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 when the worker has started successfully.
   7  */
   8 export type OnlineHandler<Worker extends IWorker> = (this: Worker) => void
   9
  10 /**
  11  * Callback invoked if the worker has received a message.
  12  */
  13 export type MessageHandler<Worker extends IWorker> = (
  14   this: Worker,
  15   message: unknown
  16 ) => void
  17
  18 /**
  19  * Callback invoked if the worker raised an error.
  20  */
  21 export type ErrorHandler<Worker extends IWorker> = (
  22   this: Worker,
  23   error: Error
  24 ) => 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
 146 /**
 147  * Worker usage statistics.
 148  *
 149  * @internal
 150  */
 151 export interface WorkerUsage {
 152   /**
 153    * Tasks statistics.
 154    */
 155   readonly tasks: TaskStatistics
 156   /**
 157    * Tasks runtime statistics.
 158    */
 159   readonly runTime: MeasurementStatistics
 160   /**
 161    * Tasks wait time statistics.
 162    */
 163   readonly waitTime: MeasurementStatistics
 164   /**
 165    * Tasks event loop utilization statistics.
 166    */
 167   readonly elu: EventLoopUtilizationMeasurementStatistics
 168 }
 169
 170 /**
 171  * Worker interface.
 172  */
 173 export interface IWorker {
 174   /**
 175    * Worker id.
 176    */
 177   readonly id?: number
 178   readonly threadId?: number
 179   /**
 180    * Registers an event listener.
 181    *
 182    * @param event - The event.
 183    * @param handler - The event handler.
 184    */
 185   readonly on: ((event: 'online', handler: OnlineHandler<this>) => void) &
 186   ((event: 'message', handler: MessageHandler<this>) => void) &
 187   ((event: 'error', handler: ErrorHandler<this>) => void) &
 188   ((event: 'exit', handler: ExitHandler<this>) => void)
 189   /**
 190    * Registers a listener to the exit event that will only be performed once.
 191    *
 192    * @param event - `'exit'`.
 193    * @param handler - The exit handler.
 194    */
 195   readonly once: (event: 'exit', handler: ExitHandler<this>) => void
 196 }
 197
 198 /**
 199  * Worker node interface.
 200  *
 201  * @typeParam Worker - Type of worker.
 202  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 203  * @internal
 204  */
 205 export interface IWorkerNode<Worker extends IWorker, Data = unknown> {
 206   /**
 207    * Worker.
 208    */
 209   readonly worker: Worker
 210   /**
 211    * Worker info.
 212    */
 213   readonly info: WorkerInfo
 214   /**
 215    * Message channel.
 216    */
 217   readonly messageChannel?: MessageChannel
 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 tasks 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    * Whether the worker node has back pressure (i.e. its tasks queue is full).
 247    *
 248    * @returns `true` if the worker node has back pressure, `false` otherwise.
 249    */
 250   readonly hasBackPressure: () => boolean
 251   /**
 252    * Resets usage statistics.
 253    */
 254   readonly resetUsage: () => void
 255   /**
 256    * Closes communication channel.
 257    */
 258   readonly closeChannel: () => void
 259   /**
 260    * Gets task function worker usage statistics.
 261    *
 262    * @param name - The task function name.
 263    * @returns The task function worker usage statistics if the task function worker usage statistics are initialized, `undefined` otherwise.
 264    */
 265   readonly getTaskFunctionWorkerUsage: (name: string) => WorkerUsage | undefined
 266 }