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  * @typeParam Worker - Type of worker.
   9  */
  10 export type OnlineHandler<Worker extends IWorker> = (this: Worker) => void
  11
  12 /**
  13  * Callback invoked if the worker has received a message.
  14  *
  15  * @typeParam Worker - Type of worker.
  16  */
  17 export type MessageHandler<Worker extends IWorker> = (
  18   this: Worker,
  19   message: unknown
  20 ) => void
  21
  22 /**
  23  * Callback invoked if the worker raised an error.
  24  *
  25  * @typeParam Worker - Type of worker.
  26  */
  27 export type ErrorHandler<Worker extends IWorker> = (
  28   this: Worker,
  29   error: Error
  30 ) => void
  31
  32 /**
  33  * Callback invoked when the worker exits successfully.
  34  *
  35  * @typeParam Worker - Type of worker.
  36  */
  37 export type ExitHandler<Worker extends IWorker> = (
  38   this: Worker,
  39   exitCode: number
  40 ) => void
  41
  42 /**
  43  * Measurement statistics.
  44  *
  45  * @internal
  46  */
  47 export interface MeasurementStatistics {
  48   /**
  49    * Measurement aggregate.
  50    */
  51   aggregate?: number
  52   /**
  53    * Measurement minimum.
  54    */
  55   minimum?: number
  56   /**
  57    * Measurement maximum.
  58    */
  59   maximum?: number
  60   /**
  61    * Measurement average.
  62    */
  63   average?: number
  64   /**
  65    * Measurement median.
  66    */
  67   median?: number
  68   /**
  69    * Measurement history.
  70    */
  71   readonly history: CircularArray<number>
  72 }
  73
  74 /**
  75  * Event loop utilization measurement statistics.
  76  *
  77  * @internal
  78  */
  79 export interface EventLoopUtilizationMeasurementStatistics {
  80   readonly idle: MeasurementStatistics
  81   readonly active: MeasurementStatistics
  82   utilization?: number
  83 }
  84
  85 /**
  86  * Task statistics.
  87  *
  88  * @internal
  89  */
  90 export interface TaskStatistics {
  91   /**
  92    * Number of executed tasks.
  93    */
  94   executed: number
  95   /**
  96    * Number of executing tasks.
  97    */
  98   executing: number
  99   /**
 100    * Number of queued tasks.
 101    */
 102   readonly queued: number
 103   /**
 104    * Maximum number of queued tasks.
 105    */
 106   readonly maxQueued?: number
 107   /**
 108    * Number of stolen tasks.
 109    */
 110   stolen: number
 111   /**
 112    * Number of failed tasks.
 113    */
 114   failed: number
 115 }
 116
 117 /**
 118  * Enumeration of worker types.
 119  */
 120 export const WorkerTypes = Object.freeze({
 121   thread: 'thread',
 122   cluster: 'cluster'
 123 } as const)
 124
 125 /**
 126  * Worker type.
 127  */
 128 export type WorkerType = keyof typeof WorkerTypes
 129
 130 /**
 131  * Worker information.
 132  *
 133  * @internal
 134  */
 135 export interface WorkerInfo {
 136   /**
 137    * Worker id.
 138    */
 139   readonly id: number | undefined
 140   /**
 141    * Worker type.
 142    */
 143   readonly type: WorkerType
 144   /**
 145    * Dynamic flag.
 146    */
 147   dynamic: boolean
 148   /**
 149    * Ready flag.
 150    */
 151   ready: boolean
 152   /**
 153    * Task function names.
 154    */
 155   taskFunctionNames?: string[]
 156 }
 157
 158 /**
 159  * Worker usage statistics.
 160  *
 161  * @internal
 162  */
 163 export interface WorkerUsage {
 164   /**
 165    * Tasks statistics.
 166    */
 167   readonly tasks: TaskStatistics
 168   /**
 169    * Tasks runtime statistics.
 170    */
 171   readonly runTime: MeasurementStatistics
 172   /**
 173    * Tasks wait time statistics.
 174    */
 175   readonly waitTime: MeasurementStatistics
 176   /**
 177    * Tasks event loop utilization statistics.
 178    */
 179   readonly elu: EventLoopUtilizationMeasurementStatistics
 180 }
 181
 182 /**
 183  * Worker choice strategy data.
