hostsblock_auto.nix

  systemd.services.hostsblock = {
    wantedBy = [ "default.target" ];
    serviceConfig = {
      Type = "simple";
      ExecStart = "${pkgs.curl}/bin/curl https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts -o /var/lib/hostsblock";
    };
  };

  systemd.timers.hostsblock = {
    timerConfig = {
      Unit = "hostsblock.service";
      OnCalendar = "daily";
    };
    wantedBy = [ "default.target" ];
  };

  networking.extraHosts = builtins.readFile /var/lib/hostsblock;