X-Git-Url: https://git.piment-noir.org/?a=blobdiff_plain;ds=sidebyside;f=src%2Fpools%2Fabstract-pool.ts;h=122e9fa5c9dbbad12f7eaf01b1db4f0b38ab35e4;hb=a9d9ea34ae4621d0babc235b10614c7c8c37d88b;hp=0763f04f9c21869e46b20414f4c998a03ad76bce;hpb=729c563db85562dd7d0f7733b1a3e2d98467134b;p=poolifier.git

diff --git a/src/pools/abstract-pool.ts b/src/pools/abstract-pool.ts
index 0763f04f..122e9fa5 100644
--- a/src/pools/abstract-pool.ts
+++ b/src/pools/abstract-pool.ts
@@ -1,136 +1,240 @@
-import EventEmitter from 'events'
-import type { MessageValue } from '../utility-types'
-import type { IPool } from './pool'
+import type {
+  MessageValue,
+  PromiseWorkerResponseWrapper
+} from '../utility-types'
+import { EMPTY_FUNCTION } from '../utils'
+import { KillBehaviors, isKillBehavior } from '../worker/worker-options'
+import type { PoolOptions } from './pool'
+import { PoolEmitter } from './pool'
+import type { IPoolInternal, TasksUsage } from './pool-internal'
+import { PoolType } from './pool-internal'
+import type { IPoolWorker } from './pool-worker'
+import {
+  WorkerChoiceStrategies,
+  type WorkerChoiceStrategy
+} from './selection-strategies/selection-strategies-types'
+import { WorkerChoiceStrategyContext } from './selection-strategies/worker-choice-strategy-context'
 
 /**
- * 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
-}
-
-/**
- * Options for a poolifier pool.
- */
-export interface PoolOptions<Worker> {
-  /**
-   * A function that will listen for error event on each worker.
-   */
-  errorHandler?: ErrorHandler<Worker>
-  /**
-   * A function that will listen for online event on each worker.
-   */
-  onlineHandler?: OnlineHandler<Worker>
-  /**
-   * A function that will listen for exit event on each worker.
-   */
-  exitHandler?: ExitHandler<Worker>
-  /**
-   * 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.
+ * Base class that implements 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.
+ * @typeParam Worker - Type of worker which manages this pool.
+ * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
+ * @typeParam Response - Type of response of execution. This can only be serializable data.
  */
 export abstract class AbstractPool<
-  Worker extends IWorker,
+  Worker extends IPoolWorker,
   Data = unknown,
   Response = unknown
-> implements IPool<Data, Response> {
-  /**
-   * List of currently available workers.
-   */
+> implements IPoolInternal<Worker, Data, Response> {
+  /** {@inheritDoc} */
   public readonly workers: Worker[] = []
 
-  /**
-   * ID for the next worker.
-   */
-  public nextWorker: number = 0
+  /** {@inheritDoc} */
+  public readonly workersTasksUsage: Map<Worker, TasksUsage> = new Map<
+  Worker,
+  TasksUsage
+  >()
 
-  /**
-   * - `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>()
+  /** {@inheritDoc} */
+  public readonly emitter?: PoolEmitter
 
   /**
-   * Emitter on which events can be listened to.
+   * The promise map.
    *
-   * Events that can currently be listened to:
+   * - `key`: This is the message Id of each submitted task.
+   * - `value`: An object that contains the worker, the resolve function and the reject function.
    *
-   * - `'FullPool'`
+   * When we receive a message from the worker we get a map entry and resolve/reject the promise based on the message.
    */
-  public readonly emitter: PoolEmitter
+  protected promiseMap: Map<
+  number,
+  PromiseWorkerResponseWrapper<Worker, Response>
+  > = new Map<number, PromiseWorkerResponseWrapper<Worker, Response>>()
 
   /**
-   * ID of the next message.
+   * Id of the next message.
    */
-  protected id: number = 0
+  protected nextMessageId: number = 0
+
+  /**
+   * Worker choice strategy instance implementing the worker choice algorithm.
+   *
+   * Default to a strategy implementing a round robin algorithm.
+   */
+  protected workerChoiceStrategyContext: WorkerChoiceStrategyContext<
+  Worker,
+  Data,
+  Response
+  >
 
