# Virtual drone fleet

Data generator. Same on-board pipeline as [03 — Data platform](../docs/03-data-platform.md): seeded kinematics, sensor streams, detection events, hot `current/` → sealed Parquet, compact UDP state broadcast.

One process = one drone. Scale swarm with Compose flag.

## Run a swarm

```bash
# 5 drones (default), 2-minute flight, shared flight id
FLIGHT_ID=$(date -u +%Y%m%dT%H%MZ)-sim docker compose up --build --scale drone=5

# 10 drones, 5-minute flight, 4x accelerated
DRONE_COUNT=10 DURATION_S=300 SPEEDUP=4 docker compose up --build --scale drone=10
```

Output lands in [`../var/t1/`](../var/t1/) ([T1](../docs/00-glossary.md#t1--warm) live lake — same path k3d fleet and warehouse offload use). Override with `SWARM_T1_DIR` if needed:

```
var/t1/dataset=telemetry/flight=…/drone=…/sensor=imu/year=…/…/hour=…/data.parquet
var/t1/dataset=detections/flight=…/drone=…/…
var/t1/dataset=state/flight=…/drone=…/…        ← sent + received broadcasts
```

Historical flights after offload: [`../var/t3/`](../var/t3/) ([T3](../docs/00-glossary.md#t3--warehouse) warehouse).

## Run a single drone without Docker

```bash
pip install -r requirements.txt
DRONE_ID=dr-01 DURATION_S=30 SPEEDUP=10 DATA_DIR=./data python -m virtual_drone.main
```

## Query the results

```bash
python - <<'EOF'
import duckdb
con = duckdb.connect()
print(con.sql("""
    SELECT drone, sensor, count(*) AS rows,
           to_timestamp(min(ts_ns)/1e9) AS first_row,
           to_timestamp(max(ts_ns)/1e9) AS last_row
    FROM read_parquet('data/dataset=telemetry/**/*.parquet', hive_partitioning=true)
    GROUP BY drone, sensor ORDER BY drone, sensor
"""))
print(con.sql("""
    SELECT drone, direction, count(*) AS frames, count(DISTINCT peer_id) AS peers
    FROM read_parquet('data/dataset=state/**/*.parquet', hive_partitioning=true)
    GROUP BY drone, direction ORDER BY drone, direction
"""))
EOF
```

## Monitoring

`monitoring` profile: DuckDB exporter → Prometheus → Grafana ([07 — Observability](../docs/07-observability.md)):

```bash
docker compose --profile monitoring up -d
FLIGHT_ID=$(date -u +%Y%m%dT%H%MZ)-sim docker compose up --scale drone=5
```

- Grafana: `http://localhost:3000` → **Swarm Fleet — generated data**
- Prometheus: `http://localhost:9090` · exporter: `http://localhost:9105/metrics`

Fleet stats derived from Parquet via SQL — no on-drone agent.

## Data-plane explorer

`monitoring` profile also starts explorer at `http://localhost:8088` (k3d: `:30088`):

- Partition tree live: `dataset → flight → drone → sensor → hour → file`
- Read-only SQL console — same [statement gate](../docs/04-swarm-sync.md) as peer query channel: `SELECT`/`WITH`/`DESCRIBE`/`SUMMARIZE`/`SHOW` only

Point: bench exploration uses same read-only SQL contract as flight peers.

## Reproducibility

Deterministic per `(SEED, DRONE_ID)`. Bug report = seed + config.

## Knobs

| Env | Default | Meaning |
| --- | --- | --- |
| `DRONE_ID` | derived from hostname | Unique per container automatically under `--scale` |
| `FLIGHT_ID` | generated | Set explicitly so all drones share one flight partition |
| `SEED` | `42` | Determinism root |
| `DURATION_S` | `120` | Simulated flight length |
| `SPEEDUP` | `1.0` | Wall-clock acceleration |
| `IMU_HZ` | `50` | High-rate sensor load |
| `STATE_HZ` | `5` | Broadcast frequency |
| `AREA_SIZE_M` | `400` | Patrol square side |