Subscriptions are dropped following reconnect

[basak]

Hi,

Thank you for trio-paho-mqtt!

Following the pattern in the README.md example, I did something equivalent to:

async with trio.open_nursery() as nursery:
    sync_client = mqtt.Client()
    client = AsyncClient(sync_client, nursery)
    client.connect(...)
    client.subscribe(topic)
    async for message in client.messages():
        ...

However I seemed to stop receiving messages after a while. I think this is because the connection timed out, the (sync) client reconnected automatically, but the subscription wasn't recreated.

https://github.com/eclipse/paho.mqtt.python/blob/master/README.rst says:

# The callback for when the client receives a CONNACK response from the server.
def on_connect(client, userdata, flags, rc):
    print("Connected with result code "+str(rc))

    # Subscribing in on_connect() means that if we lose the connection and
    # reconnect then subscriptions will be renewed.
    client.subscribe("$SYS/#")

However I can't straightforwardly do this in trio-paho-mqtt because you're already using the sync client on_connect method for internal purposes, and aren't exposing that to the API user.

I wonder if you could provide on_connect functionality directly from AsyncClient please?

[bkanuka]

You are absolutely right that this is a big. Unfortunately I don't have the time to maintain this project anymore. I will update the readme and possibly archive the project. Sorry.

[basak]

No problem. Thank you for making this, and for making your situation clear. I'd like to continue using this so it would be nice to get a fix for this and the trio hazmat/lowlevel fix into PyPI. I'd also be happy to continue reviewing minor pull requests and publishing to PyPI myself. Would you be willing to hand over PyPI maintainership of the project, please, and arrange some similar continuation for this repository? I don't intend to take on any major work; just help shepherd PRs into PyPI for essential bugfixes. Hopefully that will still be useful to others though.

[bkanuka]

100% - I'd love to hand this over to someone. I'll look into getting the pypi ownership over to you. I can also make you an owner of the repo and maybe we store the pypi keys in a github secret. In case someone else wants to help, then it's just a matter of giving them repo permissions.

…

On Tue, May 11, 2021 at 5:58 AM basak ***@***.***> wrote: No problem. Thank you for making this, and for making your situation clear. I'd like to continue using this so it would be nice to get a fix for this and the trio hazmat/lowlevel fix into PyPI. I'd also be happy to continue reviewing minor pull requests and publishing to PyPI myself. Would you be willing to hand over PyPI maintainership of the project, please, and arrange some similar continuation for this repository? I don't intend to take on any major work; just help shepherd PRs into PyPI for essential bugfixes. Hopefully that will still be useful to others though. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#10 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAUNOYYWTUQUNANLRF7XKH3TND5TRANCNFSM44RU36PA> .

[basak]

Thanks! You can just add people to a PyPI project as "collaborators". My username on PyPI is rcab.

I intend to send a pull request for this issue in the next few days.