| 1 | // Partial Copyright Jerome Benoit. 2021-2023. All Rights Reserved. |
| 2 | |
| 3 | import { Worker } from 'node:worker_threads'; |
| 4 | |
| 5 | import { WorkerAbstract } from './WorkerAbstract'; |
| 6 | import { WorkerConstants } from './WorkerConstants'; |
| 7 | import { |
| 8 | type MessageHandler, |
| 9 | type WorkerData, |
| 10 | WorkerMessageEvents, |
| 11 | type WorkerOptions, |
| 12 | type WorkerSetElement, |
| 13 | } from './WorkerTypes'; |
| 14 | import { WorkerUtils } from './WorkerUtils'; |
| 15 | |
| 16 | export class WorkerSet extends WorkerAbstract<WorkerData> { |
| 17 | private readonly workerSet: Set<WorkerSetElement>; |
| 18 | |
| 19 | /** |
| 20 | * Create a new `WorkerSet`. |
| 21 | * |
| 22 | * @param workerScript - |
| 23 | * @param workerOptions - |
| 24 | */ |
| 25 | constructor(workerScript: string, workerOptions?: WorkerOptions) { |
| 26 | super(workerScript, workerOptions); |
| 27 | this.workerSet = new Set<WorkerSetElement>(); |
| 28 | } |
| 29 | |
| 30 | get size(): number { |
| 31 | return this.workerSet.size; |
| 32 | } |
| 33 | |
| 34 | get maxElementsPerWorker(): number | undefined { |
| 35 | return this.workerOptions.elementsPerWorker; |
| 36 | } |
| 37 | |
| 38 | /** |
| 39 | * |
| 40 | * @param elementData - |
| 41 | * @returns |
| 42 | * @public |
| 43 | */ |
| 44 | public async addElement(elementData: WorkerData): Promise<void> { |
| 45 | if (!this.workerSet) { |
| 46 | throw new Error("Cannot add a WorkerSet element: workers' set does not exist"); |
| 47 | } |
| 48 | if ( |
| 49 | this.workerSet.size === 0 || |
| 50 | this.getLastWorkerSetElement().numberOfWorkerElements >= this.workerOptions.elementsPerWorker |
| 51 | ) { |
| 52 | await this.startWorker(); |
| 53 | } |
| 54 | this.getLastWorker().postMessage({ |
| 55 | id: WorkerMessageEvents.startWorkerElement, |
| 56 | data: elementData, |
| 57 | }); |
| 58 | this.getLastWorkerSetElement().numberOfWorkerElements++; |
| 59 | // Start element sequentially to optimize memory at startup |
| 60 | if (this.workerOptions.elementStartDelay > 0) { |
| 61 | await WorkerUtils.sleep(this.workerOptions.elementStartDelay); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * |
| 67 | * @returns |
| 68 | * @public |
| 69 | */ |
| 70 | public async start(): Promise<void> { |
| 71 | await this.startWorker(); |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * |
| 76 | * @returns |
| 77 | * @public |
| 78 | */ |
| 79 | public async stop(): Promise<void> { |
| 80 | for (const workerSetElement of this.workerSet) { |
| 81 | await workerSetElement.worker.terminate(); |
| 82 | } |
| 83 | this.workerSet.clear(); |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * Start a new `Worker`. |
| 88 | */ |
| 89 | private async startWorker(): Promise<void> { |
| 90 | const worker = new Worker(this.workerScript); |
| 91 | worker.on( |
| 92 | 'message', |
| 93 | (this.workerOptions?.messageHandler ?? WorkerConstants.EMPTY_FUNCTION).bind( |
| 94 | this |
| 95 | ) as MessageHandler<Worker> |
| 96 | ); |
| 97 | worker.on('error', WorkerUtils.defaultErrorHandler.bind(this) as (err: Error) => void); |
| 98 | worker.on('exit', (code) => { |
| 99 | WorkerUtils.defaultExitHandler(code); |
| 100 | this.workerSet.delete(this.getWorkerSetElementByWorker(worker)); |
| 101 | }); |
| 102 | this.workerSet.add({ worker, numberOfWorkerElements: 0 }); |
| 103 | // Start worker sequentially to optimize memory at startup |
| 104 | this.workerOptions.workerStartDelay > 0 && |
| 105 | (await WorkerUtils.sleep(this.workerOptions.workerStartDelay)); |
| 106 | } |
| 107 | |
| 108 | private getLastWorkerSetElement(): WorkerSetElement { |
| 109 | let workerSetElement: WorkerSetElement; |
| 110 | for (workerSetElement of this.workerSet) { |
| 111 | /* This is intentional */ |
| 112 | } |
| 113 | return workerSetElement; |
| 114 | } |
| 115 | |
| 116 | private getLastWorker(): Worker { |
| 117 | return this.getLastWorkerSetElement().worker; |
| 118 | } |
| 119 | |
| 120 | private getWorkerSetElementByWorker(worker: Worker): WorkerSetElement { |
| 121 | let workerSetElt: WorkerSetElement; |
| 122 | for (const workerSetElement of this.workerSet) { |
| 123 | if (workerSetElement.worker.threadId === worker.threadId) { |
| 124 | workerSetElt = workerSetElement; |
| 125 | break; |
| 126 | } |
| 127 | } |
| 128 | return workerSetElt; |
| 129 | } |
| 130 | } |