X-Git-Url: https://git.piment-noir.org/?a=blobdiff_plain;f=src%2Fpools%2Fabstract-pool.ts;h=fd8628100fe560b11c1b48765c0102d9bdb806e5;hb=301b5d97a2c9bcd278819b4f81c42c949da66d63;hp=3cb6c1f7a7b034086e6e20a56635c44f1d8af0f2;hpb=ed6dd37f9e137cf659523d9d792f0171eedcb8ed;p=poolifier.git

diff --git a/src/pools/abstract-pool.ts b/src/pools/abstract-pool.ts
index 3cb6c1f7..fd862810 100644
--- a/src/pools/abstract-pool.ts
+++ b/src/pools/abstract-pool.ts
@@ -1,19 +1,18 @@
-import type {
-  MessageValue,
-  PromiseWorkerResponseWrapper
-} from '../utility-types'
-import { EMPTY_FUNCTION } from '../utils'
+import crypto from 'node:crypto'
+import type { MessageValue, PromiseResponseWrapper } from '../utility-types'
+import { EMPTY_FUNCTION, median } from '../utils'
 import { KillBehaviors, isKillBehavior } from '../worker/worker-options'
-import type { PoolOptions } from './pool'
+import { PoolEvents, type PoolOptions } from './pool'
 import { PoolEmitter } from './pool'
-import type { IPoolInternal, TasksUsage } from './pool-internal'
+import type { IPoolInternal } from './pool-internal'
 import { PoolType } from './pool-internal'
-import type { IPoolWorker } from './pool-worker'
+import type { IWorker, Task, TasksUsage, WorkerNode } from './worker'
 import {
   WorkerChoiceStrategies,
   type WorkerChoiceStrategy
 } from './selection-strategies/selection-strategies-types'
 import { WorkerChoiceStrategyContext } from './selection-strategies/worker-choice-strategy-context'
+import { CircularArray } from '../circular-array'
 
 /**
  * Base class that implements some shared logic for all poolifier pools.
@@ -23,44 +22,33 @@ import { WorkerChoiceStrategyContext } from './selection-strategies/worker-choic
  * @typeParam Response - Type of response of execution. This can only be serializable data.
  */
 export abstract class AbstractPool<
-  Worker extends IPoolWorker,
+  Worker extends IWorker,
   Data = unknown,
   Response = unknown
 > implements IPoolInternal<Worker, Data, Response> {
-  /** {@inheritDoc} */
-  public readonly workers: Worker[] = []
+  /** @inheritDoc */
+  public readonly workerNodes: Array<WorkerNode<Worker, Data>> = []
 
-  /** {@inheritDoc} */
-  public readonly workersTasksUsage: Map<Worker, TasksUsage> = new Map<
-  Worker,
-  TasksUsage
-  >()
-
-  /** {@inheritDoc} */
+  /** @inheritDoc */
   public readonly emitter?: PoolEmitter
 
   /**
-   * The promise map.
+   * The promise response map.
    *
-   * - `key`: This is the message Id of each submitted task.
-   * - `value`: An object that contains the worker, the resolve function and the reject function.
+   * - `key`: The message id of each submitted task.
+   * - `value`: An object that contains the worker, the promise resolve and reject callbacks.
    *
-   * 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.
+   * When we receive a message from the worker we get a map entry with the promise resolve/reject bound to the message.
    */
-  protected nextMessageId: number = 0
+  protected promiseResponseMap: Map<
+  string,
+  PromiseResponseWrapper<Worker, Response>
+  > = new Map<string, PromiseResponseWrapper<Worker, Response>>()
 
   /**
-   * Worker choice strategy instance implementing the worker choice algorithm.
+   * Worker choice strategy context referencing a worker choice algorithm implementation.
    *
-   * Default to a strategy implementing a round robin algorithm.
+   * Default to a round robin algorithm.
    */
   protected workerChoiceStrategyContext: WorkerChoiceStrategyContext<
   Worker,
@@ -86,6 +74,13 @@ export abstract class AbstractPool<
     this.checkNumberOfWorkers(this.numberOfWorkers)
     this.checkFilePath(this.filePath)
     this.checkPoolOptions(this.opts)
+
+    this.chooseWorkerNode.bind(this)
+    this.internalExecute.bind(this)
+    this.checkAndEmitFull.bind(this)
+    this.checkAndEmitBusy.bind(this)
+    this.sendToWorker.bind(this)
+
     this.setupHook()
 
