# Building ROS 2 on Windows¶

This guide is about how to setup a development environment for ROS 2 on Windows.

## Prerequisites¶

First follow the steps for Installing Prerequisites on the Binary Installation page.

When building from source you’ll need a few additional prerequisites installed.

#### Install additional prerequisites from Chocolatey¶

First install git:

> choco install -y git


You will need to append the Git cmd folder C:\Program Files\Git\cmd to the PATH (you can do this by clicking the Windows icon, typing “Environment Variables”, then clicking on “Edit the system environment variables”. In the resulting dialog, click “Environment Variables”, the click “Path” on the bottom pane, then click “Edit” and add the path).

## Install developer tools¶

Now we are ready to install some our tools that we use to help in developing ROS 2.

Let’s start with vcstool:

> pip install -U vcstool


You can test it out by just running vcs (you should be able to do this in the same cmd prompt).

Next, install colcon:

> pip install -U colcon-common-extensions


You can test it out by just running colcon (you should be able to do this in the same cmd prompt).

Also, you should install curl:

> choco install -y curl


## Install dependencies¶

Next install the latest version of setuptools and pip:

> <PATH_TO_PYTHON_EXECUTABLE> -m pip install -U setuptools pip


Where PATH_TO_PYTHON_EXECUTABLE looks like: c:\python38\python.exe

Then you can continue installing other Python dependencies:

> pip install -U catkin_pkg cryptography EmPy ifcfg lark-parser lxml numpy pyparsing pyyaml


Next install testing tools like pytest and others:

> pip install -U pytest pytest-mock coverage mock


Next install linters and checkers like flake8 and others:

> pip install -U flake8 flake8-blind-except flake8-builtins flake8-class-newline flake8-comprehensions flake8-deprecated flake8-docstrings flake8-import-order flake8-quotes mypy pep8 pydocstyle


Next install cppcheck:

> choco install -y cppcheck


Next install xmllint:

### Install Qt5¶

This section is only required if you are building rviz, but it comes with our default set of sources, so if you don’t know, then assume you are building it.

First get the installer from Qt’s website:

Select the Open Source version and then the Qt Online Installer for Windows.

Run the installer and install Qt5.

We recommend you install it to the default location of C:\Qt, but if you choose somewhere else, make sure to update the paths below accordingly. When selecting components to install, the only thing you absolutely need for Foxy and later is the appropriate MSVC 64-bit component under the Qt -> Qt 5.15.0 tree. We’re using 5.15.0 as of the writing of this document and that’s what we recommend since that’s all we test on Windows, but later version will probably work too. For Foxy and later, be sure to select MSVC 2019 64-bit. After that, the default settings are fine.

Finally, set the Qt5_DIR environment variable in the cmd.exe where you intend to build so that CMake can find it:

> set Qt5_DIR=C:\Qt\5.15.0\msvc2019_64


You could set it permanently with setx -m Qt5_DIR C:\Qt\5.15.0\msvc2019_64 instead, but that requires Administrator.

Note

This path might change based on which MSVC version you’re using or if you installed it to a different directory.

#### RQt dependencies¶

> pip install -U pydot PyQt5


Follow the steps for Installing Graphviz on the Binary Installation page.

## Get the ROS 2 code¶

Now that we have the development tools we can get the ROS 2 source code.

First setup a development folder, for example C:\dev\ros2_foxy:

> md \dev\ros2_foxy\src
> cd \dev\ros2_foxy


Get the ros2.repos file which defines the repositories to clone from:

# CMD
> curl -sk https://raw.githubusercontent.com/ros2/ros2/foxy/ros2.repos -o ros2.repos

# PowerShell
> curl https://raw.githubusercontent.com/ros2/ros2/foxy/ros2.repos -o ros2.repos


Next you can use vcs to import the repositories listed in the ros2.repos file:

# CMD
> vcs import src < ros2.repos

# PowerShell
> vcs import --input ros2.repos src


### Install additional DDS implementations (optional)¶

If you would like to use another DDS or RTPS vendor besides the default, eProsima’s Fast RTPS, you can find instructions here.

## Build the ROS 2 code¶

To build ROS 2 you will need a Visual Studio Command Prompt (“x64 Native Tools Command Prompt for VS 2019”) running as Administrator.

