[Python]异步上下文管理

'''
异步上下文管理
'''
import asyncio


class ContextManager:
    def __init__(self):
        self.conn = None

    async def action(self):
        return self.conn


    async def __aenter__(self):  # 链接数据库
        print("开始连接")
        await asyncio.sleep(1)
        self.conn = "OK"
        return self


    async def __aexit__(self, exc_type, exc, tb):  # 关闭数据库链接
        print("结束连接")
        self.conn = "CLOSE"


async def main():
    async with ContextManager() as cm:
        result = await cm.action()
        print(result)


asyncio.run(main())