# WP-58 — Real notifications (celery + scripted abonnement)

Status: todo
Phase: 10 — OpenZaak production hardening

## Why

The WP-54 harness deliberately trims celery/celery-beat/celery-flower and nginx, and sets
`NOTIFICATIONS_DISABLED: 'true'` — without a Celery worker, OpenZaak 500s and rolls back on
every write to a notified resource. Fine for a fixture-driven integration harness; a real
deployment that wants live Notificaties (WP-52's webhook) needs the workers running and the
`abonnement` (subscription) actually registered against the BFF's public callback URL —
today that registration step is manual.

## Read first

- `backend/openzaak/docker-compose.openzaak.yml` (top-of-file ponytail note)
- [openzaak-integration.md](../reference/openzaak-integration.md) (Notificaties section)
- [WP-52](WP-52-openzaak-notificaties.md)

## Decisions (pre-made, don't relitigate)

- Add celery + celery-beat as additional compose services (same `openzaak/open-zaak`
  image, different command), pointed at the same redis broker already in the harness.
- Registering the `abonnement` becomes a scripted, idempotent step — not a manual
  admin-UI action — parameterized by the BFF's real public URL.
- Keep the existing WP-54 harness variant (`NOTIFICATIONS_DISABLED: 'true'`) available for
  fast local iteration where a live webhook round-trip isn't needed; this WP is additive
  (a "with notifications" profile/override), not a replacement.

## Files

- `backend/openzaak/docker-compose.openzaak.yml` (or an override file)
- New script/config for `abonnement` registration
- `docs/reference/openzaak-integration.md`

## Steps

1. Add celery/celery-beat services to a notifications-enabled compose profile.
2. Flip `NOTIFICATIONS_DISABLED` off for that profile.
3. Script the `abonnement` registration (POST to the NRC, pointed at the BFF's
   `/zgw/notificaties` endpoint from WP-52), idempotent on rerun.
4. Verify a real write (e.g. a status change) triggers a live webhook delivery to the BFF.

## Acceptance criteria

- [ ] A notifications-enabled harness profile runs celery/celery-beat and delivers a real
      notification end-to-end to the BFF's webhook.
- [ ] The `abonnement` registration step is a script, re-runnable without erroring on an
      already-registered subscription.

## Verification

Bring up the notifications-enabled profile; create a zaak/status change; confirm the BFF's
`/zgw/notificaties` endpoint receives and logs it.

## Out of scope

Cache invalidation on notification receipt (flagged separately in
`openzaak-integration.md` as a `ponytail:` marker, not part of this slice);
celery-flower/monitoring UI.

## Risks

Celery/celery-beat add real operational surface (another process to keep alive) — scope
this WP to "works, documented," not a fully monitored deployment.

Depends on: WP-56 (provisioning mechanism this extends).