Laravel auth with MYSQL stored procedure

I'm developing a Laravel 5.7 application with MYSQL database.

My question is, how to authenticate a given user with 'username' and 'password'.

The MYSQL stored procedure accepts these two parameters, and returns 'userLevel' and 'projectID' if the user exists, and 'false' otherwise.

The database can not be modified by any means, so I have to tweak the auth process in Laravel.

Note: The 'userLevel' and 'processID' should be included in auth()->user() if auth succeeded. How I'm I supposed to do this?

via Chebli Mohamed