A ROS2 example package that contains the publisher and subscriber example of both C++ & Python, with the use of custom message.

The C++ subscriber node also subscribes to the topic topic_py published by the Python publisher. Additionally, it also utilises the rtpkg helper class to generate random number, which is then published as rnd_num with the custom message structure rtpkg_msg.

‍API documentation of the rtpkg package is available here: https://quantumxt.github.io/rtpkg/

Setup

Git clone the repository into the workspace:

$ git clone https://github.com/quantumxt/rtpkg.git

Compile the package with colcon build:

$ colcon build --packages-select rtpkg cpp_pubsub py_pubsub

After that, run colcon test to test the package:

$ colcon test --packages-select rtpkg cpp_pubsub py_pubsub

‍If there's error during the build, more details on the test could be viewed via $ colcon test-result --verbose.

Script

Alternatively, a bash script is available to run the compilation & testing of the packages:

$ sudo chmod +x buildpkg.sh

$ ./buildpkg #Alternatively, -v flag could be used to export the verbose output of the test result

Usage

There are 3 available launch files that could be used:

cpp_topic.launch.py: Launches both the publisher & subscriber nodes written in C++.
py_topic.launch.py: Launches both the publisher & subscriber nodes written in Python.
alltop.launch.py: Launches both the cpp_topic.launch.py & py_topic.launch.py launch file.

Ensure that the workspace is sourced beforehand:

$ . install/setup.bash

To launch the launch file, use the ros2 launch [packageName] [launchFile] command:

$ ros2 launch rtpkg alltop.launch.py

Packages

cpp_pubsub: C++ publisher/subscriber example. (Subscriber node also publishes random number with rtpkg_msg.)
py_pubsub: Python publisher/subscriber example.
rtpkg: Contains the rtpkg helper class for random number generation & the launch file to launch both the C++ and Python publisher/subscriber example simulataneously.
rtpkg_msg: Custom ROS2 message structure for the rtpkg package, used for random number topic publication/subscription. More information could be found here.