build(deps-dev): apply updates
[e-mobility-charging-stations-simulator.git] / src / worker / WorkerSet.ts
index 5bc399189e5b079f9bad7cd4b7ab49c3353c10d0..dd7cf2d7685ac3012143e856873408307d85a8fa 100644 (file)
-// Partial Copyright Jerome Benoit. 2021. All Rights Reserved.
+// Partial Copyright Jerome Benoit. 2021-2023. All Rights Reserved.
 
-import { WorkerData, WorkerMessageEvents, WorkerOptions, WorkerSetElement } from '../types/Worker';
+import { EventEmitter } from 'node:events';
+import { SHARE_ENV, Worker } from 'node:worker_threads';
 
-import Utils from '../utils/Utils';
-import { Worker } from 'worker_threads';
-import WorkerAbstract from './WorkerAbstract';
-import { WorkerUtils } from './WorkerUtils';
+import { WorkerAbstract } from './WorkerAbstract';
+import { WorkerConstants } from './WorkerConstants';
+import {
+  type SetInfo,
+  type WorkerData,
+  WorkerMessageEvents,
+  type WorkerOptions,
+  type WorkerSetElement,
+  WorkerSetEvents,
+} from './WorkerTypes';
+import { sleep } from './WorkerUtils';
 
-export default class WorkerSet extends WorkerAbstract<WorkerData> {
+export class WorkerSet extends WorkerAbstract<WorkerData> {
+  public readonly emitter: EventEmitter;
   private readonly workerSet: Set<WorkerSetElement>;
-  private readonly messageHandler: (message: unknown) => void | Promise<void>;
 
   /**
-   * Create a new `WorkerSet`.
+   * Creates a new `WorkerSet`.
    *
-   * @param workerScript
-   * @param workerOptions
+   * @param workerScript -
+   * @param workerOptions -
    */
   constructor(workerScript: string, workerOptions?: WorkerOptions) {
     super(workerScript, workerOptions);
+    this.workerOptions.poolOptions = {
+      ...{
+        enableEvents: true,
+        restartWorkerOnError: true,
+      },
+      ...this.workerOptions.poolOptions,
+    };
     this.workerSet = new Set<WorkerSetElement>();
-    this.messageHandler = workerOptions?.messageHandler ?? (() => { /* This is intentional */ });
+    if (this.workerOptions?.poolOptions?.enableEvents) {
+      this.emitter = new EventEmitter();
+    }
+  }
+
+  get info(): SetInfo {
+    return {
+      version: WorkerConstants.version,
+      type: 'set',
+      worker: 'thread',
+      size: this.size,
+      elementsExecuting: [...this.workerSet].reduce(
+        (accumulator, workerSetElement) => accumulator + workerSetElement.numberOfWorkerElements,
+        0,
+      ),
+      elementsPerWorker: this.maxElementsPerWorker,
+    };
   }
 
   get size(): number {
     return this.workerSet.size;
   }
 
-  get maxElementsPerWorker(): number | null {
+  get maxElementsPerWorker(): number | undefined {
     return this.workerOptions.elementsPerWorker;
   }
 
-  /**
-   *
-   * @param elementData
-   * @returns
-   * @public
-   */
-  public async addElement(elementData: WorkerData): Promise<void> {
-    if (!this.workerSet) {
-      throw new Error('Cannot add a WorkerSet element: workers\' set does not exist');
-    }
-    if (this.getLastWorkerSetElement().numberOfWorkerElements >= this.workerOptions.elementsPerWorker) {
-      await this.startWorker();
-    }
-    this.getLastWorker().postMessage({
-      id: WorkerMessageEvents.START_WORKER_ELEMENT,
-      data: elementData
-    });
-    this.getLastWorkerSetElement().numberOfWorkerElements++;
-    // Start element sequentially to optimize memory at startup
-    if (this.workerOptions.elementStartDelay > 0) {
-      await Utils.sleep(this.workerOptions.elementStartDelay);
-    }
-  }
-
-  /**
-   *
-   * @returns
-   * @public
-   */
+  /** @inheritDoc */
   public async start(): Promise<void> {
-    await this.startWorker();
+    this.addWorkerSetElement();
+    // Add worker set element sequentially to optimize memory at startup
+    this.workerOptions.workerStartDelay > 0 && (await sleep(this.workerOptions.workerStartDelay));
   }
 
-  /**
-   *
-   * @returns
-   * @public
-   */
+  /** @inheritDoc */
   public async stop(): Promise<void> {
     for (const workerSetElement of this.workerSet) {
+      const workerExitPromise = new Promise<void>((resolve) => {
+        workerSetElement.worker.on('exit', () => {
+          resolve();
+        });
+      });
       await workerSetElement.worker.terminate();
+      await workerExitPromise;
     }
     this.workerSet.clear();
   }
 
