1 // Partial Copyright Jerome Benoit. 2021. All Rights Reserved.
3 import { WorkerData
, WorkerMessageEvents
, WorkerOptions
, WorkerSetElement
} from
'../types/Worker';
5 import Utils from
'../utils/Utils';
6 import { Worker
} from
'worker_threads';
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 | Promise
<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.getLastWorkerSetElement().numberOfWorkerElements
>= this.workerOptions
.elementsPerWorker
51 await this.startWorker();
53 this.getLastWorker().postMessage({
54 id
: WorkerMessageEvents
.START_WORKER_ELEMENT
,
57 this.getLastWorkerSetElement().numberOfWorkerElements
++;
58 // Start element sequentially to optimize memory at startup
59 if (this.workerOptions
.elementStartDelay
> 0) {
60 await Utils
.sleep(this.workerOptions
.elementStartDelay
);
69 public async start(): Promise
<void> {
70 await this.startWorker();
78 public async stop(): Promise
<void> {
79 for (const workerSetElement
of this.workerSet
) {
80 await workerSetElement
.worker
.terminate();
82 this.workerSet
.clear();
89 private async startWorker(): Promise
<void> {
90 const worker
= new Worker(this.workerScript
);
91 worker
.on('message', (msg
) => {
93 await this.messageHandler(msg
);
95 /* This is intentional */
98 worker
.on('error', () => {
99 /* This is intentional */
101 worker
.on('exit', (code
) => {
102 WorkerUtils
.defaultExitHandler(code
);
103 this.workerSet
.delete(this.getWorkerSetElementByWorker(worker
));
105 this.workerSet
.add({ worker
, numberOfWorkerElements
: 0 });
106 // Start worker sequentially to optimize memory at startup
107 this.workerOptions
.workerStartDelay
> 0 &&
108 (await Utils
.sleep(this.workerOptions
.workerStartDelay
));
111 private getLastWorkerSetElement(): WorkerSetElement
{
112 let workerSetElement
: WorkerSetElement
;
113 for (workerSetElement
of this.workerSet
) {
114 /* This is intentional */
116 return workerSetElement
;
119 private getLastWorker(): Worker
{
120 return this.getLastWorkerSetElement().worker
;
123 private getWorkerSetElementByWorker(worker
: Worker
): WorkerSetElement
{
124 let workerSetElt
: WorkerSetElement
;
125 for (const workerSetElement
of this.workerSet
) {
126 if (workerSetElement
.worker
.threadId
=== worker
.threadId
) {
127 workerSetElt
= workerSetElement
;