python logging 避免日志重复打印

关键点

• 日志配置：在应用启动时配置日志，确保只初始化一次。
• 检查日志配置：确保日志配置只初始化一次，避免重复添加日志处理器。
• 查看日志处理器：使用 logger.handlers 查看当前日志处理器，确保没有重复的处理器。

#!/usr/bin/env python

# -*- coding: utf-8 -*-


import logging

from logging.handlers import RotatingFileHandler

from logging import StreamHandler



class Logger(object):

    log_file = 'auditor.log'


    def __init__(self, log_name=None):

        """

        :param log_file:  日志路径+文件名称

        :param log_name:  日志名称，默认root

        """

        self.logger = logging.getLogger(log_name)

        self.logger.setLevel(logging.DEBUG)

        self.formatter = logging.Formatter(fmt="%(asctime)s %(levelname)s %(threadName)s %(name)s %(message)s", datefmt="%Y/%m/%d %X")

        
        if not Logger.has_handler(self.logger, StreamHandler):

            ch = StreamHandler()

            ch.setFormatter(self.formatter)

            ch.setLevel(logging.DEBUG)

            self.logger.addHandler(ch)


        if not Logger.has_handler(self.logger, RotatingFileHandler):

            fh = RotatingFileHandler(filename=self.log_file,

                                    mode='a',

                                    maxBytes=1024 * 1024 * 50,

                                    backupCount=10,

                                    encoding='utf-8')

            fh.setFormatter(self.formatter)

            fh.setLevel(logging.DEBUG)

            self.logger.addHandler(fh)

    
    def debug(self, msg):

        self.logger.debug(msg)


    def info(self, msg):

        self.logger.info(msg)


    def warning(self, msg):

        self.logger.warning(msg)


    def error(self, msg):

        self.logger.error(msg, exc_info=True)


    def critical(self, msg):

        self.logger.critical(msg, exc_info=True)


    @staticmethod

    def has_handler(logger, handler_type):

        """

        判断logger是否已有指定类型的handler。


        :param logger: 日志logger实例

        :param handler_type: 要检查的handler类型（例如logging.StreamHandler, logging.FileHandler）

        :return: 如果存在指定类型的handler则返回True，否则返回False

        """

        for handler in logger.handlers:

            if isinstance(handler, handler_type):

                return True

        return False