Distinguish between "no user found" and "cannot contact the DB"

[sevenseacat]

We had a case recently where the DB host in our app went down, but the homepage of our app continued to render, despite performing database queries relating to showing current-user-specific information.

AshAuthentication swallows errors relating to database connectivity under a "user not found", as part of looking up the user that a JWT belongs to - https://github.com/team-alembic/ash_authentication/blob/main/lib/ash_authentication.ex#L221-L234 - and also as part of sign in (but I'm not sure where that happens).

So in our case, the web app behaved as if no-one was logged in (even when they were), but would not allow sign-in (because DB connection errors there were also being swallowed?) which wasn't an optimal scenario!

[jimsynz]

Yeah, I think what we should do is special case database errors and (re)raise them.