You could do it in docker, that is how I was doing it. One container for SQL and one for headless Kodi. You could run that on a Pi.
You just have to backup your database and then import it on the pi.
Mysql dump should be able to handle that.
But like I mentioned when I was doing it with MariaDb this way it was corrupting the database, but then again I have a lot of things in that database, and everything else exccept the kodi db was fine.
So not sure what the culprit was. I had a daily MariaDB backup, so I was able to recover on a regular basis if corruption occurred.
Personally I’ve used mysql setup in the past and had a few issues with scraping but no corruption like issues. Once in the while if there was an issue with the mysql host then the kodi would stop functioning - normally just when you are about to use it!
I’ve prefer the reliability of local db and syncing changes between multiple devices. It’s been faultless so far.
So what is the cloud based central source of truth for your add on?
Is this open source?
Can this be used to transfer the watched status of one box (older with lots of watched episodes and movies) to another new box ?
It could do with backup/restore functionality added but not at the moment I’m afraid.
Sorry, I missed your post. I’m not sure what you mean by the question - can you expand on it?
The functionality in the cloud is to route the messages between your kodi devices.
For those that use the add-on please note there is now a version for Kodi 19 which was released over the weekend.
Other than supporting the latest version of Kodi it will also mean that you can run different versions of Kodi around the home while synchronising the video watch status between them.
If you spot any issues please report on Github Issues