index.js

'use strict';

const AWS = require('aws-sdk');
const elasticsearch = require('elasticsearch');
const httpAWSESClass = require('http-aws-es');

module.exports = {
  createClient: createClient,
  getOptions: getOptions
};

function getOptions(options) {
  options = options || {};

  // serverless-offline will set IS_OFFLINE based on whether we're offline
  const devMode = Boolean(process.env.IS_OFFLINE);

  const prefix = options.envPrefix || 'AWS';
  const region = options.region || process.env[`${prefix}_REGION`];
  const host = options.host || process.env[`${prefix}_HOST`];

  delete options.region; // this doesn't belong in ES options

  if (!region) {
    throw new TypeError('region is required');
  }
  if (!host) {
    throw new TypeError('host is required');
  }

  const credentials = options.credentials || new AWS.EnvironmentCredentials(prefix);

  const config = Object.assign({}, options, {
    host: host,
    amazonES: {
      region,
      credentials
    }
  });

  // don't sign the request in offline mode
  if (!devMode) {
    config.connectionClass = httpAWSESClass;
  }

  return config;
}

function createClient(options) {
  return new elasticsearch.Client(getOptions(options));
}