anchor.diff:      if cfg.configText != null then
         pkgs.writeText "alertmanager.yml" cfg.configText
       else mkConfigFile;
  +  cmdlineArgs = cfg.extraFlags ++ [
  +    "--config.file ${alertmanagerYml}"
  +    "--web.listen-address ${cfg.listenAddress}:${toString cfg.port}"
  +    "--log.level ${cfg.logLevel}"
  +    ] ++ (optional (cfg.webExternalUrl != null)
  +      "--web.external-url ${cfg.webExternalUrl}"
  +    ) ++ (optional (cfg.logFormat != null)
  +      "--log.format ${cfg.logFormat}"
  +  );
   in {
     options = {
       services.prometheus.alertmanager = {
  
positive.code:           Open port in firewall for incoming connections.
          '';
        };
      };
    };
  
  
negative.code:       after    = [ "network.target" ];
        script = ''
          ${pkgs.prometheus-alertmanager.bin}/bin/alertmanager \
            ${concatStringsSep " \\\n  " cmdlineArgs}
        '';
  
        serviceConfig = {
  