ros2-simple-pub-sub

Browsing through the simple pub sub model in ROS2

Publisher Subscriber with ROS2

Environment setup for Ubuntu 20.04

Download install_ros2.sh in your computer.
Open a terminal and run sudo chmod +x install_ros2.sh.
Execute the bash file by running sudo ./install_ros2.sh.
Source the bashrc file source ~/.bashrc.

Check Environment Variables

printenv | grep -i ROS

The response should be something like this:

ROS_VERSION=2
ROS_PYTHON_VERSION=3
ROS_DISTRO=foxy

Create a workspace

mkdir -p ~/dev_ws

Build packages

Clone the repository. While still at the root directory ~/dev_ws, make sure you do not have any missing dependencies.

rosdep install -i --from-path src --rosdistro foxy -y

We have two packages here for pubsub: one in python and the other in cpp. We need to build both of them before execution. Remember to run the following commands from root directory ~/dev_ws.

colcon build --packages-select cpp_pubsub
colcon build --packages-select py_pubsub

Test the code

Let's run the talker(publisher) node in python and the listener(subscriber) in cpp.

Open new terminal, navigate to ~/dev_ws and source the setup file by running . install/setup.bash
Run the talker node : ros2 run py_pubsub talker
Open another terminal, navigate to ~/dev_ws and source the setup file by running . install/setup.bash
Run the subscriber node : ros2 run cpp_pubsub listener