ros2_medkit_param_beacon

Gateway discovery plugin that polls ROS 2 node parameters for entity metadata. Enables pull-based beacon discovery where nodes advertise diagnostic hints through standard ROS 2 parameters.

How It Works

1. The plugin polls each node’s parameter service for parameters under a configurable prefix (default: ros2_medkit.discovery), mapping individual parameters to BeaconHint fields
2. Hints are validated via BeaconValidator and stored in BeaconHintStore with TTL
3. Entity metadata is mapped into the SOVD hierarchy via BeaconEntityMapper
4. Results are exposed at the x-medkit-param-beacon vendor extension endpoint

In non-hybrid discovery mode, the plugin discovers poll targets automatically from the ROS 2 graph. In hybrid mode, targets come from the manifest.

Configuration

plugins: ["param_beacon"]
plugins.param_beacon.path: "/path/to/libros2_medkit_param_beacon.so"
plugins.param_beacon.poll_interval_sec: 10.0
plugins.param_beacon.poll_budget_sec: 10.0
plugins.param_beacon.param_timeout_sec: 2.0
plugins.param_beacon.beacon_ttl_sec: 15.0
plugins.param_beacon.beacon_expiry_sec: 300.0

See discovery options for full configuration reference.

When to Use

Use the parameter beacon when entity metadata is stable and infrequently updated - hardware descriptions, capabilities, firmware versions. For real-time metadata that changes frequently, use the topic beacon instead.

License

Apache License 2.0

Changelog for package ros2_medkit_param_beacon

0.4.0 (2026-03-20)

• Initial release - parameter-based beacon discovery plugin
• ParameterBeaconPlugin with pull-based parameter reading for entity enrichment
• x-medkit-param-beacon vendor extension REST endpoint
• Poll target discovery from ROS graph in non-hybrid mode
• ParameterClientInterface for testable parameter access
• Contributors: \@bburda