src/pools/worker.ts

   1 import type { MessageChannel } from 'node:worker_threads'
   2 import type { CircularArray } from '../circular-array'
   3 import type { Task } from '../utility-types'
   4
   5 /**
   6  * Callback invoked if the worker has received a message.
   7  */
   8 export type MessageHandler<Worker extends IWorker> = (
   9   this: Worker,
  10   message: unknown
  11 ) => void
  12
  13 /**
  14  * Callback invoked if the worker raised an error.
  15  */
  16 export type ErrorHandler<Worker extends IWorker> = (
  17   this: Worker,
  18   error: Error
  19 ) => void
  20
  21 /**
  22  * Callback invoked when the worker has started successfully.
  23  */
  24 export type OnlineHandler<Worker extends IWorker> = (this: Worker) => void
  25
  26 /**
  27  * Callback invoked when the worker exits successfully.
  28  */
  29 export type ExitHandler<Worker extends IWorker> = (
  30   this: Worker,
  31   exitCode: number
  32 ) => void
  33
  34 /**
  35  * Measurement statistics.
  36  *
  37  * @internal
  38  */
  39 export interface MeasurementStatistics {
  40   /**
  41    * Measurement aggregate.
  42    */
  43   aggregate?: number
  44   /**
  45    * Measurement minimum.
  46    */
  47   minimum?: number
  48   /**
  49    * Measurement maximum.
  50    */
  51   maximum?: number
  52   /**
  53    * Measurement average.
  54    */
  55   average?: number
  56   /**
  57    * Measurement median.
  58    */
  59   median?: number
  60   /**
  61    * Measurement history.
  62    */
  63   readonly history: CircularArray<number>
  64 }
  65
  66 /**
  67  * Event loop utilization measurement statistics.
  68  *
  69  * @internal
  70  */
  71 export interface EventLoopUtilizationMeasurementStatistics {
  72   readonly idle: MeasurementStatistics
  73   readonly active: MeasurementStatistics
  74   utilization?: number
  75 }
  76
  77 /**
  78  * Task statistics.
  79  *
  80  * @internal
  81  */
  82 export interface TaskStatistics {
  83   /**
  84    * Number of executed tasks.
  85    */
  86   executed: number
  87   /**
  88    * Number of executing tasks.
  89    */
  90   executing: number
  91   /**
  92    * Number of queued tasks.
  93    */
  94   readonly queued: number
  95   /**
  96    * Maximum number of queued tasks.
  97    */
  98   readonly maxQueued?: number
  99   /**
 100    * Number of failed tasks.
 101    */
 102   failed: number
 103 }
 104
 105 /**
 106  * Enumeration of worker types.
 107  */
 108 export const WorkerTypes = Object.freeze({
 109   thread: 'thread',
 110   cluster: 'cluster'
 111 } as const)
 112
 113 /**
 114  * Worker type.
 115  */
 116 export type WorkerType = keyof typeof WorkerTypes
 117
 118 /**
 119  * Worker information.
 120  *
 121  * @internal
 122  */
 123 export interface WorkerInfo {
 124   /**
 125    * Worker id.
 126    */
 127   readonly id: number | undefined
 128   /**
 129    * Worker type.
 130    */
 131   type: WorkerType
 132   /**
 133    * Dynamic flag.
 134    */
 135   dynamic: boolean
 136   /**
 137    * Ready flag.
 138    */
 139   ready: boolean
 140   /**
 141    * Task function names.
 142    */
 143   taskFunctions?: string[]
 144   /**
 145    * Message channel.
 146    */
 147   messageChannel?: MessageChannel
 148 }
 149
 150 /**
 151  * Worker usage statistics.
 152  *
 153  * @internal
 154  */
 155 export interface WorkerUsage {
 156   /**
 157    * Tasks statistics.
 158    */
 159   readonly tasks: TaskStatistics
 160   /**
 161    * Tasks runtime statistics.
 162    */
 163   readonly runTime: MeasurementStatistics
 164   /**
 165    * Tasks wait time statistics.
 166    */
 167   readonly waitTime: MeasurementStatistics
 168   /**
 169    * Tasks event loop utilization statistics.
 170    */
 171   readonly elu: EventLoopUtilizationMeasurementStatistics
 172 }
 173
 174 /**
 175  * Worker interface.
 176  */
 177 export interface IWorker {
 178   /**
 179    * Worker id.
 180    */
 181   readonly id?: number
 182   readonly threadId?: number
 183   /**
 184    * Registers an event listener.
 185    *
 186    * @param event - The event.
 187    * @param handler - The event handler.
 188    */
 189   readonly on: ((event: 'online', handler: OnlineHandler<this>) => void) &
 190   ((event: 'message', handler: MessageHandler<this>) => void) &
 191   ((event: 'error', handler: ErrorHandler<this>) => void) &
 192   ((event: 'exit', handler: ExitHandler<this>) => void)
 193   /**
 194    * Registers a listener to the exit event that will only be performed once.
 195    *
 196    * @param event - `'exit'`.
 197    * @param handler - The exit handler.
 198    */
 199   readonly once: (event: 'exit', handler: ExitHandler<this>) => void
 200 }
 201
 202 /**
 203  * Worker node interface.
 204  *
 205  * @typeParam Worker - Type of worker.
 206  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 207  * @internal
 208  */
 209 export interface IWorkerNode<Worker extends IWorker, Data = unknown> {
 210   /**
 211    * Worker.
 212    */
 213   readonly worker: Worker
 214   /**
 215    * Worker info.
 216    */
 217   readonly info: WorkerInfo
 218   /**
 219    * Worker usage statistics.
 220    */
 221   usage: WorkerUsage
 222   /**
 223    * Tasks queue size.
 224    *
 225    * @returns The tasks queue size.
 226    */
 227   readonly tasksQueueSize: () => number
 228   /**
 229    * Enqueue task.
 230    *
 231    * @param task - The task to queue.
 232    * @returns The task queue size.
 233    */
 234   readonly enqueueTask: (task: Task<Data>) => number
 235   /**
 236    * Dequeue task.
 237    *
 238    * @returns The dequeued task.
 239    */
 240   readonly dequeueTask: () => Task<Data> | undefined
 241   /**
 242    * Clears tasks queue.
 243    */
 244   readonly clearTasksQueue: () => void
 245   /**
 246    * Resets usage statistics .
 247    */
 248   readonly resetUsage: () => void
 249   /**
 250    * Close communication channel.
 251    */
 252   readonly closeChannel: () => void
 253   /**
 254    * Gets task worker usage statistics.
 255    */
 256   readonly getTaskWorkerUsage: (name: string) => WorkerUsage | undefined
 257 }