WARNING:root:Observation deleted without explicit cancellation

[2bdkid]

I'm trying to send observation requests to a server, but before the server can send notifications back I get "WARNING:root:Observation deleted without explicit cancellation" printed on the console. I've searched through the sources but I can't find where this message originates from. I suspect one of my Request objects is being deleted.

Here's the jist of the code if anyone spots anything.

from asyncio.queues import Queue
from aiocoap import Message
from aiocoap import Context
from aiocoap import GET


async def start_server():
    protocol = await Context.create_client_context()
    get_obs_req = Message(code=GET, uri='coap://localhost/temp', observe=0)
    request = protocol.request(get_obs_req)

    # some logic

    request.observation.register_callback(handle_notification)
    await request.response
    # launch into websockets server


def main():
    asyncio.get_event_loop().create_task(start_server())
    asyncio.get_event_loop().run_forever()


if __name__ == '__main__':
    main()

[chrysn]

I'm not sure off my head and can't do a full check right now, but do you return from start_server? That'd be one way how the request would get deleted.

A quick and dirty way to check would be adding global request as first line of start_server -- not to stay there, just to narrow the debugging space as I'd see then whether it's this or something else.

(If that works, my next step is to find why register_callback doesn't keep the request object alive for until the callback is unregistered.)

[2bdkid]

I ended up using async for response in request.observation so the ClientObservation hands around. I just started learning asyncio today and I suspect my coroutine was finishing execution, destroying the Request.