1 // Partial Copyright Jerome Benoit. 2021-2023. All Rights Reserved.
3 import { EventEmitter
} from
'node:events';
4 import { SHARE_ENV
, Worker
} from
'node:worker_threads';
6 import { WorkerAbstract
} from
'./WorkerAbstract';
7 import { DEFAULT_POOL_OPTIONS
, EMPTY_FUNCTION
, workerSetVersion
} from
'./WorkerConstants';
14 type WorkerSetElement
,
16 } from
'./WorkerTypes';
17 import { sleep
} from
'./WorkerUtils';
19 export class WorkerSet
extends WorkerAbstract
<WorkerData
> {
20 public readonly emitter
!: EventEmitter
;
21 private readonly workerSet
: Set
<WorkerSetElement
>;
24 * Creates a new `WorkerSet`.
26 * @param workerScript -
27 * @param workerOptions -
29 constructor(workerScript
: string, workerOptions
: WorkerOptions
) {
30 super(workerScript
, workerOptions
);
32 this.workerOptions
.elementsPerWorker
=== null ||
33 this.workerOptions
.elementsPerWorker
=== undefined
35 throw new TypeError('Elements per worker is not defined');
37 if (!Number.isSafeInteger(this.workerOptions
.elementsPerWorker
)) {
38 throw new TypeError('Elements per worker must be an integer');
40 if (this.workerOptions
.elementsPerWorker
<= 0) {
41 throw new RangeError('Elements per worker must be greater than zero');
43 this.workerOptions
.poolOptions
= {
44 ...DEFAULT_POOL_OPTIONS
,
45 ...this.workerOptions
.poolOptions
,
47 this.workerSet
= new Set
<WorkerSetElement
>();
48 if (this.workerOptions
.poolOptions
?.enableEvents
) {
49 this.emitter
= new EventEmitter();
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 && (await sleep(this.workerOptions
.workerStartDelay
!));
83 public async stop(): Promise
<void> {
84 for (const workerSetElement
of this.workerSet
) {
85 const worker
= workerSetElement
.worker
;
86 const waitWorkerExit
= new Promise
<void>((resolve
) => {
87 worker
.on('exit', () => {
91 await worker
.terminate();
97 public async addElement(elementData
: WorkerData
): Promise
<void> {
98 if (!this.workerSet
) {
99 throw new Error("Cannot add a WorkerSet element: workers' set does not exist");
101 const workerSetElement
= await this.getWorkerSetElement();
102 workerSetElement
.worker
.postMessage({
103 event
: WorkerMessageEvents
.startWorkerElement
,
106 ++workerSetElement
.numberOfWorkerElements
;
107 // Add element sequentially to optimize memory at startup
108 if (this.workerOptions
.elementStartDelay
! > 0) {
109 await sleep(this.workerOptions
.elementStartDelay
!);
114 * Adds a new `WorkerSetElement`.
116 private addWorkerSetElement(): WorkerSetElement
{
117 const worker
= new Worker(this.workerScript
, {
119 ...this.workerOptions
.poolOptions
?.workerOptions
,
121 worker
.on('message', this.workerOptions
.poolOptions
?.messageHandler
?? EMPTY_FUNCTION
);
122 worker
.on('message', (message
: WorkerMessage
<WorkerData
>) => {
123 if (message
.event
=== WorkerMessageEvents
.startedWorkerElement
) {
124 this.emitter
?.emit(WorkerSetEvents
.elementStarted
, this.info
);
125 } else if (message
.event
=== WorkerMessageEvents
.startWorkerElementError
) {
126 this.emitter
?.emit(WorkerSetEvents
.elementError
, message
.data
);
129 worker
.on('error', this.workerOptions
.poolOptions
?.errorHandler
?? EMPTY_FUNCTION
);
130 worker
.on('error', (error
) => {
131 this.emitter
?.emit(WorkerSetEvents
.error
, error
);
132 if (this.workerOptions
.poolOptions
?.restartWorkerOnError
) {
133 this.addWorkerSetElement();
136 worker
.on('online', this.workerOptions
.poolOptions
?.onlineHandler
?? EMPTY_FUNCTION
);
137 worker
.on('exit', this.workerOptions
.poolOptions
?.exitHandler
?? EMPTY_FUNCTION
);
138 worker
.once('exit', () =>
139 this.removeWorkerSetElement(this.getWorkerSetElementByWorker(worker
)!),
141 const workerSetElement
: WorkerSetElement
= { worker
, numberOfWorkerElements
: 0 };
142 this.workerSet
.add(workerSetElement
);
143 return workerSetElement
;
146 private removeWorkerSetElement(workerSetElement
: WorkerSetElement
): void {
147 this.workerSet
.delete(workerSetElement
);
150 private async getWorkerSetElement(): Promise
<WorkerSetElement
> {
151 let chosenWorkerSetElement
: WorkerSetElement
| undefined;
152 for (const workerSetElement
of this.workerSet
) {
153 if (workerSetElement
.numberOfWorkerElements
< this.workerOptions
.elementsPerWorker
!) {
154 chosenWorkerSetElement
= workerSetElement
;
158 if (!chosenWorkerSetElement
) {
159 chosenWorkerSetElement
= this.addWorkerSetElement();
160 // Add worker set element sequentially to optimize memory at startup
161 this.workerOptions
.workerStartDelay
! > 0 &&
162 (await sleep(this.workerOptions
.workerStartDelay
!));
164 return chosenWorkerSetElement
;
167 private getWorkerSetElementByWorker(worker
: Worker
): WorkerSetElement
| undefined {
168 let workerSetElt
: WorkerSetElement
| undefined;
169 for (const workerSetElement
of this.workerSet
) {
170 if (workerSetElement
.worker
.threadId
=== worker
.threadId
) {
171 workerSetElt
= workerSetElement
;