如何轮询python asyncio任务状态

Question

使用 gevent，我可以像这样监控长时间运行的函数：

    greenlet = gevent.Greenlet(long_running_task, *args, **kwargs)
    greenlet.start()
    while not greenlet.ready():
        send_heartbeat()
        gevent.sleep(heartbeat_interval)
    if greenlet.successful():
        send_success(greenlet.value)
    else:
        send_failure(exception=greenlet.exception)

我将如何使用 asyncio 做到这一点？我尝试了以下方法，但我被卡住了：

    loop = asyncio.get_event_loop()
    async def send_heartbeat(heartbeat_interval=15):
        send_heartbeat()
        asyncio.sleep(heartbeat_interval)

    await asyncio.sleep(1)
    loop.run_until_complete(asyncio.wait([long_running_task(*args, **kwargs), send_heartbeat()]))
    loop.close()

我将如何改变它以获得预期的行为？

Answer 1

您可以使用ensure_future 安排长时间运行的任务（但不等待它）。作为回报，您将获得一个 Future 对象，该对象具有类似于 ready 的 done 方法

async def some_job():
    future = asyncio.ensure_future(long_running_task(*args, **kwargs))
    while not future.done():
        await send_heartbeat(heartbeat_interval=15)

    try:
        result = future.result()
    except asyncio.CancelledError:
        # the task has been cancelled
    except Exception:
        # some exception was raised in long running task

loop = asyncio.get_event_loop()
loop.run_until_complete(some_job())
loop.close()