WorkerSet: remove ugly hack to deal with async worker message handler

[e-mobility-charging-stations-simulator.git] / src / worker / WorkerSet.ts

diff --git a/src/worker/WorkerSet.ts b/src/worker/WorkerSet.ts
index a8aa8a37cf5820a5097689ef36b7d58ae59f9ed6..f41752fc7a2b088fda4b8c68b4b74bec347b1bf9 100644 (file)
--- a/src/worker/WorkerSet.ts
+++ b/src/worker/WorkerSet.ts
@@ -1,84 +1,126 @@
-import Constants from '../utils/Constants';
-import Utils from '../utils/Utils';
+// Partial Copyright Jerome Benoit. 2021. All Rights Reserved.
+
 import { Worker } from 'worker_threads';
-import WorkerData from '../types/WorkerData';
-import Wrk from './Worker';
 
-export default class WorkerSet extends Wrk {
-  public maxElementsPerWorker: number;
-  private workers: Set<Worker>;
-  private lastWorkerNumberOfElements: number;
+import { WorkerData, WorkerMessageEvents, WorkerOptions, WorkerSetElement } from '../types/Worker';
+import Utils from '../utils/Utils';
+import WorkerAbstract from './WorkerAbstract';
+import { WorkerUtils } from './WorkerUtils';
+
+export default class WorkerSet extends WorkerAbstract<WorkerData> {
+  private readonly workerSet: Set<WorkerSetElement>;
+  private readonly messageHandler: (message: unknown) => void;
 
   /**
    * Create a new `WorkerSet`.
    *
-   * @param {string} workerScript
-   * @param {number} maxElementsPerWorker
+   * @param workerScript
+   * @param workerOptions
    */
-  constructor(workerScript: string, maxElementsPerWorker = 1) {
-    super(workerScript);
-    this.workers = new Set<Worker>();
-    this.maxElementsPerWorker = maxElementsPerWorker;
-    this.lastWorkerNumberOfElements = 0;
+  constructor(workerScript: string, workerOptions?: WorkerOptions) {
+    super(workerScript, workerOptions);
+    this.workerSet = new Set<WorkerSetElement>();
+    this.messageHandler =
+      workerOptions?.messageHandler ??
+      (() => {
+        /* This is intentional */
+      });
   }
 
   get size(): number {
-    return this.workers.size;
+    return this.workerSet.size;
+  }
+
+  get maxElementsPerWorker(): number | null {
+    return this.workerOptions.elementsPerWorker;
   }
 
   /**
    *
-   * @return {Promise<void>}
+   * @param elementData
+   * @returns
    * @public
    */
   public async addElement(elementData: WorkerData): Promise<void> {
-    if (!this.workers) {
-      throw Error('Cannot add a WorkerSet element: workers set does not exist');
+    if (!this.workerSet) {
+      throw new Error("Cannot add a WorkerSet element: workers' set does not exist");
     }
-    if (this.lastWorkerNumberOfElements >= this.maxElementsPerWorker) {
-      void this.startWorker();
-      this.lastWorkerNumberOfElements = 0;
-      // Start worker sequentially to optimize memory at startup
-      void Utils.sleep(Constants.START_WORKER_DELAY);
+    if (
+      this.workerSet.size === 0 ||
+      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);
     }
-    this.getLastWorker().postMessage({ id: Constants.START_WORKER_ELEMENT, workerData: elementData });
-    this.lastWorkerNumberOfElements++;
   }
 
   /**
    *
-   * @return {Promise<void>}
+   * @returns
    * @public
    */
   public async start(): Promise<void> {
     await this.startWorker();
-    // Start worker sequentially to optimize memory at startup
-    await Utils.sleep(Constants.START_WORKER_DELAY);
   }
 
   /**
    *
-   * @return {Promise}
+   * @returns
+   * @public
+   */
+  public async stop(): Promise<void> {
+    for (const workerSetElement of this.workerSet) {
+      await workerSetElement.worker.terminate();
+    }
+    this.workerSet.clear();
+  }
+
+  /**
+   *
    * @private
    */
-  private async startWorker() {
-    return new Promise((resolve, reject) => {
-      const worker = new Worker(this.workerScript);
-      worker.on('message', resolve);
-      worker.on('error', reject);
-      worker.on('exit', (code) => {
-        if (code !== 0) {
-          reject(new Error(`Worker stopped with exit code ${code}`));
-        }
-      });
-      this.workers.add(worker);
+  private async startWorker(): Promise<void> {
+    const worker = new Worker(this.workerScript);
+    worker.on('message', this.messageHandler);
+    worker.on('error', WorkerUtils.defaultErrorHandler);
+    worker.on('exit', (code) => {
+      WorkerUtils.defaultExitHandler(code);
+      this.workerSet.delete(this.getWorkerSetElementByWorker(worker));
     });
+    this.workerSet.add({ worker, numberOfWorkerElements: 0 });
+    // Start worker sequentially to optimize memory at startup
+    this.workerOptions.workerStartDelay > 0 &&
+      (await Utils.sleep(this.workerOptions.workerStartDelay));
+  }
+
+  private getLastWorkerSetElement(): WorkerSetElement {
+    let workerSetElement: WorkerSetElement;
+    for (workerSetElement of this.workerSet) {
+      /* This is intentional */
+    }
+    return workerSetElement;
   }
 
   private getLastWorker(): Worker {
-    let worker: Worker;
-    // eslint-disable-next-line no-empty
-    for (worker of this.workers) { }
-    return worker;
+    return this.getLastWorkerSetElement().worker;
+  }
+
+  private getWorkerSetElementByWorker(worker: Worker): WorkerSetElement {
+    let workerSetElt: WorkerSetElement;
+    for (const workerSetElement of this.workerSet) {
+      if (workerSetElement.worker.threadId === worker.threadId) {
+        workerSetElt = workerSetElement;
+        break;
+      }
+    }
+    return workerSetElt;
   }
 }