Fast DDS Monitor and ROS 2 Humble

[boxanm]

I struggle to use the Fast DDS Monitor on Humble. I managed to make it work with Vulcanexus Docker image; however, if I follow the guide from 2022 Roscon presentation, I don't see any traffic in the Monitor tool.

To summarize my setup:

• Humble Docker image
• Building fastdds from source with colcon build --cmake-args -DFASTDDS_STATISTICS=on
• Sourcing environments: source /opt/ros/humble/setup.bas source <path to fastdds_ws>/install/setup.bash

• Enabling Statistics Module

  export FASTDDS_STATISTICS="HISTORY_LATENCY_TOPIC;NETWORK_LATENCY_TOPIC;PUBLICATION_THROUGHPUT_TOPIC;SUBSCRIPTION_THROUGHPUT_TOPIC;RTPS_SENT_TOPIC;RTPS_LOST_TOPIC;HEARTBEAT_COUNT_TOPIC;ACKNACK_COUNT_TOPIC;NACKFRAG_COUNT_TOPIC;GAP_COUNT_TOPIC;DATA_COUNT_TOPIC;RESENT_DATAS_TOPIC;SAMPLE_DATAS_TOPIC;PDP_PACKETS_TOPIC;EDP_PACKETS_TOPIC;DISCOVERY_TOPIC;PHYSICAL_DATA_TOPIC"

• Running ros2 run demo_nodes_cpp talker node and the Fast DDS Monitor in a different tab.

The difference in the Monitor's behavior is that while I can list the connected Entities, there's no traffic in the Statistics tab, and I don't see any device under the Physical tab. This, in my opinion, indicated that the talker was not, in fact, launched with the statistics enabled. Is there anything I'm missing?

[boxanm]

So the problem was related to the eProsima Fast-DDS version. After rolling back to v2.6.2, mentioned in the Roscon presentation, I got the expected behavior. Can one of the admins label this issue as a bug?

[boxanm]

Furthermore, I also noticed that the mentioned version 2.6.2, despite working well with the Monitor when built from source, does effectively block ROS 2 cli utils such as ros2 topic list or even ros2 daemon stop. These commands hang frozen with no response.

[jparisu]

Hi @boxanm . This issue does not seem related with Fast DDS Monitor, but with Fast DDS. I transfer this issue.

[JesusPoderoso]

Hello @boxanm , sorry for the late response. I have reproduced your setup in Vulcanexus humble, just by opening a docker and launching in different terminals both Fast DDS Monitor and demo_nodes_cpp talker (avoiding build with extra flags, as statistics are enabled by default in Fast DDS). In that setup, I was able to see traffic in the Statistics tab. Despite that, I also noticed that the physical table was empty, so i am moving this is issue to the Fast DDS Monitor to address it there.