Arch Linux User Repository

For the database, could have the mautrix-whatsapp user have a home directory (e.g. /var/lib/mautrix-whatsapp) which I've seen for some other bridges. That would then be the working directory for the service.

As for permissions, you are right, that is a better idea and also seems to be common among other bridges now that I've got them set up. That works for me, and unless bridges decide to formalize a shared registration directory, is probably the cleanest.

i will lock into moving the database to the directory when i have time.

regarding the registration file. I have normaly handled it by adding the synapse user to the mautrix-whatsapp group. which is in my opinion the safest option as everyone that has access to the registration file has (as far as i know) a lot of unresticted access to the homeserver. Also it is not realy possible to put the registration.yaml file into a synapse owned directory as other homeservers are starting to add appservice support and so the package can't asume that you have synapse installed. Another option would be to reach a consensus with all the other packages that add appservices for a matrix homeserver for a single canonical directory for registration files.

I think it would be handy to have a directory for the database (and any other files needing to be written by the bridge). So I created one in /var/lib/ owned by mautrix-whatsapp and set that as the working director and readwrite permissions in the service. Maybe also include some of the service settings from the docs? https://docs.mau.fi/bridges/go/whatsapp/setup/systemd.html

Also (true with I think all the bridges I've tried) there are permissions needed for synapse to read the created registration.yaml file (if made in the /etc/mautrix-whatsapp director). Not sure if normally this is put in a synapse directory or just owned by synapse or made world readable?