nixos-config/system/gitlab-runner.nix

{ pkgs, lib, ... }:
{
  mkNixRunner =
    registrationConfigFile: with lib; rec {
      # File should contain at least these two variables:
      # `CI_SERVER_URL`
      # `REGISTRATION_TOKEN`
      inherit registrationConfigFile; # 2
      dockerImage = "alpine:3.18.2";
      dockerAllowedImages = [ dockerImage ];
      dockerVolumes = [
        "/etc/nix/nix.conf:/etc/nix/nix.conf:ro"
        "/nix/store:/nix/store:ro"
        "/nix/var/nix/db:/nix/var/nix/db:ro"
        "/nix/var/nix/daemon-socket:/nix/var/nix/daemon-socket:ro"
      ];
      dockerDisableCache = true;
      preBuildScript = pkgs.writeScript "setup-container" ''
        mkdir -p -m 0755 /nix/var/log/nix/drvs
        mkdir -p -m 0755 /nix/var/nix/gcroots
        mkdir -p -m 0755 /nix/var/nix/profiles
        mkdir -p -m 0755 /nix/var/nix/temproots
        mkdir -p -m 0755 /nix/var/nix/userpool
        mkdir -p -m 1777 /nix/var/nix/gcroots/per-user
        mkdir -p -m 1777 /nix/var/nix/profiles/per-user
        mkdir -p -m 0755 /nix/var/nix/profiles/per-user/root
        mkdir -p -m 0700 "$HOME/.nix-defexpr"

        . ${pkgs.nix}/etc/profile.d/nix.sh

        ${pkgs.nix}/bin/nix-env -i ${
          concatStringsSep " " (
            with pkgs;
            [
              nix
              cacert
              git
              openssh
            ]
          )
        }
      '';
      environmentVariables = {
        ENV = "/etc/profile";
        USER = "root";
        NIX_REMOTE = "daemon";
        PATH = "/nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/default/sbin:/bin:/sbin:/usr/bin:/usr/sbin";
        NIX_SSL_CERT_FILE = "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt";
      };
      tagList = [ "nix" ];
    };
}