     for (let i = 1; i <= this.numberOfWorkers; i++) {
@@ -95,27 +90,18 @@ export abstract class AbstractPool<
     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) as Promise<void>)
-          }
-        })
-        return workerCreated
-      },
-      this.opts.workerChoiceStrategy
-    )
+    this.workerChoiceStrategyContext = new WorkerChoiceStrategyContext<
+    Worker,
+    Data,
+    Response
+    >(this, this.opts.workerChoiceStrategy)
   }
 
   private checkFilePath (filePath: string): void {
-    if (filePath == null || filePath.length === 0) {
+    if (
+      filePath == null ||
+      (typeof filePath === 'string' && filePath.trim().length === 0)
+    ) {
       throw new Error('Please specify a file with a worker implementation')
     }
   }
@@ -141,103 +127,137 @@ export abstract class AbstractPool<
   private checkPoolOptions (opts: PoolOptions<Worker>): void {
     this.opts.workerChoiceStrategy =
       opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN
+    this.checkValidWorkerChoiceStrategy(this.opts.workerChoiceStrategy)
     this.opts.enableEvents = opts.enableEvents ?? true
   }
 
-  /** {@inheritDoc} */
-  public abstract get type (): PoolType
-
-  /** {@inheritDoc} */
-  public get numberOfRunningTasks (): number {
-    return this.promiseMap.size
+  private checkValidWorkerChoiceStrategy (
+    workerChoiceStrategy: WorkerChoiceStrategy
+  ): void {
+    if (!Object.values(WorkerChoiceStrategies).includes(workerChoiceStrategy)) {
+      throw new Error(
+        `Invalid worker choice strategy '${workerChoiceStrategy}'`
+      )
+    }
   }
 
-  /** {@inheritDoc} */
-  public getWorkerIndex (worker: Worker): number {
-    return this.workers.indexOf(worker)
-  }
+  /** @inheritDoc */
+  public abstract get type (): PoolType
 
-  /** {@inheritDoc} */
-  public getWorkerRunningTasks (worker: Worker): number | undefined {
-    return this.workersTasksUsage.get(worker)?.running
+  /**
+   * Number of tasks concurrently running in the pool.
+   */
+  private get numberOfRunningTasks (): number {
+    return this.promiseResponseMap.size
   }
 
-  /** {@inheritDoc} */
-  public getWorkerAverageTasksRunTime (worker: Worker): number | undefined {
-    return this.workersTasksUsage.get(worker)?.avgRunTime
+  /**
+   * Gets the given worker its worker node key.
+   *
+   * @param worker - The worker.
+   * @returns The worker node key if the worker is found in the pool worker nodes, `-1` otherwise.
+   */
+  private getWorkerNodeKey (worker: Worker): number {
+    return this.workerNodes.findIndex(
+      workerNode => workerNode.worker === worker
+    )
   }
 
-  /** {@inheritDoc} */
+  /** @inheritDoc */
   public setWorkerChoiceStrategy (
     workerChoiceStrategy: WorkerChoiceStrategy
   ): void {
+    this.checkValidWorkerChoiceStrategy(workerChoiceStrategy)
     this.opts.workerChoiceStrategy = workerChoiceStrategy
-    for (const worker of this.workers) {
-      this.resetWorkerTasksUsage(worker)
+    for (const [index, workerNode] of this.workerNodes.entries()) {
+      this.setWorkerNode(
+        index,
+        workerNode.worker,
+        {
+          run: 0,
+          running: 0,
+          runTime: 0,
+          runTimeHistory: new CircularArray(),
+          avgRunTime: 0,
+          medRunTime: 0,
+          error: 0
+        },
+        workerNode.tasksQueue
+      )
     }
     this.workerChoiceStrategyContext.setWorkerChoiceStrategy(
       workerChoiceStrategy
     )
   }
 
-  /** {@inheritDoc} */
+  /** @inheritDoc */
+  public abstract get full (): boolean
+
+  /** @inheritDoc */
   public abstract get busy (): boolean
 
-  protected internalGetBusyStatus (): boolean {
+  protected internalBusy (): boolean {
     return (
       this.numberOfRunningTasks >= this.numberOfWorkers &&
-      this.findFreeWorker() === false
+      this.findFreeWorkerNodeKey() === -1
     )
   }
 
