Add Default for BRIDGE_UDP or warn if missing

[niondir]

There should be some log about wrongly/not configured BRIDGE_UDP. Currently it's silently ignored and the bridge is just not working without helpful logs.

[htdvisser]

Thanks for the request. Can you submit a pull request for this?

[niondir]

Sure I can. Do you prefere a default + log or just a warning? I'm usually prefere good defaults.

[htdvisser]

I also prefer having sane defaults, which is what we will do with our upcoming v3 stack. For our v2 stack we shouldn't change the defaults, we don't want to silently change the behavior of production deployments.

For now, logging a Warn() about non-configured UDP port is fine. Wrongly configured (port already taken) can log an Error(), possibly even a Fatal().

[niondir]

There is no such thing as a working default, since with the current default there is just no UDP connection opened. I think adding a default can not break any environment. Or is there any reason to not have a UDP connection open with the bridge?

[htdvisser]

We have seen production deployments with one instance of the bridge responsible for MQTT, and a second for UDP. Changing the default would make the MQTT bridge claim a UDP port, potentially breaking the deployment.

We can't make these kind of changes in a minor update.