feat: add less busy worker choice strategy
[poolifier.git] / src / pools / abstract-pool.ts
index 1b10e03c01ed8d0ce2a82b94cdd327ebca8c25df..947db17c8480ea97de0591c280042081c0ba4935 100644 (file)
@@ -1,64 +1,59 @@
+import crypto from 'node:crypto'
 import type {
   MessageValue,
   PromiseWorkerResponseWrapper
 } from '../utility-types'
 import { EMPTY_FUNCTION } from '../utils'
-import { isKillBehavior, KillBehaviors } from '../worker/worker-options'
+import { KillBehaviors, isKillBehavior } from '../worker/worker-options'
 import type { PoolOptions } from './pool'
 import { PoolEmitter } from './pool'
-import type { IPoolInternal, TasksUsage } from './pool-internal'
+import type { IPoolInternal, TasksUsage, WorkerType } from './pool-internal'
 import { PoolType } from './pool-internal'
 import type { IPoolWorker } from './pool-worker'
 import {
   WorkerChoiceStrategies,
-  WorkerChoiceStrategy
+  type WorkerChoiceStrategy
 } from './selection-strategies/selection-strategies-types'
 import { WorkerChoiceStrategyContext } from './selection-strategies/worker-choice-strategy-context'
 
 /**
  * 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. This can only be serializable data.
- * @template Response Type of response of execution. This can only be serializable data.
+ * @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 IPoolWorker,
   Data = unknown,
   Response = unknown
 > implements IPoolInternal<Worker, Data, Response> {
-  /** @inheritDoc */
-  public readonly workers: Worker[] = []
-
-  /** @inheritDoc */
-  public readonly workersTasksUsage: Map<Worker, TasksUsage> = new Map<
-    Worker,
-    TasksUsage
+  /** {@inheritDoc} */
+  public readonly workers: Map<number, WorkerType<Worker>> = new Map<
+  number,
+  WorkerType<Worker>
   >()
 
-  /** @inheritDoc */
+  /** {@inheritDoc} */
   public readonly emitter?: PoolEmitter
 
-  /** @inheritDoc */
-  public readonly max?: number
+  /**
+   * Id of the next worker.
+   */
+  protected nextWorkerId: number = 0
 
   /**
    * The promise map.
    *
-   * - `key`: This is the message Id of each submitted task.
+   * - `key`: This is the message id of each submitted task.
    * - `value`: An object that contains the worker, the resolve function and the reject function.
    *
    * When we receive a message from the worker we get a map entry and resolve/reject the promise based on the message.
    */
   protected promiseMap: Map<
-    number,
-    PromiseWorkerResponseWrapper<Worker, Response>
-  > = new Map<number, PromiseWorkerResponseWrapper<Worker, Response>>()
-
-  /**
-   * Id of the next message.
-   */
-  protected nextMessageId: number = 0
+  string,
+  PromiseWorkerResponseWrapper<Worker, Response>
+  > = new Map<string, PromiseWorkerResponseWrapper<Worker, Response>>()
 
   /**
    * Worker choice strategy instance implementing the worker choice algorithm.
@@ -66,24 +61,24 @@ export abstract class AbstractPool<
    * Default to a strategy implementing a round robin algorithm.
    */
   protected workerChoiceStrategyContext: WorkerChoiceStrategyContext<
-    Worker,
-    Data,
-    Response
+  Worker,
+  Data,
+  Response
   >
 
   /**
    * 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.
+   * @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 numberOfWorkers: number,
     public readonly filePath: string,
     public readonly opts: PoolOptions<Worker>
   ) {
-    if (this.isMain() === false) {
+    if (!this.isMain()) {
       throw new Error('Cannot start a pool from a worker!')
     }
     this.checkNumberOfWorkers(this.numberOfWorkers)
@@ -105,10 +100,10 @@ export abstract class AbstractPool<
         this.registerWorkerMessageListener(workerCreated, message => {
           if (
             isKillBehavior(KillBehaviors.HARD, message.kill) ||
-            this.getWorkerRunningTasks(workerCreated) === 0
+            this.getWorkerTasksUsage(workerCreated)?.running === 0
           ) {
             // Kill received from the worker, means that no new tasks are submitted to that worker for a while ( > maxInactiveTime)
-            this.destroyWorker(workerCreated) as void
+            void this.destroyWorker(workerCreated)
           }
         })
         return workerCreated
@@ -118,7 +113,10 @@ export abstract class AbstractPool<
   }
 
