Spring OAuth 2 through system userbase?

Question

Java

Hi, friend.

So the initial ones are:

Microservice architecture. spring gateway. Keycloak oauth 2. Everything works.

Managed user roles through Keycloak and each service knew the endpoint to receive a token with user data. Added converter JWT -> Principal. Everything is great.

The requirements have changed: now you need authorization through: GitHub, Microsoft and the system's own auth-service. It is clear how easy it is to connect.

Only as for all these people to control the rights from different systems.

That is, if a person comes in through github, then I would like to check that there is a user in the system with the given email and use the authorities and data inside the system, and not GitHub. That is, you need to store the user base inside the system.

How I want it to work as shown in the picture:



What tools do you know and what could you suggest?