jayhou / rmw_connextdds

ROS 2 RMW layer for RTI Connext DDS Professional and RTI Connext DDS Micro.

ROS 2 Middleware Layer for RTI Connext DDS

This repository contains two novel implementations of the ROS 2 RMW layer which allow developers to deploy their ROS applications on top of RTI Connext DDS Professional and RTI Connext DDS Micro.

The repository provides two RMW packages:

• rmw_connextdds

• rmw_connextddsmicro

Package rmw_connextdds is meant to be a replacement for rmw_connext_cpp. This new implementation resolves several performance issues, and it improves out-of-the-box interoperability with DDS applications.

The repository is undergoing stabilization, with some features still in active development. Please consider reporting any issue that you may experience, while monitoring the repository for frequent updates.

For any questions or feedback, feel free to reach out to [e-mail].

Quick Start

1. Load ROS into the shell environment, e.g.:

   source /opt/ros/rolling/setup.bash

2. Configure RTI Connext DDS Professional and/or RTI Connext DDS Micro on your system (see Requirements). Make the installation(s) available via environment variables, e.g. by using the provided rtisetenv_<architecture>.bash script (replace ~/rti_connext_dds-6.0.1 with the path of your Connext installation):

    source ~/rti_connext_dds-6.0.1/resource/scripts/rtisetenv_x64Linux4gcc7.3.0.bash
    export CONNEXTDDS_DIR=${NDDSHOME}

3. Create an overlay directory and clone the repository:

   mkdir -p ~/ros2_connextdds/src/ros2
   cd ~/ros2_connextdds
   git clone https://github.com/rticommunity/rmw_connextdds.git src/ros2/rmw_connextdds

4. Build the RMW:

   colcon build --symlink-install

5. Load the generated environment script:

   source ~/ros2_connextdds/install/setup.bash

6. Run ROS applications with RTI Connext DDS Professional:

   RMW_IMPLEMENTATION=rmw_connextdds ros2 run demo_nodes_cpp talker

7. Run ROS applications with RTI Connext DDS Micro:

   RMW_IMPLEMENTATION=rmw_connextddsmicro ros2 run demo_nodes_cpp talker

Requirements

Both RMW packages require the appropriate version of RTI Connext DDS to be available on the build and target systems.

rmw_connextdds requires RTI Connext DDS Professional (version 5.3.1 or later), while rmw_connextddsmicro requires RTI Connext DDS Micro (version 3 or later).

The installations must be made available via environment variables. If no valid installation is detected, the packages will be skipped and not be built.

RMW	RTI Product	Environment Variable(s)	Required	Default
rmw_connextdds	RTI Connext DDS Professional 5.3.1, or 6.x	CONNEXTDDS_DIR, or NDDSHOME	Yes	None
rmw_connextddsmicro	RTI Connext DDS Micro 3.x	RTIMEHOME	No (if RTI Connext DDS Professional 6.x is available)	Guessed from contents of RTI Connext DDS Professional installation (6.x only, 5.3.1 users must specify RTIMEHOME).

Multiple versions of RTI Connext DDS Professional

Package rti_connext_dds_cmake_module will first check variable ${CONNEXTDDS_DIR}, and then fall back to ${NDDSHOME} to determine the location of the RTI Connext DDS Professional libraries used by rmw_connextdds

This behavior allows users of the old Connext RMW (rmw_connext_cpp) who have installed RTI Connext DDS Professional 5.3.1 via the apt package rti-connext-dds-5.3.1, to have both that version, and a more recent one (e.g. 6.0.1) installed on their system, but configured via different variables.

If rmw_connext_cpp is installed via debian package ros-<version>-rmw-connext-cpp, variable ${NDDSHOME} will always be hard-coded to the install location of the apt package (/opt/rti.com/rti_connext_dds-5.3.1).

In this case, you can use ${CONNEXTDDS_DIR} to point to a Connext 6.x installation, making sure to source script rti_connext_dds-6.x.x/resource/scripts/rtisetenv_<architecture>.bash after loading your ROS installation, so that the Connext 6.x libraries and paths will be found first in the relevant environement variables (e.g. ${LD_LIBRARY_PATH}).

If you encounter any errors with selecting your desired Connext installation, consider uninstalling rmw_connext_cpp and connext_cmake_module (e.g. sudo apt remove ros-<version>-rmw-connext-cpp ros-<version>-connext-cmake-module).