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   runTime?: {
  90     minimum: number
  91     maximum: number
  92   }
  93   waitTime?: {
  94     minimum: number
  95     maximum: number
  96   }
  97 }
  98
  99 /**
 100  * Worker tasks queue options.
 101  */
 102 export interface TasksQueueOptions {
 103   /**
 104    * Maximum number of tasks that can be executed concurrently on a worker.
 105    *
 106    * @defaultValue 1
 107    */
 108   readonly concurrency?: number
 109 }
 110
 111 /**
 112  * Options for a poolifier pool.
 113  *
 114  * @typeParam Worker - Type of worker.
 115  */
 116 export interface PoolOptions<Worker extends IWorker> {
 117   /**
 118    * A function that will listen for message event on each worker.
 119    */
 120   messageHandler?: MessageHandler<Worker>
 121   /**
 122    * A function that will listen for error event on each worker.
 123    */
 124   errorHandler?: ErrorHandler<Worker>
 125   /**
 126    * A function that will listen for online event on each worker.
 127    */
 128   onlineHandler?: OnlineHandler<Worker>
 129   /**
 130    * A function that will listen for exit event on each worker.
 131    */
 132   exitHandler?: ExitHandler<Worker>
 133   /**
 134    * The worker choice strategy to use in this pool.
 135    *
 136    * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
 137    */
 138   workerChoiceStrategy?: WorkerChoiceStrategy
 139   /**
 140    * The worker choice strategy options.
 141    */
 142   workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 143   /**
 144    * Restart worker on error.
 145    */
 146   restartWorkerOnError?: boolean
 147   /**
 148    * Pool events emission.
 149    *
 150    * @defaultValue true
 151    */
 152   enableEvents?: boolean
 153   /**
 154    * Pool worker tasks queue.
 155    *
 156    * @defaultValue false
 157    */
 158   enableTasksQueue?: boolean
 159   /**
 160    * Pool worker tasks queue options.
 161    */
 162   tasksQueueOptions?: TasksQueueOptions
 163 }
 164
 165 /**
 166  * Contract definition for a poolifier pool.
 167  *
 168  * @typeParam Worker - Type of worker which manages this pool.
 169  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 170  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
 171  */
 172 export interface IPool<
 173   Worker extends IWorker,
 174   Data = unknown,
 175   Response = unknown
 176 > {
 177   /**
 178    * Pool information.
 179    */
 180   readonly info: PoolInfo
 181   /**
 182    * Pool worker nodes.
 183    */
 184   readonly workerNodes: Array<WorkerNode<Worker, Data>>
 185   /**
 186    * Emitter on which events can be listened to.
 187    *
 188    * Events that can currently be listened to:
 189    *
 190    * - `'full'`: Emitted when the pool is dynamic and full.
 191    * - `'busy'`: Emitted when the pool is busy.
 192    * - `'error'`: Emitted when an uncaught error occurs.
 193    * - `'taskError'`: Emitted when an error occurs while executing a task.
 194    */
 195   readonly emitter?: PoolEmitter
 196   /**
 197    * Executes the specified function in the worker constructor with the task data input parameter.
 198    *
 199    * @param data - The task input data for the specified worker function. This can only be structured-cloneable data.
 200    * @param name - The name of the worker function to execute. If not specified, the default worker function will be executed.
 201    * @returns Promise that will be fulfilled when the task is completed.
 202    */
 203   execute: (data?: Data, name?: string) => Promise<Response>
 204   /**
 205    * Terminates every current worker in this pool.
 206    */
 207   destroy: () => Promise<void>
 208   /**
 209    * Sets the worker choice strategy in this pool.
 210    *
 211    * @param workerChoiceStrategy - The worker choice strategy.
 212    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 213    */
 214   setWorkerChoiceStrategy: (
 215     workerChoiceStrategy: WorkerChoiceStrategy,
 216     workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 217   ) => void
 218   /**
 219    * Sets the worker choice strategy options in this pool.
 220    *
 221    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 222    */
 223   setWorkerChoiceStrategyOptions: (
 224     workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
 225   ) => void
 226   /**
 227    * Enables/disables the worker tasks queue in this pool.
 228    *
 229    * @param enable - Whether to enable or disable the worker tasks queue.
 230    * @param tasksQueueOptions - The worker tasks queue options.
 231    */
 232   enableTasksQueue: (
 233     enable: boolean,
 234     tasksQueueOptions?: TasksQueueOptions
 235   ) => void
 236   /**
 237    * Sets the worker tasks queue options in this pool.
 238    *
 239    * @param tasksQueueOptions - The worker tasks queue options.
 240    */
 241   setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
 242 }