nixos/services/acme.nix

{
  options,
  config,
  lib,
  fn,
  pkgs,
  ...
}:
with builtins;
with lib;
let
  cfg = config.machine;
in
mkIf (elem "acme" cfg.services) {
  security.acme = {
    # see https://letsencrypt.org/repository/
    acceptTerms = true;
    defaults.email = "${(elemAt cfg.mailAccounts 0).name}@${cfg.domain}";
  };
}