anchor.diff:    ###### interface
   
     options.services.graphite = {
  +    dataDir = mkOption {
  +      type = types.path;
  +      default = "/var/db/graphite";
  +      description = ''
  +        Data directory for graphite.
  +      '';
  +    };
  +
       web = {
         enable = mkOption {
           description = "Whether to enable graphite web frontend";
  
positive.code:       serviceConfig = {
          ExecStart = ''
            ${pkgs.python27Packages.waitress}/bin/waitress-serve \
            --host=${cfg.web.host} --port=${cfg.web.port} \
            --call django.core.handlers.wsgi:WSGIHandler'';
          User = "graphite";
          Group = "graphite";
        };
        preStart = ''
          if ! test -e ${dataDir}/db-created; then
            mkdir -p ${dataDir}/{whisper/,log/webapp/}
  
            # populate database
            ${pkgs.python27Packages.graphite_web}/bin/manage-graphite.py syncdb --noinput
  
negative.code: 
        port = mkOption {
          description = "Graphite web frontend port";
          default = 8080;
          type = types.int;
        };
      };
  
  