How to wait for connection ?

[nduhamel]

Hi,

I code by hobby and i never use asyncio before recently.
I would like to know if there is a way to wait for connection without using context manager.
I currently use an event object.
Here some of my code for exemple.

Thank you,
Nicolas

async def connect(client, event):
    await client.connect()
    event.set()

async def shutdown(loop, signal=None):
    if signal:
        logging.info(f"Received exit signal {signal.name}...")
    logging.info("Shutdown")
    tasks = [t for t in asyncio.all_tasks() if t is not
             asyncio.current_task()]

    [task.cancel() for task in tasks]
    await asyncio.gather(*tasks, return_exceptions=True)
    loop.stop()


def handle_exception(loop, context):
    msg = context.get("exception", context["message"])
    logging.error(f"Caught exception: {msg}")
    asyncio.create_task(shutdown(loop))

def app_main(devices, mqtt_conf):
    loop = asyncio.get_event_loop()

    signals = (signal.SIGHUP, signal.SIGTERM, signal.SIGINT)
    for s in signals:
        loop.add_signal_handler(
            s, lambda s=s: asyncio.create_task(shutdown(loop, signal=s)))

    loop.set_exception_handler(handle_exception)

    client = Client(mqtt_conf.host,\
            port=mqtt_conf.port,\
            username=mqtt_conf.username,\
            password=mqtt_conf.password)

    connected = asyncio.Event()

    try:
        loop.create_task(connect(client, connected))
        loop.create_task(
            aio.web.start_http_server(addr='', port=9641)
            )
        loop.create_task(
            messages_getter(client, connected, mqtt_conf.root_topic, devices)
            )
        loop.run_forever()
    finally:
        loop.close()

[frederikaalund]

Hi Nicolas. Thanks for opening this issue. Let me have a look. :)

I would like to know if there is a way to wait for connection without using context manager.

The short answer is no. The context manager is the preferred way. You can hack your way around it (e.g., call connect or __aenter__ directly) but that may break in a future release.

Try to ask on stackoverflow.com or similar if you're unsure about context managers and asyncio in general. :)

~Frederik

[frederikaalund]

Usually, you simply want to use asyncio.run as done in the advanced example in the README.md file.

[nduhamel]

Thank you for your reply, i take your advice.