Ueberauth is great at what it does, which is handle the initial oath authentication. That’s it’s only goal so it doesn’t offer to handle your sessions, yet alone do any kind sort of single sign on.
I did evaluate Ruby CAS years ago when looking at a single sign on solution for someone. I found the whole thing a bit over complicated but haven’t actually used it so could be wrong. It’s not being maintained either which is alarming.
More recently I was looking for a lighter approach to SSO and found a sass offering from Auth0 https://auth0.com/docs/sso/current. This looked practical for at least doing a quick prototype and assessing how it would all work.
