ROS2: Cannot read /testing_only/track through fsds_ros2_bridge

[froxec]

OS: ROS2 Humble Problem description: Whenever I try to read /testing_only/track message it shows nothing. Message flow diagram: FSDS -> fsds_ros2_bridge -> ros2 topic echo command/c++ subscriber.

Prior investigation conclusions:

1. I think that fsds_ros2_bridge is at fault.
2. /testing_only/track is a latched message.
3. Latched messages in ROS2 work by setting proper QoS profile: "The “durability” policy “transient local”, combined with any depth, provides functionality similar to that of “latching” publishers." Source
4. Requirement from point 3. is not met because message qos-durability is set to volatile (which means that samples don't persist on the publisher side) SOURCE.

Point 4. evidence (output of ros2 topic info --verbose /testing_only/track):

Type: fs_msgs/msg/Track Publisher count: 1 Node name: ros_bridge Node namespace: / Topic type: fs_msgs/msg/Track Endpoint type: PUBLISHER QoS profile: Reliability: RELIABLE History (Depth): UNKNOWN Durability: VOLATILE Lifespan: Infinite Deadline: Infinite Liveliness: AUTOMATIC Liveliness lease duration: Infinite

Possible solution: Change fsds_ros2_bridge QoS profile for /testing_only/track message (as described in point 3.) Is that possible to change QoS profile in fsds_ros2_bridge?

[wouter-heerwegh]

Hi @froxec,

I currently do not have a ROS2 environment set up. If you'd like to have this implemented quickly and would like to contribute, feel free to open a PR. Otherwise I will have to find some time (probably next week).

[froxec]

Hello @wouter-heerwegh,

I hotfixed this by writing the whole track (cones colors + locations) to json file (through Python client) and then simply loading it in c++ node.