1 // Partial Copyright Jerome Benoit. 2021. All Rights Reserved.
3 import { Worker
} from
'worker_threads';
5 import { WorkerData
, WorkerMessageEvents
, WorkerOptions
, WorkerSetElement
} from
'../types/Worker';
6 import Utils from
'../utils/Utils';
7 import WorkerAbstract from
'./WorkerAbstract';
8 import { WorkerUtils
} from
'./WorkerUtils';
10 export default class WorkerSet
extends WorkerAbstract
<WorkerData
> {
11 private readonly workerSet
: Set
<WorkerSetElement
>;
12 private readonly messageHandler
: (message
: unknown
) => void;
15 * Create a new `WorkerSet`.
18 * @param workerOptions
20 constructor(workerScript
: string, workerOptions
?: WorkerOptions
) {
21 super(workerScript
, workerOptions
);
22 this.workerSet
= new Set
<WorkerSetElement
>();
24 workerOptions
?.messageHandler
??
26 /* This is intentional */
31 return this.workerSet
.size
;
34 get
maxElementsPerWorker(): number | null {
35 return this.workerOptions
.elementsPerWorker
;
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");
49 this.workerSet
.size
=== 0 ||
50 this.getLastWorkerSetElement().numberOfWorkerElements
>= this.workerOptions
.elementsPerWorker
52 await this.startWorker();
54 this.getLastWorker().postMessage({
55 id
: WorkerMessageEvents
.START_WORKER_ELEMENT
,
58 this.getLastWorkerSetElement().numberOfWorkerElements
++;
59 // Start element sequentially to optimize memory at startup
60 if (this.workerOptions
.elementStartDelay
> 0) {
61 await Utils
.sleep(this.workerOptions
.elementStartDelay
);
70 public async start(): Promise
<void> {
71 await this.startWorker();
79 public async stop(): Promise
<void> {
80 for (const workerSetElement
of this.workerSet
) {
81 await workerSetElement
.worker
.terminate();
83 this.workerSet
.clear();
90 private async startWorker(): Promise
<void> {
91 const worker
= new Worker(this.workerScript
);
92 worker
.on('message', this.messageHandler
);
93 worker
.on('error', WorkerUtils
.defaultErrorHandler
);
94 worker
.on('exit', (code
) => {
95 WorkerUtils
.defaultExitHandler(code
);
96 this.workerSet
.delete(this.getWorkerSetElementByWorker(worker
));
98 this.workerSet
.add({ worker
, numberOfWorkerElements
: 0 });
99 // Start worker sequentially to optimize memory at startup
100 this.workerOptions
.workerStartDelay
> 0 &&
101 (await Utils
.sleep(this.workerOptions
.workerStartDelay
));
104 private getLastWorkerSetElement(): WorkerSetElement
{
105 let workerSetElement
: WorkerSetElement
;
106 for (workerSetElement
of this.workerSet
) {
107 /* This is intentional */
109 return workerSetElement
;
112 private getLastWorker(): Worker
{
113 return this.getLastWorkerSetElement().worker
;
116 private getWorkerSetElementByWorker(worker
: Worker
): WorkerSetElement
{
117 let workerSetElt
: WorkerSetElement
;
118 for (const workerSetElement
of this.workerSet
) {
119 if (workerSetElement
.worker
.threadId
=== worker
.threadId
) {
120 workerSetElt
= workerSetElement
;