   private checkFilePath (filePath: string): void {
-    if (!filePath) {
+    if (
+      filePath == null ||
+      (typeof filePath === 'string' && filePath.trim().length === 0)
+    ) {
       throw new Error('Please specify a file with a worker implementation')
     }
   }
@@ -128,12 +126,12 @@ export abstract class AbstractPool<
       throw new Error(
         'Cannot instantiate a pool without specifying the number of workers'
       )
-    } else if (Number.isSafeInteger(numberOfWorkers) === false) {
-      throw new Error(
+    } 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 Error(
+      throw new RangeError(
         'Cannot instantiate a pool with a negative number of workers'
       )
     } else if (this.type === PoolType.FIXED && numberOfWorkers === 0) {
@@ -147,43 +145,43 @@ export abstract class AbstractPool<
     this.opts.enableEvents = opts.enableEvents ?? true
   }
 
-  /** @inheritDoc */
+  /** {@inheritDoc} */
   public abstract get type (): PoolType
 
-  /** @inheritDoc */
+  /** {@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
+  /**
+   * Gets the given worker key.
+   *
+   * @param worker - The worker.
+   * @returns The worker key.
+   */
+  private getWorkerKey (worker: Worker): number | undefined {
+    return [...this.workers].find(([, value]) => value.worker === worker)?.[0]
   }
 
-  /** @inheritDoc */
+  /** {@inheritDoc} */
   public setWorkerChoiceStrategy (
     workerChoiceStrategy: WorkerChoiceStrategy
   ): void {
     this.opts.workerChoiceStrategy = workerChoiceStrategy
-    for (const worker of this.workers) {
-      this.resetWorkerTasksUsage(worker)
+    for (const [key, value] of this.workers) {
+      this.setWorker(key, value.worker, {
+        run: 0,
+        running: 0,
+        runTime: 0,
+        avgRunTime: 0
+      })
     }
     this.workerChoiceStrategyContext.setWorkerChoiceStrategy(
       workerChoiceStrategy
     )
   }
 
-  /** @inheritDoc */
+  /** {@inheritDoc} */
   public abstract get busy (): boolean
 
   protected internalGetBusyStatus (): boolean {
@@ -193,40 +191,45 @@ export abstract class AbstractPool<
     )
   }
 
-  /** @inheritDoc */
+  /** {@inheritDoc} */
   public findFreeWorker (): Worker | false {
-    for (const worker of this.workers) {
-      if (this.getWorkerRunningTasks(worker) === 0) {
+    for (const value of this.workers.values()) {
+      if (value.tasksUsage.running === 0) {
         // A worker is free, return the matching worker
-        return worker
+        return value.worker
       }
     }
     return false
   }
 
-  /** @inheritDoc */
-  public execute (data: Data): Promise<Response> {
-    // Configure worker to handle message with the specified task
+  /** {@inheritDoc} */
+  public async execute (data: Data): Promise<Response> {
     const worker = this.chooseWorker()
-    const res = this.internalExecute(worker, this.nextMessageId)
+    const messageId = crypto.randomUUID()
+    const res = this.internalExecute(worker, messageId)
     this.checkAndEmitBusy()
     this.sendToWorker(worker, {
+      // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
       data: data ?? ({} as Data),
-      id: this.nextMessageId
+      id: messageId
     })
-    ++this.nextMessageId
+    // eslint-disable-next-line @typescript-eslint/return-await
     return res
   }
 
-  /** @inheritDoc */
+  /** {@inheritDoc} */
   public async destroy (): Promise<void> {
-    await Promise.all(this.workers.map(worker => this.destroyWorker(worker)))
+    await Promise.all(
+      [...this.workers].map(async ([, value]) => {
+        await this.destroyWorker(value.worker)
+      })
+    )
   }
 
