Removing client, Subscribe topic is empty.

[sivaNbalusu5]

Hi,

I have a consumer running in aync loop and as long as there are new messages published to the topic(using another publish client running in while loop ), I don't see any issues but if the messages are not available for few seconds(using another publish client running in for loop ) I see "Operation timed out" in 12 seconds after publisher is done. I have tried setting up keepalive parameter to 600s but i still see timeout happening in 12 seconds. @halfgaar

I am using reconnect example from: https://pypi.org/project/asyncio-mqtt/

[2023-03-08 19:59:24] [NOTICE] Client '[ClientID='taFZMGPgNREbVLnAQWIMYzn', username='', fd=74, keepalive=600s, transport='TCP/SSL', address='10.105.0.1', prot=5.0, clean=1]' logged in successfully
[2023-03-08 19:59:24] [NOTICE] Removing client '[ClientID='taFZMGPgNREbVLnAQWIMYzn', username='', fd=74, keepalive=600s, transport='TCP/SSL', address='10.105.0.1', prot=5.0, clean=1]'. Reason(s): Subscribe topic is empty.
[2023-03-08 19:59:36] [NOTICE] Accepting connection from: address='10.105.0.1', transport='TCP/SSL', fd=74
[2023-03-08 19:59:36] [NOTICE] Client '[ClientID='6FklpDM4KkyVSCDK3rK7pFc', username='', fd=74, keepalive=600s, transport='TCP/SSL', address='10.105.0.1', prot=5.0, clean=1]' logged in successfully
[2023-03-08 19:59:36] [NOTICE] Removing client '[ClientID='6FklpDM4KkyVSCDK3rK7pFc', username='', fd=74, keepalive=600s, transport='TCP/SSL', address='10.105.0.1', prot=5.0, clean=1]'. Reason(s): Subscribe topic is empty.
[2023-03-08 19:59:48] [NOTICE] Accepting connection from: address='10.105.0.1', transport='TCP/SSL', fd=74
[2023-03-08 19:59:48] [NOTICE] Client '[ClientID='KArFWCJw3Csns2Ho5QXGpph', username='', fd=74, keepalive=600s, transport='TCP/SSL', address='10.105.0.1', prot=5.0, clean=1]' logged in successfully
[2023-03-08 19:59:48] [NOTICE] Removing client '[ClientID='KArFWCJw3Csns2Ho5QXGpph', username='', fd=74, keepalive=600s, transport='TCP/SSL', address='10.105.0.1', prot=5.0, clean=1]'. Reason(s): Subscribe topic is empty.

[halfgaar]

Weird. The message "Subscribe topic is empty" means a client subscribes with an empty topic. This spec says this is a protocol violation and therefore the client should be disconnected. I'd like to see the actual packet received. But, so far I am unable to reproduce. I have running as consumer:

import asyncio
import asyncio_mqtt as aiomqtt
import ssl

tls_params = aiomqtt.TLSParameters(
    ca_certs=None,
    certfile=None,
    keyfile=None,
    cert_reqs=ssl.CERT_NONE,
    tls_version=ssl.PROTOCOL_TLS,
    ciphers=None,
)

async def main():
    reconnect_interval = 5  # In seconds
    while True:
        try:
            async with aiomqtt.Client("192.168.178.127", port=8883, tls_params=tls_params) as client:
                async with client.messages() as messages:
                    await client.subscribe("#")
                    async for message in messages:
                        print(message.payload.decode())
        except aiomqtt.MqttError as error:
            print(f'Error "{error}". Reconnecting in {reconnect_interval} seconds.')
            await asyncio.sleep(reconnect_interval)



asyncio.run(main())

And as producer: ( while true; do date; sleep 1; done) | mosquitto_pub -t 'afd' -h 192.168.178.127 -l

It can turn it off or on as much as I like.

Can you provide your exact example?

[halfgaar]

If it's really the case that under certain conditions the client can send an empty topic as subscribe path, that would be a bug in that client. I was going to offer you could to connect to demo.flashmq.org after I prepared some debug stuff, but if you got it running, then I guess you're good?

[sivaNbalusu5]

@halfgaar Yes i am good for now. demo.flashmq.org option looks good as well because amqtt supports mqtt3.1.1 only where as the previous one supports mqtt5 and has way more activity from the community.

[halfgaar]

The server at demo.flashmq.org is now running a debug build that writes the mqtt packet out to disk before it throws that error. If you can reproduce it there, that would be great.

[sivaNbalusu5]

@halfgaar I have started the job, let me know whats happening on the other side.

[halfgaar]

@sivaNbalusu5 I saw your client, but nothing out of the ordinary happened. I did notice you're not connecting with SSL?

[sivaNbalusu5]

@halfgaar I need ca cert for demo.flashmq.org to connect via ssl.

[halfgaar]

I found the problem @sivaNbalusu5. I pushed the branch https://github.com/halfgaar/FlashMQ/tree/fix-empty-subscribe-topic

Can you build from source? I'm going to release this soon, but another confirmation would be nice.

[sivaNbalusu5]

@halfgaar sorry the connection was broken and I haven't paid attention. running it now!

[halfgaar]

@sivaNbalusu5 didn't you see my last message? I already fixed it.

[sivaNbalusu5]

@halfgaar I have seen it , already built the docker image, deployed and I am about to test it :) I started the client just in case if you want to debug more.

I will post more updates soon.

[halfgaar]

I'm curious to hear if you have test results :)

[sivaNbalusu5]

@halfgaar I am OOO last week, The preliminary test looks good, I will do more testing today.

[halfgaar]

I already released the fix. I had faith in it :)

[halfgaar]

Fix was released.

[sivaNbalusu5]

@halfgaar Thanks and everything looks stable.