chore: v2.6.14
[poolifier.git] / src / pools / abstract-pool.ts
index 52a2aa383da0dd89acf4b3db7e518fd18fc33f21..c200d5317da6ba47c1154cdeb15a9b5ca5c9ee30 100644 (file)
@@ -1,16 +1,20 @@
-import crypto from 'node:crypto'
+import { randomUUID } from 'node:crypto'
 import { performance } from 'node:perf_hooks'
-import type { MessageValue, PromiseResponseWrapper } from '../utility-types'
+import type {
+  MessageValue,
+  PromiseResponseWrapper,
+  Task
+} from '../utility-types'
 import {
+  DEFAULT_TASK_NAME,
   DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS,
   EMPTY_FUNCTION,
+  isKillBehavior,
   isPlainObject,
   median,
   round
 } from '../utils'
-import { KillBehaviors, isKillBehavior } from '../worker/worker-options'
-import { CircularArray } from '../circular-array'
-import { Queue } from '../queue'
+import { KillBehaviors } from '../worker/worker-options'
 import {
   type IPool,
   PoolEmitter,
@@ -19,15 +23,14 @@ import {
   type PoolOptions,
   type PoolType,
   PoolTypes,
-  type TasksQueueOptions,
-  type WorkerType,
-  WorkerTypes
+  type TasksQueueOptions
 } from './pool'
 import type {
   IWorker,
+  IWorkerNode,
   MessageHandler,
-  Task,
-  WorkerNode,
+  WorkerInfo,
+  WorkerType,
   WorkerUsage
 } from './worker'
 import {
@@ -37,6 +40,8 @@ import {
   type WorkerChoiceStrategyOptions
 } from './selection-strategies/selection-strategies-types'
 import { WorkerChoiceStrategyContext } from './selection-strategies/worker-choice-strategy-context'
+import { version } from './version'
+import { WorkerNode } from './worker-node'
 
 /**
  * Base class that implements some shared logic for all poolifier pools.
@@ -51,7 +56,7 @@ export abstract class AbstractPool<
   Response = unknown
 > implements IPool<Worker, Data, Response> {
   /** @inheritDoc */
-  public readonly workerNodes: Array<WorkerNode<Worker, Data>> = []
+  public readonly workerNodes: Array<IWorkerNode<Worker, Data>> = []
 
   /** @inheritDoc */
   public readonly emitter?: PoolEmitter
@@ -152,7 +157,25 @@ export abstract class AbstractPool<
         'Cannot instantiate a pool with a negative number of workers'
       )
     } else if (this.type === PoolTypes.fixed && numberOfWorkers === 0) {
-      throw new Error('Cannot instantiate a fixed pool with no worker')
+      throw new RangeError('Cannot instantiate a fixed pool with zero worker')
+    }
+  }
+
+  protected checkDynamicPoolSize (min: number, max: number): void {
+    if (this.type === PoolTypes.dynamic) {
+      if (min > max) {
+        throw new RangeError(
+          'Cannot instantiate a dynamic pool with a maximum pool size inferior to the minimum pool size'
+        )
+      } else if (min === 0 && max === 0) {
+        throw new RangeError(
+          'Cannot instantiate a dynamic pool with a minimum pool size and a maximum pool size equal to zero'
+        )
+      } else if (min === max) {
+        throw new RangeError(
+          'Cannot instantiate a dynamic pool with a minimum pool size equal to the maximum pool size. Use a fixed pool instead'
+        )
+      }
     }
   }
 
