| 1 | // Partial Copyright Jerome Benoit. 2021. All Rights Reserved. |
| 2 | |
| 3 | import { WorkerEvents, WorkerSetElement } from '../types/Worker'; |
| 4 | |
| 5 | import Utils from '../utils/Utils'; |
| 6 | import { Worker } from 'worker_threads'; |
| 7 | import WorkerAbstract from './WorkerAbstract'; |
| 8 | import { WorkerUtils } from './WorkerUtils'; |
| 9 | |
| 10 | export default class WorkerSet<T> extends WorkerAbstract { |
| 11 | public maxElementsPerWorker: number; |
| 12 | private workerSet: Set<WorkerSetElement>; |
| 13 | |
| 14 | /** |
| 15 | * Create a new `WorkerSet`. |
| 16 | * |
| 17 | * @param workerScript |
| 18 | * @param maxElementsPerWorker |
| 19 | * @param workerStartDelay |
| 20 | * @param messageListenerCallback |
| 21 | */ |
| 22 | constructor(workerScript: string, maxElementsPerWorker = 1, workerStartDelay?: number, messageListenerCallback: (message: any) => void = () => { /* This is intentional */ }) { |
| 23 | super(workerScript, workerStartDelay, messageListenerCallback); |
| 24 | this.workerSet = new Set<WorkerSetElement>(); |
| 25 | this.maxElementsPerWorker = maxElementsPerWorker; |
| 26 | } |
| 27 | |
| 28 | get size(): number { |
| 29 | return this.workerSet.size; |
| 30 | } |
| 31 | |
| 32 | /** |
| 33 | * |
| 34 | * @param elementData |
| 35 | * @returns |
| 36 | * @public |
| 37 | */ |
| 38 | public async addElement(elementData: T): Promise<void> { |
| 39 | if (!this.workerSet) { |
| 40 | throw new Error('Cannot add a WorkerSet element: workers\' set does not exist'); |
| 41 | } |
| 42 | if (this.getLastWorkerSetElement().numberOfWorkerElements >= this.maxElementsPerWorker) { |
| 43 | this.startWorker(); |
| 44 | // Start worker sequentially to optimize memory at startup |
| 45 | await Utils.sleep(this.workerStartDelay); |
| 46 | } |
| 47 | this.getLastWorker().postMessage({ id: WorkerEvents.START_WORKER_ELEMENT, data: elementData }); |
| 48 | this.getLastWorkerSetElement().numberOfWorkerElements++; |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * |
| 53 | * @returns |
| 54 | * @public |
| 55 | */ |
| 56 | public async start(): Promise<void> { |
| 57 | this.startWorker(); |
| 58 | // Start worker sequentially to optimize memory at startup |
| 59 | await Utils.sleep(this.workerStartDelay); |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * |
| 64 | * @returns |
| 65 | * @public |
| 66 | */ |
| 67 | public async stop(): Promise<void> { |
| 68 | for (const workerSetElement of this.workerSet) { |
| 69 | await workerSetElement.worker.terminate(); |
| 70 | } |
| 71 | this.workerSet.clear(); |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * |
| 76 | * @private |
| 77 | */ |
| 78 | private startWorker(): void { |
| 79 | const worker = new Worker(this.workerScript); |
| 80 | worker.on('message', this.messageListener); |
| 81 | worker.on('error', () => { /* This is intentional */ }); |
| 82 | worker.on('exit', (code) => { |
| 83 | WorkerUtils.defaultExitHandler(code); |
| 84 | this.workerSet.delete(this.getWorkerSetElementByWorker(worker)); |
| 85 | }); |
| 86 | this.workerSet.add({ worker, numberOfWorkerElements: 0 }); |
| 87 | } |
| 88 | |
| 89 | private getLastWorkerSetElement(): WorkerSetElement { |
| 90 | let workerSetElement: WorkerSetElement; |
| 91 | // eslint-disable-next-line no-empty |
| 92 | for (workerSetElement of this.workerSet) { /* This is intentional */ } |
| 93 | return workerSetElement; |
| 94 | } |
| 95 | |
| 96 | private getLastWorker(): Worker { |
| 97 | return this.getLastWorkerSetElement().worker; |
| 98 | } |
| 99 | |
| 100 | private getWorkerSetElementByWorker(worker: Worker): WorkerSetElement { |
| 101 | let workerSetElt: WorkerSetElement; |
| 102 | for (const workerSetElement of this.workerSet) { |
| 103 | if (workerSetElement.worker.threadId === worker.threadId) { |
| 104 | workerSetElt = workerSetElement; |
| 105 | break; |
| 106 | } |
| 107 | } |
| 108 | return workerSetElt; |
| 109 | } |
| 110 | } |