Python - logging模块 - 《编程基础》

https://www.cnblogs.com/nancyzhu/p/8551506.html
logging函数根据它们用来跟踪的事件的级别或严重程度来命名。标准级别及其适用性描述如下（以严重程度递增排序）：

原来格式为表格（table），转换较复杂，未转换，需要手动复制一下
{"cells":[{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(250, 250, 250)","value":"级别"},{"verticalAlign":"middle","value":"数字值"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(250, 250, 250)","value":"何时使用"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"DEBUG","inlineStyles":{"font-family":[{"from":0,"to":5,"value":"monospace"}]}},{"verticalAlign":"middle","value":"50"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"详细信息，一般只在调试问题时使用。"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"INFO","inlineStyles":{"font-family":[{"from":0,"to":4,"value":"monospace"}]}},{"verticalAlign":"middle","value":"40"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"证明事情按预期工作。"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"WARNING","inlineStyles":{"font-family":[{"from":0,"to":7,"value":"monospace"}]}},{"verticalAlign":"middle","value":"30"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"某些没有预料到的事件的提示，或者在将来可能会出现的问题提示。例如：磁盘空间不足。但是软件还是会照常运行。"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"ERROR","inlineStyles":{"font-family":[{"from":0,"to":5,"value":"monospace"}]}},{"verticalAlign":"middle","value":"20"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"由于更严重的问题，软件已不能执行一些功能了。"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"CRITICAL","inlineStyles":{"font-family":[{"from":0,"to":8,"value":"monospace"}]}},{"verticalAlign":"middle","value":"10"},{"textAlign":"left","verticalAlign":"middle","wrap":true,"backColor":"rgb(238, 238, 238)","value":"严重错误，表明软件已不能继续运行了。"}],"heights":[40,40,40,40,40,40],"widths":[70,70,426]}

默认等级是WARNING，这意味着仅仅这个等级及以上的才会反馈信息，除非logging模块被用来做其它事情。
利用logging.basicConfig()打印信息到控制台

import logging
logging.basicConfig(format='%(asctime)s - %(pathname)s[line:%(lineno)d] - %(levelname)s: %(message)s',
                    level=logging.DEBUG)
logging.debug('debug 信息')
logging.info('info 信息')
logging.warning('warning 信息')
logging.error('error 信息')
logging.critical('critial 信息')

输出到文件

logging.basicConfig(level=logging.DEBUG,#控制台打印的日志级别
                    filename='new.log',
                    filemode='a',##模式，有w和a，w就是写模式，每次都会重新写日志，覆盖之前的日志
                    #a是追加模式，默认如果不写的话，就是追加模式
                    format=
                    '%(asctime)s - %(pathname)s[line:%(lineno)d] - %(levelname)s: %(message)s'
                    #日志格式
                    )

同时输出到控制台和文件

import logging
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s"
    handlers=[
        logging.FileHandler("debug.log", mode = 'a'),
        logging.StreamHandler()
    ]
)

常用format

format="%(asctime)s [%(levelname)s] %(message)s"
format="%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s"