如何使用异步函数修复此错误 `sys:1: RuntimeWarning: coroutine 'finish_process' is never awaited`

Question

这段代码的目标是让它运行主函数，称为main_process()，直到结束的异步函数，称为finish_process()，将变量finish_state设置为True，并且循环不会重复一遍。

import asyncio
import time

condition = True
finish_state = False
x = 0

async def finish_process(finish_state):
    finish_state = True
    time.sleep(5)
    return finish_state

async def main_process(condition,finish_state,x):
    while condition == True:
        finish_state = await asyncio.run(finish_process(finish_state))
        
        x = x + 1
        print(x)

        #if(x > 10):
        if(finish_state == True):
            print("Termina!")
            condition = False


asyncio.run(main_process(condition,finish_state,x))

我已经将异步函数调用的 await 放在另一个异步函数中，我不明白为什么它总是用 await 报错。

我认为用await 或旧的yield from 指示应该可以解决同时等待另一个函数的结果。

raise RuntimeError(
RuntimeError: asyncio.run() cannot be called from a running event loop
sys:1: RuntimeWarning: coroutine 'finish_process' was never awaited

Answer 1

你的程序有以下问题：

1. 您应该使用asyncio.create_task 或asyncio.gather 来运行异步任务，而不是asyncio.run。
2. 可以用await asyncio.sleep(5)替换time.sleep(5)

import asyncio
import time

condition = True
finish_state = False
x = 0

async def finish_process(finish_state):
    finish_state = True
    await asyncio.sleep(5)
    return finish_state

async def main_process(condition,finish_state,x):
    while condition == True:
        finish_state = await asyncio.create_task(finish_process(finish_state))
        
        x = x + 1
        print(x)

        #if(x > 10):
        if(finish_state == True):
            print("Termina!")
            condition = False


asyncio.run(main_process(condition,finish_state,x))

输出：

1
Termina!