gcRootsDir = mkOption {
        type = types.path;
        default = "/nix/var/nix/gcroots/hydra";
        description = "Directory that holds Hydra garbage collector roots.";
      };

        gc_roots_dir ${cfg.gcRootsDir}

          if [ ! -e ${cfg.gcRootsDir} ]; then
            # Move legacy roots directory.
            if [ -e /nix/var/nix/gcroots/per-user/hydra/hydra-roots ]; then
              mv /nix/var/nix/gcroots/per-user/hydra/hydra-roots ${cfg.gcRootsDir}
            fi
            mkdir -p ${cfg.gcRootsDir}
          fi
          # Move legacy hydra-www roots.
          if [ -e /nix/var/nix/gcroots/per-user/hydra-www/hydra-roots ]; then
            find /nix/var/nix/gcroots/per-user/hydra-www/hydra-roots/ -type f \
              | xargs -r mv -f -t ${cfg.gcRootsDir}/
            rmdir /nix/var/nix/gcroots/per-user/hydra-www/hydra-roots
          fi
          chown hydra.hydra ${cfg.gcRootsDir}
          chmod 2775 ${cfg.gcRootsDir}

my $hydraConfig;

    return $hydraConfig if defined $hydraConfig;

    return {} unless -f $conf;
    my %config = new Config::General($conf)->getall;
    return \%config;

    if (-f $conf) {
        my %h = new Config::General($conf)->getall;
        $hydraConfig = \%h;
    } else {
        $hydraConfig = {};
    }
    return $hydraConfig;

    die unless defined $ENV{LOGNAME};
    my $dir = ($ENV{NIX_STATE_DIR} || "/nix/var/nix" ) . "/gcroots/per-user/$ENV{LOGNAME}/hydra-roots";

    my $config = getHydraConfig();
    my $dir = $config->{gc_roots_dir};
    unless (defined $dir) {
        die unless defined $ENV{LOGNAME};
        $dir = ($ENV{NIX_STATE_DIR} || "/nix/var/nix" ) . "/gcroots/per-user/$ENV{LOGNAME}/hydra-roots";
    }