Extending the Foxglove Visualizer¶

This page is the maintainer guide to extending the GCS visualizer node — foxglove_visualizer_node — with new or modified marker types, and to bridging new topics to the GCS. For what the node visualizes today, the topic tables, layouts, and troubleshooting, see GCS Foxglove Visualization. The agent workflow for adding a topic is .agents/skills/visualize-in-foxglove.

How to modify or add a marker type¶

The visualizer is designed to be extended in-place. The pattern, taken from gcs/ros_ws/src/gcs_visualizer/gcs_visualizer/foxglove_visualizer_node.py:

1. Add a suffix and regex¶

PLAN_SUFFIX = '/global_plan'
self._plan_pattern = re.compile(rf'^/({re.escape(self._prefix)}_\w+){re.escape(PLAN_SUFFIX)}$')

2. Add state¶

self._global_plans   = {}   # robot_name -> latest msg
self._subscribed_plan = set()

3. Subscribe in `_discover_robots`¶

if topic not in self._subscribed_plan:
    m = self._plan_pattern.match(topic)
    if m and 'nav_msgs/msg/Path' in type_list:
        name = m.group(1)
        self.create_subscription(
            Path, topic,
            lambda msg, n=name: self._plan_callback(msg, n),
            10,   # 10 = default RELIABLE for planning topics;
                  # SENSOR_QOS for high-rate sensor streams
        )
        self._subscribed_plan.add(topic)

4. Add a callback¶

def _plan_callback(self, msg: Path, robot_name: str):
    self._global_plans[robot_name] = msg

5. Render in `_publish_markers`¶

plan = self._global_plans.get(robot_name)
boot = self._gps_boot.get(robot_name)
if plan is not None and boot is not None:
    bx, by, bz = boot
    line = Marker()
    line.header.frame_id = 'map'
    line.ns = f'{robot_name}_global_plan'
    line.type = Marker.LINE_STRIP
    for ps in plan.poses:
        p = ps.pose.position
        line.points.append(Point(x=p.x + bx, y=p.y + by, z=p.z + bz))
    array.markers.append(line)

6. Bridge the source topic across DDS domains¶

The visualizer can only subscribe to topics that crossed the DDS bridge. Add the source topic to robot/ros_ws/src/autonomy_bringup/config/dds_router.yaml under allowlist (or, for the split stack, to stacks/lite_offload_global/bridge.yaml and regenerate):

allowlist:
  - name: "rt/$(env ROBOT_NAME)/your/new_topic"

Then restart the robot containers — the router only re-reads its allowlist on startup.

Bridging a topic without writing a callback¶

If your topic is already in a Foxglove-native type (nav_msgs/Path, sensor_msgs/PointCloud2, visualization_msgs/MarkerArray) and doesn't need the GPS offset, you can skip the visualizer entirely — just bridge it through the DDS router and add a panel in Foxglove pointing at the topic. The visualizer is only required when you need georeferencing or want everything to flow through the combined /gcs/robot_markers namespace.