Python:日志模块logging的应用

最后更新于:2022-04-01 19:39:41

通常,在商用软件中均会有完整的日志机制,之前使用C语言实现过一个[《简单的分级别写日志程序》](http://blog.csdn.net/dyx1024/article/details/4720484),具有以下功能和不足: ~~~ /************************************/ * 摘 要:此文件实现了普通WINDOWS程序中的日志功能 * 主要有以下特点: * 1. 根据日期创建日志文件目录,每天的日志分别存放在不同的日志目录中; * 2. 日志内容分三种类型,根据不同需要,写不同的日志类型的日志文件, * 方便通过日志定位、分析问题; * 3. 函数经过比较好的封装,便于复用; * 待改进点: * 1. 为了方便,日志内容打印时使用了time函数,其精确度较低; * 2. 可将这些函数封装为一个日志类,或者动态库,使其更通用; * 3. 没有考虑跨平台情景,目前只使用于WINDOWS下 * 4. 日志文件内容还可进一步改进,比如打印出当前文件名与行号,使用日志功能 * 更加实用; * * 当前版本:1.0 * 作 者:duanyongxing * 完成日期:2009年10月11日 /************************************/ ~~~ 在Python中,上面以实现的和已经实现的,均可以使用logging模块迅速搞定,且仅仅只需要一个配置文件,两行代码,实现过程如下(仅以输出的磁盘文件为例,命令输出只需要修改配置文件即可,具体可查API手册): 1. 定义配置文件logging.conf: ~~~ [loggers] keys=root,applog [handlers] keys=rotateFileHandler [formatters] keys=applog_format [formatter_applog_format] format=[%(asctime)s - %(name)s]%(levelname)s: %(message)s - %(filename)s:%(lineno)d [logger_root] level=NOTSET handlers=rotateFileHandler [logger_applog] level=NOTSET handlers=rotateFileHandler qualname=simple_example [handler_rotateFileHandler] class=handlers.RotatingFileHandler level=NOTSET formatter=applog_format args=('log_1.log', 'a', 10000, 9) ~~~ 注意前三个[ ]中的keys,这个在后面各[ ]中定义定义,section的取名格式如looger_自定义名称, handler_自定义名称,我偷懒直接使用了标准名称,其他一样,最后一个要注意的就是format,即日志文件中内容的格式,具体见后面附一。level参数是日志级别,可扩展,如果使用python自己的,有以下四个级别: ~~~ Level Numeric value CRITICAL 50 ERROR 40 WARNING 30 INFO 20 DEBUG 10 NOTSET 0 ~~~ 例如配置文件中level定义为WARN,则INFO, DEBUG,NOTSET三个级别的日志点则不会输出,很方便的做到了日志级别控制。 args定义了日志方件名,写方式,最大大小,保存最多个数等属性。 2.编码,测试 ~~~ #!/usr/bin/env python # -*- coding: utf-8 -*- import logging import logging.config #日志初始化 LOG_FILENAME = 'logging.conf' logging.config.fileConfig(LOG_FILENAME) logger = logging.getLogger("simple_log_example") #测试代码 logger.debug("debug message") logger.info("info message") logger.warn("warn message") logger.error("error message") logger.critical("critical message") ~~~ 运行后,查看日志文件,内容如下: ~~~ [2012-02-11 14:47:05,483 - simple_log_example]DEBUG: debug message - test_log.py:48 [2012-02-11 14:47:05,483 - simple_log_example]INFO: info message - test_log.py:49 [2012-02-11 14:47:05,483 - simple_log_example]WARNING: warn message - test_log.py:50 [2012-02-11 14:47:05,483 - simple_log_example]ERROR: error message - test_log.py:51 [2012-02-11 14:47:05,483 - simple_log_example]CRITICAL: critical message - test_log.py:52 ~~~ 如将日志级别设置为WARN,再次运行,查看日志: ~~~ [2012-02-11 14:54:20,046 - simple_log_example]WARNING: warn message - test_log.py:50 [2012-02-11 14:54:20,092 - simple_log_example]ERROR: error message - test_log.py:51 [2012-02-11 14:54:20,092 - simple_log_example]CRITICAL: critical message - test_log.py:52 ~~~ 附一:format参数格式说明: ~~~ Format Description %(name)s Name of the logger (logging channel). %(levelno)s Numeric logging level for the message (DEBUG, INFO, WARNING, ERROR, CRITICAL). %(levelname)s Text logging level for the message ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'). %(pathname)s Full pathname of the source file where the logging call was issued (if available). %(filename)s Filename portion of pathname. %(module)s Module (name portion of filename). %(funcName)s Name of function containing the logging call. %(lineno)d Source line number where the logging call was issued (if available). %(created)f Time when the LogRecord was created (as returned by time.time()). %(relativeCreated)d Time in milliseconds when the LogRecord was created, relative to the time the logging module was loaded. %(asctime)s Human-readable time when the LogRecord was created. By default this is of the form “2003-07-08 16:49:45,896” (the numbers after the comma are millisecond portion of the time). %(msecs)d Millisecond portion of the time when the LogRecord was created. %(thread)d Thread ID (if available). %(threadName)s Thread name (if available). %(process)d Process ID (if available). %(message)s The logged message, computed as msg % args. ~~~
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