   /**
    * Shutdowns given worker.
    *
-   * @param worker A worker within `workers`.
+   * @param worker A worker within `workers`.
    */
   protected abstract destroyWorker (worker: Worker): void | Promise<void>
 
@@ -247,37 +250,48 @@ export abstract class AbstractPool<
    * Hook executed before the worker task promise resolution.
    * Can be overridden.
    *
-   * @param worker The worker.
+   * @param worker The worker.
    */
   protected beforePromiseWorkerResponseHook (worker: Worker): void {
-    this.increaseWorkerRunningTasks(worker)
+    ++(this.getWorkerTasksUsage(worker) as TasksUsage).running
   }
 
   /**
    * Hook executed after the worker task promise resolution.
    * Can be overridden.
    *
-   * @param message The received message.
-   * @param promise The Promise response.
+   * @param message The received message.
+   * @param promise The Promise response.
    */
   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)
+    const workerTasksUsage = this.getWorkerTasksUsage(
+      promise.worker
+    ) as TasksUsage
+    --workerTasksUsage.running
+    ++workerTasksUsage.run
+    if (
+      this.workerChoiceStrategyContext.getWorkerChoiceStrategy()
+        .requiredStatistics.runTime
+    ) {
+      workerTasksUsage.runTime += message.taskRunTime ?? 0
+      if (workerTasksUsage.run !== 0) {
+        workerTasksUsage.avgRunTime =
+          workerTasksUsage.runTime / workerTasksUsage.run
+      }
+    }
   }
 
   /**
    * Removes the given worker from the pool.
    *
-   * @param worker The worker that will be removed.
+   * @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)
+    this.workers.delete(this.getWorkerKey(worker) as number)
+    --this.nextWorkerId
   }
 
   /**
@@ -294,8 +308,8 @@ export abstract class AbstractPool<
   /**
    * Sends a message to the given worker.
    *
-   * @param worker The worker which should receive the message.
-   * @param message The message.
+   * @param worker The worker which should receive the message.
+   * @param message The message.
    */
   protected abstract sendToWorker (
     worker: Worker,
@@ -305,22 +319,12 @@ export abstract class AbstractPool<
   /**
    * Registers a listener callback on a given worker.
    *
-   * @param worker The worker which should register a listener.
-   * @param listener The message listener callback.
+   * @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
-
-  protected internalExecute (
-    worker: Worker,
-    messageId: number
-  ): Promise<Response> {
-    this.beforePromiseWorkerResponseHook(worker)
-    return new Promise<Response>((resolve, reject) => {
-      this.promiseMap.set(messageId, { resolve, reject, worker })
-    })
-  }
+  >(worker: Worker, listener: (message: MessageValue<Message>) => void): void
 
   /**
    * Returns a newly created worker.
@@ -330,9 +334,9 @@ export abstract class AbstractPool<
   /**
    * 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.
+   * 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.
+   * @param worker The newly created worker.
    */
   protected abstract afterWorkerSetup (worker: Worker): void
 
@@ -348,12 +352,17 @@ export abstract class AbstractPool<
     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)
+    worker.once('exit', () => {
+      this.removeWorker(worker)
+    })
 
-    // Init worker tasks usage map
-    this.initWorkerTasksUsage(worker)
+    this.setWorker(this.nextWorkerId, worker, {
+      run: 0,
+      running: 0,
+      runTime: 0,
+      avgRunTime: 0
+    })
+    ++this.nextWorkerId
 
     this.afterWorkerSetup(worker)
 
@@ -370,7 +379,7 @@ export abstract class AbstractPool<
       if (message.id !== undefined) {
         const promise = this.promiseMap.get(message.id)
         if (promise !== undefined) {
-          if (message.error) {
+          if (message.error != null) {
             promise.reject(message.error)
           } else {
             promise.resolve(message.data as Response)
@@ -382,126 +391,46 @@ export abstract class AbstractPool<
     }
   }
 
