| 1 | // Partial Copyright Jerome Benoit. 2021. All Rights Reserved. |
| 2 | |
| 3 | import { WorkerData, WorkerMessageEvents, WorkerOptions, 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 extends WorkerAbstract<WorkerData> { |
| 11 | private readonly workerSet: Set<WorkerSetElement>; |
| 12 | private readonly messageHandler: (message: unknown) => void | Promise<void>; |
| 13 | |
| 14 | /** |
| 15 | * Create a new `WorkerSet`. |
| 16 | * |
| 17 | * @param workerScript |
| 18 | * @param workerOptions |
| 19 | */ |
| 20 | constructor(workerScript: string, workerOptions?: WorkerOptions) { |
| 21 | super(workerScript, workerOptions); |
| 22 | this.workerSet = new Set<WorkerSetElement>(); |
| 23 | this.messageHandler = workerOptions?.messageHandler ?? (() => { /* This is intentional */ }); |
| 24 | } |
| 25 | |
| 26 | get size(): number { |
| 27 | return this.workerSet.size; |
| 28 | } |
| 29 | |
| 30 | get maxElementsPerWorker(): number | null { |
| 31 | return this.workerOptions.elementsPerWorker; |
| 32 | } |
| 33 | |
| 34 | /** |
| 35 | * |
| 36 | * @param elementData |
| 37 | * @returns |
| 38 | * @public |
| 39 | */ |
| 40 | public async addElement(elementData: WorkerData): Promise<void> { |
| 41 | if (!this.workerSet) { |
| 42 | throw new Error('Cannot add a WorkerSet element: workers\' set does not exist'); |
| 43 | } |
| 44 | if (this.getLastWorkerSetElement().numberOfWorkerElements >= this.workerOptions.elementsPerWorker) { |
| 45 | await this.startWorker(); |
| 46 | } |
| 47 | this.getLastWorker().postMessage({ id: WorkerMessageEvents.START_WORKER_ELEMENT, data: elementData }); |
| 48 | this.getLastWorkerSetElement().numberOfWorkerElements++; |
| 49 | this.workerOptions.elementStartDelay > 0 && await Utils.sleep(this.workerOptions.elementStartDelay); |
| 50 | } |
| 51 | |
| 52 | /** |
| 53 | * |
| 54 | * @returns |
| 55 | * @public |
| 56 | */ |
| 57 | public async start(): Promise<void> { |
| 58 | await this.startWorker(); |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * |
| 63 | * @returns |
| 64 | * @public |
| 65 | */ |
| 66 | public async stop(): Promise<void> { |
| 67 | for (const workerSetElement of this.workerSet) { |
| 68 | await workerSetElement.worker.terminate(); |
| 69 | } |
| 70 | this.workerSet.clear(); |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * |
| 75 | * @private |
| 76 | */ |
| 77 | private async startWorker(): Promise<void> { |
| 78 | const worker = new Worker(this.workerScript); |
| 79 | worker.on('message', (msg) => { |
| 80 | (async () => { |
| 81 | await this.messageHandler(msg); |
| 82 | })().catch(() => { /* This is intentional */ }); |
| 83 | }); |
| 84 | worker.on('error', () => { /* This is intentional */ }); |
| 85 | worker.on('exit', (code) => { |
| 86 | WorkerUtils.defaultExitHandler(code); |
| 87 | this.workerSet.delete(this.getWorkerSetElementByWorker(worker)); |
| 88 | }); |
| 89 | this.workerSet.add({ worker, numberOfWorkerElements: 0 }); |
| 90 | // Start worker sequentially to optimize memory at startup |
| 91 | this.workerOptions.workerStartDelay > 0 && await Utils.sleep(this.workerOptions.workerStartDelay); |
| 92 | } |
| 93 | |
| 94 | private getLastWorkerSetElement(): WorkerSetElement { |
| 95 | let workerSetElement: WorkerSetElement; |
| 96 | for (workerSetElement of this.workerSet) { /* This is intentional */ } |
| 97 | return workerSetElement; |
| 98 | } |
| 99 | |
| 100 | private getLastWorker(): Worker { |
| 101 | return this.getLastWorkerSetElement().worker; |
| 102 | } |
| 103 | |
| 104 | private getWorkerSetElementByWorker(worker: Worker): WorkerSetElement { |
| 105 | let workerSetElt: WorkerSetElement; |
| 106 | for (const workerSetElement of this.workerSet) { |
| 107 | if (workerSetElement.worker.threadId === worker.threadId) { |
| 108 | workerSetElt = workerSetElement; |
| 109 | break; |
| 110 | } |
| 111 | } |
| 112 | return workerSetElt; |
| 113 | } |
| 114 | } |