Bootstrap from source

When developing colcon you want to have a local checkout of all involved packages.


The following steps use the command line tool vcstool to fetch a set of repositories. You can e.g. install it using pip install vcstool.


While the following instructions use a Linux shell the same can be done on other platforms like Windows with slightly adjusted commands.

Virtual environment

While not strictly necessary it is recommended to use a virtual environment for developing Python packages.

$ mkdir colcon-venv
$ python3 -m venv colcon-venv
$ . colcon-venv/bin/activate


On Windows the Python 3 executable is likely named python and the activation script is invoked with colcon-venv\Scripts\activate

You might want to make sure that the venv is using up-to-date versions of the some foundational packages.

$ pip install -U pip setuptools

Fetch the sources

$ mkdir colcon-from-source && cd colcon-from-source
$ curl --output colcon.repos
$ mkdir src
$ vcs import src < colcon.repos


Depending on your platform you might not want to use all cloned packages. On Windows you must ignore or remove colcon-argcomplete, and may want to do the same for colcon-bash. If you don’t use PowerShell you might want to ignore / remove the package colcon-powershell. To ignore a package add an empty file named COLCON_IGNORE to the folder.

Ignore colcon-argcomplete and colcon-bash on Windows.

> type nul > src\colcon-argcomplete\COLCON_IGNORE
> type nul > src\colcon-bash\COLCON_IGNORE


Make sure the dependencies are available:

$ curl --output requirements.txt
$ pip install -r requirements.txt

Build the sources - first time

In the first build we will use the minimal features provided by colcon-core to build the set of cloned packages.

$ ./src/colcon-core/bin/colcon build --paths src/*


On Windows the command needs to be prefixed with python.

The build of the packages will run sequentially and for each package the output will be printed directly to the console. The install directory will contain a (or .bat on Windows).

In order to generate scripts for additional shells the set of packages have to be built a second time but this time using all extension provided by the various cloned packages.

Build the sources - second time

$ . install/
$ colcon build


On Windows the setup file ends with .bat and is just being called. Also the colcon executable can’t be invoked directly here since while it is being used it can’t be overwritten by the build. Instead invoke the following command: python install\colcon-core\Scripts\ build.


The second build will process packages in parallel as long as their dependencies are finished. Also the output of all packages is not shown on the console (until there are errors) but is being redirected to log files. Depending on the platform you might also notice a status line during the build, a continuously updated title of the shell windows, and a desktop notification at the end of the build.

To use the full functionality you can source the generated script for your shell:

$ . install/local_setup.bash


With bash you should now also have completion for all arguments if you have the Python package argcomplete installed. Try typing colcon <tab> to see the completion of global options and verbs.