Python标准库系列之logging模块

This module defines functions and classes which implement a flexible event logging system for applications and libraries.

The key benefit of having the logging API provided by a standard library module is that all Python modules can participate in logging, so your application log can include your own messages integrated with messages from third-party modules.

官方文档：https://docs.python.org/3.5/library/logging.html

logging模块用于便捷记录日志且线程安全。

日志级别

只有大于当前日志等级的操作才会被记录。

实例

写入单文件

代码

#!/usr/bin/env python
# _*_ coding:utf-8 _*_
# 导入logging模块
import logging# 创建一个log.log日志文件
logging.basicConfig(filename='log.log',# 格式化的字符串format='%(asctime)s - %(name)s - %(levelname)s - %(module)s: %(message)s',# 时间datefmt='%Y-%m-%d %H:%M:%S %p',# 错误级别level=logging.NOTSET)logging.critical('critical')
logging.error('error')
logging.warning('warning')
logging.info('info')
logging.debug('debug')
logging.log(logging.INFO, 'NOTSET')

执行结果

ansheng@ansheng-me:~$ ls
log.py
ansheng@ansheng-me:~$ python log.py
ansheng@ansheng-me:~$ ls
log.log  log.py
ansheng@ansheng-me:~$ cat log.log
2016-05-27 21:46:15 PM - root - CRITICAL - log: critical
2016-05-27 21:46:15 PM - root - ERROR - log: error
2016-05-27 21:46:15 PM - root - WARNING - log: warning
2016-05-27 21:46:15 PM - root - INFO - log: info
2016-05-27 21:46:15 PM - root - DEBUG - log: debug
2016-05-27 21:46:15 PM - root - INFO - log: NOTSET

logging.basicConfig函数各参数

format参数

多文件日志

对于上述记录日志的功能，只能将日志记录在单文件中，如果想要设置多个日志文件，logging.basicConfig将无法完成，需要自定义文件和日志操作对象。

#!/usr/bin/env python
# _*_ coding:utf-8 _*_import logging# 创建文件
file_1 = logging.FileHandler("log1.log", "a")
# 创建写入的日志格式
fmt1 = logging.Formatter(fmt="%(asctime)s - %(name)s - %(levelname)s - %(module)s : %(message)s")
# 文件用格式
file_1.setFormatter(fmt1)file_2 = logging.FileHandler("log2.log", "a")
fmt2 = logging.Formatter()
file_2.setFormatter(fmt2)logger1 = logging.Logger("s1", level=logging.ERROR)
logger1.addHandler(file_1)
logger1.addHandler(file_2)logger1.critical("1111")

# 定义文件
file_2_1 = logging.FileHandler('l2_1.log', 'a')
fmt = logging.Formatter()
file_2_1.setFormatter(fmt)# 定义日志
logger2 = logging.Logger('s2', level=logging.INFO)
logger2.addHandler(file_2_1)

如上述创建的两个日志对象

1. 当使用logger1写日志时，会将相应的内容写入 l1_1.log 和 l1_2.log 文件中

2. 当使用logger2写日志时，会将相应的内容写入 l2_1.log 文件中

#Python标准库 #Logging