# rotor

CDP JS Functions runner. Executes user-supplied JavaScript inside V8 isolates
(via `isolated-vm`), enforcing a memory + wall-clock limit per invocation.

## Endpoints

| Method | Path | Body | Notes |
|--------|------|------|-------|
| `POST` | `/v1/run` | `{ code, event }` | run ad-hoc code on one event |
| `POST` | `/v1/transform` | `{ workspace_id, function, event }` | run a registered function |
| `POST` | `/v1/functions` | `{ workspace_id, slug, code }` | upsert function code (admin) |
| `DELETE` | `/v1/functions/:workspace/:slug` | — | invalidate cache entry |
| `GET` | `/health` | — | liveness |
| `GET` | `/ready` | — | readiness |

## User function contract

The submitted code must define a global function `transform(event)`. The
function can return:

- `event` (possibly mutated) — emit one event
- `null` / `undefined` — drop the event
- `Array<event>` — fan-out into multiple events

Sync return only (no `async`). The runner enforces:

- Memory limit: `ROTOR_ISOLATE_MEMORY_MB` (default 128MB)
- CPU/wall limit: `ROTOR_FUNCTION_TIMEOUT_MS` (default 2000ms)

## Local dev

```bash
npm install
npm run dev
```

Smoke test:

```bash
curl -s -X POST localhost:3401/v1/run -H 'content-type: application/json' -d '{
  "code": "function transform(event) { event.properties = { tagged: true }; return event; }",
  "event": { "message_id": "m1", "workspace_id": "ws", "type": "track" }
}'
```