lru.js

/**
 * @description
 *
 * DOING: Should node modules and files required
 * to separate them from the rest.
 */
const Sequelize = require('sequelize');

const SequelizeAutoBin = 'node_modules/sequelize-auto/bin/sequelize-auto';
const Joi = require('joi');
const LRU = require('lru-cache-node');
const shell = require('shelljs');

/**
 * @description
 *
 * DOING: Should libraries and files required
 * to separate them from the rest.
 */
const language = require('../locale/default');

const dataSchema = Joi.object().keys({
  handler: Joi.string().required(),
  env: Joi.string().optional(),
  config: Joi.object().required(),
});
const cacheOptions = {
  maxSize: 100,
  maxAge: 1000 * 60 * 60,
};
const cache = new LRU(cacheOptions);

/**
 * @method sequelize
 *
 * @description
 *
 * DOING: Should return a sequelize connection instance object
 * upon request using the retrieved configuration.
 *
 * {@link lib/sequelize}
 * @returns {Promise}
 */
module.exports = config => () => {
  const { error, value } = Joi.validate(config, dataSchema, { abortEarly: false });

  if (error) {
    throw error;
  }

  const {
    database,
    user,
    pass,
    extraConf,
  } = value.config;

  const defaultConfiguration = {
    dialect: 'postgres',
    logging: (process.env.DB_VERBOSE) ? (process.env.DB_VERBOSE.toLowerCase() === 'true') : false,
    pool: {
      max: 25,
      min: 0,
      idle: 2000,
      evict: 5000,
      handleDisconnects: true,
      acquire: 2000,
    },
    dialectOptions: {
      requestTimeout: 5000,
    },
    isolationLevel: 'READ UNCOMMITTED',
  };

  const pgsqlConfig = Object.assign({}, extraConf, defaultConfiguration);

  if (Array.isArray(extraConf.schema) && extraConf.directory) {
    const cmd = [];

    extraConf.port = (extraConf.port) ? extraConf.port : 5432;

    /**
      * @description
      *
      * CLARIFY: Should iterate the schemas from the configuration
      * and write files to disk using SequelizeAutoBin
      * expects model directory path and schema array.
      * @returns {*.<stdout>}
      */
    const build = () => Object.values(extraConf.schema).forEach((schema, index) => {
      cmd[index] = `${SequelizeAutoBin} -o ${extraConf.directory} -d ${database} -h ${extraConf.host} -s ${schema} -u ${user} -p ${extraConf.port} -x ${pass} -e ${extraConf.dialect}`;
      return shell.exec(cmd[index], (code, stdout, stderror) =>
        ((code !== 0 || stderror) ? process.exit(language.ERROR_FS) : process.exit(stdout)));
    });

    return setImmediate(build);
  }

  let db = cache.get(pgsqlConfig);

  if (!db) {
    db = new Sequelize(database, user, pass, pgsqlConfig);
    cache.set(pgsqlConfig, db);
  }

  return db;
};