python利用with语句分割长函数代码块的小技巧

如果某个函数实现很长, 有时候希望把函数分割成若干部分, 并且可以折叠, 执行时能够打印日志. 可以采用下面的办法来实现:

from mylog import logger
import time

class MyTask:
    def __init__(self,task:str) -> None:
        self.task:str = task
        self.start_time = time.time()
    def __enter__(self):
        logger.trace(f'开始执行: {self.task} ...')
        return self
    def __exit__(self, exc_type, exc_val, exc_tb):
        end_time = time.time()
        spend_time = round(end_time - self.start_time,2)
        if not exc_type: logger.success(f'执行完毕({spend_time}s): {self.task}')
        else: logger.error(f'执行失败({spend_time}s): {self.task}')
        return False  # 如果有异常, 继续抛出异常
    
def run():
    with MyTask('task1') as task1:
        print('task1')

    with MyTask('task2') as task1:
        print('task2')

run()

打印如下信息: