redis_client.js

const redis = require('redis');
const bluebird = require('bluebird');
const config = require('better-config');
const fs = require('fs');

// Add extra definitions for RedisTimeSeries commands.
redis.addCommand('ts.add'); // redis.ts_addAsync
redis.addCommand('ts.range'); // redis.ts_rangeAsync

// Promisify all the functions exported by node_redis.
bluebird.promisifyAll(redis);

// Create a client and connect to Redis using configuration
// from config.json.
const clientConfig = {
  host: config.get('dataStores.redis.host'),
  port: config.get('dataStores.redis.port')
};

if (config.get('dataStores.redis.database')) {
  database: parseInt(config.get('dataStores.redis.database'))
}

if (config.get('dataStores.redis.password')) {
  clientConfig.password = config.get('dataStores.redis.password');
}

if (config.get('dataStores.redis.username')) {
  clientConfig.username = config.get('dataStores.redis.username');
}

if (config.get('dataStores.redis.ca-file')) {
  clientConfig.tls = {};
  clientConfig.tls.ca = [ fs.readFileSync(config.get('dataStores.redis.ca-file')) ];
  clientConfig.tls.rejectUnauthorized = false;
  clientConfig.tls.requestCert = true;
}

const client = redis.createClient(clientConfig);

// This is a catch all basic error handler.
client.on('error', error => console.log(error));

module.exports = {
  /**
   * Get the application's connected Redis client instance.
   *
   * @returns {Object} - a connected node_redis client instance.
   */
  getClient: () => client,
};