相关疑难解决方法(0)

如何找出事件循环中有多少活动任务？在文档中我只找到asyncio.Task.all_tasks()但它是简单的增量计数器:

import asyncio


async def coro():
    await asyncio.sleep(1)


async def main():
    tasks = []
    print('Tasks count: ', len(asyncio.Task.all_tasks()))
    for idx in range(3):
        task = asyncio.ensure_future(coro())
        tasks.append(task)
        print('Tasks count: ', len(asyncio.Task.all_tasks()))
    await asyncio.gather(*tasks)
    print('Tasks count: ', len(asyncio.Task.all_tasks()))


loop = asyncio.get_event_loop()
loop.run_until_complete(main())

输出:

Tasks count:  1
Tasks count:  2
Tasks count:  3
Tasks count:  4
Tasks count:  4

预期产量:

Tasks count:  1
Tasks count:  2
Tasks count:  3
Tasks count:  4
Tasks count:  1