@@ -248,11 +271,17 @@ export abstract class AbstractPool<
   /** @inheritDoc */
   public get info (): PoolInfo {
     return {
+      version,
       type: this.type,
       worker: this.worker,
+      ready: this.ready,
+      strategy: this.opts.workerChoiceStrategy as WorkerChoiceStrategy,
       minSize: this.minSize,
       maxSize: this.maxSize,
-      utilization: round(this.utilization),
+      ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+        .runTime.aggregate &&
+        this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+          .waitTime.aggregate && { utilization: round(this.utilization) }),
       workerNodes: this.workerNodes.length,
       idleWorkerNodes: this.workerNodes.reduce(
         (accumulator, workerNode) =>
@@ -283,24 +312,112 @@ export abstract class AbstractPool<
       ),
       maxQueuedTasks: this.workerNodes.reduce(
         (accumulator, workerNode) =>
-          accumulator + workerNode.usage.tasks.maxQueued,
+          accumulator + (workerNode.usage.tasks?.maxQueued ?? 0),
         0
       ),
       failedTasks: this.workerNodes.reduce(
         (accumulator, workerNode) =>
           accumulator + workerNode.usage.tasks.failed,
         0
-      )
+      ),
+      ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+        .runTime.aggregate && {
+        runTime: {
+          minimum: round(
+            Math.min(
+              ...this.workerNodes.map(
+                workerNode => workerNode.usage.runTime?.minimum ?? Infinity
+              )
+            )
+          ),
+          maximum: round(
+            Math.max(
+              ...this.workerNodes.map(
+                workerNode => workerNode.usage.runTime?.maximum ?? -Infinity
+              )
+            )
+          ),
+          average: round(
+            this.workerNodes.reduce(
+              (accumulator, workerNode) =>
+                accumulator + (workerNode.usage.runTime?.aggregate ?? 0),
+              0
+            ) /
+              this.workerNodes.reduce(
+                (accumulator, workerNode) =>
+                  accumulator + (workerNode.usage.tasks?.executed ?? 0),
+                0
+              )
+          ),
+          ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+            .runTime.median && {
+            median: round(
+              median(
+                this.workerNodes.map(
+                  workerNode => workerNode.usage.runTime?.median ?? 0
+                )
+              )
+            )
+          })
+        }
+      }),
+      ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+        .waitTime.aggregate && {
+        waitTime: {
+          minimum: round(
+            Math.min(
+              ...this.workerNodes.map(
+                workerNode => workerNode.usage.waitTime?.minimum ?? Infinity
+              )
+            )
+          ),
+          maximum: round(
+            Math.max(
+              ...this.workerNodes.map(
+                workerNode => workerNode.usage.waitTime?.maximum ?? -Infinity
+              )
+            )
+          ),
+          average: round(
+            this.workerNodes.reduce(
+              (accumulator, workerNode) =>
+                accumulator + (workerNode.usage.waitTime?.aggregate ?? 0),
+              0
+            ) /
+              this.workerNodes.reduce(
+                (accumulator, workerNode) =>
+                  accumulator + (workerNode.usage.tasks?.executed ?? 0),
+                0
+              )
+          ),
+          ...(this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+            .waitTime.median && {
+            median: round(
+              median(
+                this.workerNodes.map(
+                  workerNode => workerNode.usage.waitTime?.median ?? 0
+                )
+              )
+            )
+          })
+        }
+      })
     }
   }
 
-  /**
-   * Gets the pool run time.
-   *
-   * @returns The pool run time in milliseconds.
-   */
-  private get runTime (): number {
-    return performance.now() - this.startTimestamp
+  private get starting (): boolean {
+    return (
+      this.workerNodes.length < this.minSize ||
+      (this.workerNodes.length >= this.minSize &&
+        this.workerNodes.some(workerNode => !workerNode.info.ready))
+    )
+  }
+
+  private get ready (): boolean {
+    return (
+      this.workerNodes.length >= this.minSize &&
+      this.workerNodes.every(workerNode => workerNode.info.ready)
+    )
   }
 
   /**
@@ -309,15 +426,16 @@ export abstract class AbstractPool<
    * @returns The pool utilization.
    */
   private get utilization (): number {
-    const poolRunTimeCapacity = this.runTime * this.maxSize
+    const poolRunTimeCapacity =
+      (performance.now() - this.startTimestamp) * this.maxSize
     const totalTasksRunTime = this.workerNodes.reduce(
       (accumulator, workerNode) =>
-        accumulator + workerNode.usage.runTime.aggregate,
+        accumulator + (workerNode.usage.runTime?.aggregate ?? 0),
       0
     )
     const totalTasksWaitTime = this.workerNodes.reduce(
       (accumulator, workerNode) =>
-        accumulator + workerNode.usage.waitTime.aggregate,
+        accumulator + (workerNode.usage.waitTime?.aggregate ?? 0),
       0
     )
     return (totalTasksRunTime + totalTasksWaitTime) / poolRunTimeCapacity
@@ -356,6 +474,17 @@ export abstract class AbstractPool<
       ?.worker
   }
 
