# Authentik OIDC setup

Local auth (bcrypt + session, the saved Vaultwarden password) is always available.
When `OIDC_ENABLED=true`, the login page additionally shows a "Sign in with Authentik"
button — this is additive, not a replacement, so the existing admin login keeps working.

## How the Authentik side was provisioned

No API token or admin credentials were needed. Authentik supports **blueprints** —
declarative YAML files it applies automatically — so the OAuth2 Provider + Application
were created via `/opt/authentik/blueprints-local/homelab-monitor-oidc.yaml` on CT121,
picked up by the `worker` container on startup. This is purely additive: it doesn't
touch any existing user, group, or admin credential.

- Blueprint volume mount added to `/opt/authentik/docker-compose.yml` (backed up as
  `docker-compose.yml.bak-homelab-monitor` before editing) for both `server` and `worker`.
- Provider: confidential client, `default-provider-authorization-implicit-consent` flow
  (auto-approve — reasonable for a single-user personal dashboard), signed with
  Authentik's existing self-signed cert.
- Redirect URIs (both registered): `https://monitor.jerodrigged.com/api/auth/oidc/callback` (primary,
  set in `.env`) and `http://192.168.1.103:8090/api/auth/oidc/callback` (LAN fallback, works if the
  tunnel/DNS is down).
- Application slug: `homelab-monitor`.

To change anything (redirect URI, flow, scopes), edit the blueprint file on CT121 and
either wait for Authentik's file-watcher or `docker restart authentik-worker-1` — it
re-applies on any change to the file.

## Bug: LAN-IP issuer sent browsers somewhere they couldn't reach

First deploy used `OIDC_ISSUER_URL=https://192.168.1.208:9443/application/o/homelab-monitor/`
(Authentik's LAN IP) for discovery. Authentik's discovery document **echoes back whichever
host you queried it through** — so `authorization_endpoint` came back as that same LAN IP.
That value gets handed straight to the *browser* as a redirect target. Anyone off the LAN
(or just not on wifi) got redirected to an address they couldn't reach at all — reported as
"signed in via Authentik, got sent to the local IP, and it failed."

Fix: Authentik was **already** publicly exposed at `https://auth.jerodrigged.com` (NPM proxy
host id 9, predates this project) with a real Let's Encrypt cert — just wasn't the one used
for `OIDC_ISSUER_URL`. Switched to it; `OIDC_ALLOW_INSECURE_TLS` could then go back to `false`
too, since it's not a self-signed cert. **Always use the public issuer URL for anything a
browser is ever redirected through**, even though the app's own server-to-server calls
(token exchange, userinfo, jwks — all made directly by the Node process, never by a browser)
would have worked fine against the LAN IP too.

## API-side implementation

`apps/api/src/auth/oidc.ts` uses `openid-client` v6 with PKCE + state, with an optional
insecure-TLS fetch override (`OIDC_ALLOW_INSECURE_TLS`) for the rare case the issuer is
LAN-only with a self-signed cert — not needed now that the issuer is the public URL, but
kept since Authentik's LAN address still works as a fallback if `auth.jerodrigged.com` is
ever unreachable. Routes in `apps/api/src/routes/oidc.ts`:

- `GET /api/auth/oidc/login` — redirects to Authentik's authorization endpoint
- `GET /api/auth/oidc/callback` — exchanges the code, sets `req.session.username` from
  the `preferred_username` (falls back to `email`, then `sub`) ID token claim, and stores
  `authMethod: "oidc"` + the raw `id_token` in the session
- `GET /api/auth/oidc/logout` — RP-Initiated Logout (issue #19). Only takes this path if
  `req.session.authMethod === "oidc"` (a locally-authenticated session has no Authentik
  session to end); redirects through Authentik's `end_session_endpoint` with
  `id_token_hint` + `post_logout_redirect_uri` (via `openid-client`'s `buildEndSessionUrl`,
  not hand-rolled) before landing back on `/`. **Must be a full-page navigation, not a
  fetch** — the frontend does `window.location.href = ...`, since Authentik needs to see a
  real browser request to clear its own session cookie on `auth.jerodrigged.com`. Plain
  `POST /api/auth/logout` still exists for local sessions and just clears the local one.

Authentik has no dedicated `post_logout_redirect_uri` allowlist field (unlike
`redirect_uris`) as of the version this was built against — confirmed by checking the
provider's DB schema (`\d authentik_providers_oauth2_oauth2provider`) before
implementing, not assumed.

## Credentials

`OIDC_CLIENT_ID`/`OIDC_CLIENT_SECRET` are in CT122's `.env` and saved in Vaultwarden
alongside the local admin login.