一个使用日志记录的例子。使用basicConfig而不是logging.fileHandler()

logging.basicConfig(filename=logname,
                    filemode='a',
                    format='%(asctime)s,%(msecs)d %(name)s %(levelname)s %(message)s',
                    datefmt='%H:%M:%S',
                    level=logging.DEBUG)

logging.info("Running Urban Planning")

logger = logging.getLogger('urbanGUI')

按顺序，这五个部分做以下工作:

设置输出文件(filename=logname) 将其设置为追加而不是覆盖(filemode='a') 确定输出消息的格式(format=…) 确定输出时间的格式(datefmt='%H:%M:%S') 并确定它将接受的最小消息级别(level=logging.DEBUG)。

我更喜欢使用配置文件。它允许我在从开发到发布的过程中切换日志级别、位置等，而无需更改代码。我只是用相同的名称打包了一个不同的配置文件，并定义了相同的记录器。

import logging.config
if __name__ == '__main__':
    # Configure the logger
    # loggerConfigFileName: The name and path of your configuration file
    logging.config.fileConfig(path.normpath(loggerConfigFileName))

    # Create the logger
    # Admin_Client: The name of a logger defined in the config file
    mylogger = logging.getLogger('Admin_Client')

    msg='Bite Me'
    myLogger.debug(msg)
    myLogger.info(msg)
    myLogger.warn(msg)
    myLogger.error(msg)
    myLogger.critical(msg)

    # Shut down the logger
    logging.shutdown()

下面是日志配置文件的代码

#These are the loggers that are available from the code
#Each logger requires a handler, but can have more than one
[loggers]
keys=root,Admin_Client


#Each handler requires a single formatter
[handlers]
keys=fileHandler, consoleHandler


[formatters]
keys=logFormatter, consoleFormatter


[logger_root]
level=DEBUG
handlers=fileHandler


[logger_Admin_Client]
level=DEBUG
handlers=fileHandler, consoleHandler
qualname=Admin_Client
#propagate=0 Does not pass messages to ancestor loggers(root)
propagate=0


# Do not use a console logger when running scripts from a bat file without a console
# because it hangs!
[handler_consoleHandler]
class=StreamHandler
level=DEBUG
formatter=consoleFormatter
args=(sys.stdout,)# The comma is correct, because the parser is looking for args


[handler_fileHandler]
class=FileHandler
level=DEBUG
formatter=logFormatter
# This causes a new file to be created for each script
# Change time.strftime("%Y%m%d%H%M%S") to time.strftime("%Y%m%d")
# And only one log per day will be created. All messages will be amended to it.
args=("D:\\Logs\\PyLogs\\" + time.strftime("%Y%m%d%H%M%S")+'.log', 'a')


[formatter_logFormatter]
#name is the name of the logger root or Admin_Client
#levelname is the log message level debug, warn, ect 
#lineno is the line number from where the call to log is made
#04d is simple formatting to ensure there are four numeric places with leading zeros
#4s would work as well, but would simply pad the string with leading spaces, right justify
#-4s would work as well, but would simply pad the string with trailing spaces, left justify
#filename is the file name from where the call to log is made
#funcName is the method name from where the call to log is made
#format=%(asctime)s | %(lineno)d | %(message)s
#format=%(asctime)s | %(name)s | %(levelname)s | %(message)s
#format=%(asctime)s | %(name)s | %(module)s-%(lineno) | %(levelname)s | %(message)s
#format=%(asctime)s | %(name)s | %(module)s-%(lineno)04d | %(levelname)s | %(message)s
#format=%(asctime)s | %(name)s | %(module)s-%(lineno)4s | %(levelname)-8s | %(message)s

format=%(asctime)s | %(levelname)-8s | %(lineno)04d | %(message)s


#Use a separate formatter for the console if you want
[formatter_consoleFormatter]
format=%(asctime)s | %(levelname)-8s | %(filename)s-%(funcName)s-%(lineno)04d | %(message)s

虽然这是一个老问题，但对于现在遇到这个问题的人来说，您也可以使用dictConfig。例如，对于info级别以上的文件:

logging.config.dictConfig({
    'version': 1,
    'formatters': {
        'default': {
            'format': '[%(asctime)s] %(message)s',
        }
    },
    'handlers': {
        'info': {
            'level': logging.INFO,
            'class': 'logging.FileHandler',
            'filename': 'info.log',
        },
    },
    "root": {
        "level": logging.INFO,
        "handlers": ["info"]
    }
})

或者另一个更具体的例子，在一个特定的目录下旋转文件:

today = datetime.date.today()
folder = './log'
Path(folder).mkdir(parents=True, exist_ok=False) # Create folder if not exists
logging.config.dictConfig({
        ...
        'info': {
            'level': logging.INFO,
            'class': 'logging.handlers.TimedRotatingFileHandler',
            'filename': f'{folder}/info-{today.month:02}-{today.year}.log',
            # Roll over on the first day of the weekday
            'when': 'W0',
            # Roll over at midnight
            'atTime': datetime.time(hour=0),
            # Number of files to keep.
            'backupCount': 8
        },
        ...

http://docs.python.org/library/logging.handlers.html#filehandler

FileHandler类位于核心日志包中，它将日志输出发送到磁盘文件。

import sys
import logging

from util import reducer_logfile
logging.basicConfig(filename=reducer_logfile, format='%(message)s',
                    level=logging.INFO, filemode='w')

import logging

from datetime import datetime

filename = datetime.now().strftime("%d-%m-%Y %H-%M-%S")#Setting the filename from current date and time
logging.basicConfig(filename=filename, filemode='a',
                    format="%(asctime)s, %(msecs)d %(name)s %(levelname)s [ %(filename)s-%(module)s-%(lineno)d ]  : %(message)s",
                    datefmt="%H:%M:%S",
                    level=logging.DEBUG)

asctime %(asctime)s Human-readable time when the LogRecord was created. By default this is of the form ‘2003-07-08 16:49:45,896’ (the numbers after the comma are millisecond portion of the time). created %(created)f Time when the LogRecord was created (as returned by time.time()). exc_info You shouldn’t need to format this yourself. Exception tuple (à la sys.exc_info) or, if no exception has occurred, None. filename %(filename)s Filename portion of pathname. funcName %(funcName)s Name of function containing the logging call. levelname %(levelname)s Text logging level for the message ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'). levelno %(levelno)s Numeric logging level for the message (DEBUG, INFO, WARNING, ERROR, CRITICAL). lineno %(lineno)d Source line number where the logging call was issued (if available). message %(message)s The logged message, computed as msg % args. This is set when Formatter.format() is invoked. module %(module)s Module (name portion of filename). msecs %(msecs)d Millisecond portion of the time when the LogRecord was created. msg You shouldn’t need to format this yourself. The format string passed in the original logging call. Merged with args to produce message, or an arbitrary object (see Using arbitrary objects as messages). name %(name)s Name of the logger used to log the call. pathname %(pathname)s Full pathname of the source file where the logging call was issued (if available). process %(process)d Process ID (if available). processName %(processName)s Process name (if available). relativeCreated %(relativeCreated)d Time in milliseconds when the LogRecord was created, relative to the time the logging module was loaded. stack_info You shouldn’t need to format this yourself. Stack frame information (where available) from the bottom of the stack in the current thread, up to and including the stack frame of the logging call which resulted in the creation of this record. thread %(thread)d Thread ID (if available). threadName %(threadName)s Thread name (if available).

有关日志记录的更多信息，请转到python3官方页面。