src/charging-station/Worker.js

   1 const Configuration = require('../utils/Configuration');
   2 const EventEmitter = require('events');
   3 const {Worker} = require('worker_threads');
   4 const Pool = require('worker-threads-pool');
   5
   6 class Wrk {
   7   /**
   8    * Create a new `Wrk`.
   9    *
  10    * @param {String} workerScript
  11    * @param {Object} workerData
  12    */
  13   constructor(workerScript, workerData) {
  14     if (Configuration.useWorkerPool()) {
  15       this._pool = new Pool({max: Configuration.getWorkerPoolSize()});
  16     }
  17     this._workerData = workerData;
  18     this._workerScript = workerScript;
  19   }
  20
  21   /**
  22    *
  23    * @return {Promise}
  24    * @private
  25    */
  26   _startWorkerWithPool() {
  27     return new Promise((resolve, reject) => {
  28       this._pool.acquire(this._workerScript, {workerData: this._workerData}, (err, worker) => {
  29         if (err) {
  30           return reject(err);
  31         }
  32         worker.once('message', resolve);
  33         worker.once('error', reject);
  34       });
  35     });
  36   }
  37
  38   /**
  39    *
  40    * @return {Promise}
  41    * @private
  42    */
  43   _startWorker() {
  44     return new Promise((resolve, reject) => {
  45       const worker = new Worker(this._workerScript, {workerData: this._workerData});
  46       worker.on('message', resolve);
  47       worker.on('error', reject);
  48       worker.on('exit', (code) => {
  49         if (code !== 0) {
  50           reject(new Error(`Worker stopped with exit code ${code}`));
  51         }
  52       });
  53     });
  54   }
  55
  56   /**
  57    *
  58    * @return {Promise}
  59    * @public
  60    */
  61   start() {
  62     if (Configuration.useWorkerPool()) {
  63       if (Configuration.getWorkerPoolSize() > 10) {
  64         EventEmitter.defaultMaxListeners = Configuration.getWorkerPoolSize() + 1;
  65       }
  66       return this._startWorkerWithPool();
  67     }
  68     return this._startWorker();
  69   }
  70 }
  71
  72 module.exports = Wrk;