1. 简单配置
使用logging.basicConfig进行配置
#!/usr/local/bin/python
# -*- coding:utf-8 -*-
import logging
# 通过下面的方式进行简单配置输出方式与日志级别
logging.basicConfig(filename='logger.log', level=logging.INFO)
logging.debug('debug message')
logging.info('info message')
logging.warning('warn message')
logging.error('error message')
logging.critical('critical message')
代码创建了一个logger.log文件，文件中写入如下内容
INFO:root:info message
WARNING:root:warn message
ERROR:root:error message
CRITICAL:root:critical message
如果多次运行该函数，log文件会持续追加basicConfig可以包含有如下参数，下面是官方文档
Do basic configuration for the logging system.
This function does nothing if the root logger already has handlers
configured, unless the keyword argument *force* is set to ``True``.
It is a convenience method intended for use by simple scripts
to do one-shot configuration of the logging package.
The default behaviour is to create a StreamHandler which writes to
sys.stderr, set a formatter using the BASIC_FORMAT format string, and
add the handler to the root logger.
A number of optional keyword arguments may be specified, which can alter
the default behaviour.
filename Specifies that a FileHandler be created, using the specified
filename, rather than a StreamHandler.
filemode Specifies the mode to open the file, if filename is specified
(if filemode is unspecified, it defaults to 'a').
format Use the specified format string for the handler.
datefmt Use the specified date/time format.
style If a format string is specified, use this to specify the
type of format string (possible values '%', '{', '$', for
%-formatting, :meth:`str.format` and :class:`string.Template`
- defaults to '%').
level Set the root logger level to the specified level.
stream Use the specified stream to initialize the StreamHandler. Note
that this argument is incompatible with 'filename' - if both
are present, 'stream' is ignored.
handlers If specified, this should be an iterable of already created
handlers, which will be added to the root handler. Any handler
in the list which does not have a formatter assigned will be
assigned the formatter created in this function.
force If this keyword is specified as true, any existing handlers
attached to the root logger are removed and closed, before
carrying out the configuration as specified by the other
arguments.
Note that you could specify a stream created using open(filename, mode)
rather than passing the filename and mode in. However, it should be
remembered that StreamHandler does not close its stream (since it may be
using sys.stdout or sys.stderr), whereas FileHandler closes its stream
when the handler is closed.
2. 使用FileHandler和Formatter进行配置
步骤如下
- 创建logger对象
- 创建FileHandler和Formatter对象
- 使用FileHandler和Formatter对logger进行配置
示例代码如下:
# -*- encoding:utf-8 -*-
import logging
# create logger
logger_name = "example"
logger = logging.getLogger(logger_name)
logger.setLevel(logging.DEBUG)
# create file handler
log_path = "./log.log"
fh = logging.FileHandler(log_path)
fh.setLevel(logging.WARN)
# create formatter
fmt = "%(asctime)-15s %(levelname)s %(filename)s %(lineno)d %(process)d %(message)s"
datefmt = "%a %d %b %Y %H:%M:%S"
formatter = logging.Formatter(fmt, datefmt)
# add handler and formatter to logger
fh.setFormatter(formatter)
logger.addHandler(fh)
# print log info
logger.debug('debug message')
logger.info('info message')
logger.warning('warn message')
logger.error('error message')
logger.critical('critical message')
注意: %(levelname)s 是python风格的格式化字符串，参考文章python格式化字符串