X-Git-Url: https://git.piment-noir.org/?a=blobdiff_plain;f=src%2Fpools%2Fabstract-pool.ts;h=f6ed280cc3bbcf39b6a4aed1faa37603bf17786d;hb=45dbbb14328a173cad05ddcf21b5acf7f6460bb8;hp=d169afadb1df863cfbf8f37f1dbd623b211f3b07;hpb=cda5cc74c77bdfc37b220ef19637876e221b5061;p=poolifier.git

diff --git a/src/pools/abstract-pool.ts b/src/pools/abstract-pool.ts
index d169afad..f6ed280c 100644
--- a/src/pools/abstract-pool.ts
+++ b/src/pools/abstract-pool.ts
@@ -2,16 +2,34 @@ import EventEmitter from 'events'
 import type { MessageValue } from '../utility-types'
 import type { IPool } from './pool'
 
+/**
+ * Callback invoked if the worker raised an error.
+ */
 export type ErrorHandler<Worker> = (this: Worker, e: Error) => void
+
+/**
+ * Callback invoked when the worker has started successfully.
+ */
 export type OnlineHandler<Worker> = (this: Worker) => void
+
+/**
+ * Callback invoked when the worker exits successfully.
+ */
 export type ExitHandler<Worker> = (this: Worker, code: number) => void
 
+/**
+ * Basic interface that describes the minimum required implementation of listener events for a pool-worker.
+ */
 export interface IWorker {
   on(event: 'error', handler: ErrorHandler<this>): void
   on(event: 'online', handler: OnlineHandler<this>): void
   on(event: 'exit', handler: ExitHandler<this>): void
+  once(event: 'exit', handler: ExitHandler<this>): void
 }
 
+/**
+ * Options for a poolifier pool.
+ */
 export interface PoolOptions<Worker> {
   /**
    * A function that will listen for error event on each worker.
@@ -26,36 +44,72 @@ export interface PoolOptions<Worker> {
    */
   exitHandler?: ExitHandler<Worker>
   /**
-   * This is just to avoid not useful warnings message, is used to set `maxListeners` on event emitters (workers are event emitters).
+   * This is just to avoid non-useful warning messages.
+   *
+   * Will be used to set `maxListeners` on event emitters (workers are event emitters).
    *
    * @default 1000
+   * @see [Node events emitter.setMaxListeners(n)](https://nodejs.org/api/events.html#events_emitter_setmaxlisteners_n)
    */
   maxTasks?: number
 }
 
+/**
+ * Internal poolifier pool emitter.
+ */
 class PoolEmitter extends EventEmitter {}
 
+/**
+ * Base class containing some shared logic for all poolifier pools.
+ *
+ * @template Worker Type of worker which manages this pool.
+ * @template Data Type of data sent to the worker.
+ * @template Response Type of response of execution.
+ */
 export abstract class AbstractPool<
   Worker extends IWorker,
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  Data = any,
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  Response = any
+  Data = unknown,
+  Response = unknown
 > implements IPool<Data, Response> {
+  /**
+   * List of currently available workers.
+   */
   public readonly workers: Worker[] = []
-  public nextWorker: number = 0
 
   /**
-   * `workerId` as key and an integer value
+   * Index for the next worker.
+   */
+  public nextWorkerIndex: number = 0
+
+  /**
+   * - `key`: The `Worker`
+   * - `value`: Number of tasks that has been assigned to that worker since it started
    */
   public readonly tasks: Map<Worker, number> = new Map<Worker, number>()
 
+  /**
+   * Emitter on which events can be listened to.
+   *
+   * Events that can currently be listened to:
+   *
+   * - `'FullPool'`
+   */
   public readonly emitter: PoolEmitter
 
-  protected id: number = 0
+  /**
+   * ID of the next message.
+   */
+  protected nextMessageId: number = 0
 
+  /**
+   * Constructs a new poolifier pool.
+   *
+   * @param numberOfWorkers Number of workers that this pool should manage.
+   * @param filePath Path to the worker-file.
+   * @param opts Options for the pool. Default: `{ maxTasks: 1000 }`
+   */
   public constructor (
-    public readonly numWorkers: number,
+    public readonly numberOfWorkers: number,
     public readonly filePath: string,
     public readonly opts: PoolOptions<Worker> = { maxTasks: 1000 }
   ) {
@@ -69,57 +123,119 @@ export abstract class AbstractPool<
 
     this.setupHook()
 
-    for (let i = 1; i <= this.numWorkers; i++) {
-      this.internalNewWorker()
+    for (let i = 1; i <= this.numberOfWorkers; i++) {
+      this.createAndSetupWorker()
     }
 
     this.emitter = new PoolEmitter()
   }
 
-  protected setupHook (): void {
-    // Can be overridden
+  /**
+   * Number of workers that this pool should manage.
+   *
+   * @returns Number of workers that this pool manages.
+   * @deprecated Only here for backward compatibility.
+   */
+  // eslint-disable-next-line spellcheck/spell-checker
+  public get numWorkers (): number {
+    return this.numberOfWorkers
   }
 
-  protected abstract isMain (): boolean
+  /**
+   * Index for the next worker.
+   *
+   * @returns Index for the next worker.
+   * @deprecated Only here for backward compatibility.
+   */
+  public get nextWorker (): number {
+    return this.nextWorkerIndex
+  }
+
+  public execute (data: Data): Promise<Response> {
+    // Configure worker to handle message with the specified task
+    const worker = this.chooseWorker()
+    this.increaseWorkersTask(worker)
+    const messageId = ++this.nextMessageId
+    const res = this.internalExecute(worker, messageId)
+    this.sendToWorker(worker, { data: data || ({} as Data), id: messageId })
+    return res
+  }
 
   public async destroy (): Promise<void> {
-    for (const worker of this.workers) {
-      await this.destroyWorker(worker)
-    }
+    await Promise.all(this.workers.map(worker => this.destroyWorker(worker)))
   }
 
