ros2nix

Tool to convert ROS package.xml to Nix expressions compatible with nix-ros-overlay. Under the hood, it uses rosdep to convert ROS package names to nixpkgs attributes so that you don't have to be concerned with it.

Installation

• With nix-env:

  nix-env --install -f https://github.com/wentasah/ros2nix/archive/main.tar.gz

  or try it out without installation:

  nix-shell -p '(import (fetchTarball "https://github.com/wentasah/ros2nix/archive/main.tar.gz")).default'

• With Nix flakes experimental feature:

  nix profile install github:wentasah/ros2nix

  or try it out without installation:

  nix shell github:wentasah/ros2nix

Usage examples

Nixifying local ROS workspace

1. Create Nix expressions for local packages

   ros2nix $(find -name package.xml)

   This also creates ./overlay.nix and ./default.nix for easy integration and/or testing of created packages.

2. Try building some of your packages (replace my-package with real name):

   nix-build -A rosPackages.humble.my-package
   nix-build -A rosPackages.jazzy.my-package

   If the build succeeds, you're probably done. Failures can be caused by several things:

   • Missing dependencies in your package.xml
   • Missing/stale nixos keys for nixpkgs packages in rosdep yaml database
   • Bugs in your packages (e.g. in CMakeLists.txt)
   • Bugs in ros2nix – please, report them
   • Bugs in nix-ros-overlay – report them too :-)

Nixifying 3rd party ROS packages

You can use 3rd party ROS packages (which are not a part of ROS distribution) in your project as follows. We'll show the procedure on the Autoware project as an example.

1. Clone the 3rd party repositories, e.g.

   git clone https://github.com/autowarefoundation/autoware.git
   cd autoware
   mkdir src
   vcs import src < autoware.repos
   cd ..
   
   ros2nix --output-as-nix-pkg-name --fetch $(find -name package.xml|grep -v ament_cmake)

   This will create all Nix expressions in the current directory and named according to their package names. The expressions will fetch the source code from GitHub instead of from local filesystem. Note that we ignore ament_cmake packages forked by autoware since they break the build.

2. Try building some packages:

   nix-build -A rosPackages.humble.autoware-overlay-rviz-plugin
   

   Note that not all autoware packages can be build successfully.

Tip

To build all generated packages, run ros2nix with the --flake switch and then run nix flake check (depending on your configuration, you may need to add --experimental-features 'nix-command flakes').

ros2nix reference

usage: ros2nix [-h]
               [--output OUTPUT | --output-as-ros-pkg-name | --output-as-nix-pkg-name]
               [--output-dir OUTPUT_DIR] [--fetch] [--distro DISTRO]
               [--src-param SRC_PARAM] [--source-root SOURCE_ROOT]
               [--do-check] [--extra-build-inputs DEP1,DEP2,...]
               [--extra-propagated-build-inputs DEP1,DEP2,...]
               [--extra-check-inputs DEP1,DEP2,...]
               [--extra-native-build-inputs DEP1,DEP2,...] [--flake]
               [--default | --no-default] [--overlay | --no-overlay]
               [--nix-ros-overlay FLAKEREF] [--nixfmt] [--compare]
               [--copyright-holder COPYRIGHT_HOLDER] [--license LICENSE]
               package.xml [package.xml ...]

positional arguments:
  package.xml           Path to package.xml

options:
  -h, --help            show this help message and exit
  --output OUTPUT       Output filename (default: package.nix)
  --output-as-ros-pkg-name
                        Name output files based on ROS package name, e.g.,
                        package_name.nix. Implies --output-dir=. (default:
                        False)
  --output-as-nix-pkg-name
                        Name output files based on Nix package name, e.g.,
                        package-name.nix. Implies --output-dir=. (default:
                        False)
  --output-dir OUTPUT_DIR
                        Directory to generate output files in. By default,
                        package files are stored next to their corresponding
                        package.xml, top-level files like overlay.nix in the
                        current directory. (default: None)
  --fetch               Use fetches like fetchFromGitHub in src attribute
                        values. The fetch function and its parameters are
                        determined from the local git work tree. sourceRoot
                        attribute is set if needed and not overridden by
                        --source-root. (default: False)
  --distro DISTRO       ROS distro (used as a context for evaluation of
                        conditions in package.xml, in the name of the Nix
                        expression and in flake.nix). Note that the generated
                        Nix expression can be used with any ROS distro if its
                        package.xml contains no conditions. (default: rolling)
  --src-param SRC_PARAM
                        Adds a parameter to the generated function and uses it
                        as a value of the src attribute (default: None)
  --source-root SOURCE_ROOT
                        Set sourceRoot attribute value in the generated Nix
                        expression. Substring '{package_name}' gets replaced
                        with the package name. (default: None)
  --do-check            Set doCheck attribute to true (default: False)
  --extra-build-inputs DEP1,DEP2,...
                        Additional dependencies to add to the generated Nix
                        expressions (default: [])
  --extra-propagated-build-inputs DEP1,DEP2,...
                        Additional dependencies to add to the generated Nix
                        expressions (default: [])
  --extra-check-inputs DEP1,DEP2,...
                        Additional dependencies to add to the generated Nix
                        expressions (default: [])
  --extra-native-build-inputs DEP1,DEP2,...
                        Additional dependencies to add to the generated Nix
                        expressions (default: [])
  --flake               Generate top-level flake.nix instead of default.nix.
                        Use with --fetch if some package.xml files are outside
                        of the flake repo (default: False)
  --default, --no-default
                        Enforce/suppress generation of default.nix (default:
                        None)
  --overlay, --no-overlay
                        Generate overlay.nix (default: True)
  --nix-ros-overlay FLAKEREF
                        Flake reference of nix-ros-overlay. You may want to
                        change the branch from master to develop or use your
                        own fork. (default: github:lopsided98/nix-ros-
                        overlay/master)
  --nixfmt              Format the resulting expressions with nixfmt (default:
                        False)
  --compare             Don't write any file, but check whether writing the
                        file would change existing files. Exit with exit code
                        2 if a change is detected. Useful for CI. (default:
                        False)
  --copyright-holder COPYRIGHT_HOLDER
                        Copyright holder of the generated Nix expressions.
                        (default: None)
  --license LICENSE     License of the generated Nix expressions, e.g. 'BSD'
                        (default: None)