Python log output

Import logging

Logger = Logging.getlogger () #生成一个日志对象, () is the name of the log object, can not take, the name is not given is root

Handler=logging. Filehandler ("Log_test.txt") #生成一个handler (processor),

#formatter The following code to specify the output format of the log

FMT = '% (asctime) s-% (filename) s:% (lineno) s-% (name) s-% (message) s '

Formatter = logging. Formatter (FMT) # instantiation Formatter

Handler.setformatter (Formatter) # Add formatter for handler

Logger.addhandler (Handler)

Logger.setlevel (logging. NOTSET) #设置日志输出信息的级别

Logger.error ("This was an error message") #输出设置小于级别的将不会输出, so the settings here should be higher than setlevel

Logger.info ("This was an info message")

Logger.critical ("This is a critical message")

Python can generate a lot of handler, responsible for sending the log information created by logger to the specified destination, and the different handler types sent to different destinations. Filehandler writes the log information to the file, Streamhandler the log information to the console, Smtphandler sends the log information in the form of a message, and Sockethandler sends the log information to the TCP socket Datagramhandler send the log information with a UDP datagram

Format of the Formatter

Property name	Format	Description
Name	% (name) s	The name of the log
Asctime	% (Asctime) s	Readable time, default format ' 2003-07-08 16:49:45,896 ', comma followed by milliseconds
FileName	% (filename) s	File name, part of pathname
Pathname	% (pathname) s	Full path name of the file
FuncName	% (FuncName) s	Call log multiple corresponding method name
LevelName	% (LevelName) s	Rank of log
Levelno	% (Levelno) s	Digitized log level
Lineno	% (Lineno) d	The number of rows recorded in the source code
Module	% (module) s	Module name
Msecs	% (msecs) d	The millisecond part of the time
Process	% (process) d	ID of the process
ProcessName	% (ProcessName) s	The name of the process
Thread	% (thread) d	The ID of the thread
ThreadName	% (ThreadName) s	The name of the thread
relativecreated	% (relativecreated) d	The relative time, in milliseconds, that the log was created

Log level size relationships are: CRITICAL > ERROR > WARNING > INFO > DEBUG > NOTSET, and of course you can define the log level yourself

Python log output