Asko Soukka: Creating Nix-expressions with buildout

Announcing collective.recipe.nix

collective.recipe.nix is my try for generating nix expressions for arbitrary Python projects. It's an experimental buildout recipe, which re-uses zc.recipe.egg for figuring out all the required packages and their dependencies.

Example of usage

At first, bootstrap your environment by defining python with buildout in ./default.nix:

with import <nixpkgs> {}; {
  myEnv = stdenv.mkDerivation {
    name = "myEnv";
    buildInputs = [
      pythonPackages.buildout
    ];
    shellHook = ''
      export SSL_CERT_FILE=~/.nix-profile/etc/ca-bundle.crt
    '';
  };
}

And example ./buildout.cfg:

[buildout]
parts=
    i18ndude
    releaser
    robot
    sphinx

[i18ndude]
recipe=collective.recipe.nix
eggs=i18ndude

[releaser]
recipe=collective.recipe.nix
eggs=zest.releaser[recommended]

[robot]
recipe=collective.recipe.nix
eggs=robotframework
propagated-build-inputs=
    robotframework=robotframework-debuglibrary
    robotframework=robotframework-selenium2library
    robotframework=robotframework-selenium2screenshots

[sphinx]
recipe=collective.recipe.nix
eggs=sphinx
propagated-build-inputs=
    sphinx=sphinxcontrib_robotframework[docs]

Run the buildout:

$ nix-shell --run buildout

The recipe generates three kind of expressions:

• default [name].nix usable with nix-shell
• buildEnv based [name]-env.nix usable with nix-build
• buildPythonPackage based [name]-package.nix usable with nix-env -i -f

So, now you should be able to run zest.releaser with:

$ nix-shell releaser.nix --run fullrelease

You could also build Nix-environment with symlinks in folder ./releaser or into a Docker image with:

$ nix-build releaser-env.nix -o releaser

Finally, you could install zest.releaser into your current Nix-profile with:

$ nix-env -i -f releaser-zest_releaser.nix