python3 异步 asyncio 动态添加任务

迈不过友情╰ 2021-08-30 17:01 650阅读 0赞

asyncio.run\_forever()下动态添加任务

方法一、asyncio.run\_coroutine\_threadsafe(coroutine, loop)

方法二、asyncio.call\_soon\_threadsafe(callback, \*args, context=None)

方法一、实例run\_coroutine\_threadsafe

通过添加新的coroutin对象，放入loop内，动态添加。（爬虫正解）

import asyncio
    import time
    
    from threading import Thread
    
    
    def start_loop(loop):
        asyncio.set_event_loop(loop)
        print("start loop", time.time())
        loop.run_forever()
    
    
    async def do_some_work(x):
        print('start {}'.format(x))
        await asyncio.sleep(x)
        print('Done after {}s'.format(x))
    
    
    new_loop = asyncio.new_event_loop()
    t = Thread(target=start_loop, args=(new_loop,))
    t.start()
    
    asyncio.run_coroutine_threadsafe(do_some_work(6), new_loop)
    asyncio.run_coroutine_threadsafe(do_some_work(4), new_loop)

方法二、实例call\_soon\_threadsafe

如果是io操作，就会相当于变成线程去阻塞执行添加进去的函数，密集型则没关系。

import asyncio
    import time
    from threading import Thread
    
    
    def start_loop(loop):
        asyncio.set_event_loop(loop)
        print("start loop")
        loop.run_forever()
    
    
    def more_work(x):
        print('start work {}'.format(x))
        time.sleep(x)
        print('Finished work {}'.format(x))
    
    
    new_loop = asyncio.new_event_loop()
    t = Thread(target=start_loop, args=(new_loop,))
    t.start()
    
    new_loop.call_soon_threadsafe(more_work, 6)
    new_loop.call_soon_threadsafe(more_work, 3)