+  private checkMessageWorkerId (message: MessageValue<Response>): void {
+    if (
+      message.workerId != null &&
+      this.getWorkerById(message.workerId) == null
+    ) {
+      throw new Error(
+        `Worker message received from unknown worker '${message.workerId}'`
+      )
+    }
+  }
+
   /**
    * Gets the given worker its worker node key.
    *
@@ -381,11 +510,8 @@ export abstract class AbstractPool<
     if (workerChoiceStrategyOptions != null) {
       this.setWorkerChoiceStrategyOptions(workerChoiceStrategyOptions)
     }
-    for (const [workerNodeKey, workerNode] of this.workerNodes.entries()) {
-      this.setWorkerNodeTasksUsage(
-        workerNode,
-        this.getWorkerUsage(workerNodeKey)
-      )
+    for (const workerNode of this.workerNodes) {
+      workerNode.resetUsage()
       this.setWorkerStatistics(workerNode.worker)
     }
   }
@@ -466,11 +592,12 @@ export abstract class AbstractPool<
     const timestamp = performance.now()
     const workerNodeKey = this.chooseWorkerNode()
     const submittedTask: Task<Data> = {
-      name,
+      name: name ?? DEFAULT_TASK_NAME,
       // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
       data: data ?? ({} as Data),
       timestamp,
-      id: crypto.randomUUID()
+      workerId: this.getWorkerInfo(workerNodeKey).id as number,
+      id: randomUUID()
     }
     const res = new Promise<Response>((resolve, reject) => {
       this.promiseResponseMap.set(submittedTask.id as string, {
@@ -501,7 +628,13 @@ export abstract class AbstractPool<
       this.workerNodes.map(async (workerNode, workerNodeKey) => {
         this.flushTasksQueue(workerNodeKey)
         // FIXME: wait for tasks to be finished
+        const workerExitPromise = new Promise<void>(resolve => {
+          workerNode.worker.on('exit', () => {
+            resolve()
+          })
+        })
         await this.destroyWorker(workerNode.worker)
+        await workerExitPromise
       })
     )
   }
@@ -542,6 +675,11 @@ export abstract class AbstractPool<
     const workerUsage = this.workerNodes[workerNodeKey].usage
     ++workerUsage.tasks.executing
     this.updateWaitTimeWorkerUsage(workerUsage, task)
+    const taskWorkerUsage = this.workerNodes[workerNodeKey].getTaskWorkerUsage(
+      task.name as string
+    ) as WorkerUsage
+    ++taskWorkerUsage.tasks.executing
+    this.updateWaitTimeWorkerUsage(taskWorkerUsage, task)
   }
 
   /**
@@ -555,10 +693,17 @@ export abstract class AbstractPool<
     worker: Worker,
     message: MessageValue<Response>
   ): void {
-    const workerUsage = this.workerNodes[this.getWorkerNodeKey(worker)].usage
+    const workerNodeKey = this.getWorkerNodeKey(worker)
+    const workerUsage = this.workerNodes[workerNodeKey].usage
     this.updateTaskStatisticsWorkerUsage(workerUsage, message)
     this.updateRunTimeWorkerUsage(workerUsage, message)
     this.updateEluWorkerUsage(workerUsage, message)
+    const taskWorkerUsage = this.workerNodes[workerNodeKey].getTaskWorkerUsage(
+      message.taskPerformance?.name ?? DEFAULT_TASK_NAME
+    ) as WorkerUsage
+    this.updateTaskStatisticsWorkerUsage(taskWorkerUsage, message)
+    this.updateRunTimeWorkerUsage(taskWorkerUsage, message)
+    this.updateEluWorkerUsage(taskWorkerUsage, message)
   }
 
