ros2_examples

• Forked from https://github.com/eborghi10/ros2_examples
• Examples using ROS 2 for the Packt video course "ROS 2 - New Features" by Emiliano Javier Borghi Orué.
• Updated to support ROS 2 Foxy Fitzroy.
  • Major updates starting from ROS 2 Dashing Diademata:
    • https://index.ros.org/doc/ros2/Releases/Release-Dashing-Diademata/#changes-to-creating-publishers-and-subscriptions
    • https://index.ros.org/doc/ros2/Releases/Release-Dashing-Diademata/#changes-to-creating-publishers-subscriptions-and-qos-profiles
• Course Link: https://learning.oreilly.com/videos/ros-2-new/9781838552893 (requires O'Reilly account). Highly recommended course!

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Git

1. Clone 'foxy' Git branch in C:\

C:\> git clone -b foxy https://github.com/elikun/ros2_examples.git

Docker

• https://hub.docker.com/_/ros
• http://wiki.ros.org/docker/Tutorials/Docker
• http://wiki.ros.org/docker

1. Pull official ROS 2 Docker image

C:\> docker pull ros

2. Mount this repository's files to /colcon_ws/src in the Docker container

C:\> docker run -it --rm -v /c/ros2_examples:/colcon_ws ros

3. Open up another bash terminal when needed to start another ROS 2 node.

C:\> docker exec -it <container-identifier> bash

C++

• http://docs.ros2.org/latest/api/rclcpp/index.html
• https://index.ros.org/doc/ros2/Releases/Release-Dashing-Diademata/#rclcpp
• http://wiki.ros.org/CppStyleGuide

1. Compile with ROS 2's colcon build tool

root@123456abcdef:/colcon_ws# colcon build --event-handlers console_direct+ |& tee colcon_build.log

2. Source installed files

root@123456abcdef:/colcon_ws# source install/setup.bash

3. Run listener node

root@123456abcdef:/colcon_ws# ros2 run packt_rclcpp_demo listener

4. Run talker node (in a separate bash terminal)

root@123456abcdef:/colcon_ws# ros2 run packt_rclcpp_demo talker

Python3

• http://docs.ros2.org/latest/api/rclpy/index.html
• https://index.ros.org/doc/ros2/Releases/Release-Dashing-Diademata/#rclpy
• http://wiki.ros.org/PyStyleGuide

1. Compile with ROS 2's colcon build tool

root@123456abcdef:/colcon_ws# colcon build --event-handlers console_direct+ |& tee colcon_build.log

2. Source installed files

root@123456abcdef:/colcon_ws# source install/setup.bash

3. Run listener node

root@123456abcdef:/colcon_ws# ros2 run packt_rclpy_demo listener

4. Run talker node (in a separate bash terminal)

root@123456abcdef:/colcon_ws# ros2 run packt_rclpy_demo talker

Other useful commands

• List existing ROS 2 nodes

root@123456abcdef:/colcon_ws# ros2 node list

• Get more info on '/publisher' node

root@123456abcdef:/colcon_ws# ros2 node info /publisher

• List existing ROS 2 topics

root@123456abcdef:/colcon_ws# ros2 topic list

• "Peek" into the contents of the '/chatter' topic

root@123456abcdef:/colcon_ws# ros2 topic echo chatter

• Publish a ROS 2 topic called '/estop' manually

root@123456abcdef:/colcon_ws# ros2 topic pub /estop std_msgs/String "data: Stop"

• Initialize a C++ ROS 2 Package named packt_rclcpp_demo

root@123456abcdef:/colcon_ws# ros2 pkg create packt_rclcpp_demo

• Execute launch file called composition_demo.launch.py file in composition

root@123456abcdef:/colcon_ws# ros2 launch composition demo.launch.py

• Clean up colcon build artifacts

root@123456abcdef:/colcon_ws# rm -rf build install log colcon_build.log

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Other useful links

• https://github.com/ros2/demos
• https://github.com/ros2/examples
• https://index.ros.org/doc/ros2/Tutorials/
• https://index.ros.org/doc/ros2/Tutorials/Composition/
• https://index.ros.org/doc/ros2/Tutorials/Launch-system/