2.0.16 regression: Unable to establish bridging connection over TLS with custom CA

[thedmi]

TLS connections for bridging fail on 2.0.16 when using a custom CA. The configuration looks something like this:

connection cloud

address the-broker:8883
bridge_cafile /mosquitto/ca.pem
#bridge_insecure true # doesn't work whether this is true or not

bridge_protocol_version mqttv50
notifications_local_only true

remote_clientid the-client
remote_username the-username
remote_password the-password

topic some-topic out 1 "" ""

In the logs, I get

Bridge the-client sending CONNECT
Client local.the-client closed its connection.

repeatedly (every few seconds).

The same configuration works on 2.0.15, but unreliably due to #2634 . On 2.0.14 the same configuration works reliably.

Tested with docker image eclipse-mosquitto, tagged according to versions mentioned above.

[ralight]

I tried to reproduce this with a config of:

listener 1883

log_type all

connection tmo
address test.mosquitto.org:8883
bridge_cafile /mosquitto/config/mosquitto.org.crt
bridge_protocol_version mqttv50
notifications_local_only true

#remote_clientid the-client
#remote_username the-username
#remote_password the-password

topic some-topic out 1 "" ""

The file mosquitto.org.crt was downloaded from https://test.mosquitto.org/

Running this, I got this log, which shows it is working.

docker run -it -v $(pwd)/config:/mosquitto/config eclipse-mosquitto:2.0.16 
1692687410: mosquitto version 2.0.16 starting
1692687410: Config loaded from /mosquitto/config/mosquitto.conf.
1692687410: Opening ipv4 listen socket on port 1883.
1692687410: Opening ipv6 listen socket on port 1883.
1692687410: Bridge local.2b7fe1a336b5.tmo doing local SUBSCRIBE on topic some-topic
1692687410: Connecting bridge tmo (test.mosquitto.org:8883)
1692687410: Bridge 2b7fe1a336b5.tmo sending CONNECT
1692687410: mosquitto version 2.0.16 running
1692687410: Received CONNACK on connection local.2b7fe1a336b5.tmo.
1692687410: Bridge local.2b7fe1a336b5.tmo sending UNSUBSCRIBE (Mid: 1, Topic: some-topic)
1692687410: Received UNSUBACK from local.2b7fe1a336b5.tmo
1692687412: mosquitto version 2.0.16 terminating

Could you please try and reproduce that in the same way I have done? If it works, we need to figure out the difference in your setup.

[thedmi]

I just tried the new 2.0.17 release and my problem is gone. I suspect that I misinterpreted the situation to be related to the custom CA. It was probably due to max_queued_messages 0 and thus #2879 .

Thanks a lot for your repro and the fix for the other bug!