   private updateTaskStatisticsWorkerUsage (
@@ -567,8 +712,9 @@ export abstract class AbstractPool<
   ): void {
     const workerTaskStatistics = workerUsage.tasks
     --workerTaskStatistics.executing
-    ++workerTaskStatistics.executed
-    if (message.taskError != null) {
+    if (message.taskError == null) {
+      ++workerTaskStatistics.executed
+    } else {
       ++workerTaskStatistics.failed
     }
   }
@@ -581,15 +727,24 @@ export abstract class AbstractPool<
       this.workerChoiceStrategyContext.getTaskStatisticsRequirements().runTime
         .aggregate
     ) {
-      workerUsage.runTime.aggregate += message.taskPerformance?.runTime ?? 0
+      const taskRunTime = message.taskPerformance?.runTime ?? 0
+      workerUsage.runTime.aggregate =
+        (workerUsage.runTime.aggregate ?? 0) + taskRunTime
+      workerUsage.runTime.minimum = Math.min(
+        taskRunTime,
+        workerUsage.runTime?.minimum ?? Infinity
+      )
+      workerUsage.runTime.maximum = Math.max(
+        taskRunTime,
+        workerUsage.runTime?.maximum ?? -Infinity
+      )
       if (
         this.workerChoiceStrategyContext.getTaskStatisticsRequirements().runTime
           .average &&
         workerUsage.tasks.executed !== 0
       ) {
         workerUsage.runTime.average =
-          workerUsage.runTime.aggregate /
-          (workerUsage.tasks.executed - workerUsage.tasks.failed)
+          workerUsage.runTime.aggregate / workerUsage.tasks.executed
       }
       if (
         this.workerChoiceStrategyContext.getTaskStatisticsRequirements().runTime
@@ -612,20 +767,27 @@ export abstract class AbstractPool<
       this.workerChoiceStrategyContext.getTaskStatisticsRequirements().waitTime
         .aggregate
     ) {
-      workerUsage.waitTime.aggregate += taskWaitTime ?? 0
+      workerUsage.waitTime.aggregate =
+        (workerUsage.waitTime?.aggregate ?? 0) + taskWaitTime
+      workerUsage.waitTime.minimum = Math.min(
+        taskWaitTime,
+        workerUsage.waitTime?.minimum ?? Infinity
+      )
+      workerUsage.waitTime.maximum = Math.max(
+        taskWaitTime,
+        workerUsage.waitTime?.maximum ?? -Infinity
+      )
       if (
         this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
           .waitTime.average &&
         workerUsage.tasks.executed !== 0
       ) {
         workerUsage.waitTime.average =
-          workerUsage.waitTime.aggregate /
-          (workerUsage.tasks.executed - workerUsage.tasks.failed)
+          workerUsage.waitTime.aggregate / workerUsage.tasks.executed
       }
       if (
         this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
-          .waitTime.median &&
-        taskWaitTime != null
+          .waitTime.median
       ) {
         workerUsage.waitTime.history.push(taskWaitTime)
         workerUsage.waitTime.median = median(workerUsage.waitTime.history)
@@ -641,39 +803,58 @@ export abstract class AbstractPool<
       this.workerChoiceStrategyContext.getTaskStatisticsRequirements().elu
         .aggregate
     ) {
-      if (workerUsage.elu != null && message.taskPerformance?.elu != null) {
-        workerUsage.elu.idle.aggregate += message.taskPerformance.elu.idle
-        workerUsage.elu.active.aggregate += message.taskPerformance.elu.active
-        workerUsage.elu.utilization =
-          (workerUsage.elu.utilization +
-            message.taskPerformance.elu.utilization) /
-          2
-      } else if (message.taskPerformance?.elu != null) {
-        workerUsage.elu.idle.aggregate = message.taskPerformance.elu.idle
-        workerUsage.elu.active.aggregate = message.taskPerformance.elu.active
-        workerUsage.elu.utilization = message.taskPerformance.elu.utilization
