kibana-123/src/core_plugins/elasticsearch/lib/migrate_config.js

Kibana is an open source (Apache Licensed), browser based analytics and search dashboard for Elasticsearch. Kibana is a snap to setup and start using. Kibana strives to be easy to get started with, while also being flexible and powerful, just like Elastic

import upgrade from './upgrade_config';
import { mappings } from './kibana_index_mappings';

module.exports = function (server) {
  const config = server.config();
  const { callWithInternalUser } = server.plugins.elasticsearch.getCluster('admin');

  const options =  {
    index: config.get('kibana.index'),
    type: 'config',
    body: {
      size: 1000,
      sort: [
        {
          buildNum: {
            order: 'desc',
            unmapped_type: mappings.config.properties.buildNum.type
          }
        }
      ]
    }
  };

  return callWithInternalUser('search', options).then(upgrade(server));
};