What Is This?

This demo provides an example of further Quality-Of-Service (QoS) configurability as well as Publication Modes in a ROS 2 node via the use of rmw_fastrtps_cpp Application Programming Interface (API).

The example utilitises eprosima::fastdds::statistics::dds::DomainParticipant as well as eprosima::fastdds::dds::DataWriter.

A DomainParticipant defines a singular working unit which groups a set of Publishers and Subscribers together. See References - DomainParticipant for more details.

A DataWriter is created by a Publisher and writes data to a topic with configurable behaviors. See References - DataWriter for more details.

Build

colcon build --packages-up-to demo_nodes_cpp_native

Run

ros2 run demo_nodes_cpp_native talker

Verify

When executed correctly, the following strings should be printed to the terminal similar to what is shown below:

[INFO] [1674525877.083735645] [talker_native]: eprosima::fastdds::dds::DomainParticipant * 94193367466752
[INFO] [1674525877.084105822] [talker_native]: eprosima::fastdds::dds::DataWriter * 94193370040688
[INFO] [1674525877.584006930] [talker_native]: Publishing: 'Hello World: 1'
[INFO] [1674525878.083967966] [talker_native]: Publishing: 'Hello World: 2'
[INFO] [1674525878.583917242] [talker_native]: Publishing: 'Hello World: 3'
[INFO] [1674525879.083963276] [talker_native]: Publishing: 'Hello World: 4'
[INFO] [1674525879.583918839] [talker_native]: Publishing: 'Hello World: 5'
#...

FAQ

Q: Why use rmw_fastrtps_cpp API directly?

A: ROS 2 only allows for the configuration of certain middleware QoS (see ROS 2 QoS policies). In addition to ROS 2 QoS policies, rmw_fastrtps sets two more Fast DDS configurable parameters:

History memory policy: PREALLOCATED_WITH_REALLOC_MEMORY_MODE

Publication mode: ASYNCHRONOUS_PUBLISH_MODE

In addition, rmw_fastrtps offers the possibility to further configure Fast DDS:

Change publication mode

Full QoS configuration

Q: Is it still called Fast RTPS?

A: No. Fast RTPS has been renamed to Fast DDS since ROS 2 Foxy.

References

1. Fast DDS
2. What Is RTPS?
3. Fast RTPS Becomes Fast DDS in Foxy
4. Advanced Usage
5. DomainParticipant
6. DataWriter

Changelog for package demo_nodes_cpp_native

0.31.1 (2023-09-07)

0.31.0 (2023-08-21)

0.30.1 (2023-07-11)

0.30.0 (2023-06-12)

0.29.0 (2023-06-07)

0.28.1 (2023-05-11)

0.28.0 (2023-04-27)

0.27.0 (2023-04-13)

• Change all ROS2 -> ROS 2. (#610)
• Contributors: Chris Lalancette

0.26.0 (2023-04-11)

• Added README.md for demo_cpp_nodes_native (#597)
• Contributors: Gary Bey

0.25.0 (2023-03-01)

0.24.1 (2023-02-24)

0.24.0 (2023-02-14)

• Update the demos to C++17. (#594)
• [rolling] Update maintainers - 2022-11-07 (#589)
• Make demo_nodes_cpp_native install stuff only when it builds (#590)
• Contributors: Audrow Nash, Chris Lalancette, Shane Loretz

0.23.0 (2022-11-02)

0.22.0 (2022-09-13)

0.21.0 (2022-04-29)

0.20.1 (2022-04-08)

0.20.0 (2022-03-01)

0.19.0 (2022-01-14)

0.18.0 (2021-12-17)

• Update maintainers to Audrow Nash and Michael Jeronimo (#543)
• Fix typo in demo_nodes_cpp_native package description (#536)
• Contributors: Audrow Nash, V