python logging 模块

logging模块是Python内置的标准模块，主要用于输出运行日志，可以设置输出日志的等级、日志保存路径、日志文件回滚等；

 

1. 控制台基本使用：

import logging

logging.basicConfig(level = logging.INFO,format = '%(asctime)s - %(name)s - %(levelname)s - %(message)s')
logger = logging.getLogger(__name__)

logger.info("Start print log")
logger.debug("Do something")
logger.warning("Something maybe fail.")
logger.info("Finish")

2. 将日志输出到文件

import logging


# logger 绑定 handler(可以多个)， handler 绑定formatter
logger = logging.getLogger(__name__)    #将当前文件名作为日志名生成logger 对象
logger.setLevel(level = logging.INFO)   # 为logger设置默认等级，低于此等级的信息均被忽略  Debug<Info<Warning<ERROR<critical<fatal
handler = logging.FileHandler("log.txt")  #生成 fileHandler（用的最多的就是 streamhandler 和filehandler）
handler.setLevel(logging.INFO)           #为handler 设置等级
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')  #设置日志格式
handler.setFormatter(formatter)          handler 绑定格式

console = logging.StreamHandler()    
console.setLevel(logging.INFO)

logger.addHandler(handler)
logger.addHandler(console)

logger.info("Start print log")
logger.debug("Do something")
logger.warning("Something maybe fail.")
logger.info("Finish")

3 旋转型日志

　　生成给定数量日志，不带数字的是最新生成，可以设置每个日志的大小

import logging
from logging.handlers import RotatingFileHandler

logger = logging.getLogger(__name__) 
logger.setLevel(level = logging.INFO)

#定义一个RotatingFileHandler，最多备份3个日志文件，每个日志文件最大1K
rHandler = RotatingFileHandler("log.txt",maxBytes = 1*1024,backupCount = 3)
rHandler.setLevel(logging.INFO)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
rHandler.setFormatter(formatter)

console = logging.StreamHandler()
console.setLevel(logging.INFO)
console.setFormatter(formatter)

logger.addHandler(rHandler)
logger.addHandler(console)

logger.info("Start print log")
logger.debug("Do something")
logger.warning("Something maybe fail.")
logger.info("Finish")