fix: ensure not more than one task is executed on a worker with tasks
[poolifier.git] / src / pools / abstract-pool.ts
index fd8628100fe560b11c1b48765c0102d9bdb806e5..a8104e9e26bdb31dd7d0374794538eafd9acb116 100644 (file)
@@ -33,12 +33,12 @@ export abstract class AbstractPool<
   public readonly emitter?: PoolEmitter
 
   /**
-   * The promise response map.
+   * The execution response promise map.
    *
    * - `key`: The message id of each submitted task.
-   * - `value`: An object that contains the worker, the promise resolve and reject callbacks.
+   * - `value`: An object that contains the worker, the execution response promise resolve and reject callbacks.
    *
-   * When we receive a message from the worker we get a map entry with the promise resolve/reject bound to the message.
+   * When we receive a message from the worker, we get a map entry with the promise resolve/reject bound to the message id.
    */
   protected promiseResponseMap: Map<
   string,
@@ -77,8 +77,7 @@ export abstract class AbstractPool<
 
     this.chooseWorkerNode.bind(this)
     this.internalExecute.bind(this)
-    this.checkAndEmitFull.bind(this)
-    this.checkAndEmitBusy.bind(this)
+    this.checkAndEmitEvents.bind(this)
     this.sendToWorker.bind(this)
 
     this.setupHook()
@@ -94,7 +93,11 @@ export abstract class AbstractPool<
     Worker,
     Data,
     Response
-    >(this, this.opts.workerChoiceStrategy)
+    >(
+      this,
+      this.opts.workerChoiceStrategy,
+      this.opts.workerChoiceStrategyOptions
+    )
   }
 
   private checkFilePath (filePath: string): void {
@@ -128,7 +131,10 @@ export abstract class AbstractPool<
     this.opts.workerChoiceStrategy =
       opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN
     this.checkValidWorkerChoiceStrategy(this.opts.workerChoiceStrategy)
+    this.opts.workerChoiceStrategyOptions =
+      opts.workerChoiceStrategyOptions ?? { medRunTime: false }
     this.opts.enableEvents = opts.enableEvents ?? true
+    this.opts.enableTasksQueue = opts.enableTasksQueue ?? false
   }
 
   private checkValidWorkerChoiceStrategy (
@@ -145,10 +151,26 @@ export abstract class AbstractPool<
   public abstract get type (): PoolType
 
   /**
-   * Number of tasks concurrently running in the pool.
+   * Number of tasks running in the pool.
    */
   private get numberOfRunningTasks (): number {
-    return this.promiseResponseMap.size
+    return this.workerNodes.reduce(
+      (accumulator, workerNode) => accumulator + workerNode.tasksUsage.running,
+      0
+    )
+  }
+
+  /**
+   * Number of tasks queued in the pool.
+   */
+  private get numberOfQueuedTasks (): number {
+    if (this.opts.enableTasksQueue === false) {
+      return 0
+    }
+    return this.workerNodes.reduce(
+      (accumulator, workerNode) => accumulator + workerNode.tasksQueue.length,
+      0
+    )
   }
 
   /**
@@ -169,21 +191,16 @@ export abstract class AbstractPool<
   ): void {
     this.checkValidWorkerChoiceStrategy(workerChoiceStrategy)
     this.opts.workerChoiceStrategy = workerChoiceStrategy
-    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
-      )
+    for (const workerNode of this.workerNodes) {
+      this.setWorkerNodeTasksUsage(workerNode, {
+        run: 0,
+        running: 0,
+        runTime: 0,
+        runTimeHistory: new CircularArray(),
+        avgRunTime: 0,
+        medRunTime: 0,
+        error: 0
+      })
     }
     this.workerChoiceStrategyContext.setWorkerChoiceStrategy(
       workerChoiceStrategy
@@ -219,17 +236,15 @@ export abstract class AbstractPool<
       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>
+    if (
+      this.opts.enableTasksQueue === true &&
+      (this.busy || this.workerNodes[workerNodeKey].tasksUsage.running > 0)
+    ) {
       this.enqueueTask(workerNodeKey, submittedTask)
     } else {
-      currentTask = submittedTask
+      this.sendToWorker(workerNode.worker, submittedTask)
     }
-    this.sendToWorker(workerNode.worker, currentTask)
-    this.checkAndEmitFull()
-    this.checkAndEmitBusy()
+    this.checkAndEmitEvents()
     // eslint-disable-next-line @typescript-eslint/return-await
     return res
   }
@@ -238,6 +253,7 @@ export abstract class AbstractPool<
   public async destroy (): Promise<void> {
     await Promise.all(
       this.workerNodes.map(async workerNode => {
+        this.flushTasksQueueByWorker(workerNode.worker)
         await this.destroyWorker(workerNode.worker)
       })
     )
@@ -329,7 +345,8 @@ export abstract class AbstractPool<
           (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)
+          // Kill message received from the worker: no new tasks are submitted to that worker for a while ( > maxInactiveTime)
+          this.flushTasksQueueByWorker(workerCreated)
           void this.destroyWorker(workerCreated)
         }
       })
@@ -399,14 +416,14 @@ export abstract class AbstractPool<
   }
 