-      }
-      if (
-        this.workerChoiceStrategyContext.getTaskStatisticsRequirements().elu
-          .average &&
-        workerUsage.tasks.executed !== 0
-      ) {
-        const executedTasks =
-          workerUsage.tasks.executed - workerUsage.tasks.failed
-        workerUsage.elu.idle.average =
-          workerUsage.elu.idle.aggregate / executedTasks
-        workerUsage.elu.active.average =
-          workerUsage.elu.active.aggregate / executedTasks
-      }
-      if (
-        this.workerChoiceStrategyContext.getTaskStatisticsRequirements().elu
-          .median &&
-        message.taskPerformance?.elu != null
-      ) {
-        workerUsage.elu.idle.history.push(message.taskPerformance.elu.idle)
-        workerUsage.elu.active.history.push(message.taskPerformance.elu.active)
-        workerUsage.elu.idle.median = median(workerUsage.elu.idle.history)
-        workerUsage.elu.active.median = median(workerUsage.elu.active.history)
+      if (message.taskPerformance?.elu != null) {
+        workerUsage.elu.idle.aggregate =
+          (workerUsage.elu.idle?.aggregate ?? 0) +
+          message.taskPerformance.elu.idle
+        workerUsage.elu.active.aggregate =
+          (workerUsage.elu.active?.aggregate ?? 0) +
+          message.taskPerformance.elu.active
+        if (workerUsage.elu.utilization != null) {
+          workerUsage.elu.utilization =
+            (workerUsage.elu.utilization +
+              message.taskPerformance.elu.utilization) /
+            2
+        } else {
+          workerUsage.elu.utilization = message.taskPerformance.elu.utilization
+        }
+        workerUsage.elu.idle.minimum = Math.min(
+          message.taskPerformance.elu.idle,
+          workerUsage.elu.idle?.minimum ?? Infinity
+        )
+        workerUsage.elu.idle.maximum = Math.max(
+          message.taskPerformance.elu.idle,
+          workerUsage.elu.idle?.maximum ?? -Infinity
+        )
+        workerUsage.elu.active.minimum = Math.min(
+          message.taskPerformance.elu.active,
+          workerUsage.elu.active?.minimum ?? Infinity
+        )
+        workerUsage.elu.active.maximum = Math.max(
+          message.taskPerformance.elu.active,
+          workerUsage.elu.active?.maximum ?? -Infinity
+        )
+        if (
+          this.workerChoiceStrategyContext.getTaskStatisticsRequirements().elu
+            .average &&
+          workerUsage.tasks.executed !== 0
+        ) {
+          workerUsage.elu.idle.average =
+            workerUsage.elu.idle.aggregate / workerUsage.tasks.executed
+          workerUsage.elu.active.average =
+            workerUsage.elu.active.aggregate / workerUsage.tasks.executed
+        }
+        if (
+          this.workerChoiceStrategyContext.getTaskStatisticsRequirements().elu
+            .median
+        ) {
+          workerUsage.elu.idle.history.push(message.taskPerformance.elu.idle)
+          workerUsage.elu.active.history.push(
+            message.taskPerformance.elu.active
+          )
+          workerUsage.elu.idle.median = median(workerUsage.elu.idle.history)
+          workerUsage.elu.active.median = median(workerUsage.elu.active.history)
+        }
       }
     }
   }
@@ -746,6 +927,13 @@ export abstract class AbstractPool<
   protected afterWorkerSetup (worker: Worker): void {
     // Listen to worker messages.
     this.registerWorkerMessageListener(worker, this.workerListener())
+    // Send startup message to worker.
+    this.sendToWorker(worker, {
+      ready: false,
+      workerId: this.getWorkerInfo(this.getWorkerNodeKey(worker)).id as number
+    })
+    // Setup worker task statistics computation.
+    this.setWorkerStatistics(worker)
   }
 