 184  *
 185  * @internal
 186  */
 187 export interface StrategyData {
 188   virtualTaskEndTimestamp?: number
 189 }
 190
 191 /**
 192  * Worker interface.
 193  */
 194 export interface IWorker {
 195   /**
 196    * Worker id.
 197    */
 198   readonly id?: number
 199   readonly threadId?: number
 200   /**
 201    * Registers an event listener.
 202    *
 203    * @param event - The event.
 204    * @param handler - The event handler.
 205    */
 206   readonly on: ((event: 'online', handler: OnlineHandler<this>) => void) &
 207   ((event: 'message', handler: MessageHandler<this>) => void) &
 208   ((event: 'error', handler: ErrorHandler<this>) => void) &
 209   ((event: 'exit', handler: ExitHandler<this>) => void)
 210   /**
 211    * Registers a listener to the exit event that will only be performed once.
 212    *
 213    * @param event - The `'exit'` event.
 214    * @param handler - The exit handler.
 215    */
 216   readonly once: (event: 'exit', handler: ExitHandler<this>) => void
 217 }
 218
 219 /**
 220  * Worker node event detail.
 221  *
 222  * @internal
 223  */
 224 export interface WorkerNodeEventDetail {
 225   workerId: number
 226 }
 227
 228 /**
 229  * Worker node interface.
 230  *
 231  * @typeParam Worker - Type of worker.
 232  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 233  * @internal
 234  */
 235 export interface IWorkerNode<Worker extends IWorker, Data = unknown>
 236   extends EventTarget {
 237   /**
 238    * Worker.
 239    */
 240   readonly worker: Worker
 241   /**
 242    * Worker info.
 243    */
 244   readonly info: WorkerInfo
 245   /**
 246    * Worker usage statistics.
 247    */
 248   readonly usage: WorkerUsage
 249   /**
 250    * Worker choice strategy data.
 251    * This is used to store data that are specific to the worker choice strategy.
 252    */
 253   strategyData?: StrategyData
 254   /**
 255    * Message channel (worker_threads only).
 256    */
 257   readonly messageChannel?: MessageChannel
 258   /**
 259    * Tasks queue back pressure size.
 260    * This is the number of tasks that can be enqueued before the worker node has back pressure.
 261    */
 262   tasksQueueBackPressureSize: number
 263   /**
 264    * Tasks queue size.
 265    *
 266    * @returns The tasks queue size.
 267    */
 268   readonly tasksQueueSize: () => number
 269   /**
 270    * Enqueue task.
 271    *
 272    * @param task - The task to queue.
 273    * @returns The tasks queue size.
 274    */
 275   readonly enqueueTask: (task: Task<Data>) => number
 276   /**
 277    * Prepends a task to the tasks queue.
 278    *
 279    * @param task - The task to prepend.
 280    * @returns The tasks queue size.
 281    */
 282   readonly unshiftTask: (task: Task<Data>) => number
 283   /**
 284    * Dequeue task.
 285    *
 286    * @returns The dequeued task.
 287    */
 288   readonly dequeueTask: () => Task<Data> | undefined
 289   /**
 290    * Pops a task from the tasks queue.
 291    *
 292    * @returns The popped task.
 293    */
 294   readonly popTask: () => Task<Data> | undefined
 295   /**
 296    * Clears tasks queue.
 297    */
 298   readonly clearTasksQueue: () => void
 299   /**
 300    * Whether the worker node has back pressure (i.e. its tasks queue is full).
 301    *
 302    * @returns `true` if the worker node has back pressure, `false` otherwise.
 303    */
 304   readonly hasBackPressure: () => boolean
 305   /**
 306    * Resets usage statistics.
 307    */
 308   readonly resetUsage: () => void
 309   /**
 310    * Closes communication channel.
 311    */
 312   readonly closeChannel: () => void
 313   /**
 314    * Gets task function worker usage statistics.
 315    *
 316    * @param name - The task function name.
 317    * @returns The task function worker usage statistics if the task function worker usage statistics are initialized, `undefined` otherwise.
 318    */
 319   readonly getTaskFunctionWorkerUsage: (name: string) => WorkerUsage | undefined
 320   /**
 321    * Deletes task function worker usage statistics.
 322    *
 323    * @param name - The task function name.
 324    * @returns `true` if the task function worker usage statistics were deleted, `false` otherwise.
 325    */
 326   readonly deleteTaskFunctionWorkerUsage: (name: string) => boolean
 327 }