src/pools/worker.ts

   1 import type { CircularArray } from '../circular-array'
   2 import type { Queue } from '../queue'
   3
   4 /**
   5  * Callback invoked if the worker has received a message.
   6  */
   7 export type MessageHandler<Worker extends IWorker> = (
   8   this: Worker,
   9   message: unknown
  10 ) => void
  11
  12 /**
  13  * Callback invoked if the worker raised an error.
  14  */
  15 export type ErrorHandler<Worker extends IWorker> = (
  16   this: Worker,
  17   error: Error
  18 ) => void
  19
  20 /**
  21  * Callback invoked when the worker has started successfully.
  22  */
  23 export type OnlineHandler<Worker extends IWorker> = (this: Worker) => void
  24
  25 /**
  26  * Callback invoked when the worker exits successfully.
  27  */
  28 export type ExitHandler<Worker extends IWorker> = (
  29   this: Worker,
  30   exitCode: number
  31 ) => void
  32
  33 /**
  34  * Message object that is passed as a task between main worker and worker.
  35  *
  36  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  37  * @internal
  38  */
  39 export interface Task<Data = unknown> {
  40   /**
  41    * Task name.
  42    */
  43   readonly name?: string
  44   /**
  45    * Task input data that will be passed to the worker.
  46    */
  47   readonly data?: Data
  48   /**
  49    * Timestamp.
  50    */
  51   readonly timestamp?: number
  52   /**
  53    * Message UUID.
  54    */
  55   readonly id?: string
  56 }
  57
  58 /**
  59  * Measurement statistics.
  60  *
  61  * @internal
  62  */
  63 export interface MeasurementStatistics {
  64   /**
  65    * Measurement aggregate.
  66    */
  67   aggregate: number
  68   /**
  69    * Measurement average.
  70    */
  71   average: number
  72   /**
  73    * Measurement median.
  74    */
  75   median: number
  76   /**
  77    * Measurement history.
  78    */
  79   history: CircularArray<number>
  80 }
  81
  82 /**
  83  * Event loop utilization measurement statistics.
  84  *
  85  * @internal
  86  */
  87 export interface EventLoopUtilizationMeasurementStatistics {
  88   idle: MeasurementStatistics
  89   active: MeasurementStatistics
  90   utilization: number
  91 }
  92
  93 /**
  94  * Task statistics.
  95  *
  96  * @internal
  97  */
  98 export interface TaskStatistics {
  99   /**
 100    * Number of executed tasks.
 101    */
 102   executed: number
 103   /**
 104    * Number of executing tasks.
 105    */
 106   executing: number
 107   /**
 108    * Number of queued tasks.
 109    */
 110   readonly queued: number
 111   /**
 112    * Maximum number of queued tasks.
 113    */
 114   readonly maxQueued: number
 115   /**
 116    * Number of failed tasks.
 117    */
 118   failed: number
 119 }
 120
 121 /**
 122  * Worker information.
 123  *
 124  * @internal
 125  */
 126 export interface WorkerInfo {
 127   /**
 128    * Worker id.
 129    */
 130   id: number | undefined
 131   /**
 132    * Started flag.
 133    */
 134   started: boolean
 135 }
 136
 137 /**
 138  * Worker usage statistics.
 139  *
 140  * @internal
 141  */
 142 export interface WorkerUsage {
 143   /**
 144    * Tasks statistics.
 145    */
 146   tasks: TaskStatistics
 147   /**
 148    * Tasks runtime statistics.
 149    */
 150   runTime: MeasurementStatistics
 151   /**
 152    * Tasks wait time statistics.
 153    */
 154   waitTime: MeasurementStatistics
 155   /**
 156    * Tasks event loop utilization statistics.
 157    */
 158   elu: EventLoopUtilizationMeasurementStatistics
 159 }
 160
 161 /**
 162  * Worker interface.
 163  */
 164 export interface IWorker {
 165   /**
 166    * Worker id.
 167    */
 168   readonly id?: number
 169   readonly threadId?: number
 170   /**
 171    * Register an event listener.
 172    *
 173    * @param event - The event.
 174    * @param handler - The event handler.
 175    */
 176   on: ((event: 'message', handler: MessageHandler<this>) => void) &
 177   ((event: 'error', handler: ErrorHandler<this>) => void) &
 178   ((event: 'online', handler: OnlineHandler<this>) => void) &
 179   ((event: 'exit', handler: ExitHandler<this>) => void)
 180   /**
 181    * Register a listener to the exit event that will only be performed once.
 182    *
 183    * @param event - `'exit'`.
 184    * @param handler - The exit handler.
 185    */
 186   once: (event: 'exit', handler: ExitHandler<this>) => void
 187 }
 188
 189 /**
 190  * Worker node interface.
 191  *
 192  * @typeParam Worker - Type of worker.
 193  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 194  * @internal
 195  */
 196 export interface WorkerNode<Worker extends IWorker, Data = unknown> {
 197   /**
 198    * Worker node worker.
 199    */
 200   readonly worker: Worker
 201   /**
 202    * Worker node worker info.
 203    */
 204   info: WorkerInfo
 205   /**
 206    * Worker node worker usage statistics.
 207    */
 208   usage: WorkerUsage
 209   /**
 210    * Worker node tasks queue.
 211    */
 212   readonly tasksQueue: Queue<Task<Data>>
 213 }