feat: introduce worker node queue back pressure detection

[poolifier.git] / src / pools / pool.ts

diff --git a/src/pools/pool.ts b/src/pools/pool.ts
index 78d298f90f20381d3cb2157d276e32ced109f4a2..26ca4c03279ad9969df3940141cf0bade3b815b4 100644 (file)
--- a/src/pools/pool.ts
+++ b/src/pools/pool.ts
@@ -1,4 +1,5 @@
 import { EventEmitter } from 'node:events'
+import { type TransferListItem } from 'node:worker_threads'
 import type {
   ErrorHandler,
   ExitHandler,
@@ -41,11 +42,13 @@ export class PoolEmitter extends EventEmitter {}
  * Enumeration of pool events.
  */
 export const PoolEvents = Object.freeze({
-  full: 'full',
   ready: 'ready',
   busy: 'busy',
+  full: 'full',
+  destroy: 'destroy',
   error: 'error',
-  taskError: 'taskError'
+  taskError: 'taskError',
+  backPressure: 'backPressure'
 } as const)
 
 /**
@@ -64,18 +67,18 @@ export interface PoolInfo {
   readonly strategy: WorkerChoiceStrategy
   readonly minSize: number
   readonly maxSize: number
-  /** Pool utilization ratio. */
+  /** Pool utilization. */
   readonly utilization?: number
-  /** Pool total worker nodes */
+  /** Pool total worker nodes. */
   readonly workerNodes: number
-  /** Pool idle worker nodes */
+  /** Pool idle worker nodes. */
   readonly idleWorkerNodes: number
-  /** Pool busy worker nodes */
+  /** Pool busy worker nodes. */
   readonly busyWorkerNodes: number
   readonly executedTasks: number
   readonly executingTasks: number
-  readonly queuedTasks: number
-  readonly maxQueuedTasks: number
+  readonly queuedTasks?: number
+  readonly maxQueuedTasks?: number
   readonly failedTasks: number
   readonly runTime?: {
     readonly minimum: number
@@ -109,6 +112,10 @@ export interface TasksQueueOptions {
  * @typeParam Worker - Type of worker.
  */
 export interface PoolOptions<Worker extends IWorker> {
+  /**
+   * A function that will listen for online event on each worker.
+   */
+  onlineHandler?: OnlineHandler<Worker>
   /**
    * A function that will listen for message event on each worker.
    */
@@ -117,10 +124,6 @@ export interface PoolOptions<Worker extends IWorker> {
    * A function that will listen for error event on each worker.
    */
   errorHandler?: ErrorHandler<Worker>
-  /**
-   * A function that will listen for online event on each worker.
-   */
-  onlineHandler?: OnlineHandler<Worker>
   /**
    * A function that will listen for exit event on each worker.
    */
@@ -182,9 +185,10 @@ export interface IPool<
    *
    * Events that can currently be listened to:
    *
-   * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
-   * - `'ready'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are ready.
+   * - `'ready'`: Emitted when the number of workers created in the pool has reached the minimum size expected and are ready.
    * - `'busy'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are executing at least one task.
+   * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
+   * - '`destroy`': Emitted when the pool is destroyed.
    * - `'error'`: Emitted when an uncaught error occurs.
    * - `'taskError'`: Emitted when an error occurs while executing a task.
    */
@@ -192,15 +196,26 @@ export interface IPool<
   /**
    * Executes the specified function in the worker constructor with the task data input parameter.
    *
-   * @param data - The task input data for the specified worker function. This can only be structured-cloneable data.
-   * @param name - The name of the worker function to execute. If not specified, the default worker function will be executed.
+   * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
+   * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
+   * @param transferList - An optional array of transferable objects to transfer ownership of. Ownership of the transferred objects is given to the pool's worker_threads worker and they should not be used in the main thread afterwards.
    * @returns Promise that will be fulfilled when the task is completed.
    */
-  readonly execute: (data?: Data, name?: string) => Promise<Response>
+  readonly execute: (
+    data?: Data,
+    name?: string,
+    transferList?: TransferListItem[]
+  ) => Promise<Response>
   /**
-   * Terminates every current worker in this pool.
+   * Terminates all workers in this pool.
    */
   readonly destroy: () => Promise<void>
+  /**
+   * Lists the names of task function available in this pool.
+   *
+   * @returns The names of task function available in this pool.
+   */
+  readonly listTaskFunctions: () => string[]
   /**
    * Sets the worker choice strategy in this pool.
    *