Python模块学习——logging
模块级函数
logging.getLogger([name]):返回一个logger对象，如果没有指定名字将返回root logger
logging.debug()、logging.info()、logging.warning()、logging.error()、logging.critical()：设定root logger的日志级别
logging.basicConfig():用默认Formatter为日志系统建立一个StreamHandler，设置基础配置并加到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'
)
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$ 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):指定最低的日志级别，低于lel的级别将被忽略。debug是最低的内置级别，critical为最高
Logger.addFilter(filt)、Logger.removeFilter(filt):添加或删除指定的filter
Logger.addHandler(hdlr)、Logger.removeHandler(hdlr)：增加或删除指定的handler
Logger.debug()、Logger.info()、Logger.warning()、Logger.error()、Logger.critical()：可以设置的日志级别
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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对象负责发送相关的信息到指定目的地。可以通过addHandler()方法添加多个多handler
Handler.setLevel(lel):指定被处理的信息级别，低于lel级别的信息将被忽略
Handler.setFormatter()：给这个handler选择一个格式
Handler.addFilter(filt)、Handler.removeFilter(filt)：新增或删除一个filter对象
Formatters
Formatter对象设置日志信息最后的规则、结构和内容，默认的时间格式为%Y-%m-%d %H:%M:%S，下面是Formatter常用的一些信息
| %(name)s |
Logger的名字 |
| %(levelno)s |
数字形式的日志级别 |
| %(levelname)s |
文本形式的日志级别 |
| %(pathname)s |
调用日志输出函数的模块的完整路径名，可能没有 |
| %(filename)s |
调用日志输出函数的模块的文件名 |
| %(module)s |
调用日志输出函数的模块名 |
| %(funcName)s |
调用日志输出函数的函数名 |
| %(lineno)d |
调用日志输出函数的语句所在的代码行 |
| %(created)f |
当前时间，用UNIX标准的表示时间的浮 点数表示 |
| %(relativeCreated)d |
输出日志信息时的，自Logger创建以 来的毫秒数 |
| %(asctime)s |
字符串形式的当前时间。默认格式是 “2003-07-08 16:49:45,896”。逗号后面的是毫秒 |
| %(thread)d |
线程ID。可能没有 |
| %(threadName)s |
线程名。可能没有 |
| %(process)d |
进程ID。可能没有 |
| %(message)s |
用户输出的消息 |
最后来个例子
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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.'
)
|
运行后，在终端看到的结果
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.
在日志文件中的结果
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.
发现DEBUG信息只有在文件中出现，这是因为StreamHandler中setLevel是INFO，可以看出Logger.setLevel()和handler.setLevel()的区别