nixos-config/shared/nix.nix

{ config, lib, nixpkgs, ... }:
{
  nix = {
    # expose all flake inputs through nix Path and registry
    registry = {
      nixpkgs.flake = nixpkgs;
    };
    nixPath = lib.mapAttrsToList (key: value: "${key}=${value.to.path}") config.nix.registry;
    distributedBuilds = true;
    settings = {
      auto-optimise-store = true;
      experimental-features = [ "nix-command" "flakes" "repl-flake" ];
      substituters = [
        "https://cache.rfive.de"
        "https://cache.ifsr.de"
      ];
      trusted-public-keys = [
        "cache.rfive.de:of5d+o6mfGXQSR3lk6ApfDBr4ampAUaNHux1O/XY3Tw="
        "cache.ifsr.de:y55KBAMF4YkjIzXwYOKVk9fcQS+CZ9RM1zAAMYQJtsg="
      ];
    };
    buildMachines = [
      # {
      #   hostName = "quitte.ifsr.de";
      #   sshUser = "rouven.seifert";
      #   system = "x86_64-linux";
      #   protocol = "ssh-ng";
      #   supportedFeatures = [ "nixos-test" "benchmark" "big-parallel" "kvm" ];
      #   maxJobs = 4;
      #   speedFactor = 10;
      # }
      {
        hostName = "fujitsu.vpn.rfive.de";
        system = "x86_64-linux";
        protocol = "ssh-ng";
        supportedFeatures = [ "nixos-test" "benchmark" "big-parallel" "kvm" ];
        maxJobs = 4;
        speedFactor = 5;
      }
    ];
    extraOptions = ''
      builders-use-substitutes = true
    '';
  };
}