# Control plane and agent

Two long-running pieces: `drm serve` holds the state and the dashboard, `drm agent
run` keeps credentials fresh using real phones.

## drm serve

```bash
./bin/drm serve --bind 127.0.0.1:8083 --data .cache/streamd --token SECRET
```

| Flag | Default | Purpose |
|---|---|---|
| `--bind` | `0.0.0.0:8083` | listen address |
| `--data` | `.cache/streamd` | SQLite, work dirs, HLS output, logs |
| `--token` | `$STREAMD_TOKEN` | bearer token for mutating routes |
| `--nre` | `$NRE_PATH`, `bin/`, `PATH` | downloader binary |
| `--ffmpeg` | `$FFMPEG_PATH`, `bin/`, `PATH` | ffmpeg |
| `--mp4decrypt` | `$MP4DECRYPT_PATH`, `bin/`, `PATH` | decrypter |

Open <http://127.0.0.1:8083>. GET routes are unauthenticated; anything mutating
needs `Authorization: Bearer <token>`.

### API

| Route | Purpose |
|---|---|
| `GET /api/health` | liveness + uptime |
| `GET /api/apps` | compiled-in modules, their channels, registered rewriters |
| `GET /api/streams` | all streams with runtime state |
| `POST /api/streams` | create |
| `PATCH /api/streams/:id` | update |
| `DELETE /api/streams/:id` | remove |
| `POST /api/streams/:id/start\|stop\|restart` | desired state |
| `POST /api/streams/:id/credentials` | push a fresh manifest + keys |
| `POST /api/streams/:id/claim` | agent claims the stream |

The dashboard's app and channel pickers are filled from `/api/apps`, so they reflect
whatever modules the binary was built with. Nothing about a provider is hardcoded in
the UI or the schema.

### Creating a stream

```bash
./bin/drm catalog --app tg4 --channel ioi --keys --wvd data/device.wvd --json > s.json

curl -X POST http://127.0.0.1:8083/api/streams \
  -H 'Authorization: Bearer SECRET' -H 'Content-Type: application/json' \
  --data @s.json
```

A stream created without `app`, `video_select`, `audio_select` or `rewriter` keeps
those empty on purpose. They are resolved when the stream starts:

```text
stored row  ->  the stream's app module (app.StreamDefaults)  ->  neutral defaults
```

So a module decides its own downloader settings, an operator override in the row
still wins, and an unknown app gets something harmless rather than another
provider's preferences.

### Refreshing credentials

```bash
curl -X POST http://127.0.0.1:8083/api/streams/1/credentials \
  -H 'Authorization: Bearer SECRET' -H 'Content-Type: application/json' \
  -d '{"mpd":"https://...","key":"KID:KEY\nKID:KEY","headers_json":"{}"}'
```

This is exactly what the agent does after a successful capture.

### Manifest rewriting

If a stream's `rewriter` names a registered rewriter and the manifest is not HLS,
the supervisor starts a local rewrite server and points the downloader at it:

```text
stream rewriter="rte"  ->  mpd.Lookup("rte")  ->  http://127.0.0.1:PORT/manifest.mpd
```

The log line is `stream X: rewritten MPD http://127.0.0.1:…`. Streamd never imports
a provider package to do this — the module registered the rewriter under that name
at init time.

## drm agent run

```bash
export STREAMD_TOKEN=SECRET
./bin/drm agent run --config apps/agent/agent.yaml
```

What it does, in a loop:

1. poll streamd for enabled streams that are down or missing credentials
2. enqueue a job in a durable SQLite queue
3. claim a free ADB device that already has the app installed
4. run a phone capture through the stream's app module
5. `POST /api/streams/:id/credentials`
6. force-stop the app and release the device

It never installs apps and never runs a downloader. A websocket heartbeat keeps its
claims alive, so claims expire automatically if the agent dies.

### Subcommands

```bash
./bin/drm agent devices                              # phones it can use
./bin/drm agent status                               # recent jobs
./bin/drm agent enqueue --stream tg4-ioi --reason manual
./bin/drm agent cancel --job 3
```

### Config

`apps/agent/agent.yaml`:

```yaml
streamd_url: http://127.0.0.1:8083
# token: taken from $STREAMD_TOKEN when unset
poll_interval_sec: 30
data_dir: .cache/agent
workers: 1
max_attempts: 5
capture_wait_sec: 180
# devices: [SERIAL1, SERIAL2]    # empty = any authorised device
# python: path to python for wvkey.py
# wvd: data/device.wvd
# user_agent: ""
# agent_id: defaults to hostname
```

There is no modules directory to configure — app modules are compiled into the
binary.

`wvd` must be set (here or on the phone capture) or key fetches fail.

## Running both locally

```bash
# terminal 1
./bin/drm serve --bind 127.0.0.1:8083 --data .cache/streamd --token SECRET

# terminal 2
export STREAMD_TOKEN=SECRET
./bin/drm agent run --config apps/agent/agent.yaml
```

Then create a stream, enable it, and watch the agent pick it up:

```bash
./bin/drm agent status
```

## External tools

The media supervisor shells out to three binaries. Put them on `PATH`, in `bin/`,
or name them with flags/env:

| Tool | Flag | Env |
|---|---|---|
| N_m3u8DL-RE | `--nre` | `NRE_PATH`, `N_M3U8DL_RE` |
| ffmpeg | `--ffmpeg` | `FFMPEG_PATH`, `FFMPEG` |
| mp4decrypt | `--mp4decrypt` | `MP4DECRYPT_PATH`, `MP4DECRYPT` |

Streams can be created, claimed and credentialed without any of them; only actually
pulling media needs them. The supervisor is the least exercised part of the system —
treat its health reporting as control-plane bookkeeping.

## Data

```text
.cache/streamd/
  streamd.db        SQLite: streams, runtime, claims
  work/<name>/      downloader scratch + keys.txt
  www/<name>/       HLS output
  logs/             per-stream downloader + ffmpeg logs

.cache/agent/
  queue.db          durable job queue
```

Back up `streamd.db` before upgrading — schema defaults change between versions.