refactor: limit pool internals public exposure
[poolifier.git] / src / pools / abstract-pool.ts
index b778fe17e4c42bea82c6e39c3edf36149a2f3b2c..538d66c797fabc98e93a130953fdde2ee9edfdc8 100644 (file)
@@ -13,9 +13,12 @@ import {
   type IPool,
   PoolEmitter,
   PoolEvents,
+  type PoolInfo,
   type PoolOptions,
-  PoolType,
-  type TasksQueueOptions
+  type PoolType,
+  PoolTypes,
+  type TasksQueueOptions,
+  type WorkerType
 } from './pool'
 import type { IWorker, Task, TasksUsage, WorkerNode } from './worker'
 import {
@@ -133,7 +136,7 @@ export abstract class AbstractPool<
       throw new RangeError(
         'Cannot instantiate a pool with a negative number of workers'
       )
-    } else if (this.type === PoolType.FIXED && numberOfWorkers === 0) {
+    } else if (this.type === PoolTypes.fixed && numberOfWorkers === 0) {
       throw new Error('Cannot instantiate a fixed pool with no worker')
     }
   }
@@ -146,6 +149,10 @@ export abstract class AbstractPool<
       this.opts.workerChoiceStrategyOptions =
         opts.workerChoiceStrategyOptions ??
         DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
+      this.checkValidWorkerChoiceStrategyOptions(
+        this.opts.workerChoiceStrategyOptions
+      )
+      this.opts.restartWorkerOnError = opts.restartWorkerOnError ?? true
       this.opts.enableEvents = opts.enableEvents ?? true
       this.opts.enableTasksQueue = opts.enableTasksQueue ?? false
       if (this.opts.enableTasksQueue) {
@@ -179,6 +186,14 @@ export abstract class AbstractPool<
         'Invalid worker choice strategy options: must be a plain object'
       )
     }
+    if (
+      workerChoiceStrategyOptions.weights != null &&
+      Object.keys(workerChoiceStrategyOptions.weights).length !== this.maxSize
+    ) {
+      throw new Error(
+        'Invalid worker choice strategy options: must have a weight for each worker node'
+      )
+    }
   }
 
   private checkValidTasksQueueOptions (
@@ -197,33 +212,61 @@ export abstract class AbstractPool<
   }
 
   /** @inheritDoc */
-  public abstract get type (): PoolType
+  public get info (): PoolInfo {
+    return {
+      type: this.type,
+      worker: this.worker,
+      minSize: this.minSize,
+      maxSize: this.maxSize,
+      workerNodes: this.workerNodes.length,
+      idleWorkerNodes: this.workerNodes.reduce(
+        (accumulator, workerNode) =>
+          workerNode.tasksUsage.running === 0 ? accumulator + 1 : accumulator,
+        0
+      ),
+      busyWorkerNodes: this.workerNodes.reduce(
+        (accumulator, workerNode) =>
+          workerNode.tasksUsage.running > 0 ? accumulator + 1 : accumulator,
+        0
+      ),
+      runningTasks: this.workerNodes.reduce(
+        (accumulator, workerNode) =>
+          accumulator + workerNode.tasksUsage.running,
+        0
+      ),
+      queuedTasks: this.workerNodes.reduce(
+        (accumulator, workerNode) => accumulator + workerNode.tasksQueue.size,
+        0
+      ),
+      maxQueuedTasks: this.workerNodes.reduce(
+        (accumulator, workerNode) =>
+          accumulator + workerNode.tasksQueue.maxSize,
+        0
+      )
+    }
+  }
 
-  /** @inheritDoc */
-  public abstract get size (): number
+  /**
+   * Pool type.
+   *
+   * If it is `'dynamic'`, it provides the `max` property.
+   */
+  protected abstract get type (): PoolType
 
   /**
-   * Number of tasks running in the pool.
+   * Gets the worker type.
    */
-  private get numberOfRunningTasks (): number {
-    return this.workerNodes.reduce(
-      (accumulator, workerNode) => accumulator + workerNode.tasksUsage.running,
-      0
-    )
-  }
+  protected abstract get worker (): WorkerType
 
   /**
-   * Number of tasks queued in the pool.
+   * Pool minimum size.
    */
-  private get numberOfQueuedTasks (): number {
-    if (this.opts.enableTasksQueue === false) {
-      return 0
-    }
-    return this.workerNodes.reduce(
-      (accumulator, workerNode) => accumulator + workerNode.tasksQueue.size,
-      0
-    )
-  }
+  protected abstract get minSize (): number
+
+  /**
+   * Pool maximum size.
+   */
+  protected abstract get maxSize (): number
 
