    (function () {
      'use strict';

      const elasticsearch = require('elasticsearch');
      const esClient = new elasticsearch.Client({
        host: '127.0.0.1:9200',
        log: 'error'
      });

      const indices = function indices() {
        return esClient.cat.indices({v: true})
        .then(console.log)
        .catch(err => console.error(`Error connecting to the es client: ${err}`));
      };

      // only for testing purposes
      // all calls should be initiated through the module
      const test = function test() {
        console.log(`elasticsearch indices information:`);
        indices();
      };

      test();

      module.exports = {
        indices
      };
    } ());