-  /** {@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 findFreeWorkerNodeKey (): number {
+    return this.workerNodes.findIndex(workerNode => {
+      return workerNode.tasksUsage?.running === 0
+    })
   }
 
-  /** {@inheritDoc} */
+  /** @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)
+    const [workerNodeKey, workerNode] = this.chooseWorkerNode()
+    const submittedTask: Task<Data> = {
+      // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
+      data: data ?? ({} as Data),
+      id: crypto.randomUUID()
+    }
+    const res = this.internalExecute(workerNodeKey, workerNode, submittedTask)
+    let currentTask: Task<Data>
+    // FIXME: Add sensible conditions to start tasks queuing on the worker node
+    if (this.tasksQueueLength(workerNodeKey) > 0) {
+      currentTask = this.dequeueTask(workerNodeKey) as Task<Data>
+      this.enqueueTask(workerNodeKey, submittedTask)
+    } else {
+      currentTask = submittedTask
+    }
+    this.sendToWorker(workerNode.worker, currentTask)
+    this.checkAndEmitFull()
     this.checkAndEmitBusy()
-    this.sendToWorker(worker, {
-      data,
-      id: this.nextMessageId
-    })
-    ++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(async worker => {
-        await this.destroyWorker(worker)
+      this.workerNodes.map(async workerNode => {
+        await this.destroyWorker(workerNode.worker)
       })
     )
   }
 
   /**
-   * Shutdowns given worker.
+   * Shutdowns the given worker.
    *
-   * @param worker - A worker within `workers`.
+   * @param worker - A worker within `workerNodes`.
    */
   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.
+   * Setup hook to run code before worker node are created in the abstract constructor.
+   * Can be overridden
+   *
+   * @virtual
    */
   protected setupHook (): void {
-    // Can be overridden
+    // Intentionally empty
   }
 
   /**
@@ -249,48 +269,75 @@ export abstract class AbstractPool<
    * Hook executed before the worker task promise resolution.
    * Can be overridden.
    *
-   * @param worker - The worker.
+   * @param workerNodeKey - The worker node key.
    */
-  protected beforePromiseWorkerResponseHook (worker: Worker): void {
-    this.increaseWorkerRunningTasks(worker)
+  protected beforePromiseResponseHook (workerNodeKey: number): void {
+    ++this.workerNodes[workerNodeKey].tasksUsage.running
   }
 
   /**
    * Hook executed after the worker task promise resolution.
    * Can be overridden.
    *
+   * @param worker - The worker.
    * @param message - The received message.
-   * @param promise - The Promise response.
    */
-  protected afterPromiseWorkerResponseHook (
-    message: MessageValue<Response>,
-    promise: PromiseWorkerResponseWrapper<Worker, Response>
+  protected afterPromiseResponseHook (
+    worker: Worker,
+    message: MessageValue<Response>
   ): void {
-    this.decreaseWorkerRunningTasks(promise.worker)
-    this.stepWorkerRunTasks(promise.worker, 1)
-    this.updateWorkerTasksRunTime(promise.worker, message.taskRunTime)
-  }
-
-  /**
-   * Removes the given worker from the pool.
-   *
-   * @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)
+    const workerTasksUsage = this.getWorkerTasksUsage(worker) as TasksUsage
+    --workerTasksUsage.running
+    ++workerTasksUsage.run
+    if (message.error != null) {
+      ++workerTasksUsage.error
+    }
+    if (this.workerChoiceStrategyContext.getRequiredStatistics().runTime) {
+      workerTasksUsage.runTime += message.runTime ?? 0
+      if (
+        this.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime &&
+        workerTasksUsage.run !== 0
+      ) {
+        workerTasksUsage.avgRunTime =
+          workerTasksUsage.runTime / workerTasksUsage.run
+      }
+      if (this.workerChoiceStrategyContext.getRequiredStatistics().medRunTime) {
+        workerTasksUsage.runTimeHistory.push(message.runTime ?? 0)
+        workerTasksUsage.medRunTime = median(workerTasksUsage.runTimeHistory)
+      }
+    }
   }
 