   /**
    * Gets the given worker its worker node key.
@@ -252,6 +295,10 @@ export abstract class AbstractPool<
         runTimeHistory: new CircularArray(),
         avgRunTime: 0,
         medRunTime: 0,
+        waitTime: 0,
+        waitTimeHistory: new CircularArray(),
+        avgWaitTime: 0,
+        medWaitTime: 0,
         error: 0
       })
     }
@@ -322,25 +369,27 @@ export abstract class AbstractPool<
   protected internalBusy (): boolean {
     return (
       this.workerNodes.findIndex(workerNode => {
-        return workerNode.tasksUsage?.running === 0
+        return workerNode.tasksUsage.running === 0
       }) === -1
     )
   }
 
   /** @inheritDoc */
   public async execute (data?: Data, name?: string): Promise<Response> {
-    const [workerNodeKey, workerNode] = this.chooseWorkerNode()
+    const submissionTimestamp = performance.now()
+    const workerNodeKey = this.chooseWorkerNode()
     const submittedTask: Task<Data> = {
       name,
       // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
       data: data ?? ({} as Data),
+      submissionTimestamp,
       id: crypto.randomUUID()
     }
     const res = new Promise<Response>((resolve, reject) => {
       this.promiseResponseMap.set(submittedTask.id as string, {
         resolve,
         reject,
-        worker: workerNode.worker
+        worker: this.workerNodes[workerNodeKey].worker
       })
     })
     if (
@@ -354,6 +403,7 @@ export abstract class AbstractPool<
     } else {
       this.executeTask(workerNodeKey, submittedTask)
     }
+    this.workerChoiceStrategyContext.update(workerNodeKey)
     this.checkAndEmitEvents()
     // eslint-disable-next-line @typescript-eslint/return-await
     return res
@@ -364,6 +414,7 @@ export abstract class AbstractPool<
     await Promise.all(
       this.workerNodes.map(async (workerNode, workerNodeKey) => {
         this.flushTasksQueue(workerNodeKey)
+        // FIXME: wait for tasks to be finished
         await this.destroyWorker(workerNode.worker)
       })
     )
@@ -412,12 +463,21 @@ export abstract class AbstractPool<
     worker: Worker,
     message: MessageValue<Response>
   ): void {
-    const workerTasksUsage = this.getWorkerTasksUsage(worker)
+    const workerTasksUsage =
+      this.workerNodes[this.getWorkerNodeKey(worker)].tasksUsage
     --workerTasksUsage.running
     ++workerTasksUsage.run
     if (message.error != null) {
       ++workerTasksUsage.error
     }
+    this.updateRunTimeTasksUsage(workerTasksUsage, message)
+    this.updateWaitTimeTasksUsage(workerTasksUsage, message)
+  }
+
+  private updateRunTimeTasksUsage (
+    workerTasksUsage: TasksUsage,
+    message: MessageValue<Response>
+  ): void {
     if (this.workerChoiceStrategyContext.getRequiredStatistics().runTime) {
       workerTasksUsage.runTime += message.runTime ?? 0
       if (
@@ -427,33 +487,60 @@ export abstract class AbstractPool<
         workerTasksUsage.avgRunTime =
           workerTasksUsage.runTime / workerTasksUsage.run
       }
-      if (this.workerChoiceStrategyContext.getRequiredStatistics().medRunTime) {
-        workerTasksUsage.runTimeHistory.push(message.runTime ?? 0)
+      if (
+        this.workerChoiceStrategyContext.getRequiredStatistics().medRunTime &&
+        message.runTime != null
+      ) {
+        workerTasksUsage.runTimeHistory.push(message.runTime)
         workerTasksUsage.medRunTime = median(workerTasksUsage.runTimeHistory)
       }
     }
-    this.workerChoiceStrategyContext.update()
+  }
+
+  private updateWaitTimeTasksUsage (
+    workerTasksUsage: TasksUsage,
+    message: MessageValue<Response>
+  ): void {
+    if (this.workerChoiceStrategyContext.getRequiredStatistics().waitTime) {
+      workerTasksUsage.waitTime += message.waitTime ?? 0
+      if (
+        this.workerChoiceStrategyContext.getRequiredStatistics().avgWaitTime &&
+        workerTasksUsage.run !== 0
+      ) {
+        workerTasksUsage.avgWaitTime =
+          workerTasksUsage.waitTime / workerTasksUsage.run
+      }
+      if (
+        this.workerChoiceStrategyContext.getRequiredStatistics().medWaitTime &&
+        message.waitTime != null
+      ) {
+        workerTasksUsage.waitTimeHistory.push(message.waitTime)
+        workerTasksUsage.medWaitTime = median(workerTasksUsage.waitTimeHistory)
+      }
+    }
   }
 
