This tutorial will teach you how to create your first ROS 2 application. It is intended for developers who want to learn how to create custom packages in ROS 2, not for people who want to use ROS 2 with its existing packages.

Creating a package:

All ROS 2 packages begin by running the command

ros2 pkg create <pkg-name> --dependencies [deps]

in your workspace (usually ~/ros2_ws/src).

To create a package for a specific client library:

• For C++:

  
  ros2 pkg create <pkg-name> --dependencies [deps] --build-type ament_cmake
  
  

• For Python:

  
  ros2 pkg create <pkg-name> --dependencies [deps] --build-type ament_python
  
  

You can then update the package.xml with your package info such as dependencies, descriptions, and authorship.

C++ Packages

You will mostly use the add_executable() CMake macro along with

ament_target_dependencies(<executable-name> [dependencies])

to create executable nodes and link dependencies.

To install your launch files and nodes, you can use the install() macro placed towards the end of the file but before the ament_package() macro.

An example for launch files and nodes:

# Install launch files
install(
  DIRECTORY launch
  DESTINATION share/${PROJECT_NAME}
)

# Install nodes
install(
  TARGETS [node-names]
  DESTINATION lib/${PROJECT_NAME}
)

Python Packages

ROS 2 follows Python’s standard module distribution process that uses setuptools. For Python packages, the setup.py file complements a C++ package’s CMakeLists.txt. More details on distribution can be found in the official documentation.

In your ROS 2 package, you should have a setup.cfg file which looks like:

[develop]
script_dir=$base/lib/<package-name>
[install]
install_scripts=$base/lib/<package-name>