日志级别设置为 logging.DEBUG 或 logging.INFO 无效

Question

我正在尝试做一个非常简单的日志记录设置。我只希望我所有的日志输出都转到终端和我的日志文件。我在 Real Python 上找到了以下示例，它演示了流和文件日志处理程序的设置：

# logging_example.py

import logging

# Create a custom logger
logger = logging.getLogger(__name__)

# Create handlers
c_handler = logging.StreamHandler()
f_handler = logging.FileHandler('file.log')
c_handler.setLevel(logging.WARNING)
f_handler.setLevel(logging.ERROR)

# Create formatters and add it to handlers
c_format = logging.Formatter('%(name)s - %(levelname)s - %(message)s')
f_format = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
c_handler.setFormatter(c_format)
f_handler.setFormatter(f_format)

# Add handlers to the logger
logger.addHandler(c_handler)
logger.addHandler(f_handler)

logger.warning('This is a warning')
logger.error('This is an error')

## Log Output
# 2019-08-31 22:16:02,478 - __main__ - WARNING - This is a warning
# 2019-08-31 22:16:02,478 - __main__ - ERROR - This is an error

并且如您所料，这会记录到控制台和文件中。但是，当我修改程序使其也记录 INFO 时，如下所示：

import logging

# Create a custom logger
logger = logging.getLogger(__name__)

# Create handlers
c_handler = logging.StreamHandler()
f_handler = logging.FileHandler('file.log')
c_handler.setLevel(logging.DEBUG)
f_handler.setLevel(logging.DEBUG)

# Create formatters and add it to handlers
c_format = logging.Formatter('%(name)s - %(levelname)s - %(message)s')
f_format = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
c_handler.setFormatter(c_format)
f_handler.setFormatter(f_format)

# Add handlers to the logger
logger.addHandler(c_handler)
logger.addHandler(f_handler)


logger.warning('logs')
logger.error('logs')
logger.info('should log but doesn\'t')
logger.debug('should log but doesn\'t')

## Log Output
# __main__ - WARNING - logs
# __main__ - ERROR - logs

我做错了什么？任何帮助将不胜感激！

Answer 1

您还需要在 logger 对象本身上调用 setLevel(level)，因为默认情况下，它将使用 ROOT 的日志记录级别（如果它没有任何其他祖先），即 WARNING:

logger.setLevel(logging.DEBUG)

带输出的完整代码：

import logging

logger = logging.getLogger(__name__)

# Create handlers
c_handler = logging.StreamHandler()
f_handler = logging.FileHandler('file.log')
logger.setLevel(logging.DEBUG) # <<< Added Line
c_handler.setLevel(logging.DEBUG)
f_handler.setLevel(logging.INFO)

# Create formatters and add it to handlers
c_format = logging.Formatter('%(name)s - %(levelname)s - %(message)s')
f_format = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
c_handler.setFormatter(c_format)
f_handler.setFormatter(f_format)

# Add handlers to the logger
logger.addHandler(c_handler)
logger.addHandler(f_handler)


logger.warning('logs')
logger.error('logs')
logger.info('should log but doesn\'t')
logger.debug('should log but doesn\'t')

输出：

__main__ - WARNING - logs
__main__ - ERROR - logs
__main__ - INFO - should log but doesn't
__main__ - DEBUG - should log but doesn't

Answer 2

有两个地方可以设置级别：Logger，Handler。它们都会影响日志设置的输出——在日志流的不同节点。您也可以将 Fliter 添加到这两个使用更复杂的规则过滤日志记录的实例。

office docment 中的流动字符清楚记录日志时发生的情况。

将日志级别设置为 logging.DEBUG 或 logging.INFO 无效

Setting log level to logging.DEBUG or logging.INFO has no effect

python

logging

python-3.6