metriplane_ros — ROS 2 Bridge

A ROS 2 package that subscribes to the Metriplane WebSocket stream and republishes each frame, its alerts, and its incidents as std_msgs/String JSON topics. It lives outside the core Python package so installing Metriplane never pulls in ROS dependencies.

Topics

Parameters

ws_url (default ws://127.0.0.1:8765), frame_topic (/metriplane/frame_state), alerts_topic (/metriplane/alerts), incidents_topic (/metriplane/incidents), reconnect_s (2.0), publish_full_frame, publish_alerts, and publish_incidents.

Build

mkdir -p ~/metriplane_ros_ws/src
cp -r integrations/ros2/metriplane_ros ~/metriplane_ros_ws/src/
cd ~/metriplane_ros_ws
colcon build
source install/setup.bash

Run

# 1) start Metriplane producing a WebSocket stream (replay or live)
python -m metriplane.cli --config configs/<replay_config>.yaml
# 2) start the bridge
ros2 launch metriplane_ros bridge.launch.py
# 3) verify
ros2 topic list | grep metriplane
ros2 topic echo /metriplane/frame_state --once
ros2 topic echo /metriplane/alerts

The installed executable should also be visible to ROS 2:

ros2 run metriplane_ros metriplane_bridge --help

Tests (no ROS required)

PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 python -m pytest -q \
  integrations/ros2/metriplane_ros/tests

The bridge logic that can be tested without ROS lives in metriplane_ros/msg_adapters.py (pure functions). The node (bridge_node.py) imports rclpy/websockets lazily.

Limitations (MVP)

• JSON std_msgs/String messages first — no custom typed messages yet.
• No TF / MarkerArray publishing yet (planned stretch goals).
• Reconnect is a fixed delay loop.