   /**
    * Chooses a worker node for the next task.
    *
-   * The default uses a round robin algorithm to distribute the load.
+   * The default worker choice strategy uses a round robin algorithm to distribute the load.
    *
-   * @returns [worker node key, worker node].
+   * @returns The worker node key
    */
-  protected chooseWorkerNode (): [number, WorkerNode<Worker, Data>] {
+  protected chooseWorkerNode (): number {
     let workerNodeKey: number
-    if (this.type === PoolType.DYNAMIC && !this.full && this.internalBusy()) {
+    if (this.type === PoolTypes.dynamic && !this.full && this.internalBusy()) {
       const workerCreated = this.createAndSetupWorker()
       this.registerWorkerMessageListener(workerCreated, message => {
+        const currentWorkerNodeKey = this.getWorkerNodeKey(workerCreated)
         if (
           isKillBehavior(KillBehaviors.HARD, message.kill) ||
           (message.kill != null &&
-            this.getWorkerTasksUsage(workerCreated)?.running === 0)
+            this.workerNodes[currentWorkerNodeKey].tasksUsage.running === 0)
         ) {
           // Kill message received from the worker: no new tasks are submitted to that worker for a while ( > maxInactiveTime)
-          this.flushTasksQueueByWorker(workerCreated)
+          this.flushTasksQueue(currentWorkerNodeKey)
+          // FIXME: wait for tasks to be finished
           void (this.destroyWorker(workerCreated) as Promise<void>)
         }
       })
@@ -461,7 +548,7 @@ export abstract class AbstractPool<
     } else {
       workerNodeKey = this.workerChoiceStrategyContext.execute()
     }
-    return [workerNodeKey, this.workerNodes[workerNodeKey]]
+    return workerNodeKey
   }
 
   /**
@@ -509,6 +596,16 @@ export abstract class AbstractPool<
 
     worker.on('message', this.opts.messageHandler ?? EMPTY_FUNCTION)
     worker.on('error', this.opts.errorHandler ?? EMPTY_FUNCTION)
+    worker.on('error', error => {
+      if (this.emitter != null) {
+        this.emitter.emit(PoolEvents.error, error)
+      }
+    })
+    if (this.opts.restartWorkerOnError === true) {
+      worker.on('error', () => {
+        this.createAndSetupWorker()
+      })
+    }
     worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION)
     worker.on('exit', this.opts.exitHandler ?? EMPTY_FUNCTION)
     worker.once('exit', () => {
@@ -535,6 +632,12 @@ export abstract class AbstractPool<
         if (promiseResponse != null) {
           if (message.error != null) {
             promiseResponse.reject(message.error)
+            if (this.emitter != null) {
+              this.emitter.emit(PoolEvents.taskError, {
+                error: message.error,
+                errorData: message.errorData
+              })
+            }
           } else {
             promiseResponse.resolve(message.data as Response)
           }
@@ -556,12 +659,12 @@ export abstract class AbstractPool<
   }
 
   private checkAndEmitEvents (): void {
-    if (this.opts.enableEvents === true) {
+    if (this.emitter != null) {
       if (this.busy) {
-        this.emitter?.emit(PoolEvents.busy)
+        this.emitter?.emit(PoolEvents.busy, this.info)
       }
-      if (this.type === PoolType.DYNAMIC && this.full) {
-        this.emitter?.emit(PoolEvents.full)
+      if (this.type === PoolTypes.dynamic && this.full) {
+        this.emitter?.emit(PoolEvents.full, this.info)
       }
     }
   }
@@ -579,21 +682,6 @@ export abstract class AbstractPool<
     workerNode.tasksUsage = tasksUsage
   }
 
-  /**
-   * Gets the given worker its tasks usage in the pool.
-   *
-   * @param worker - The worker.
-   * @throws Error if the worker is not found in the pool worker nodes.
-   * @returns The worker tasks usage.
-   */
-  private getWorkerTasksUsage (worker: Worker): TasksUsage {
-    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')
-  }
-
   /**
    * Pushes the given worker in the pool worker nodes.
    *
@@ -610,6 +698,10 @@ export abstract class AbstractPool<
         runTimeHistory: new CircularArray(),
         avgRunTime: 0,
         medRunTime: 0,
+        waitTime: 0,
+        waitTimeHistory: new CircularArray(),
+        avgWaitTime: 0,
+        medWaitTime: 0,
         error: 0
       },
       tasksQueue: new Queue<Task<Data>>()
@@ -644,8 +736,10 @@ export abstract class AbstractPool<
    */
   private removeWorkerNode (worker: Worker): void {
     const workerNodeKey = this.getWorkerNodeKey(worker)
-    this.workerNodes.splice(workerNodeKey, 1)
-    this.workerChoiceStrategyContext.remove(workerNodeKey)
+    if (workerNodeKey !== -1) {
+      this.workerNodes.splice(workerNodeKey, 1)
+      this.workerChoiceStrategyContext.remove(workerNodeKey)
+    }
   }
 
   private executeTask (workerNodeKey: number, task: Task<Data>): void {
@@ -676,11 +770,6 @@ export abstract class AbstractPool<
     }
   }
 
-  private flushTasksQueueByWorker (worker: Worker): void {
-    const workerNodeKey = this.getWorkerNodeKey(worker)
-    this.flushTasksQueue(workerNodeKey)
-  }
-
   private flushTasksQueues (): void {
     for (const [workerNodeKey] of this.workerNodes.entries()) {
       this.flushTasksQueue(workerNodeKey)