我怎样才能防止一个孩子取消整个托儿所引发的异常

问题描述

考虑以下代码：

import trio


async def broken_fn():
    await trio.sleep(4)
    print(1 / 0)


async def worker_fn():
    while True:
        print("working...")
        await trio.sleep(1)


async def main():
    async with trio.open_nursery() as nursery:
        nursery.start_soon(broken_fn)
        nursery.start_soon(worker_fn)


trio.run(main)

如何在不触及 broken_fn 的定义的情况下防止 broken_fn 引发的异常中止它在 Nurseries 中的兄弟姐妹？以下是最好的方法吗？

async def main():
    async def supress(fn):
        try:
            await fn()
        except Exception as e:
            print(f"caught {e}!")

    async with trio.open_nursery() as nursery:
        nursery.start_soon(supress,broken_fn)
        nursery.start_soon(worker_fn)

我还有其他选择吗？

解决方法

start_soon() 中没有机制可以忽略异常（如果这就是您要寻找的东西）。

您也可以以通用方式执行此操作，以免为每个单独的函数构建包装器：

from contextlib import suppress
from functools import wraps
from typing import Callable

def suppressed(func: Callable,*exceptions: BaseException):
    @wraps(func)
    async def wrapper(*args,**kwargs):
        with suppress(*exceptions):
            return await func(*args,**kwargs)
        
    return wrapper

那么：

async with trio.open_nursery() as nursery:
    nursery.start_soon(suppressed(broken_fn,Exception))
    nursery.start_soon(worker_fn)

python python-trio