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   m: 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   e: 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   code: 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 serializable data.
  37  * @internal
  38  */
  39 export interface Task<Data = unknown> {
  40   /**
  41    * Task input data that will be passed to the worker.
  42    */
  43   readonly data?: Data
  44   /**
  45    * UUID of the message.
  46    */
  47   readonly id?: string
  48 }
  49
  50 /**
  51  * Worker tasks usage statistics.
  52  *
  53  * @internal
  54  */
  55 export interface TasksUsage {
  56   /**
  57    * Number of tasks executed.
  58    */
  59   run: number
  60   /**
  61    * Number of tasks running.
  62    */
  63   running: number
  64   /**
  65    * Tasks runtime.
  66    */
  67   runTime: number
  68   /**
  69    * Tasks runtime history.
  70    */
  71   runTimeHistory: CircularArray<number>
  72   /**
  73    * Average tasks runtime.
  74    */
  75   avgRunTime: number
  76   /**
  77    * Median tasks runtime.
  78    */
  79   medRunTime: number
  80   /**
  81    * Number of tasks errored.
  82    */
  83   error: number
  84 }
  85
  86 /**
  87  * Worker interface.
  88  */
  89 export interface IWorker {
  90   /**
  91    * Register an event listener.
  92    *
  93    * @param event - The event.
  94    * @param handler - The event handler.
  95    */
  96   on: ((event: 'message', handler: MessageHandler<this>) => void) &
  97   ((event: 'error', handler: ErrorHandler<this>) => void) &
  98   ((event: 'online', handler: OnlineHandler<this>) => void) &
  99   ((event: 'exit', handler: ExitHandler<this>) => void)
 100   /**
 101    * Register a listener to the exit event that will only be performed once.
 102    *
 103    * @param event - `'exit'`.
 104    * @param handler - The exit handler.
 105    */
 106   once: (event: 'exit', handler: ExitHandler<this>) => void
 107 }
 108
 109 /**
 110  * Worker node interface.
 111  *
 112  * @typeParam Worker - Type of worker.
 113  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
 114  * @internal
 115  */
 116 export interface WorkerNode<Worker extends IWorker, Data = unknown> {
 117   /**
 118    * Worker node worker.
 119    */
 120   readonly worker: Worker
 121   /**
 122    * Worker node tasks usage statistics.
 123    */
 124   tasksUsage: TasksUsage
 125   /**
 126    * Worker node tasks queue.
 127    */
 128   readonly tasksQueue: Queue<Task<Data>>
 129 }