+  /**
+   * Shut down given worker.
+   *
+   * @param worker A worker within `workers`.
+   */
   protected abstract destroyWorker (worker: Worker): void | Promise<void>
 
-  protected abstract sendToWorker (
-    worker: Worker,
-    message: MessageValue<Data>
-  ): void
+  /**
+   * Setup hook that can be overridden by a Poolifier pool implementation
+   * to run code before workers are created in the abstract constructor.
+   */
+  protected setupHook (): void {
+    // Can be overridden
+  }
+
+  /**
+   * Should return whether the worker is the main worker or not.
+   */
+  protected abstract isMain (): boolean
 
-  protected addWorker (worker: Worker): void {
-    const previousWorkerIndex = this.tasks.get(worker)
-    if (previousWorkerIndex !== undefined) {
-      this.tasks.set(worker, previousWorkerIndex + 1)
+  /**
+   * Increase the number of tasks that the given workers has done.
+   *
+   * @param worker Workers whose tasks are increased.
+   */
+  protected increaseWorkersTask (worker: Worker): void {
+    const numberOfTasksTheWorkerHas = this.tasks.get(worker)
+    if (numberOfTasksTheWorkerHas !== undefined) {
+      this.tasks.set(worker, numberOfTasksTheWorkerHas + 1)
     } else {
       throw Error('Worker could not be found in tasks map')
     }
   }
 
   /**
-   * Execute the task specified into the constructor with the data parameter.
+   * Removes the given worker from the pool.
    *
-   * @param data The input for the task specified.
-   * @returns Promise that is resolved when the task is done.
+   * @param worker Worker that will be removed.
    */
-  public execute (data: Data): Promise<Response> {
-    // configure worker to handle message with the specified task
-    const worker = this.chooseWorker()
-    this.addWorker(worker)
-    const id = ++this.id
-    const res = this.internalExecute(worker, id)
-    this.sendToWorker(worker, { data: data || ({} as Data), id: id })
-    return res
+  protected removeWorker (worker: Worker): void {
+    // Clean worker from data structure
+    const workerIndex = this.workers.indexOf(worker)
+    this.workers.splice(workerIndex, 1)
+    this.tasks.delete(worker)
   }
 
+  /**
+   * Choose a worker for the next task.
+   *
+   * The default implementation uses a round robin algorithm to distribute the load.
+   *
+   * @returns Worker.
+   */
+  protected chooseWorker (): Worker {
+    const chosenWorker = this.workers[this.nextWorkerIndex]
+    this.nextWorkerIndex++
+    this.nextWorkerIndex %= this.workers.length
+    return chosenWorker
+  }
+
+  /**
+   * Send a message to the given worker.
+   *
+   * @param worker The worker which should receive the message.
+   * @param message The message.
+   */
+  protected abstract sendToWorker (
+    worker: Worker,
+    message: MessageValue<Data>
+  ): void
+
   protected abstract registerWorkerMessageListener (
     port: Worker,
     listener: (message: MessageValue<Response>) => void
@@ -130,12 +246,15 @@ export abstract class AbstractPool<
     listener: (message: MessageValue<Response>) => void
   ): void
 
-  protected internalExecute (worker: Worker, id: number): Promise<Response> {
+  protected internalExecute (
+    worker: Worker,
+    messageId: number
+  ): Promise<Response> {
     return new Promise((resolve, reject) => {
       const listener: (message: MessageValue<Response>) => void = message => {
-        if (message.id === id) {
+        if (message.id === messageId) {
           this.unregisterWorkerMessageListener(worker, listener)
-          this.addWorker(worker)
+          this.increaseWorkersTask(worker)
           if (message.error) reject(message.error)
           else resolve(message.data as Response)
         }
@@ -144,30 +263,40 @@ export abstract class AbstractPool<
     })
   }
 
-  protected chooseWorker (): Worker {
-    if (this.workers.length - 1 === this.nextWorker) {
-      this.nextWorker = 0
-      return this.workers[this.nextWorker]
-    } else {
-      this.nextWorker++
-      return this.workers[this.nextWorker]
-    }
-  }
+  /**
+   * Returns a newly created worker.
+   */
+  protected abstract createWorker (): Worker
 
-  protected abstract newWorker (): Worker
+  /**
+   * Function that can be hooked up when a worker has been newly created and moved to the workers registry.
+   *
+   * Can be used to update the `maxListeners` or binding the `main-worker`<->`worker` connection if not bind by default.
+   *
+   * @param worker The newly created worker.
+   */
+  protected abstract afterWorkerSetup (worker: Worker): void
 
-  protected abstract afterNewWorkerPushed (worker: Worker): void
+  /**
+   * Creates a new worker for this pool and sets it up completely.
+   *
+   * @returns New, completely set up worker.
+   */
+  protected createAndSetupWorker (): Worker {
+    const worker: Worker = this.createWorker()
 
-  protected internalNewWorker (): Worker {
-    const worker: Worker = this.newWorker()
     worker.on('error', this.opts.errorHandler ?? (() => {}))
     worker.on('online', this.opts.onlineHandler ?? (() => {}))
-    // TODO handle properly when a worker exit
     worker.on('exit', this.opts.exitHandler ?? (() => {}))
+    worker.once('exit', () => this.removeWorker(worker))
+
     this.workers.push(worker)
-    this.afterNewWorkerPushed(worker)
-    // init tasks map
+
+    // Init tasks map
     this.tasks.set(worker, 0)
+
+    this.afterWorkerSetup(worker)
+
     return worker
   }
 }