{ config, lib, pkgs, ... }: with lib; # Config common to all hosts, which don't belong anywhere else { config = let hashed-build-seed = pkgs.stdenv.mkDerivation { name = "build-seed-hash"; phases = [ "installPhase" ]; buildInputs = with pkgs; [ coreutils ]; installPhase = '' echo "${config.instance.build-seed}" | sha1sum | grep -o "^[^ ]*" > $out ''; }; in { nix.nixPath = lib.mkBefore [ "/nix/var/nix/profiles/per-user/$USER/channels" ]; environment.etc = { build-timestamp.text = toString config.instance.build-timestamp; "build-seed.sha1sum".source = "${hashed-build-seed}"; }; }; }