1.效果如下： 

2.代码如下：

import logging
import threading
import os
import sys
sys.path.append(os.getcwd())

class Mylog(object):
    _instance_lock = threading.Lock()

    def __init__(self):#,path = "log.txt"):
        # 配置日志输出格式
        path = os.path.join(os.getcwd(),'applog.log')
        # formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(pathname)s - %(message)s')
        formatter = logging.Formatter("%(asctime)s - %(pathname)s[line:%(lineno)d] - %(levelname)s: %(message)s")
        self.logger = logging.getLogger()
        self.logger.setLevel(logging.DEBUG)
        
        # 创建文件处理器并设置日志级别为DEBUG
        file_handler = logging.FileHandler(path,mode='a',encoding='utf-8')# 输出到log文件的handler 'w'覆盖 'a'添加
        file_handler.setLevel(logging.DEBUG)
        file_handler.setFormatter(formatter)
        # 输出到控制台
        # file_handler = logging.StreamHandler()
        # file_handler.setLevel(logging.INFO)
        # 将文件处理器添加到日志记录器中
        self.logger.addHandler(file_handler)

    @classmethod
    def instance(cls, *args, **kwargs):
        if not hasattr(Mylog, "_instance"):
            with Mylog._instance_lock:
                if not hasattr(Mylog, "_instance"):
                    Mylog._instance = Mylog(*args, **kwargs)
        return Mylog._instance


def testlog():
    mylog = Mylog.instance()
    mylog.logger.debug("This is a debug message")
    mylog.logger.info("This is a info message")
    Mylog.instance().logger.debug("This is another debug message")
    Mylog.instance().logger.error("This is an  错误信息")

if __name__ == '__main__':
    testlog()