We were using the `client_options` hash for the default tenant, defined
in the Devise initializer, but we forgot to include that key in the
multitenant code. This means OIDC wasn't working when different tenants
used different configurations.
- name: :oidc → Identifier for this login provider in the app.
- scope: [:openid, :email, :profile] → Tells the provider we want the user’s ID (openid), their email, and basic profile info (name, picture, etc.).
- response_type: :code → Uses Authorization Code Flow, which is more secure because tokens are not exposed in the URL.
- issuer: Rails.application.secrets.oidc_issuer → The base URL of the OIDC provider (e.g., Auth0). Used to find its config.
- discovery: true → Automatically fetches the provider’s endpoints from its discovery document instead of manually setting them.
- client_auth_method: :basic → Sends client ID and secret using HTTP Basic Auth when exchanging the code for tokens.
Add system tests for OIDC Auth
Edit the oauth docs to support OIDC auth
