src/pools/pool.ts

   1 import EventEmitterAsyncResource 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 EventEmitterAsyncResource {}
  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   type: PoolType
  72   worker: WorkerType
  73   minSize: number
  74   maxSize: number
  75   workerNodes: number
  76   idleWorkerNodes: number
  77   busyWorkerNodes: number
  78   executedTasks: number
  79   executingTasks: number
  80   queuedTasks: number
  81   maxQueuedTasks: number
  82   failedTasks: number
  83 }
  84
  85 /**
  86  * Worker tasks queue options.
  87  */
  88 export interface TasksQueueOptions {
  89   /**
  90    * Maximum number of tasks that can be executed concurrently on a worker.
  91    *
  92    * @defaultValue 1
  93    */
  94   concurrency?: number
  95 }
  96
  97 /**
  98  * Options for a poolifier pool.
  99  *
 100  * @typeParam Worker - Type of worker.
 101  */
 102 export interface PoolOptions<Worker extends IWorker> {
 103   /**
 104    * A function that will listen for message event on each worker.
 105    */
 106   messageHandler?: MessageHandler<Worker>
 107   /**
 108    * A function that will listen for error event on each worker.
 109    */
 110   errorHandler?: ErrorHandler<Worker>
 111   /**
 112    * A function that will listen for online event on each worker.
 113    */
 114   onlineHandler?: OnlineHandler<Worker>
 115   /**
 116    * A function that will listen for exit event on each worker.
 117    */
 118   exitHandler?: ExitHandler<Worker>
 119   /**
 120    * The worker choice strategy to use in this pool.
 121    *
 122    * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
 123    */
 124   workerChoiceStrategy?: WorkerChoiceStrategy
 125   /**
 126    * The worker choice strategy options.
 127    */
 128   workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 129   /**
 130    * Restart worker on error.
 131    */
 132   restartWorkerOnError?: boolean
 133   /**
 134    * Pool events emission.
 135    *
 136    * @defaultValue true
 137    */
 138   enableEvents?: boolean
 139   /**
 140    * Pool worker tasks queue.
 141    *
 142    * @defaultValue false
 143    */
 144   enableTasksQueue?: boolean
 145   /**
 146    * Pool worker tasks queue options.
 147    */
 148   tasksQueueOptions?: TasksQueueOptions
 149 }
 150
 151 /**
 152  * Contract definition for a poolifier pool.
 153  *
 154  * @typeParam Worker - Type of worker which manages this pool.
 155  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
 156  * @typeParam Response - Type of execution response. This can only be serializable data.
 157  */
 158 export interface IPool<
 159   Worker extends IWorker,
 160   Data = unknown,
 161   Response = unknown
 162 > {
 163   /**
 164    * Pool information.
 165    */
 166   readonly info: PoolInfo
 167   /**
 168    * Pool worker nodes.
 169    */
 170   readonly workerNodes: Array<WorkerNode<Worker, Data>>
 171   /**
 172    * Emitter on which events can be listened to.
 173    *
 174    * Events that can currently be listened to:
 175    *
 176    * - `'full'`: Emitted when the pool is dynamic and full.
 177    * - `'busy'`: Emitted when the pool is busy.
 178    * - `'error'`: Emitted when an uncaught error occurs.
 179    * - `'taskError'`: Emitted when an error occurs while executing a task.
 180    */
 181   readonly emitter?: PoolEmitter
 182   /**
 183    * Executes the specified function in the worker constructor with the task data input parameter.
 184    *
 185    * @param data - The task input data for the specified worker function. This can only be serializable data.
 186    * @param name - The name of the worker function to execute. If not specified, the default worker function will be executed.
 187    * @returns Promise that will be fulfilled when the task is completed.
 188    */
 189   execute: (data?: Data, name?: string) => Promise<Response>
 190   /**
 191    * Terminate every current worker in this pool.
 192    */
 193   destroy: () => Promise<void>
 194   /**
 195    * Sets the worker choice strategy in this pool.
 196    *
 197    * @param workerChoiceStrategy - The worker choice strategy.
 198    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 199    */
 200   setWorkerChoiceStrategy: (
 201     workerChoiceStrategy: WorkerChoiceStrategy,
 202     workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 203   ) => void
 204   /**
 205    * Sets the worker choice strategy options in this pool.
 206    *
 207    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 208    */
 209   setWorkerChoiceStrategyOptions: (
 210     workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
 211   ) => void
 212   /**
 213    * Enables/disables the worker tasks queue in this pool.
 214    *
 215    * @param enable - Whether to enable or disable the worker tasks queue.
 216    * @param tasksQueueOptions - The worker tasks queue options.
 217    */
 218   enableTasksQueue: (
 219     enable: boolean,
 220     tasksQueueOptions?: TasksQueueOptions
 221   ) => void
 222   /**
 223    * Sets the worker tasks queue options in this pool.
 224    *
 225    * @param tasksQueueOptions - The worker tasks queue options.
 226    */
 227   setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
 228 }