src/pools/pool.ts

   1 import EventEmitter from 'events'
   2 import type {
   3   ErrorHandler,
   4   ExitHandler,
   5   MessageHandler,
   6   OnlineHandler
   7 } from './pool-worker'
   8 import type { WorkerChoiceStrategy } from './selection-strategies/selection-strategies-types'
   9
  10 /**
  11  * Pool events emitter.
  12  */
  13 export class PoolEmitter extends EventEmitter {}
  14
  15 /**
  16  * Options for a poolifier pool.
  17  */
  18 export interface PoolOptions<Worker> {
  19   /**
  20    * A function that will listen for message event on each worker.
  21    */
  22   messageHandler?: MessageHandler<Worker>
  23   /**
  24    * A function that will listen for error event on each worker.
  25    */
  26   errorHandler?: ErrorHandler<Worker>
  27   /**
  28    * A function that will listen for online event on each worker.
  29    */
  30   onlineHandler?: OnlineHandler<Worker>
  31   /**
  32    * A function that will listen for exit event on each worker.
  33    */
  34   exitHandler?: ExitHandler<Worker>
  35   /**
  36    * The worker choice strategy to use in this pool.
  37    */
  38   workerChoiceStrategy?: WorkerChoiceStrategy
  39   /**
  40    * Pool events emission.
  41    *
  42    * @defaultValue true
  43    */
  44   enableEvents?: boolean
  45 }
  46
  47 /**
  48  * Contract definition for a poolifier pool.
  49  *
  50  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  51  * @typeParam Response - Type of response of execution. This can only be serializable data.
  52  */
  53 export interface IPool<Data = unknown, Response = unknown> {
  54   /**
  55    * Emitter on which events can be listened to.
  56    *
  57    * Events that can currently be listened to:
  58    *
  59    * - `'busy'`
  60    */
  61   readonly emitter?: PoolEmitter
  62   /**
  63    * Performs the task specified in the constructor with the data parameter.
  64    *
  65    * @param data - The input for the specified task. This can only be serializable data.
  66    * @returns Promise that will be resolved when the task is successfully completed.
  67    */
  68   execute: (data: Data) => Promise<Response>
  69   /**
  70    * Shutdowns every current worker in this pool.
  71    */
  72   destroy: () => Promise<void>
  73   /**
  74    * Sets the worker choice strategy in this pool.
  75    *
  76    * @param workerChoiceStrategy - The worker choice strategy.
  77    */
  78   setWorkerChoiceStrategy: (workerChoiceStrategy: WorkerChoiceStrategy) => void
  79 }