python logging 輸出到文件，Python Logging Handler

class logging.Handler

import logging
logger = logging.getLogger("AppName")
# 定義handler,來控制日志的輸出,這里同時輸出到test.log文件和控制臺
file_handler = logging.FileHandler("test.log")
console_handler = logging.StreamHandler()
logger.addHandler(file_handler)
logger.addHandler(console_handler)
logger.error('this is error message')  # test.log核控制臺都有
logger.removeHandler(file_handler)  # 移除對文件日志的輸入
logger.error('this is error message2')  # 只有控制臺有

class logging.StreamHandler(stream=None)
如果stream指定,則會輸出,如果不指定默認是sys.stderr

class logging.FileHandler(filename, mode='a', encoding=None, delay=False)
mode默認為追加,encoding默認是輸出文件的編碼

python logging 輸出到文件，參考:
https://docs.python.org/3/library/logging.handlers.html#logging.StreamHandler