1. 程式人生 > >Python模組學習——logging

Python模組學習——logging

logging模組是在2.3新引進的功能,下面是一些常用的類和模組級函式

模組級函式

logging.getLogger([name]):返回一個logger物件,如果沒有指定名字將返回root logger

logging.debug()、logging.info()、logging.warning()、logging.error()、logging.critical():設定root logger的日誌級別

logging.basicConfig():用預設Formatter為日誌系統建立一個StreamHandler,設定基礎配置並加到root logger中

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import logging

import sys

LEVELS = {'debug': logging.DEBUG,

'info': logging.INFO,

'warning': logging.WARNING,

'error': logging.ERROR,

'critical'

: logging.CRITICAL}

if len(sys.argv) > 1:

level_name = sys.argv[1]

level = LEVELS.get(level_name, logging.NOTSET)

logging.basicConfig(level=level)

logging.debug('This is a debug message')

logging.info('This is an info message')

logging.warning('This is a warning message'

)

logging.error('This is an error message')

logging.critical('This is a critical error message')

$ python logging_level_example.py debug DEBUG:root:This is a debug message INFO:root:This is an info message WARNING:root:This is a warning message ERROR:root:This is an error message CRITICAL:root:This is a critical error message $ python logging_level_example.py info INFO:root:This is an info message WARNING:root:This is a warning message ERROR:root:This is an error message CRITICAL:root:This is a critical error message

Loggers

Logger.setLevel(lel):指定最低的日誌級別,低於lel的級別將被忽略。debug是最低的內建級別,critical為最高

Logger.addFilter(filt)、Logger.removeFilter(filt):新增或刪除指定的filter

Logger.addHandler(hdlr)、Logger.removeHandler(hdlr):增加或刪除指定的handler

Logger.debug()、Logger.info()、Logger.warning()、Logger.error()、Logger.critical():可以設定的日誌級別

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import logging

# create logger

logger = logging.getLogger("simple_example")

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")

$ python simple_logging_module.py
2005-03-19 15:10:26,618 - simple_example - DEBUG - debug message
2005-03-19 15:10:26,620 - simple_example - INFO - info message
2005-03-19 15:10:26,695 - simple_example - WARNING - warn message
2005-03-19 15:10:26,697 - simple_example - ERROR - error message
2005-03-19 15:10:26,773 - simple_example - CRITICAL - critical message

Handlers

handler物件負責傳送相關的資訊到指定目的地。可以通過addHandler()方法新增多個多handler

Handler.setLevel(lel):指定被處理的資訊級別,低於lel級別的資訊將被忽略

Handler.setFormatter():給這個handler選擇一個格式

Handler.addFilter(filt)、Handler.removeFilter(filt):新增或刪除一個filter物件

Formatters

Formatter物件設定日誌資訊最後的規則、結構和內容,預設的時間格式為%Y-%m-%d %H:%M:%S,下面是Formatter常用的一些資訊

%(name)s

Logger的名字

%(levelno)s

數字形式的日誌級別

%(levelname)s

文字形式的日誌級別

%(pathname)s

呼叫日誌輸出函式的模組的完整路徑名,可能沒有

%(filename)s

呼叫日誌輸出函式的模組的檔名

%(module)s

呼叫日誌輸出函式的模組名

%(funcName)s

呼叫日誌輸出函式的函式名

%(lineno)d

呼叫日誌輸出函式的語句所在的程式碼行

%(created)f

當前時間,用UNIX標準的表示時間的浮 點數表示

%(relativeCreated)d

輸出日誌資訊時的,自Logger建立以 來的毫秒數

%(asctime)s

字串形式的當前時間。預設格式是 “2003-07-08 16:49:45,896”。逗號後面的是毫秒

%(thread)d

執行緒ID。可能沒有

%(threadName)s

執行緒名。可能沒有

%(process)d

程序ID。可能沒有

%(message)s

使用者輸出的訊息

最後來個例子

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import logging

# set up logging to file - see previous section for more details

logging.basicConfig(level=logging.DEBUG,

format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s',

datefmt='%m-%d %H:%M',

filename='/temp/myapp.log',

filemode='w')

# define a Handler which writes INFO messages or higher to the sys.stderr

console = logging.StreamHandler()

console.setLevel(logging.INFO)

# set a format which is simpler for console use

formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')

# tell the handler to use this format

console.setFormatter(formatter)

# add the handler to the root logger

logging.getLogger('').addHandler(console)

# Now, we can log to the root logger, or any other logger. First the root...

logging.info('Jackdaws love my big sphinx of quartz.')

# Now, define a couple of other loggers which might represent areas in your

# application:

logger1 = logging.getLogger('myapp.area1')

logger2 = logging.getLogger('myapp.area2')

logger1.debug('Quick zephyrs blow, vexing daft Jim.')

logger1.info('How quickly daft jumping zebras vex.')

logger2.warning('Jail zesty vixen who grabbed pay from quack.')

logger2.error('The five boxing wizards jump quickly.')

執行後,在終端看到的結果

root        : INFO     Jackdaws love my big sphinx of quartz.
myapp.area1 : INFO     How quickly daft jumping zebras vex.
myapp.area2 : WARNING  Jail zesty vixen who grabbed pay from quack.
myapp.area2 : ERROR    The five boxing wizards jump quickly.

在日誌檔案中的結果

10-22 22:19 root         INFO     Jackdaws love my big sphinx of quartz.
10-22 22:19 myapp.area1  DEBUG    Quick zephyrs blow, vexing daft Jim.
10-22 22:19 myapp.area1  INFO     How quickly daft jumping zebras vex.
10-22 22:19 myapp.area2  WARNING  Jail zesty vixen who grabbed pay from quack.
10-22 22:19 myapp.area2  ERROR    The five boxing wizards jump quickly.

發現DEBUG資訊只有在檔案中出現,這是因為StreamHandler中setLevel是INFO,可以看出Logger.setLevel()和handler.setLevel()的區別