   /**
-   * This function is the listener registered for each worker.
+   * This function is the listener registered for each worker message.
    *
    * @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 != null) {
-        // Task response received
+        // Task execution response received
         const promiseResponse = this.promiseResponseMap.get(message.id)
         if (promiseResponse != null) {
           if (message.error != null) {
@@ -416,6 +433,16 @@ export abstract class AbstractPool<
           }
           this.afterPromiseResponseHook(promiseResponse.worker, message)
           this.promiseResponseMap.delete(message.id)
+          const workerNodeKey = this.getWorkerNodeKey(promiseResponse.worker)
+          if (
+            this.opts.enableTasksQueue === true &&
+            this.tasksQueueSize(workerNodeKey) > 0
+          ) {
+            this.sendToWorker(
+              promiseResponse.worker,
+              this.dequeueTask(workerNodeKey) as Task<Data>
+            )
+          }
         }
       }
     }
@@ -436,20 +463,28 @@ export abstract class AbstractPool<
     })
   }
 
-  private checkAndEmitBusy (): void {
-    if (this.opts.enableEvents === true && this.busy) {
-      this.emitter?.emit(PoolEvents.busy)
+  private checkAndEmitEvents (): void {
+    if (this.opts.enableEvents === true) {
+      if (this.busy) {
+        this.emitter?.emit(PoolEvents.busy)
+      }
+      if (this.type === PoolType.DYNAMIC && this.full) {
+        this.emitter?.emit(PoolEvents.full)
+      }
     }
   }
 
-  private checkAndEmitFull (): void {
-    if (
-      this.type === PoolType.DYNAMIC &&
-      this.opts.enableEvents === true &&
-      this.full
-    ) {
-      this.emitter?.emit(PoolEvents.full)
-    }
+  /**
+   * Sets the given worker node its tasks usage in the pool.
+   *
+   * @param workerNode - The worker node.
+   * @param tasksUsage - The worker node tasks usage.
+   */
+  private setWorkerNodeTasksUsage (
+    workerNode: WorkerNode<Worker, Data>,
+    tasksUsage: TasksUsage
+  ): void {
+    workerNode.tasksUsage = tasksUsage
   }
 
   /**
@@ -514,21 +549,35 @@ export abstract class AbstractPool<
    *
    * @param worker - The worker.
    */
-  protected removeWorkerNode (worker: Worker): void {
+  private removeWorkerNode (worker: Worker): void {
     const workerNodeKey = this.getWorkerNodeKey(worker)
     this.workerNodes.splice(workerNodeKey, 1)
     this.workerChoiceStrategyContext.remove(workerNodeKey)
   }
 
-  protected enqueueTask (workerNodeKey: number, task: Task<Data>): void {
+  private enqueueTask (workerNodeKey: number, task: Task<Data>): void {
     this.workerNodes[workerNodeKey].tasksQueue.push(task)
   }
 
-  protected dequeueTask (workerNodeKey: number): Task<Data> | undefined {
+  private dequeueTask (workerNodeKey: number): Task<Data> | undefined {
     return this.workerNodes[workerNodeKey].tasksQueue.shift()
   }
 
-  protected tasksQueueLength (workerNodeKey: number): number {
+  private tasksQueueSize (workerNodeKey: number): number {
     return this.workerNodes[workerNodeKey].tasksQueue.length
   }
+
+  private flushTasksQueue (workerNodeKey: number): void {
+    if (this.tasksQueueSize(workerNodeKey) > 0) {
+      for (const task of this.workerNodes[workerNodeKey].tasksQueue) {
+        this.sendToWorker(this.workerNodes[workerNodeKey].worker, task)
+      }
+      this.workerNodes[workerNodeKey].tasksQueue = []
+    }
+  }
+
+  private flushTasksQueueByWorker (worker: Worker): void {
+    const workerNodeKey = this.getWorkerNodeKey(worker)
+    this.flushTasksQueue(workerNodeKey)
+  }
 }