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 usage statistics.
 123  *
 124  * @internal
 125  */
 126 export interface WorkerUsage {
 127   /**
 128    * Tasks statistics.
 129    */
 130   tasks: TaskStatistics
 131   /**
 132    * Tasks runtime statistics.
 133    */
 134   runTime: MeasurementStatistics
 135   /**
 136    * Tasks wait time statistics.
 137    */
 138   waitTime: MeasurementStatistics
 139   /**
 140    * Tasks event loop utilization statistics.
 141    */
 142   elu: EventLoopUtilizationMeasurementStatistics
 143 }
 144
 145 /**
 146  * Worker interface.
 147  */
 148 export interface IWorker {
 149   /**
 150    * Register an event listener.
 151    *
 152    * @param event - The event.
 153    * @param handler - The event handler.
 154    */
 155   on: ((event: 'message', handler: MessageHandler<this>) => void) &
 156   ((event: 'error', handler: ErrorHandler<this>) => void) &
 157   ((event: 'online', handler: OnlineHandler<this>) => void) &
 158   ((event: 'exit', handler: ExitHandler<this>) => void)
 159   /**
 160    * Register a listener to the exit event that will only be performed once.
 161    *
 162    * @param event - `'exit'`.
 163    * @param handler - The exit handler.
 164    */
 165   once: (event: 'exit', handler: ExitHandler<this>) => void
 166 }
 167
 168 /**
 169  * Worker node interface.
 170  *
 171  * @typeParam Worker - Type of worker.
 172  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 173  * @internal
 174  */
 175 export interface WorkerNode<Worker extends IWorker, Data = unknown> {
 176   /**
 177    * Worker node worker.
 178    */
 179   readonly worker: Worker
 180   /**
 181    * Worker node worker usage statistics.
 182    */
 183   workerUsage: WorkerUsage
 184   /**
 185    * Worker node tasks queue.
 186    */
 187   readonly tasksQueue: Queue<Task<Data>>
 188 }