1、When to use logging
| level | when to use |
|---|---|
| DEBUG | 细节信息，调试程序 |
| INFO | 证实程序如期运行 |
| WARNING | 出现异常，但程序仍运行 |
| ERROR | 严重问题，程序部分功能不能运行 |
| CRITICAL | 出错，程序不能运行 |
2、A simple example
默认是warning！
import logging
logging.warning('Watch out!') # will print a message to the console
logging.info('I told you so') # will not print anything
consle_result:
WARNING:root:Watch out!
3、Logging to a file
import logging
logging.basicConfig(filename='example.log',level=logging.DEBUG)
logging.debug('This message should go to the log file')
logging.info('So should this')
logging.warning('And this, too')
file_result:
DEBUG:root:This message should go to the log file
INFO:root:So should this
WARNING:root:And this, too
上例中默认是输出文件为a+模式，可以自定义：
logging.basicConfig(filename='example.log', filemode='w', level=logging.DEBUG)
4、Logging variable data
import logging
logging.warning('%s before you %s', 'Look', 'leap!')
result:
WARNING:root:Look before you leap!
This is for backwards compatibility: the logging package pre-dates newer formatting options such as str.format()
and string.Template
. These newer formatting options are supported
5、格式
import logginglogging.basicConfig(format='%(levelname)s[%(asctime)s] :%(message)s', datefmt='%m/%d/%Y %I:%M:%S %p', level=logging.DEBUG)
6、一般使用方法
import logging
# create logger
logger = logging.getLogger('simple_example')#getLogger自定义值可替换root
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 - %(name)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')
7、同时打印到控制台和输出文件
import logging
import os
log = logging.getLogger()
formatter = logging.Formatter('[%(asctime)s] [%(name)s] %(levelname)s: %(message)s')
stream_handler = logging.StreamHandler()
file_handler = logging.FileHandler(os.path.join(os.getcwd(), 'test.log'))
file_handler.setFormatter(formatter)
stream_handler.setFormatter(formatter)
log.addHandler(file_handler)
log.addHandler(stream_handler)
log.setLevel(logging.DEBUG)
8、使用配置文件
import logging
import logging.config
logging.config.fileConfig('logging.conf')
# create logger
logger = logging.getLogger('simpleExample')
# 'application' code
logger.debug('debug message')
logger.info('info message')
logger.warn('warn message')
logger.error('error message')
logger.critical('critical message')
logging.conf 文件格式：
[loggers]
keys=root,simpleExample
[handlers]
keys=consoleHandler
[formatters]
keys=simpleFormatter
[logger_root]
level=DEBUG
handlers=consoleHandler
[logger_simpleExample]
level=DEBUG
handlers=consoleHandler
qualname=simpleExample
propagate=0
[handler_consoleHandler]
class=StreamHandler
level=DEBUG
formatter=simpleFormatter
args=(sys.stdout,)
[formatter_simpleFormatter]
format=%(asctime)s - %(name)s - %(levelname)s - %(message)s
datefmt=
