如何自定义 Python 日志记录的时间格式？

Question

我是 Python 的日志记录包的新手，并计划将它用于我的项目。我想根据自己的喜好自定义时间格式。这是我从教程中复制的简短代码：

import logging

# create logger
logger = logging.getLogger("logging_tryout2")
logger.setLevel(logging.DEBUG)

# create console handler and set level to debug
ch = logging.StreamHandler()
ch.setLevel(logging.DEBUG)

# create formatter
formatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s")

# add formatter to ch
ch.setFormatter(formatter)

# add ch to logger
logger.addHandler(ch)

# "application" code
logger.debug("debug message")
logger.info("info message")
logger.warn("warn message")
logger.error("error message")
logger.critical("critical message")

这是输出：

2010-07-10 10:46:28,811;DEBUG;debug message
2010-07-10 10:46:28,812;INFO;info message
2010-07-10 10:46:28,812;WARNING;warn message
2010-07-10 10:46:28,812;ERROR;error message
2010-07-10 10:46:28,813;CRITICAL;critical message

我想将时间格式缩短为：'2010-07-10 10:46:28'，去掉毫秒后缀。我查看了 Formatter.formatTime，但很困惑。感谢您为实现我的目标所提供的帮助。谢谢。

Answer 1

试试这些格式：

格式 1：

'formatters': {
        'standard': {
            'format' : '%(asctime)s |:| LEVEL: %(levelname)s |:| FILE PATH: %(pathname)s |:| FUNCTION/METHOD: %(funcName)s %(message)s |:| LINE NO.: %(lineno)d |:| PROCESS ID: %(process)d |:| THREAD ID: %(thread)d',
            'datefmt' : "%y/%b/%Y %H:%M:%S"
                    },
              }

格式 1 的输出：

格式 2：

'formatters': {
        'standard': {
            'format' : '%(asctime)s |:| LEVEL: %(levelname)s |:| FILE PATH: %(pathname)s |:| FUNCTION/METHOD: %(funcName)s %(message)s |:| LINE NO.: %(lineno)d |:| PROCESS ID: %(process)d |:| THREAD ID: %(thread)d',
            'datefmt' : "%Y-%m-%d %H:%M:%S"
                    },
              }

格式 2 的输出：

Answer 2

使用logging.basicConfig，以下示例适用于我：

logging.basicConfig(
    filename='HISTORYlistener.log',
    level=logging.DEBUG,
    format='%(asctime)s.%(msecs)03d %(levelname)s %(module)s - %(funcName)s: %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S',
)

这允许您在一行中进行格式化和配置。生成的日志记录如下所示：

2014-05-26 12:22:52.376 CRITICAL historylistener - main: History log failed to start

Answer 3

要添加到其他答案，这里是 Python 文档中的 variable list。

Directive   Meaning Notes

%a  Locale’s abbreviated weekday name.   
%A  Locale’s full weekday name.  
%b  Locale’s abbreviated month name.     
%B  Locale’s full month name.    
%c  Locale’s appropriate date and time representation.   
%d  Day of the month as a decimal number [01,31].    
%H  Hour (24-hour clock) as a decimal number [00,23].    
%I  Hour (12-hour clock) as a decimal number [01,12].    
%j  Day of the year as a decimal number [001,366].   
%m  Month as a decimal number [01,12].   
%M  Minute as a decimal number [00,59].  
%p  Locale’s equivalent of either AM or PM. (1)
%S  Second as a decimal number [00,61]. (2)
%U  Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0.    (3)
%w  Weekday as a decimal number [0(Sunday),6].   
%W  Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0.    (3)
%x  Locale’s appropriate date representation.    
%X  Locale’s appropriate time representation.    
%y  Year without century as a decimal number [00,99].    
%Y  Year with century as a decimal number.   
%z  Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59].  
%Z  Time zone name (no characters if no time zone exists).   
%%  A literal '%' character.     

Answer 4

来自official documentation 关于 Formatter 类：

构造函数有两个可选参数：一个消息格式字符串和一个日期格式字符串。

所以改变

# create formatter
formatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s")

到

# create formatter
formatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s",
                              "%Y-%m-%d %H:%M:%S")

Answer 5

如果将 logging.config.fileConfig 与配置文件一起使用，请使用以下内容：

[formatter_simpleFormatter]
format=%(asctime)s - %(name)s - %(levelname)s - %(message)s
datefmt=%Y-%m-%d %H:%M:%S