   /**
-   * Chooses a worker for the next task.
+   * Chooses a worker node for the next task.
    *
-   * The default implementation uses a round robin algorithm to distribute the load.
+   * The default uses a round robin algorithm to distribute the load.
    *
-   * @returns Worker.
+   * @returns [worker node key, worker node].
    */
-  protected chooseWorker (): Worker {
-    return this.workerChoiceStrategyContext.execute()
+  protected chooseWorkerNode (): [number, WorkerNode<Worker, Data>] {
+    let workerNodeKey: number
+    if (
+      this.type === PoolType.DYNAMIC &&
+      !this.full &&
+      this.findFreeWorkerNodeKey() === -1
+    ) {
+      const workerCreated = this.createAndSetupWorker()
+      this.registerWorkerMessageListener(workerCreated, message => {
+        if (
+          isKillBehavior(KillBehaviors.HARD, message.kill) ||
+          (message.kill != null &&
+            this.getWorkerTasksUsage(workerCreated)?.running === 0)
+        ) {
+          // Kill message received from the worker, means that no new tasks are submitted to that worker for a while ( > maxInactiveTime)
+          void this.destroyWorker(workerCreated)
+        }
+      })
+      workerNodeKey = this.getWorkerNodeKey(workerCreated)
+    } else {
+      workerNodeKey = this.workerChoiceStrategyContext.execute()
+    }
+    return [workerNodeKey, this.workerNodes[workerNodeKey]]
   }
 
   /**
@@ -305,7 +352,7 @@ export abstract class AbstractPool<
   ): void
 
   /**
-   * Registers a listener callback on a given worker.
+   * Registers a listener callback on the given worker.
    *
    * @param worker - The worker which should register a listener.
    * @param listener - The message listener callback.
@@ -320,7 +367,7 @@ export abstract class AbstractPool<
   protected abstract createWorker (): Worker
 
   /**
-   * Function that can be hooked up when a worker has been newly created and moved to the workers registry.
+   * Function that can be hooked up when a worker has been newly created and moved to the pool worker nodes.
    *
    * Can be used to update the `maxListeners` or binding the `main-worker`\<-\>`worker` connection if not bind by default.
    *
@@ -329,7 +376,7 @@ export abstract class AbstractPool<
   protected abstract afterWorkerSetup (worker: Worker): void
 
   /**
-   * Creates a new worker for this pool and sets it up completely.
+   * Creates a new worker and sets it up completely in the pool worker nodes.
    *
    * @returns New, completely set up worker.
    */
@@ -341,13 +388,10 @@ export abstract class AbstractPool<
     worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION)
     worker.on('exit', this.opts.exitHandler ?? EMPTY_FUNCTION)
     worker.once('exit', () => {
-      this.removeWorker(worker)
+      this.removeWorkerNode(worker)
     })
 
-    this.workers.push(worker)
-
-    // Init worker tasks usage map
-    this.initWorkerTasksUsage(worker)
+    this.pushWorkerNode(worker)
 
     this.afterWorkerSetup(worker)
 
@@ -361,151 +405,130 @@ export abstract class AbstractPool<
    */
   protected workerListener (): (message: MessageValue<Response>) => void {
     return message => {
-      if (message.id !== undefined) {
-        const promise = this.promiseMap.get(message.id)
-        if (promise !== undefined) {
+      if (message.id != null) {
+        // Task response received
+        const promiseResponse = this.promiseResponseMap.get(message.id)
+        if (promiseResponse != null) {
           if (message.error != null) {
-            promise.reject(message.error)
+            promiseResponse.reject(message.error)
           } else {
-            promise.resolve(message.data as Response)
+            promiseResponse.resolve(message.data as Response)
           }
-          this.afterPromiseWorkerResponseHook(message, promise)
-          this.promiseMap.delete(message.id)
+          this.afterPromiseResponseHook(promiseResponse.worker, message)
+          this.promiseResponseMap.delete(message.id)
         }
       }
     }
   }
 
   private async internalExecute (
-    worker: Worker,
-    messageId: number
+    workerNodeKey: number,
+    workerNode: WorkerNode<Worker, Data>,
+    task: Task<Data>
   ): Promise<Response> {
-    this.beforePromiseWorkerResponseHook(worker)
+    this.beforePromiseResponseHook(workerNodeKey)
     return await new Promise<Response>((resolve, reject) => {
-      this.promiseMap.set(messageId, { resolve, reject, worker })
+      this.promiseResponseMap.set(task.id, {
+        resolve,
+        reject,
+        worker: workerNode.worker
+      })
     })
   }
 
   private checkAndEmitBusy (): void {
     if (this.opts.enableEvents === true && this.busy) {
-      this.emitter?.emit('busy')
+      this.emitter?.emit(PoolEvents.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 checkAndEmitFull (): void {
+    if (
+      this.type === PoolType.DYNAMIC &&
+      this.opts.enableEvents === true &&
+      this.full
+    ) {
+      this.emitter?.emit(PoolEvents.full)
+    }
   }
 