   /**
    * Constructs a new poolifier pool.
    *
-   * @param numWorkers Number of workers that this pool should manage.
-   * @param filePath Path to the worker-file.
-   * @param opts Options for the pool. Default: `{ maxTasks: 1000 }`
+   * @param numberOfWorkers - Number of workers that this pool should manage.
+   * @param filePath - Path to the worker-file.
+   * @param opts - Options for the pool.
    */
   public constructor (
-    public readonly numWorkers: number,
+    public readonly numberOfWorkers: number,
     public readonly filePath: string,
-    public readonly opts: PoolOptions<Worker> = { maxTasks: 1000 }
+    public readonly opts: PoolOptions<Worker>
   ) {
     if (!this.isMain()) {
       throw new Error('Cannot start a pool from a worker!')
     }
-    // TODO christopher 2021-02-07: Improve this check e.g. with a pattern or blank check
-    if (!this.filePath) {
+    this.checkNumberOfWorkers(this.numberOfWorkers)
+    this.checkFilePath(this.filePath)
+    this.checkPoolOptions(this.opts)
+    this.setupHook()
+
+    for (let i = 1; i <= this.numberOfWorkers; i++) {
+      this.createAndSetupWorker()
+    }
+
+    if (this.opts.enableEvents === true) {
+      this.emitter = new PoolEmitter()
+    }
+    this.workerChoiceStrategyContext = new WorkerChoiceStrategyContext(
+      this,
+      () => {
+        const workerCreated = this.createAndSetupWorker()
+        this.registerWorkerMessageListener(workerCreated, message => {
+          if (
+            isKillBehavior(KillBehaviors.HARD, message.kill) ||
+            this.getWorkerRunningTasks(workerCreated) === 0
+          ) {
+            // Kill received from the worker, means that no new tasks are submitted to that worker for a while ( > maxInactiveTime)
+            void this.destroyWorker(workerCreated)
+          }
+        })
+        return workerCreated
+      },
+      this.opts.workerChoiceStrategy
+    )
+  }
+
+  private checkFilePath (filePath: string): void {
+    if (filePath == null || filePath.length === 0) {
       throw new Error('Please specify a file with a worker implementation')
     }
+  }
 
-    this.setupHook()
+  private checkNumberOfWorkers (numberOfWorkers: number): void {
+    if (numberOfWorkers == null) {
+      throw new Error(
+        'Cannot instantiate a pool without specifying the number of workers'
+      )
+    } else if (!Number.isSafeInteger(numberOfWorkers)) {
+      throw new TypeError(
+        'Cannot instantiate a pool with a non integer number of workers'
+      )
+    } else if (numberOfWorkers < 0) {
+      throw new RangeError(
+        'Cannot instantiate a pool with a negative number of workers'
+      )
+    } else if (this.type === PoolType.FIXED && numberOfWorkers === 0) {
+      throw new Error('Cannot instantiate a fixed pool with no worker')
+    }
+  }
+
+  private checkPoolOptions (opts: PoolOptions<Worker>): void {
+    this.opts.workerChoiceStrategy =
+      opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN
+    this.opts.enableEvents = opts.enableEvents ?? true
+  }
+
+  /** {@inheritDoc} */
+  public abstract get type (): PoolType
+
+  /** {@inheritDoc} */
+  public get numberOfRunningTasks (): number {
+    return this.promiseMap.size
+  }
+
+  /** {@inheritDoc} */
+  public getWorkerIndex (worker: Worker): number {
+    return this.workers.indexOf(worker)
+  }
+
+  /** {@inheritDoc} */
+  public getWorkerRunningTasks (worker: Worker): number | undefined {
+    return this.workersTasksUsage.get(worker)?.running
+  }
+
+  /** {@inheritDoc} */
+  public getWorkerAverageTasksRunTime (worker: Worker): number | undefined {
+    return this.workersTasksUsage.get(worker)?.avgRunTime
+  }
 
