I would like to have a notification like "Device Activity Check" that would send out a warning if an error pops up in the log.
Is there anything existing? Is it possible?
My system is running pretty well. Unless I want to change something I don't log into the controller for maybe a week. And if I'm doing something simple I may not look at the live logs.
There is no official API into the logs, but this is one community effort that I'm aware of. I don't think it's received much attention since it's release due to apparent lack of interest and appears not to be fully fleshed out (or functional for some people), but it may work for you:
That being said, I usually take the low-tech approach of going into "Past Logs" once in a while and searching for "error" (and sometimes "warn"), which will turn anything up if it's still recent enough. Of course, this requires your logs be non-chatty enough for the entries to still be there (Hubitat's default driver behavior of disabling debug logging after 30 minutes works well to this goal, but look out for community drivers that may be chattier--or event/info/descriptionText logging which remains enabled indefinitely by convention if you don't care to keep that, though I usually find it helpful).
But I understand your request; I rarely think to do this unless I just installed a beta, am working on a custom app/driver, or notice problems ... which I haven't been but just looked now and noticed one of my Sonos devices, currently playing music, is warning that it's unreachable. 
(But I'm not going to worry too much about that.)
Download the Hubitat app
