cloudflare-dyndns: configurable systemd frequency

        '';

      };

      frequency = mkOption {

        type = types.nullOr types.str;

        default = "*:0/5";

        description = ''

          Run cloudflare-dyndns with the given frequency (see

          {manpage}`systemd.time(7)` for the format).

          If null, do not run automatically.

        '';

      };

      proxied = mkOption {

        type = types.bool;

        default = false;

      description = "CloudFlare Dynamic DNS Client";

      after = [ "network.target" ];

      wantedBy = [ "multi-user.target" ];

      startAt = "*:0/5";

      environment = {

        CLOUDFLARE_DOMAINS = toString cfg.domains;

          in

          "${pkgs.cloudflare-dyndns}/bin/cloudflare-dyndns ${toString args}";

      };

    } // optionalAttrs (cfg.frequency != null) {

      startAt = cfg.frequency;

    };

  };

}