ravel/dist/util/kvstore.js

Ravel Rapid Application Development Framework

'use strict';

const ApplicationError = require('./application_error');
const redis = require('redis');

/*!
                                 * Reconnection strategy for redis
                                 */
function retryStrategy(ravelInstance) {
  return function (options) {
    if (options.error.code === 'ECONNREFUSED') {
      // End reconnecting on a specific error and flush all commands with a individual error
      ravelInstance.log.error(`Lost connection to redis: ${options.error.code}.`);
      return new ApplicationError.General(`Lost connection to redis: ${options.error.code}.`);
    } else if (options.attempt > ravelInstance.get('redis max retries')) {
      ravelInstance.log.error(`Lost connection to redis: ${options.error.code}. Max retry attempts exceeded.`);
      // End reconnecting with built in error
      return new ApplicationError.General(
      `Lost connection to redis: ${options.error.code}. Max retry attempts reached.`);
    } else {
      const time = Math.pow(options.attempt, 2) * 100;
      ravelInstance.log.error(`Lost connection to redis: ${options.error.code}. Reconnecting in ${time} milliseconds.`);
      // reconnect after
      return time;
    }
  };
}

/**
   * Abstraction for redis-like data store.
   *
   * @param {Ravel} ravelInstance - An instance of a Ravel app.
   * @private
   */
module.exports = function (ravelInstance) {
  const client = redis.createClient(
  ravelInstance.get('redis port'),
  ravelInstance.get('redis host'),
  {
    'no_ready_check': true,
    'retry_strategy': retryStrategy(ravelInstance) });

  if (ravelInstance.get('redis password')) {
    client.auth(ravelInstance.get('redis password'));
  }
  const channel = `ravel-keepalive/`;
  const msg = `${Date.now()}/${Math.random()}`;

  // keepalive when not testing
  const redisKeepaliveInterval = setInterval(() => {
    client && client.publish && client.publish(channel, msg);
  }, ravelInstance.get('redis keepalive interval'));
  ravelInstance.once('end', () => {
    clearInterval(redisKeepaliveInterval);
  });

  return client;
};

module.exports.retryStrategy = retryStrategy;