   /**
-   * Steps the number of tasks that the given worker has applied.
+   * Gets the given worker its tasks usage in the pool.
    *
-   * @param worker - Worker which running tasks are stepped.
-   * @param step - Number of running tasks step.
+   * @param worker - The worker.
+   * @returns The worker tasks usage.
    */
-  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)
+  private getWorkerTasksUsage (worker: Worker): TasksUsage | undefined {
+    const workerNodeKey = this.getWorkerNodeKey(worker)
+    if (workerNodeKey !== -1) {
+      return this.workerNodes[workerNodeKey].tasksUsage
     }
+    throw new Error('Worker could not be found in the pool worker nodes')
   }
 
   /**
-   * Steps the number of tasks that the given worker has run.
+   * Pushes the given worker in the pool worker nodes.
    *
-   * @param worker - Worker which has run tasks.
-   * @param step - Number of run tasks step.
+   * @param worker - The worker.
+   * @returns The worker nodes length.
    */
-  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)
-    }
+  private pushWorkerNode (worker: Worker): number {
+    return this.workerNodes.push({
+      worker,
+      tasksUsage: {
+        run: 0,
+        running: 0,
+        runTime: 0,
+        runTimeHistory: new CircularArray(),
+        avgRunTime: 0,
+        medRunTime: 0,
+        error: 0
+      },
+      tasksQueue: []
+    })
   }
 
   /**
-   * Updates tasks runtime for the given worker.
+   * Sets the given worker in the pool worker nodes.
    *
-   * @param worker - Worker which run the task.
-   * @param taskRunTime - Worker task runtime.
+   * @param workerNodeKey - The worker node key.
+   * @param worker - The worker.
+   * @param tasksUsage - The worker tasks usage.
+   * @param tasksQueue - The worker task queue.
    */
-  private updateWorkerTasksRunTime (
+  private setWorkerNode (
+    workerNodeKey: number,
     worker: Worker,
-    taskRunTime: number | undefined
+    tasksUsage: TasksUsage,
+    tasksQueue: Array<Task<Data>>
   ): 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.workersTasksUsage.set(worker, tasksUsage)
+    this.workerNodes[workerNodeKey] = {
+      worker,
+      tasksUsage,
+      tasksQueue
     }
   }
 
   /**
-   * Checks if the given worker is registered in the workers tasks usage map.
+   * Removes the given worker from the pool worker nodes.
    *
-   * @param worker - Worker to check.
-   * @returns `true` if the worker is registered in the workers tasks usage map. `false` otherwise.
+   * @param worker - The worker.
    */
-  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
+  protected removeWorkerNode (worker: Worker): void {
+    const workerNodeKey = this.getWorkerNodeKey(worker)
+    this.workerNodes.splice(workerNodeKey, 1)
+    this.workerChoiceStrategyContext.remove(workerNodeKey)
   }
 
-  /**
-   * Initializes tasks usage statistics.
-   *
-   * @param worker - The worker.
-   */
-  private initWorkerTasksUsage (worker: Worker): void {
-    this.workersTasksUsage.set(worker, {
-      run: 0,
-      running: 0,
-      runTime: 0,
-      avgRunTime: 0
-    })
+  protected enqueueTask (workerNodeKey: number, task: Task<Data>): void {
+    this.workerNodes[workerNodeKey].tasksQueue.push(task)
   }
 
-  /**
-   * Removes worker tasks usage statistics.
-   *
-   * @param worker - The worker.
-   */
-  private removeWorkerTasksUsage (worker: Worker): void {
-    this.workersTasksUsage.delete(worker)
+  protected dequeueTask (workerNodeKey: number): Task<Data> | undefined {
+    return this.workerNodes[workerNodeKey].tasksQueue.shift()
   }
 
-  /**
-   * Resets worker tasks usage statistics.
-   *
-   * @param worker - The worker.
-   */
-  private resetWorkerTasksUsage (worker: Worker): void {
-    this.removeWorkerTasksUsage(worker)
-    this.initWorkerTasksUsage(worker)
+  protected tasksQueueLength (workerNodeKey: number): number {
+    return this.workerNodes[workerNodeKey].tasksQueue.length
   }
 }