Fast RTPS is bundled with the ROS 2 source and will always be built unless you put an AMENT_IGNORE file in the src\eProsima folder.

To build the \dev\ros2_foxy folder tree:

> colcon build --merge-install


Note

We’re using --merge-install here to avoid a PATH variable that is too long at the end of the build. If you’re adapting these instructions to build a smaller workspace then you might be able to use the default behavior which is isolated install, i.e. where each package is installed to a different folder.

Note

If you are doing a debug build use python_d path\to\colcon_executable colcon. See Extra stuff for debug mode for more info on running Python code in debug builds on Windows.

## Environment setup¶

Start a command shell and source the ROS 2 setup file to set up the workspace:

> call C:\dev\ros2_foxy\install\local_setup.bat


This will automatically set up the environment for any DDS vendors that support was built for.

It is normal that the previous command, if nothing else went wrong, outputs “The system cannot find the path specified.” exactly once.

## Test and run¶

Note that the first time you run any executable you will have to allow access to the network through a Windows Firewall popup.

You can run the tests using this command:

> colcon test --merge-install


Note

--merge-install should only be used if it was also used in the build step.

Afterwards you can get a summary of the tests using this command:

> colcon test-result


To run the examples, first open a clean new cmd.exe and set up the workspace by sourcing the local_setup.bat file. Then, run a C++ talker:

> call install\local_setup.bat
> ros2 run demo_nodes_cpp talker


In a separate shell you can do the same, but instead run a Python listener:

> call install\local_setup.bat
> ros2 run demo_nodes_py listener


You should see the talker saying that it’s Publishing messages and the listener saying I heard those messages. This verifies both the C++ and Python APIs are working properly. Hooray!

See the tutorials and demos for other things to try.

Note

It is not recommended to build in the same cmd prompt that you’ve sourced the local_setup.bat.

## Extra stuff for Debug mode¶

If you want to be able to run all the tests in Debug mode, you’ll need to install a few more things:

• To be able to extract the Python source tarball, you can use PeaZip:

> choco install -y peazip

• You’ll also need SVN, since some of the Python source-build dependencies are checked out via SVN:

> choco install -y svn hg

• You’ll need to quit and restart the command prompt after installing the above.

• Get and extract the Python 3.8.3 source from the tgz:

• Now, build the Python source in debug mode from a Visual Studio command prompt:

> cd C:\dev\Python-3.8.3\PCbuild
> get_externals.bat
> build.bat -p x64 -d

• Finally, copy the build products into the Python38 installation directories, next to the Release-mode Python executable and DLL’s:

> cd C:\dev\Python-3.8.3\PCbuild\amd64
> copy python_d.exe C:\Python38 /Y
> copy python38_d.dll C:\Python38 /Y
> copy python3_d.dll C:\Python38 /Y
> copy python38_d.lib C:\Python38\libs /Y
> copy python3_d.lib C:\Python38\libs /Y
> for %I in (*_d.pyd) do copy %I C:\Python38\DLLs /Y

• Now, from a fresh command prompt, make sure that python_d works:

> python_d
> import _ctypes

• Once you have verified the operation of python_d, it is necessary to reinstall a few dependencies with the debug-enabled libraries:

> python_d -m pip install --force-reinstall https://github.com/ros2/ros2/releases/download/numpy-archives/numpy-1.18.4-cp38-cp38d-win_amd64.whl

• To verify the installation of these dependencies:

> python_d
# No import errors should appear when executing the following lines
> from lxml import etree
> import numpy

• When you wish to return to building release binaries, it is necessary to uninstall the debug variants and use the release variants:

> python -m pip uninstall numpy lxml
> python -m pip install numpy lxml

• To create executables python scripts(.exe), python_d should be used to invoke colcon

> python_d path\to\colcon_executable build

• Hooray, you’re done!

## Stay up to date¶

See Maintaining a source checkout of ROS 2 to periodically refresh your source installation.

## Troubleshooting¶

Troubleshooting techniques can be found here.

## Uninstall¶

1. If you installed your workspace with colcon as instructed above, “uninstalling” could be just a matter of opening a new terminal and not sourcing the workspace’s setup file. This way, your environment will behave as though there is no Foxy install on your system.

2. If you’re also trying to free up space, you can delete the entire workspace directory with:

rmdir /s /q \ros2_foxy