-    for (let i = 1; i <= this.numWorkers; i++) {
-      this.internalNewWorker()
+  /** {@inheritDoc} */
+  public setWorkerChoiceStrategy (
+    workerChoiceStrategy: WorkerChoiceStrategy
+  ): void {
+    this.opts.workerChoiceStrategy = workerChoiceStrategy
+    for (const worker of this.workers) {
+      this.resetWorkerTasksUsage(worker)
     }
+    this.workerChoiceStrategyContext.setWorkerChoiceStrategy(
+      workerChoiceStrategy
+    )
+  }
+
+  /** {@inheritDoc} */
+  public abstract get busy (): boolean
 
-    this.emitter = new PoolEmitter()
+  protected internalGetBusyStatus (): boolean {
+    return (
+      this.numberOfRunningTasks >= this.numberOfWorkers &&
+      this.findFreeWorker() === false
+    )
+  }
+
+  /** {@inheritDoc} */
+  public findFreeWorker (): Worker | false {
+    for (const worker of this.workers) {
+      if (this.getWorkerRunningTasks(worker) === 0) {
+        // A worker is free, return the matching worker
+        return worker
+      }
+    }
+    return false
+  }
+
+  /** {@inheritDoc} */
+  public async execute (data: Data): Promise<Response> {
+    // Configure worker to handle message with the specified task
+    const worker = this.chooseWorker()
+    const res = this.internalExecute(worker, this.nextMessageId)
+    this.checkAndEmitBusy()
+    this.sendToWorker(worker, {
+      // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
+      data: data ?? ({} as Data),
+      id: this.nextMessageId
+    })
+    ++this.nextMessageId
+    // eslint-disable-next-line @typescript-eslint/return-await
+    return res
+  }
+
+  /** {@inheritDoc} */
+  public async destroy (): Promise<void> {
+    await Promise.all(
+      this.workers.map(async worker => {
+        await this.destroyWorker(worker)
+      })
+    )
   }
 
   /**
-   * Setup hook that can be overridden by a Poolifer pool implementation
+   * Shutdowns given worker.
+   *
+   * @param worker - A worker within `workers`.
+   */
+  protected abstract destroyWorker (worker: Worker): void | Promise<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 {
@@ -142,24 +246,59 @@ export abstract class AbstractPool<
    */
   protected abstract isMain (): boolean
 
-  public async destroy (): Promise<void> {
-    for (const worker of this.workers) {
-      await this.destroyWorker(worker)
-    }
+  /**
+   * Hook executed before the worker task promise resolution.
+   * Can be overridden.
+   *
+   * @param worker - The worker.
+   */
+  protected beforePromiseWorkerResponseHook (worker: Worker): void {
+    this.increaseWorkerRunningTasks(worker)
   }
 
   /**
-   * Shut down given worker.
+   * Hook executed after the worker task promise resolution.
+   * Can be overridden.
    *
-   * @param worker A worker within `workers`.
+   * @param message - The received message.
+   * @param promise - The Promise response.
    */
-  protected abstract destroyWorker (worker: Worker): void | Promise<void>
+  protected afterPromiseWorkerResponseHook (
+    message: MessageValue<Response>,
+    promise: PromiseWorkerResponseWrapper<Worker, Response>
+  ): void {
+    this.decreaseWorkerRunningTasks(promise.worker)
+    this.stepWorkerRunTasks(promise.worker, 1)
+    this.updateWorkerTasksRunTime(promise.worker, message.taskRunTime)
+  }
 
   /**
-   * Send a message to the given worker.
+   * Removes the given worker from the pool.
    *
-   * @param worker The worker which should receive the message.
-   * @param message The message.
+   * @param worker - The worker that will be removed.
+   */
+  protected removeWorker (worker: Worker): void {
+    // Clean worker from data structure
+    this.workers.splice(this.getWorkerIndex(worker), 1)
+    this.removeWorkerTasksUsage(worker)
+  }
+
+  /**
+   * Chooses a worker for the next task.
+   *
+   * The default implementation uses a round robin algorithm to distribute the load.
+   *
+   * @returns Worker.
+   */
+  protected chooseWorker (): Worker {
+    return this.workerChoiceStrategyContext.execute()
+  }
+
+  /**
+   * Sends a message to the given worker.
+   *
+   * @param worker - The worker which should receive the message.
+   * @param message - The message.
    */
   protected abstract sendToWorker (
     worker: Worker,
@@ -167,103 +306,207 @@ export abstract class AbstractPool<
   ): void
 
