src/pools/pool.ts

   1 import { EventEmitter } from 'node:events'
   2 import type {
   3   ErrorHandler,
   4   ExitHandler,
   5   IWorker,
   6   MessageHandler,
   7   OnlineHandler,
   8   WorkerNode
   9 } from './worker'
  10 import type {
  11   WorkerChoiceStrategy,
  12   WorkerChoiceStrategyOptions
  13 } from './selection-strategies/selection-strategies-types'
  14
  15 /**
  16  * Enumeration of pool types.
  17  */
  18 export const PoolTypes = Object.freeze({
  19   /**
  20    * Fixed pool type.
  21    */
  22   fixed: 'fixed',
  23   /**
  24    * Dynamic pool type.
  25    */
  26   dynamic: 'dynamic'
  27 } as const)
  28
  29 /**
  30  * Pool type.
  31  */
  32 export type PoolType = keyof typeof PoolTypes
  33
  34 /**
  35  * Enumeration of worker types.
  36  */
  37 export const WorkerTypes = Object.freeze({
  38   cluster: 'cluster',
  39   thread: 'thread'
  40 } as const)
  41
  42 /**
  43  * Worker type.
  44  */
  45 export type WorkerType = keyof typeof WorkerTypes
  46
  47 /**
  48  * Pool events emitter.
  49  */
  50 export class PoolEmitter extends EventEmitter {}
  51
  52 /**
  53  * Enumeration of pool events.
  54  */
  55 export const PoolEvents = Object.freeze({
  56   full: 'full',
  57   busy: 'busy',
  58   error: 'error',
  59   taskError: 'taskError'
  60 } as const)
  61
  62 /**
  63  * Pool event.
  64  */
  65 export type PoolEvent = keyof typeof PoolEvents
  66
  67 /**
  68  * Pool information.
  69  */
  70 export interface PoolInfo {
  71   version: string
  72   type: PoolType
  73   worker: WorkerType
  74   minSize: number
  75   maxSize: number
  76   /** Pool utilization ratio. */
  77   utilization?: number
  78   /** Pool total worker nodes */
  79   workerNodes: number
  80   /** Pool idle worker nodes */
  81   idleWorkerNodes: number
  82   /** Pool busy worker nodes */
  83   busyWorkerNodes: number
  84   executedTasks: number
  85   executingTasks: number
  86   queuedTasks: number
  87   maxQueuedTasks: number
  88   failedTasks: number
  89 }
  90
  91 /**
  92  * Worker tasks queue options.
  93  */
  94 export interface TasksQueueOptions {
  95   /**
  96    * Maximum number of tasks that can be executed concurrently on a worker.
  97    *
  98    * @defaultValue 1
  99    */
 100   readonly concurrency?: number
 101 }
 102
 103 /**
 104  * Options for a poolifier pool.
 105  *
 106  * @typeParam Worker - Type of worker.
 107  */
 108 export interface PoolOptions<Worker extends IWorker> {
 109   /**
 110    * A function that will listen for message event on each worker.
 111    */
 112   messageHandler?: MessageHandler<Worker>
 113   /**
 114    * A function that will listen for error event on each worker.
 115    */
 116   errorHandler?: ErrorHandler<Worker>
 117   /**
 118    * A function that will listen for online event on each worker.
 119    */
 120   onlineHandler?: OnlineHandler<Worker>
 121   /**
 122    * A function that will listen for exit event on each worker.
 123    */
 124   exitHandler?: ExitHandler<Worker>
 125   /**
 126    * The worker choice strategy to use in this pool.
 127    *
 128    * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
 129    */
 130   workerChoiceStrategy?: WorkerChoiceStrategy
 131   /**
 132    * The worker choice strategy options.
 133    */
 134   workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 135   /**
 136    * Restart worker on error.
 137    */
 138   restartWorkerOnError?: boolean
 139   /**
 140    * Pool events emission.
 141    *
 142    * @defaultValue true
 143    */
 144   enableEvents?: boolean
 145   /**
 146    * Pool worker tasks queue.
 147    *
 148    * @defaultValue false
 149    */
 150   enableTasksQueue?: boolean
 151   /**
 152    * Pool worker tasks queue options.
 153    */
 154   tasksQueueOptions?: TasksQueueOptions
 155 }
 156
 157 /**
 158  * Contract definition for a poolifier pool.
 159  *
 160  * @typeParam Worker - Type of worker which manages this pool.
 161  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 162  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
 163  */
 164 export interface IPool<
 165   Worker extends IWorker,
 166   Data = unknown,
 167   Response = unknown
 168 > {
 169   /**
 170    * Pool information.
 171    */
 172   readonly info: PoolInfo
 173   /**
 174    * Pool worker nodes.
 175    */
 176   readonly workerNodes: Array<WorkerNode<Worker, Data>>
 177   /**
 178    * Emitter on which events can be listened to.
 179    *
 180    * Events that can currently be listened to:
 181    *
 182    * - `'full'`: Emitted when the pool is dynamic and full.
 183    * - `'busy'`: Emitted when the pool is busy.
 184    * - `'error'`: Emitted when an uncaught error occurs.
 185    * - `'taskError'`: Emitted when an error occurs while executing a task.
 186    */
 187   readonly emitter?: PoolEmitter
 188   /**
 189    * Executes the specified function in the worker constructor with the task data input parameter.
 190    *
 191    * @param data - The task input data for the specified worker function. This can only be structured-cloneable data.
 192    * @param name - The name of the worker function to execute. If not specified, the default worker function will be executed.
 193    * @returns Promise that will be fulfilled when the task is completed.
 194    */
 195   execute: (data?: Data, name?: string) => Promise<Response>
 196   /**
 197    * Terminates every current worker in this pool.
 198    */
 199   destroy: () => Promise<void>
 200   /**
 201    * Sets the worker choice strategy in this pool.
 202    *
 203    * @param workerChoiceStrategy - The worker choice strategy.
 204    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 205    */
 206   setWorkerChoiceStrategy: (
 207     workerChoiceStrategy: WorkerChoiceStrategy,
 208     workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 209   ) => void
 210   /**
 211    * Sets the worker choice strategy options in this pool.
 212    *
 213    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 214    */
 215   setWorkerChoiceStrategyOptions: (
 216     workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
 217   ) => void
 218   /**
 219    * Enables/disables the worker tasks queue in this pool.
 220    *
 221    * @param enable - Whether to enable or disable the worker tasks queue.
 222    * @param tasksQueueOptions - The worker tasks queue options.
 223    */
 224   enableTasksQueue: (
 225     enable: boolean,
 226     tasksQueueOptions?: TasksQueueOptions
 227   ) => void
 228   /**
 229    * Sets the worker tasks queue options in this pool.
 230    *
 231    * @param tasksQueueOptions - The worker tasks queue options.
 232    */
 233   setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
 234 }