   /**
@@ -762,8 +950,15 @@ export abstract class AbstractPool<
       if (this.emitter != null) {
         this.emitter.emit(PoolEvents.error, error)
       }
-      if (this.opts.restartWorkerOnError === true) {
-        this.createAndSetupWorker()
+      if (this.opts.enableTasksQueue === true) {
+        this.redistributeQueuedTasks(worker)
+      }
+      if (this.opts.restartWorkerOnError === true && !this.starting) {
+        if (this.getWorkerInfo(this.getWorkerNodeKey(worker)).dynamic) {
+          this.createAndSetupDynamicWorker()
+        } else {
+          this.createAndSetupWorker()
+        }
       }
     })
     worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION)
@@ -774,13 +969,39 @@ export abstract class AbstractPool<
 
     this.pushWorkerNode(worker)
 
-    this.setWorkerStatistics(worker)
-
     this.afterWorkerSetup(worker)
 
     return worker
   }
 
+  private redistributeQueuedTasks (worker: Worker): void {
+    const workerNodeKey = this.getWorkerNodeKey(worker)
+    while (this.tasksQueueSize(workerNodeKey) > 0) {
+      let targetWorkerNodeKey: number = workerNodeKey
+      let minQueuedTasks = Infinity
+      for (const [workerNodeId, workerNode] of this.workerNodes.entries()) {
+        if (
+          workerNodeId !== workerNodeKey &&
+          workerNode.usage.tasks.queued === 0
+        ) {
+          targetWorkerNodeKey = workerNodeId
+          break
+        }
+        if (
+          workerNodeId !== workerNodeKey &&
+          workerNode.usage.tasks.queued < minQueuedTasks
+        ) {
+          minQueuedTasks = workerNode.usage.tasks.queued
+          targetWorkerNodeKey = workerNodeId
+        }
+      }
+      this.enqueueTask(
+        targetWorkerNodeKey,
+        this.dequeueTask(workerNodeKey) as Task<Data>
+      )
+    }
+  }
+
   /**
    * Creates a new dynamic worker and sets it up completely in the pool worker nodes.
    *
@@ -803,6 +1024,12 @@ export abstract class AbstractPool<
         void (this.destroyWorker(worker) as Promise<void>)
       }
     })
+    const workerInfo = this.getWorkerInfo(this.getWorkerNodeKey(worker))
+    workerInfo.dynamic = true
+    this.sendToWorker(worker, {
+      checkAlive: true,
+      workerId: workerInfo.id as number
+    })
     return worker
   }
 
@@ -813,69 +1040,71 @@ export abstract class AbstractPool<
    */
   protected workerListener (): (message: MessageValue<Response>) => void {
     return message => {
-      if (message.workerId != null && message.started != null) {
-        // Worker started message received
-        const worker = this.getWorkerById(message.workerId)
-        if (worker != null) {
-          this.workerNodes[this.getWorkerNodeKey(worker)].info.started =
-            message.started
-        } else {
-          throw new Error(
-            `Worker started message received from unknown worker '${message.workerId}'`
-          )
-        }
+      this.checkMessageWorkerId(message)
+      if (message.ready != null && message.workerId != null) {
+        // Worker ready message received
+        this.handleWorkerReadyMessage(message)
       } else if (message.id != null) {
         // Task execution response received
-        const promiseResponse = this.promiseResponseMap.get(message.id)
-        if (promiseResponse != null) {
-          if (message.taskError != null) {
-            if (this.emitter != null) {
-              this.emitter.emit(PoolEvents.taskError, message.taskError)
-            }
-            promiseResponse.reject(message.taskError.message)
-          } else {
-            promiseResponse.resolve(message.data as Response)
-          }
-          this.afterTaskExecutionHook(promiseResponse.worker, message)
-          this.promiseResponseMap.delete(message.id)
-          const workerNodeKey = this.getWorkerNodeKey(promiseResponse.worker)
-          if (
-            this.opts.enableTasksQueue === true &&
-            this.tasksQueueSize(workerNodeKey) > 0
-          ) {
-            this.executeTask(
-              workerNodeKey,
-              this.dequeueTask(workerNodeKey) as Task<Data>
-            )
-          }
-          this.workerChoiceStrategyContext.update(workerNodeKey)
+        this.handleTaskExecutionResponse(message)
+      }
+    }
+  }
+
+  private handleWorkerReadyMessage (message: MessageValue<Response>): void {
+    const worker = this.getWorkerById(message.workerId)
+    this.getWorkerInfo(this.getWorkerNodeKey(worker as Worker)).ready =
+      message.ready as boolean
+    if (this.emitter != null && this.ready) {
+      this.emitter.emit(PoolEvents.ready, this.info)
+    }
+  }
+
+  private handleTaskExecutionResponse (message: MessageValue<Response>): void {
+    const promiseResponse = this.promiseResponseMap.get(message.id as string)
+    if (promiseResponse != null) {
+      if (message.taskError != null) {
+        if (this.emitter != null) {
+          this.emitter.emit(PoolEvents.taskError, message.taskError)
         }
+        promiseResponse.reject(message.taskError.message)
+      } else {
+        promiseResponse.resolve(message.data as Response)
       }
+      this.afterTaskExecutionHook(promiseResponse.worker, message)
+      this.promiseResponseMap.delete(message.id as string)
+      const workerNodeKey = this.getWorkerNodeKey(promiseResponse.worker)
+      if (
+        this.opts.enableTasksQueue === true &&
+        this.tasksQueueSize(workerNodeKey) > 0
+      ) {
+        this.executeTask(
+          workerNodeKey,
+          this.dequeueTask(workerNodeKey) as Task<Data>
+        )
+      }
+      this.workerChoiceStrategyContext.update(workerNodeKey)
     }
   }
 