   /**
-   * Adds the given worker to the pool.
+   * Registers a listener callback on a given worker.
+   *
+   * @param worker - The worker which should register a listener.
+   * @param listener - The message listener callback.
+   */
+  protected abstract registerWorkerMessageListener<
+    Message extends Data | Response
+  >(worker: Worker, listener: (message: MessageValue<Message>) => void): void
+
+  /**
+   * Returns a newly created worker.
+   */
+  protected abstract createWorker (): 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 Worker that will be added.
+   * @param worker - The newly created worker.
    */
-  protected addWorker (worker: Worker): void {
-    const previousWorkerIndex = this.tasks.get(worker)
-    if (previousWorkerIndex !== undefined) {
-      this.tasks.set(worker, previousWorkerIndex + 1)
-    } else {
-      throw Error('Worker could not be found in tasks map')
+  protected abstract afterWorkerSetup (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 = this.createWorker()
+
+    worker.on('message', this.opts.messageHandler ?? EMPTY_FUNCTION)
+    worker.on('error', this.opts.errorHandler ?? EMPTY_FUNCTION)
+    worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION)
+    worker.on('exit', this.opts.exitHandler ?? EMPTY_FUNCTION)
+    worker.once('exit', () => {
+      this.removeWorker(worker)
+    })
+
+    this.workers.push(worker)
+
+    // Init worker tasks usage map
+    this.initWorkerTasksUsage(worker)
+
+    this.afterWorkerSetup(worker)
+
+    return worker
+  }
+
+  /**
+   * This function is the listener registered for each worker.
+   *
+   * @returns The listener function to execute when a message is received from a worker.
+   */
+  protected workerListener (): (message: MessageValue<Response>) => void {
+    return message => {
+      if (message.id !== undefined) {
+        const promise = this.promiseMap.get(message.id)
+        if (promise !== undefined) {
+          if (message.error != null) {
+            promise.reject(message.error)
+          } else {
+            promise.resolve(message.data as Response)
+          }
+          this.afterPromiseWorkerResponseHook(message, promise)
+          this.promiseMap.delete(message.id)
+        }
+      }
+    }
+  }
+
+  private async internalExecute (
+    worker: Worker,
+    messageId: number
+  ): Promise<Response> {
+    this.beforePromiseWorkerResponseHook(worker)
+    return await new Promise<Response>((resolve, reject) => {
+      this.promiseMap.set(messageId, { resolve, reject, worker })
+    })
+  }
+
+  private checkAndEmitBusy (): void {
+    if (this.opts.enableEvents === true && this.busy) {
+      this.emitter?.emit('busy')
     }
   }
 
   /**
-   * Removes the given worker from the pool.
+   * Increases the number of tasks that the given worker has applied.
    *
-   * @param worker Worker that will be removed.
+   * @param worker - Worker which running tasks is increased.
    */
-  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)
+  private increaseWorkerRunningTasks (worker: Worker): void {
+    this.stepWorkerRunningTasks(worker, 1)
   }
 
-  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
+  /**
+   * Decreases the number of tasks that the given worker has applied.
+   *
+   * @param worker - Worker which running tasks is decreased.
+   */
+  private decreaseWorkerRunningTasks (worker: Worker): void {
+    this.stepWorkerRunningTasks(worker, -1)
   }
 
-  protected abstract registerWorkerMessageListener (
-    port: Worker,
-    listener: (message: MessageValue<Response>) => void
-  ): void
+  /**
+   * Steps the number of tasks that the given worker has applied.
+   *
+   * @param worker - Worker which running tasks are stepped.
+   * @param step - Number of running tasks step.
+   */
+  private stepWorkerRunningTasks (worker: Worker, step: number): void {
+    if (this.checkWorkerTasksUsage(worker)) {
+      const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
+      tasksUsage.running = tasksUsage.running + step
+      this.workersTasksUsage.set(worker, tasksUsage)
+    }
+  }
 
