# ingest-service (Go)

Status: implemented (MVP).

Responsibility:
- Subscribe to MQTT topics `devices/{device_id}/telemetry`.
- Validate/parse payload (device_id, sensor_type, value, timestamp).
- Batch-write raw readings into ClickHouse `telemetry` table.
- Publish a "new reading" event to RabbitMQ for rule-engine-service.

Not this service's job: interpreting what a sensor reading *means* (thresholds,
actions) — that belongs to rule-engine-service. This service only ingests and
stores.

Note on `zone_id`: the telemetry payload carries `zone_id` directly (the
publishing device/emulator is configured with its own zone), rather than
ingest-service looking it up from PostgreSQL. This keeps ingest-service's
dependencies limited to MQTT/ClickHouse/RabbitMQ, matching the architecture
diagram in the root README. A real fleet where devices don't know their own
zone would need a device-registry lookup (cached, like rule-engine caches
rules) — that's a natural follow-up, not implemented yet.

## Running

```bash
cd services/ingest-service
go test ./...
go build ./cmd/ingest-service
```

Configuration is env-var driven (see the ingest-service section of the
repo-root `.env.example`). Via `docker compose up ingest-service` it talks to
the `mosquitto`/`clickhouse`/`rabbitmq` containers directly; connect from a
local `go run` by exporting `MQTT_HOST=localhost`, `CLICKHOUSE_HOST=localhost`, etc.