src/pools/worker-node.ts

   1 import { MessageChannel } from 'node:worker_threads'
   2 import { CircularArray } from '../circular-array'
   3 import type { Task } from '../utility-types'
   4 import {
   5   DEFAULT_TASK_NAME,
   6   EMPTY_FUNCTION,
   7   exponentialDelay,
   8   getWorkerId,
   9   getWorkerType,
  10   sleep
  11 } from '../utils'
  12 import { Deque } from '../deque'
  13 import {
  14   type IWorker,
  15   type IWorkerNode,
  16   type StrategyData,
  17   type WorkerInfo,
  18   type WorkerNodeEventDetail,
  19   type WorkerType,
  20   WorkerTypes,
  21   type WorkerUsage
  22 } from './worker'
  23 import { checkWorkerNodeArguments } from './utils'
  24
  25 /**
  26  * Worker node.
  27  *
  28  * @typeParam Worker - Type of worker.
  29  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  30  */
  31 export class WorkerNode<Worker extends IWorker, Data = unknown>
  32   extends EventTarget
  33   implements IWorkerNode<Worker, Data> {
  34   /** @inheritdoc */
  35   public readonly worker: Worker
  36   /** @inheritdoc */
  37   public readonly info: WorkerInfo
  38   /** @inheritdoc */
  39   public usage: WorkerUsage
  40   /** @inheritdoc */
  41   public strategyData?: StrategyData
  42   /** @inheritdoc */
  43   public messageChannel?: MessageChannel
  44   /** @inheritdoc */
  45   public tasksQueueBackPressureSize: number
  46   private readonly tasksQueue: Deque<Task<Data>>
  47   private onBackPressureStarted: boolean
  48   private onEmptyQueueCount: number
  49   private readonly taskFunctionsUsage: Map<string, WorkerUsage>
  50
  51   /**
  52    * Constructs a new worker node.
  53    *
  54    * @param worker - The worker.
  55    * @param tasksQueueBackPressureSize - The tasks queue back pressure size.
  56    */
  57   constructor (worker: Worker, tasksQueueBackPressureSize: number) {
  58     super()
  59     checkWorkerNodeArguments<Worker>(worker, tasksQueueBackPressureSize)
  60     this.worker = worker
  61     this.info = this.initWorkerInfo(worker)
  62     this.usage = this.initWorkerUsage()
  63     if (this.info.type === WorkerTypes.thread) {
  64       this.messageChannel = new MessageChannel()
  65     }
  66     this.tasksQueueBackPressureSize = tasksQueueBackPressureSize
  67     this.tasksQueue = new Deque<Task<Data>>()
  68     this.onBackPressureStarted = false
  69     this.onEmptyQueueCount = 0
  70     this.taskFunctionsUsage = new Map<string, WorkerUsage>()
  71   }
  72
  73   /** @inheritdoc */
  74   public tasksQueueSize (): number {
  75     return this.tasksQueue.size
  76   }
  77
  78   /** @inheritdoc */
  79   public enqueueTask (task: Task<Data>): number {
  80     const tasksQueueSize = this.tasksQueue.push(task)
  81     if (this.hasBackPressure() && !this.onBackPressureStarted) {
  82       this.onBackPressureStarted = true
  83       this.dispatchEvent(
  84         new CustomEvent<WorkerNodeEventDetail>('backpressure', {
  85           detail: { workerId: this.info.id as number }
  86         })
  87       )
  88       this.onBackPressureStarted = false
  89     }
  90     return tasksQueueSize
  91   }
  92
  93   /** @inheritdoc */
  94   public unshiftTask (task: Task<Data>): number {
  95     const tasksQueueSize = this.tasksQueue.unshift(task)
  96     if (this.hasBackPressure() && !this.onBackPressureStarted) {
  97       this.onBackPressureStarted = true
  98       this.dispatchEvent(
  99         new CustomEvent<WorkerNodeEventDetail>('backpressure', {
 100           detail: { workerId: this.info.id as number }
 101         })
 102       )
 103       this.onBackPressureStarted = false
 104     }
 105     return tasksQueueSize
 106   }
 107
 108   /** @inheritdoc */
 109   public dequeueTask (): Task<Data> | undefined {
 110     const task = this.tasksQueue.shift()
 111     if (this.tasksQueue.size === 0 && this.onEmptyQueueCount === 0) {
 112       this.startOnEmptyQueue().catch(EMPTY_FUNCTION)
 113     }
 114     return task
 115   }
 116
 117   /** @inheritdoc */
 118   public popTask (): Task<Data> | undefined {
 119     const task = this.tasksQueue.pop()
 120     if (this.tasksQueue.size === 0 && this.onEmptyQueueCount === 0) {
 121       this.startOnEmptyQueue().catch(EMPTY_FUNCTION)
 122     }
 123     return task
 124   }
 125
 126   /** @inheritdoc */
 127   public clearTasksQueue (): void {
 128     this.tasksQueue.clear()
 129   }
 130
 131   /** @inheritdoc */