-  protected abstract unregisterWorkerMessageListener (
-    port: Worker,
-    listener: (message: MessageValue<Response>) => void
-  ): void
+  /**
+   * Steps the number of tasks that the given worker has run.
+   *
+   * @param worker - Worker which has run tasks.
+   * @param step - Number of run tasks step.
+   */
+  private stepWorkerRunTasks (worker: Worker, step: number): void {
+    if (this.checkWorkerTasksUsage(worker)) {
+      const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
+      tasksUsage.run = tasksUsage.run + step
+      this.workersTasksUsage.set(worker, tasksUsage)
+    }
+  }
 
-  protected internalExecute (worker: Worker, id: number): Promise<Response> {
-    return new Promise((resolve, reject) => {
-      const listener: (message: MessageValue<Response>) => void = message => {
-        if (message.id === id) {
-          this.unregisterWorkerMessageListener(worker, listener)
-          this.addWorker(worker)
-          if (message.error) reject(message.error)
-          else resolve(message.data as Response)
-        }
+  /**
+   * Updates tasks runtime for the given worker.
+   *
+   * @param worker - Worker which run the task.
+   * @param taskRunTime - Worker task runtime.
+   */
+  private updateWorkerTasksRunTime (
+    worker: Worker,
+    taskRunTime: number | undefined
+  ): void {
+    if (
+      this.workerChoiceStrategyContext.getWorkerChoiceStrategy()
+        .requiredStatistics.runTime &&
+      this.checkWorkerTasksUsage(worker)
+    ) {
+      const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
+      tasksUsage.runTime += taskRunTime ?? 0
+      if (tasksUsage.run !== 0) {
+        tasksUsage.avgRunTime = tasksUsage.runTime / tasksUsage.run
       }
-      this.registerWorkerMessageListener(worker, listener)
-    })
+      this.workersTasksUsage.set(worker, tasksUsage)
+    }
   }
 
   /**
-   * Choose a worker for the next task.
+   * Checks if the given worker is registered in the workers tasks usage map.
    *
-   * The default implementation uses a round robin algorithm to distribute the load.
+   * @param worker - Worker to check.
+   * @returns `true` if the worker is registered in the workers tasks usage map. `false` otherwise.
    */
-  protected chooseWorker (): Worker {
-    this.nextWorker =
-      this.nextWorker === this.workers.length - 1 ? 0 : this.nextWorker + 1
-    return this.workers[this.nextWorker]
+  private checkWorkerTasksUsage (worker: Worker): boolean {
+    const hasTasksUsage = this.workersTasksUsage.has(worker)
+    if (!hasTasksUsage) {
+      throw new Error('Worker could not be found in workers tasks usage map')
+    }
+    return hasTasksUsage
   }
 
   /**
-   * Returns a newly created worker.
+   * Initializes tasks usage statistics.
+   *
+   * @param worker - The worker.
    */
-  protected abstract newWorker (): Worker
+  private initWorkerTasksUsage (worker: Worker): void {
+    this.workersTasksUsage.set(worker, {
+      run: 0,
+      running: 0,
+      runTime: 0,
+      avgRunTime: 0
+    })
+  }
 
   /**
-   * 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.
+   * Removes worker tasks usage statistics.
    *
-   * @param worker The newly created worker.
+   * @param worker - The worker.
    */
-  protected abstract afterNewWorkerPushed (worker: Worker): void
+  private removeWorkerTasksUsage (worker: Worker): void {
+    this.workersTasksUsage.delete(worker)
+  }
 
   /**
-   * Creates a new worker for this pool and sets it up completely.
+   * Resets worker tasks usage statistics.
+   *
+   * @param worker - The worker.
    */
-  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 ?? (() => {}))
-    this.workers.push(worker)
-    this.afterNewWorkerPushed(worker)
-    // init tasks map
-    this.tasks.set(worker, 0)
-    return worker
+  private resetWorkerTasksUsage (worker: Worker): void {
+    this.removeWorkerTasksUsage(worker)
+    this.initWorkerTasksUsage(worker)
   }
 }