Hugr App Data Source
The hugr-app data source type connects hugr to external applications via the DuckDB Airport extension (Arrow Flight gRPC protocol).
Unlike other data sources, hugr-app sources are self-registering — the application connects to hugr and registers itself. You don't need to manually configure them.
How It Works
- The app starts a gRPC server (Airport protocol)
- The app calls hugr's API to register as a data source
- Hugr attaches via
ATTACH ... (TYPE AIRPORT) - Hugr reads the app's catalog (functions, tables) and compiles into GraphQL
- Heartbeat monitor detects crashes and auto-recovers
Configuration
Hugr-app sources are registered automatically by the application. The stored configuration in CoreDB:
| Field | Value |
|---|---|
type | hugr-app |
path | grpc://host:port?secret_key=TOKEN&version=X.Y.Z |
as_module | true |
self_defined | true |
Server-Side Settings
| Environment Variable | Description | Default |
|---|---|---|
HUGR_APP_HEARTBEAT_INTERVAL | Health check interval | 30s |
HUGR_APP_HEARTBEAT_TIMEOUT | Per-check timeout | 10s |
HUGR_APP_HEARTBEAT_RETRIES | Failures before suspend | 3 |
Building Apps
See the Hugr Apps section for the complete developer guide.