   private checkAndEmitEvents (): void {
     if (this.emitter != null) {
       if (this.busy) {
-        this.emitter?.emit(PoolEvents.busy, this.info)
+        this.emitter.emit(PoolEvents.busy, this.info)
       }
       if (this.type === PoolTypes.dynamic && this.full) {
-        this.emitter?.emit(PoolEvents.full, this.info)
+        this.emitter.emit(PoolEvents.full, this.info)
       }
     }
   }
 
   /**
-   * Sets the given worker node its tasks usage in the pool.
+   * Gets the worker information.
    *
-   * @param workerNode - The worker node.
-   * @param workerUsage - The worker usage.
+   * @param workerNodeKey - The worker node key.
    */
-  private setWorkerNodeTasksUsage (
-    workerNode: WorkerNode<Worker, Data>,
-    workerUsage: WorkerUsage
-  ): void {
-    workerNode.usage = workerUsage
+  private getWorkerInfo (workerNodeKey: number): WorkerInfo {
+    return this.workerNodes[workerNodeKey].info
   }
 
   /**
@@ -885,58 +1114,9 @@ export abstract class AbstractPool<
    * @returns The worker nodes length.
    */
   private pushWorkerNode (worker: Worker): number {
-    this.workerNodes.push({
-      worker,
-      info: { id: this.getWorkerId(worker), started: true },
-      usage: this.getWorkerUsage(),
-      tasksQueue: new Queue<Task<Data>>()
-    })
-    const workerNodeKey = this.getWorkerNodeKey(worker)
-    this.setWorkerNodeTasksUsage(
-      this.workerNodes[workerNodeKey],
-      this.getWorkerUsage(workerNodeKey)
-    )
-    return this.workerNodes.length
-  }
-
-  /**
-   * Gets the worker id.
-   *
-   * @param worker - The worker.
-   * @returns The worker id.
-   */
-  private getWorkerId (worker: Worker): number | undefined {
-    if (this.worker === WorkerTypes.thread) {
-      return worker.threadId
-    } else if (this.worker === WorkerTypes.cluster) {
-      return worker.id
-    }
+    return this.workerNodes.push(new WorkerNode(worker, this.worker))
   }
 