-  private checkAndEmitBusy (): void {
-    if (this.opts.enableEvents === true && this.busy === true) {
-      this.emitter?.emit('busy')
-    }
-  }
-
-  /**
-   * Increases the number of tasks that the given worker has applied.
-   *
-   * @param worker Worker which running tasks is increased.
-   */
-  private increaseWorkerRunningTasks (worker: Worker): void {
-    this.stepWorkerRunningTasks(worker, 1)
-  }
-
-  /**
-   * 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)
+  private async internalExecute (
+    worker: Worker,
+    messageId: string
+  ): Promise<Response> {
+    this.beforePromiseWorkerResponseHook(worker)
+    return await new Promise<Response>((resolve, reject) => {
+      this.promiseMap.set(messageId, { resolve, reject, worker })
+    })
   }
 
-  /**
-   * 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) === true) {
-      const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
-      tasksUsage.running = tasksUsage.running + step
-      this.workersTasksUsage.set(worker, tasksUsage)
+  private checkAndEmitBusy (): void {
+    if (this.opts.enableEvents === true && this.busy) {
+      this.emitter?.emit('busy')
     }
   }
 
-  /**
-   * 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) === true) {
-      const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
-      tasksUsage.run = tasksUsage.run + step
-      this.workersTasksUsage.set(worker, tasksUsage)
+  /** {@inheritDoc} */
+  public getWorkerTasksUsage (worker: Worker): TasksUsage | undefined {
+    const workerKey = this.getWorkerKey(worker)
+    if (workerKey !== undefined) {
+      return (this.workers.get(workerKey) as WorkerType<Worker>).tasksUsage
     }
+    throw new Error('Worker could not be found in the pool')
   }
 
   /**
-   * Updates tasks runtime for the given worker.
+   * Sets the given worker.
    *
-   * @param worker Worker which run the task.
-   * @param taskRunTime Worker task runtime.
+   * @param workerKey - The worker key.
+   * @param worker - The worker.
+   * @param tasksUsage - The worker tasks usage.
    */
-  private updateWorkerTasksRunTime (
+  private setWorker (
+    workerKey: number,
     worker: Worker,
-    taskRunTime: number | undefined
+    tasksUsage: TasksUsage
   ): void {
-    if (
-      this.workerChoiceStrategyContext.getWorkerChoiceStrategy()
-        .requiredStatistics.runTime === true &&
-      this.checkWorkerTasksUsage(worker) === true
-    ) {
-      const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
-      tasksUsage.runTime += taskRunTime ?? 0
-      if (tasksUsage.run !== 0) {
-        tasksUsage.avgRunTime = tasksUsage.runTime / tasksUsage.run
-      }
-      this.workersTasksUsage.set(worker, tasksUsage)
-    }
-  }
-
-  /**
-   * Checks if the given worker is registered in the workers tasks usage map.
-   *
-   * @param worker Worker to check.
-   * @returns `true` if the worker is registered in the workers tasks usage map. `false` otherwise.
-   */
-  private checkWorkerTasksUsage (worker: Worker): boolean {
-    const hasTasksUsage = this.workersTasksUsage.has(worker)
-    if (hasTasksUsage === false) {
-      throw new Error('Worker could not be found in workers tasks usage map')
-    }
-    return hasTasksUsage
-  }
-
-  /**
-   * Initializes tasks usage statistics.
-   *
-   * @param worker The worker.
-   */
-  initWorkerTasksUsage (worker: Worker): void {
-    this.workersTasksUsage.set(worker, {
-      run: 0,
-      running: 0,
-      runTime: 0,
-      avgRunTime: 0
+    this.workers.set(workerKey, {
+      worker,
+      tasksUsage
     })
   }
-
-  /**
-   * Removes worker tasks usage statistics.
-   *
-   * @param worker The worker.
-   */
-  private removeWorkerTasksUsage (worker: Worker): void {
-    this.workersTasksUsage.delete(worker)
-  }
-
-  /**
-   * Resets worker tasks usage statistics.
-   *
-   * @param worker The worker.
-   */
-  private resetWorkerTasksUsage (worker: Worker): void {
-    this.removeWorkerTasksUsage(worker)
-    this.initWorkerTasksUsage(worker)
-  }
 }