1 // Partial Copyright Jerome Benoit. 2021-2023. All Rights Reserved.
3 import { EventEmitterAsyncResource
} from
'node:events';
4 import { SHARE_ENV
, Worker
} from
'node:worker_threads';
6 import { WorkerAbstract
} from
'./WorkerAbstract';
7 import { EMPTY_FUNCTION
, workerSetVersion
} from
'./WorkerConstants';
14 type WorkerSetElement
,
16 } from
'./WorkerTypes';
17 import { randomizeDelay
, sleep
} from
'./WorkerUtils';
19 export class WorkerSet
extends WorkerAbstract
<WorkerData
> {
20 public readonly emitter
: EventEmitterAsyncResource
| undefined;
21 private readonly workerSet
: Set
<WorkerSetElement
>;
22 private started
: boolean;
23 private workerStartup
: boolean;
26 * Creates a new `WorkerSet`.
28 * @param workerScript -
29 * @param workerOptions -
31 constructor(workerScript
: string, workerOptions
: WorkerOptions
) {
32 super(workerScript
, workerOptions
);
34 this.workerOptions
.elementsPerWorker
=== null ||
35 this.workerOptions
.elementsPerWorker
=== undefined
37 throw new TypeError('Elements per worker is not defined');
39 if (!Number.isSafeInteger(this.workerOptions
.elementsPerWorker
)) {
40 throw new TypeError('Elements per worker must be an integer');
42 if (this.workerOptions
.elementsPerWorker
<= 0) {
43 throw new RangeError('Elements per worker must be greater than zero');
45 this.workerSet
= new Set
<WorkerSetElement
>();
46 if (this.workerOptions
.poolOptions
?.enableEvents
) {
47 this.emitter
= new EventEmitterAsyncResource({ name
: 'workerset' });
50 this.workerStartup
= false;
55 version
: workerSetVersion
,
59 elementsExecuting
: [...this.workerSet
].reduce(
60 (accumulator
, workerSetElement
) => accumulator
+ workerSetElement
.numberOfWorkerElements
,
63 elementsPerWorker
: this.maxElementsPerWorker
!,
68 return this.workerSet
.size
;
71 get
maxElementsPerWorker(): number | undefined {
72 return this.workerOptions
.elementsPerWorker
;
76 public async start(): Promise
<void> {
77 this.addWorkerSetElement();
78 // Add worker set element sequentially to optimize memory at startup
79 this.workerOptions
.workerStartDelay
! > 0 &&
80 (await sleep(randomizeDelay(this.workerOptions
.workerStartDelay
!)));
81 this.emitter
?.emit(WorkerSetEvents
.started
, this.info
);
86 public async stop(): Promise
<void> {
87 for (const workerSetElement
of this.workerSet
) {
88 const worker
= workerSetElement
.worker
;
89 const waitWorkerExit
= new Promise
<void>((resolve
) => {
90 worker
.once('exit', () => {
94 await worker
.terminate();
96 this.emitter
?.emit(WorkerSetEvents
.stopped
, this.info
);
97 this.emitter
?.emitDestroy();
103 public async addElement(elementData
: WorkerData
): Promise
<void> {
105 throw new Error('Cannot add a WorkerSet element: not started');
107 if (!this.workerSet
) {
108 throw new Error("Cannot add a WorkerSet element: 'workerSet' property does not exist");
110 const workerSetElement
= await this.getWorkerSetElement();
111 workerSetElement
.worker
.postMessage({
112 event
: WorkerMessageEvents
.startWorkerElement
,
115 ++workerSetElement
.numberOfWorkerElements
;
116 // Add element sequentially to optimize memory at startup
117 if (this.workerOptions
.elementStartDelay
! > 0) {
118 await sleep(randomizeDelay(this.workerOptions
.elementStartDelay
!));
123 * Adds a new `WorkerSetElement`.
125 private addWorkerSetElement(): WorkerSetElement
{
126 this.workerStartup
= true;
127 const worker
= new Worker(this.workerScript
, {
129 ...this.workerOptions
.poolOptions
?.workerOptions
,
131 worker
.on('message', this.workerOptions
.poolOptions
?.messageHandler
?? EMPTY_FUNCTION
);
132 worker
.on('message', (message
: WorkerMessage
<WorkerData
>) => {
133 if (message
.event
=== WorkerMessageEvents
.startedWorkerElement
) {
134 this.emitter
?.emit(WorkerSetEvents
.elementStarted
, this.info
);
135 } else if (message
.event
=== WorkerMessageEvents
.startWorkerElementError
) {
136 this.emitter
?.emit(WorkerSetEvents
.elementError
, message
.data
);
139 worker
.on('error', this.workerOptions
.poolOptions
?.errorHandler
?? EMPTY_FUNCTION
);
140 worker
.on('error', (error
) => {
141 this.emitter
?.emit(WorkerSetEvents
.error
, error
);
143 this.workerOptions
.poolOptions
?.restartWorkerOnError
&&
147 this.addWorkerSetElement();
150 worker
.on('online', this.workerOptions
.poolOptions
?.onlineHandler
?? EMPTY_FUNCTION
);
151 worker
.on('exit', this.workerOptions
.poolOptions
?.exitHandler
?? EMPTY_FUNCTION
);
152 worker
.once('exit', () =>
153 this.removeWorkerSetElement(this.getWorkerSetElementByWorker(worker
)!),
155 const workerSetElement
: WorkerSetElement
= { worker
, numberOfWorkerElements
: 0 };
156 this.workerSet
.add(workerSetElement
);
157 this.workerStartup
= false;
158 return workerSetElement
;
161 private removeWorkerSetElement(workerSetElement
: WorkerSetElement
): void {
162 this.workerSet
.delete(workerSetElement
);
165 private async getWorkerSetElement(): Promise
<WorkerSetElement
> {
166 let chosenWorkerSetElement
: WorkerSetElement
| undefined;
167 for (const workerSetElement
of this.workerSet
) {
168 if (workerSetElement
.numberOfWorkerElements
< this.workerOptions
.elementsPerWorker
!) {
169 chosenWorkerSetElement
= workerSetElement
;
173 if (!chosenWorkerSetElement
) {
174 chosenWorkerSetElement
= this.addWorkerSetElement();
175 // Add worker set element sequentially to optimize memory at startup
176 this.workerOptions
.workerStartDelay
! > 0 &&
177 (await sleep(randomizeDelay(this.workerOptions
.workerStartDelay
!)));
179 return chosenWorkerSetElement
;
182 private getWorkerSetElementByWorker(worker
: Worker
): WorkerSetElement
| undefined {
183 let workerSetElt
: WorkerSetElement
| undefined;
184 for (const workerSetElement
of this.workerSet
) {
185 if (workerSetElement
.worker
.threadId
=== worker
.threadId
) {
186 workerSetElt
= workerSetElement
;