-  // /**
-  //  * Sets the given worker in the pool worker nodes.
-  //  *
-  //  * @param workerNodeKey - The worker node key.
-  //  * @param worker - The worker.
-  //  * @param workerInfo - The worker info.
-  //  * @param workerUsage - The worker usage.
-  //  * @param tasksQueue - The worker task queue.
-  //  */
-  // private setWorkerNode (
-  //   workerNodeKey: number,
-  //   worker: Worker,
-  //   workerInfo: WorkerInfo,
-  //   workerUsage: WorkerUsage,
-  //   tasksQueue: Queue<Task<Data>>
-  // ): void {
-  //   this.workerNodes[workerNodeKey] = {
-  //     worker,
-  //     info: workerInfo,
-  //     usage: workerUsage,
-  //     tasksQueue
-  //   }
-  // }
-
   /**
    * Removes the given worker from the pool worker nodes.
    *
@@ -956,31 +1136,25 @@ export abstract class AbstractPool<
   }
 
   private enqueueTask (workerNodeKey: number, task: Task<Data>): number {
-    return this.workerNodes[workerNodeKey].tasksQueue.enqueue(task)
+    return this.workerNodes[workerNodeKey].enqueueTask(task)
   }
 
   private dequeueTask (workerNodeKey: number): Task<Data> | undefined {
-    return this.workerNodes[workerNodeKey].tasksQueue.dequeue()
+    return this.workerNodes[workerNodeKey].dequeueTask()
   }
 
   private tasksQueueSize (workerNodeKey: number): number {
-    return this.workerNodes[workerNodeKey].tasksQueue.size
-  }
-
-  private tasksMaxQueueSize (workerNodeKey: number): number {
-    return this.workerNodes[workerNodeKey].tasksQueue.maxSize
+    return this.workerNodes[workerNodeKey].tasksQueueSize()
   }
 
   private flushTasksQueue (workerNodeKey: number): void {
-    if (this.tasksQueueSize(workerNodeKey) > 0) {
-      for (let i = 0; i < this.tasksQueueSize(workerNodeKey); i++) {
-        this.executeTask(
-          workerNodeKey,
-          this.dequeueTask(workerNodeKey) as Task<Data>
-        )
-      }
+    while (this.tasksQueueSize(workerNodeKey) > 0) {
+      this.executeTask(
+        workerNodeKey,
+        this.dequeueTask(workerNodeKey) as Task<Data>
+      )
     }
-    this.workerNodes[workerNodeKey].tasksQueue.clear()
+    this.workerNodes[workerNodeKey].clearTasksQueue()
   }
 
   private flushTasksQueues (): void {
@@ -997,56 +1171,8 @@ export abstract class AbstractPool<
             .runTime.aggregate,
         elu: this.workerChoiceStrategyContext.getTaskStatisticsRequirements()
           .elu.aggregate
-      }
-    })
-  }
-
-  private getWorkerUsage (workerNodeKey?: number): WorkerUsage {
-    const getTasksQueueSize = (workerNodeKey?: number): number => {
-      return workerNodeKey != null ? this.tasksQueueSize(workerNodeKey) : 0
-    }
-    const getTasksMaxQueueSize = (workerNodeKey?: number): number => {
-      return workerNodeKey != null ? this.tasksMaxQueueSize(workerNodeKey) : 0
-    }
-    return {
-      tasks: {
-        executed: 0,
-        executing: 0,
-        get queued (): number {
-          return getTasksQueueSize(workerNodeKey)
-        },
-        get maxQueued (): number {
-          return getTasksMaxQueueSize(workerNodeKey)
-        },
-        failed: 0
-      },
-      runTime: {
-        aggregate: 0,
-        average: 0,
-        median: 0,
-        history: new CircularArray()
       },
-      waitTime: {
-        aggregate: 0,
-        average: 0,
-        median: 0,
-        history: new CircularArray()
-      },
-      elu: {
-        idle: {
-          aggregate: 0,
-          average: 0,
-          median: 0,
-          history: new CircularArray()
-        },
-        active: {
-          aggregate: 0,
-          average: 0,
-          median: 0,
-          history: new CircularArray()
-        },
-        utilization: 0
-      }
-    }
+      workerId: this.getWorkerInfo(this.getWorkerNodeKey(worker)).id as number
+    })
   }
 }