Introducing nix-install-pkgs-action
One of the more frustrating experiences is when your project is nicely Nix-ified, and yet your CI/CD workflow is full of "install this, install that" steps. Even worse, the install steps duplicate a lot of information already contained in your Nix files. At YAXI, we wanted to re-use our projects' Nix packaging. And this is why we came up with nix-install-pkgs-action: It allows you to re-use your project's flake in a GitHub Actions workflow.
Prerequisites
The action requires a flake-enabled Nix with support for profiles. If you aren't running a self-hosted GitHub runner on NixOS, you can use the cachix/install-nix-action to install a flake-enabled Nix.
Usage
The action takes a comma-separated list of packages to install as input packages. The following step will install myPackage from your flake's package output:
- uses: yaxitech/nix-install-pkgs-action@v3
with:
packages: ".#myPackage"
The package's binaries will be added to PATH and following steps can use them.
Each package can be prefixed with a flake reference. If no flake reference is given, nixpkgs is assumed. Extending on the previous example, the following step will install figlet and swift from nixpkgs and myPackage from your flake's package output.
- uses: yaxitech/nix-install-pkgs-action@v3
with:
packages: "figlet, nixpkgs#swift, .#myPackage"
You can also install derivations using some Nix expression. Within the expression, pkgs will refer to your flake's imported nixpkgs. For example, if you want a Python environment with lxml and py.test installed, you can use the following step:
- uses: yaxitech/nix-install-pkgs-action@v3
with:
expr: 'pkgs.python3.withPackages(ps: with ps; [lxml pytest])'
The above example shows that the action is also useful if your project doesn't use Nix or flakes at all. You can still use it to install any package from the Nix packages collection.
Please try it out! We've been using the action for quite some time now and find it immensely useful. Still, don't hesitate to open an issue in case you encounter any road blocks.