[keycloak-user] Federated and Dynamic Users/Attributes

Hi! In an upcoming system we aim to use Keycloak as a "OIDC/OAuth security proxy/broker". All information basically resides in other systems (federated); * An external IdP provides ID federation via SAML v2 * Permissions are fetched dynamically each time the user authenticates from an external system via a web service call. KC is not the system of record for this information. After the user is authenticated, the client (web app) retrieves the full set of permissions info via the /userinfo endpoint by providing an Access Token (resource owner credentials grant). My first question is; is this approach at all advisable? Can it be done using KC? I got a clue from this ; https://stackoverflow.com/ questions/44014260/how-to-programmatically-assign-particular-roles-at-user- registration-in-keycloak If so I assume we'd have to extend KC using one of the SPIs. The documentation on the SPIs don't give me much confidence on where to best put such extensions. Where would I put a web service call? How can I dynamically assign roles and/or attributes to a provisioned user? Should I use the Authentication SPI, User Federation SPI, User Storage SPI or possibly piggyback on a callback event of Event Listener SPI ? Best Regards Andreas Tell