+  /** @inheritDoc */
+  public async addElement(elementData: WorkerData): Promise<void> {
+    if (!this.workerSet) {
+      throw new Error("Cannot add a WorkerSet element: workers' set does not exist");
+    }
+    const workerSetElement = await this.getWorkerSetElement();
+    workerSetElement.worker.postMessage({
+      id: WorkerMessageEvents.startWorkerElement,
+      data: elementData,
+    });
+    ++workerSetElement.numberOfWorkerElements;
+    // Add element sequentially to optimize memory at startup
+    if (this.workerOptions.elementStartDelay > 0) {
+      await sleep(this.workerOptions.elementStartDelay);
+    }
+  }
+
   /**
-   *
-   * @private
+   * Adds a new `WorkerSetElement`.
    */
-  private async startWorker(): Promise<void> {
-    const worker = new Worker(this.workerScript);
-    worker.on('message', (msg) => {
-      (async () => {
-        await this.messageHandler(msg);
-      })().catch(() => { /* This is intentional */ });
+  private addWorkerSetElement(): WorkerSetElement {
+    const worker = new Worker(this.workerScript, {
+      env: SHARE_ENV,
+      ...this.workerOptions.poolOptions.workerOptions,
     });
-    worker.on('error', () => { /* This is intentional */ });
-    worker.on('exit', (code) => {
-      WorkerUtils.defaultExitHandler(code);
-      this.workerSet.delete(this.getWorkerSetElementByWorker(worker));
+    worker.on(
+      'message',
+      this.workerOptions?.poolOptions?.messageHandler ?? WorkerConstants.EMPTY_FUNCTION,
+    );
+    worker.on(
+      'error',
+      this.workerOptions?.poolOptions?.errorHandler ?? WorkerConstants.EMPTY_FUNCTION,
+    );
+    worker.on('error', (error) => {
+      if (this.emitter !== undefined) {
+        this.emitter.emit(WorkerSetEvents.error, error);
+      }
+      if (this.workerOptions?.poolOptions?.restartWorkerOnError) {
+        this.addWorkerSetElement();
+      }
     });
-    this.workerSet.add({ worker, numberOfWorkerElements: 0 });
-    // Start worker sequentially to optimize memory at startup
-    this.workerOptions.workerStartDelay > 0 && await Utils.sleep(this.workerOptions.workerStartDelay);
+    worker.on(
+      'online',
+      this.workerOptions?.poolOptions?.onlineHandler ?? WorkerConstants.EMPTY_FUNCTION,
+    );
+    worker.on(
+      'exit',
+      this.workerOptions?.poolOptions?.exitHandler ?? WorkerConstants.EMPTY_FUNCTION,
+    );
+    worker.once('exit', () =>
+      this.removeWorkerSetElement(this.getWorkerSetElementByWorker(worker)),
+    );
+    const workerSetElement: WorkerSetElement = { worker, numberOfWorkerElements: 0 };
+    this.workerSet.add(workerSetElement);
+    return workerSetElement;
   }
 
-  private getLastWorkerSetElement(): WorkerSetElement {
-    let workerSetElement: WorkerSetElement;
-    for (workerSetElement of this.workerSet) { /* This is intentional */ }
-    return workerSetElement;
+  private removeWorkerSetElement(workerSetElement: WorkerSetElement): void {
+    this.workerSet.delete(workerSetElement);
   }
 
-  private getLastWorker(): Worker {
-    return this.getLastWorkerSetElement().worker;
+  private async getWorkerSetElement(): Promise<WorkerSetElement> {
+    let chosenWorkerSetElement: WorkerSetElement;
+    for (const workerSetElement of this.workerSet) {
+      if (workerSetElement.numberOfWorkerElements < this.workerOptions.elementsPerWorker) {
+        chosenWorkerSetElement = workerSetElement;
+        break;
+      }
+    }
+    if (!chosenWorkerSetElement) {
+      chosenWorkerSetElement = this.addWorkerSetElement();
+      // Add worker set element sequentially to optimize memory at startup
+      this.workerOptions.workerStartDelay > 0 && (await sleep(this.workerOptions.workerStartDelay));
+    }
+    return chosenWorkerSetElement;
   }
 
-  private getWorkerSetElementByWorker(worker: Worker): WorkerSetElement {
+  private getWorkerSetElementByWorker(worker: Worker): WorkerSetElement | undefined {
     let workerSetElt: WorkerSetElement;
     for (const workerSetElement of this.workerSet) {
       if (workerSetElement.worker.threadId === worker.threadId) {