ROS2 setup tutorial

ROS2 is the newest version of ROS, Robot Operating System, which is a set of libraries and tools designed for robot applications.

This tutorial describes how to use CLion as an IDE for developing ROS2 applications built with colcon. If you are working with an older ROS distribution, which uses catkin build tools, please refer to the previous tutorial.

Instructions below show the following procedures on Windows: creating a ROS2 workspace, opening it as a compilation database project in CLion, building, running/debugging a package, adding another package, and rebuilding the workspace.

Prepare the ROS2 environment

Install ROS2 on your system.
Make sure that sourcing the ROS2 installation succeeds. Follow the tips in the same guide in case of issues.

Create a workspace

We will take the official Simple publisher and subscriber (C++) guide as an example.

Open a terminal in Administrator mode.
Source the ROS2 installation. In our case the command is
call C:\dev\ros2\ros2-windows\local_setup.bat
If you get an RTI Connext DDS environment script not found warning, you can safely ignore it in the scope of this tutorial.
Create a directory for a new workspace and navigate into it
md \dev_ws\src cd \dev_ws\src
Create a publisher-subscriber package
ros2 pkg create --build-type ament_cmake cpp_pubsub
Follow the next steps to get the source files, CMakeLists.txt, and package.xml, up until building.

At this point, we have the following folder structure:

                |_dev_ws
                   |_src
                      |_cpp_pubsub
                         |_include
                         |_src
                               subscriber_member_function.cpp
                               publisher_member_function.cpp
                           CMakeLists.txt
                           package.xml
            

Build a workspace in terminal and generate a compilation database

In order to be able to open a ROS2 workspace in CLion, we will generate a JSON compilation database using the CMAKE_EXPORT_COMPILE_COMMANDS CMake flag.

This option is supported in CMake only for the Makefile and Ninja generators, so we also need to switch between the generators using -G.

In the same terminal where you initially sourced the ROS2 installation, navigate to the workspace-level folder (dev_ws in our case) and run
colcon build --cmake-args -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -G Ninja
If you get the Generator: execution of make failed error, try initializing the Visual C++ environment before building. Customize the path in the following command as required:
call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvarsall.bat" x86_amd64
Then run the build command again.
When build is finished, make sure that dev_ws\build contains a compile_commands.json file. In case it is not there, make sure your colcon version supports generating workspace-level compilation databases (see this issue).

Launch CLion in the sourced environment

In the same terminal, source the workspace setup files:
call install/setup.bat
Next, launch CLion from the same shell. Refer to Command-line interface for instructions.
For example, in the case of using Toolbox, you can create a script for launching the IDE. In our case, it is located in C:\IDE_shell_scripts.
cd C:\IDE_shell_scripts\ clion
As the result, CLion will be launched with the ROS2 environment already prepared.

Open a workspace in CLion

In CLion, call File | Open from the main menu and select the compile_commands.json file in the top-level build directory:
Click Open as project:
Check that the project is loaded successfully:

Change the project root

By default, CLions considers the directory containing the compile_commands.json file as project root. In our case, it is the build directory. In the Project tree, the actual source files are marked as external:

To get the correct project structure, we need to set the project root to the actual workspace directory.

Call Tools | Compilation Database | Change Project Root from the main menu and select the workspace directory (dev_ws in our case).
Check the changes in Project view:

At this point, all the CLion editing features are fully available for the workspace sources.

How to build a package

In order to build and then launch a package inside CLion, we will create a custom build target for CMake commands actually performed during colcon build, and then create a custom application configuration for that target.

1. Create a script for the 'colcon build' commands

Navigate to the build logs directory. In our case, it's C:\dev_ws\log\latest_build\cpp_pubsub. Open the command.txt file from the latest build.
Copy the commands into another file and modify them to the following:
"C:\Program Files\CMake\bin\cmake.EXE" C:\dev_ws\src\cpp_pubsub -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -G Ninja -DCMAKE_INSTALL_PREFIX=C:\dev_ws\install\cpp_pubsub "C:\Program Files\CMake\bin\cmake.EXE" --build C:\dev_ws\build\cpp_pubsub -- -j8 -l8 "C:\Program Files\CMake\bin\cmake.EXE" --install C:\dev_ws\build\cpp_pubsub
This script will be called from the package build directory, build/cpp_pubsub, and the compilation database file will be generated there. For consistency, you can copy that file up to the workspace build level by adding the following command at the end:
copy C:\dev_ws\build\cpp_pubsub\compile_commands.json C:\dev_ws\build
Save the file as a .bat script. In our example, it is called cmake_commands.bat and placed into c:\dev_ws\src\cpp_pubsub\.

2. Create a custom build target

In CLion, go to Settings | Build, Execution, Deployment | Custom Build Targets and click to add a new target.
- Set the Toolchain to Visual Studio. Refer to our Windows tutorial for details on how to configure a Visual Studio toolchain in CLion.
- Click next to the Build field. Then click to add an external.
  In the Program field, select the newly created script. Set the Working directory to the package build directory.
Save the custom target.

3. Create a run/debug configuration for the custom build target

To be able to build and then launch the target we have for the package, we need to create a corresponding configuration.

Go to Run | Edit Configurations, click and select Custom Build Application.
In the configuration settings, select the Target and make sure to remove Build from the Before launch area.

4. Build a package

Select the configuration in the toolbar switcher:
Click the hammer icon or press Ctrl + F9. Alternatively, call Build | Build 'Build cpp_pubsub' from the main menu.
Check the result in the Run tool window.

Run/debug a package

Open the Edit Configurations dialog again.
Modify the configuration for build to the following:
- Set the Executable to the actual package binary.
- Select the Run with Administrator privileges checkbox. See Debug as root for more information.
After saving the configuration, it is ready to be Run or Debugged. All the CLion debugging and dynamic analysis features will be available for the workspace code.
CLion will take the debugger from target's toolchain. In our case, it is MSVC LLDB.

How to build a workspace

Now let’s take a look at how we can add a new package and rebuild the entire workspace in CLion. To illustrate this, we’ll take an example of adding a Simple service and client package to our dev_ws workspace.

Prepare new package files

In a terminal, source the ROS2 installation and navigate to dev_ws\src
Create a new package
ros2 pkg create --build-type ament_cmake cpp_srvcli --dependencies rclcpp example_interfaces
Follow the steps to get the source files, CMakeLists.txt, and package.xml, up until building.

Build the whole workspace

To (re)build the entire workspace, we will configure an external tool for colcon build and call it without leaving CLion.

Go to Settings | Tools | External Tools and click to add a new tool.
Configure the tool to perform the same colcon build command as we used when building from the command line:
Make sure to set the Working directory.
After saving the tool, call it via Tools | External Tools on the main menu.
Check the results in the Run tool window:
Next time use the button in the Run tool window to rebuild the workspace again.
Check that compile_commands.json has been regenerated and now includes the entities for both packages:
Make sure to reload the compilation database (press Ctrl+Shift+O or call Tools | Compilation Database | Reload Compilation Database Project form the main menu). To avoid reloading the project manually, configure auto-reload.

At this point, both of the packages are included in CLion project model and you can work with them as usual. To build and run the second package, follow the steps described above.

Last modified: 11 January 2023