fixed.js

   1 'use strict'
   2 const {
   3   Worker, isMainThread, MessageChannel
   4 } = require('worker_threads')
   5
   6 console.log('Fixed required')
   7
   8 // FixedThreadPool , TrampolineThreadPool
   9 /**
  10  * A thread pool with a static number of threads , is possible to execute tasks in sync or async mode as you prefer
  11  * @author Alessandro Pio Ardizio
  12  * @since 0.0.1
  13  */
  14 class FixedThreadPool {
  15   /**
  16      *
  17      * @param {Number} numThreads  Num of threads for this worker pool
  18      * @param {Object} an object with possible options for example maxConcurrency
  19      */
  20   constructor (numThreads, opts) {
  21     if (!isMainThread) {
  22       throw new Error('Cannot start a thread pool from a worker thread !!!')
  23     }
  24     this.numThreads = numThreads
  25     this.workers = []
  26     for (let i = 1; i <= numThreads; i++) {
  27       const worker = new Worker(__filename)
  28       this.workers.push(worker)
  29       const { port1, port2 } = new MessageChannel()
  30       worker.receiverPort = port1
  31       worker.sendPort = port2
  32     }
  33   }
  34
  35   /**
  36    *
  37    * @param {Function} task , a function to execute
  38    * @param {Any} the input for the task specified
  39    */
  40   execute (task, data) {
  41     // TODO select a worker
  42     // configure worker to handle message with the specified task
  43     const res = this._execute(this.workers[0], task)
  44     this.workers[0].sendPort.postMessage(data)
  45     return res
  46   }
  47
  48   _execute (worker, task) {
  49     return new Promise((resolve, reject) => {
  50       worker.receiverPort.on('message', (data) => {
  51         try {
  52           resolve(task(data))
  53         } catch (e) {
  54           reject(e)
  55         }
  56       })
  57     })
  58   }
  59 }
  60
  61 module.exports = FixedThreadPool