Hydra looks like another popular open source solution, but it leaves you to implement the user login and challenge. I have been writing a hobby OpenID server a

Hydra looks like another popular open source solution, but it leaves you to implement the user login and challenge. I have been writing a hobby OpenID server as a way to learn Go and to understand auth. Reading the OpenID connect spec is SO much more educational & clearer than the OAuth RFC on its own.