nixos/modules/nix.nix

{ pkgs, config, ... }:

{
  config = {
    nix = {
      useSandbox = true;
      package = pkgs.nixFlakes;
      generateRegistryFromInputs = true;
      generateNixPathFromInputs = true;
      linkInputs = true;

      autoOptimiseStore = true;
      trustedUsers = [ "root" ] ++ config.elss.users.admins;

      # Enable flakes
      # Free up to 50 GiB whenever there is less than 10 GiB left.
      extraOptions = ''
        experimental-features = nix-command flakes
        min-free = ${toString (10 * 1024 * 1024 * 1024)}
        max-free = ${toString (50 * 1024 * 1024 * 1024)}
      '';

      # Disable automatic (periodic) GC, since it might interfere with benchmarks
      gc = {
        automatic = true;
        dates = "weekly";
        options = "--delete-older-than 30d";
      };
    };
  };
}