The log module in Python

The simplest usage:

ImportLogginglogging.debug ("Logging Debug") Logging.info ("Logging Info") logging.warning ("user [Qianduoduo] attempted wrong password more than 3 times") Logging.error ("Logging Error") logging.critical ("Logging Critical")#OutputWARNING:root:user [Qianduoduo] attempted wrong password more than 3timesERROR:root:logging errorCRITICAL:root:logging Critical#root is the default user name

Focus: Why the above Debug and info No output, that is because a module default log level is warning, lower than his level will not output

Write the logs to the file system.

Import logginglogging.basicconfig (filename= ' Duoduo.log ',                    level=logging. DEBUG,                    format= '% (asctime) s% (message) s ', #asctime字符串形式的当前时间, message user output messages                    datefmt= '%y-%m-%d%i:%m:%s%p ') Logging.debug ("Logging Debug") Logging.info ("Logging info") logging.warning ("User [Qianduoduo] attempted wrong Password more than 3 times ") Logging.error (" Logging Error ") logging.critical (" Logging critical ") #输出到文件 ' Duoduo.log ' 2018-01-27 07:33:30 pm  Logging debug2018-01-27 07:33:30 pm  Logging info2018-01-27 07:33:30 pm  User [ Qianduoduo] attempted wrong password more than 3 times2018-01-27 07:33:30 pm  Logging error2018-01-27 07:33:30 pm  L Ogging Critical

log format for format

	Logger's name.
% (Levelno) s	Log level in digital form
% (LevelName) s	Log level in text form
% (pathname) s	The full path name of the module that called the log output function may not have
% (filename) s	The file name of the module that called the log output function
% (module) s	Call the module name of the log output function
% (FuncName) s	Function name of the call log output function
% (Lineno) d	The line of code where the statement that called the log output function is located
% (created) f	Current time, represented by the UNIX standard floating-point number representing the time
% (relativecreated) d	The number of milliseconds since logger was created when the log information is output
% (Asctime) s	The current time in string form. The default format is "2003-07-08 16:49:45,896". The comma is followed by milliseconds
% (thread) d	The thread ID. Probably not.
% (ThreadName) s	The name of the thread. Probably not.
% (process) d	The process ID. Probably not.
% (message) s	User-Output messages

Configure log with configuration file

{"Version": 1, "disable_existing_loggers": false, "formatters": {"simple": {"format": "% (asctime) S-% (name) s-% (levelname) s-% (message) S "}}," handlers ": {" console ": {" class ":" Logging.        Streamhandler "," Level ":" DEBUG "," Formatter ":" Simple "," stream ":" Ext://sys.stdout "            }, "Info_file_handler": {"Class": "Logging.handlers.RotatingFileHandler", "Level": "Info", "Formatter": "Simple", "filename": "Logs/info.log", "MaxBytes": 10485760, "Backupcou NT ": $," encoding ":" UTF8 "}," Error_file_handler ": {" Class ":" Logging.handlers.Rotating            Filehandler "," Level ":" ERROR "," Formatter ":" Simple "," filename ":" Logs/errors.log ", "MaxBytes": 10485760, "Backupcount": "Encoding": "UTF8"}}, "loggers": {"            My_module ": {"Level": "DEBUG", "Handlers": ["Info_file_handler"], "propagate": "No"}, "root": { "Level": "INFO", "Handlers": ["Console", "Info_file_handler", "Error_file_handler"]}}

Referencing in programs

Import jsonimport loggingimport logging.configimport osdef setup_logging (default_path= "Logging.json", default_level= Logging.info, env_key= "Log_cfg"):    Path = default_path    value = os.getenv (Env_key, None)    if value:        path = value    if os.path.exists (path):        with open (path, "R") as f:            config = json.load (f)            Logging.config.dictConfig (config)    else:        logging.basicconfig (level=default_level) If __name__ = = "__main__" :    setup_logging (default_path= "Logging.json")

The log module in Python