 132   public hasBackPressure (): boolean {
 133     return this.tasksQueue.size >= this.tasksQueueBackPressureSize
 134   }
 135
 136   /** @inheritdoc */
 137   public resetUsage (): void {
 138     this.usage = this.initWorkerUsage()
 139     this.taskFunctionsUsage.clear()
 140   }
 141
 142   /** @inheritdoc */
 143   public closeChannel (): void {
 144     if (this.messageChannel != null) {
 145       this.messageChannel?.port1.unref()
 146       this.messageChannel?.port2.unref()
 147       this.messageChannel?.port1.close()
 148       this.messageChannel?.port2.close()
 149       delete this.messageChannel
 150     }
 151   }
 152
 153   /** @inheritdoc */
 154   public getTaskFunctionWorkerUsage (name: string): WorkerUsage | undefined {
 155     if (!Array.isArray(this.info.taskFunctionNames)) {
 156       throw new Error(
 157         `Cannot get task function worker usage for task function name '${name}' when task function names list is not yet defined`
 158       )
 159     }
 160     if (
 161       Array.isArray(this.info.taskFunctionNames) &&
 162       this.info.taskFunctionNames.length < 3
 163     ) {
 164       throw new Error(
 165         `Cannot get task function worker usage for task function name '${name}' when task function names list has less than 3 elements`
 166       )
 167     }
 168     if (name === DEFAULT_TASK_NAME) {
 169       name = this.info.taskFunctionNames[1]
 170     }
 171     if (!this.taskFunctionsUsage.has(name)) {
 172       this.taskFunctionsUsage.set(name, this.initTaskFunctionWorkerUsage(name))
 173     }
 174     return this.taskFunctionsUsage.get(name)
 175   }
 176
 177   /** @inheritdoc */
 178   public deleteTaskFunctionWorkerUsage (name: string): boolean {
 179     return this.taskFunctionsUsage.delete(name)
 180   }
 181
 182   private async startOnEmptyQueue (): Promise<void> {
 183     if (
 184       this.onEmptyQueueCount > 0 &&
 185       (this.usage.tasks.executing > 0 || this.tasksQueue.size > 0)
 186     ) {
 187       this.onEmptyQueueCount = 0
 188       return
 189     }
 190     ++this.onEmptyQueueCount
 191     this.dispatchEvent(
 192       new CustomEvent<WorkerNodeEventDetail>('emptyqueue', {
 193         detail: { workerId: this.info.id as number }
 194       })
 195     )
 196     await sleep(exponentialDelay(this.onEmptyQueueCount))
 197     await this.startOnEmptyQueue()
 198   }
 199
 200   private initWorkerInfo (worker: Worker): WorkerInfo {
 201     return {
 202       id: getWorkerId(worker),
 203       type: getWorkerType(worker) as WorkerType,
 204       dynamic: false,
 205       ready: false
 206     }
 207   }
 208
 209   private initWorkerUsage (): WorkerUsage {
 210     const getTasksQueueSize = (): number => {
 211       return this.tasksQueue.size
 212     }
 213     const getTasksQueueMaxSize = (): number => {
 214       return this.tasksQueue.maxSize
 215     }
 216     return {
 217       tasks: {
 218         executed: 0,
 219         executing: 0,
 220         get queued (): number {
 221           return getTasksQueueSize()
 222         },
 223         get maxQueued (): number {
 224           return getTasksQueueMaxSize()
 225         },
 226         stolen: 0,
 227         failed: 0
 228       },
 229       runTime: {
 230         history: new CircularArray<number>()
 231       },
 232       waitTime: {
 233         history: new CircularArray<number>()
 234       },
 235       elu: {
 236         idle: {
 237           history: new CircularArray<number>()
 238         },
 239         active: {
 240           history: new CircularArray<number>()
 241         }
 242       }
 243     }
 244   }
 245
 246   private initTaskFunctionWorkerUsage (name: string): WorkerUsage {
 247     const getTaskFunctionQueueSize = (): number => {
 248       let taskFunctionQueueSize = 0
 249       for (const task of this.tasksQueue) {
 250         if (
 251           (task.name === DEFAULT_TASK_NAME &&
 252             name === (this.info.taskFunctionNames as string[])[1]) ||
 253           (task.name !== DEFAULT_TASK_NAME && name === task.name)
 254         ) {
 255           ++taskFunctionQueueSize
 256         }
 257       }
 258       return taskFunctionQueueSize
 259     }
 260     return {
 261       tasks: {
 262         executed: 0,
 263         executing: 0,
 264         get queued (): number {
 265           return getTaskFunctionQueueSize()
 266         },
 267         stolen: 0,
 268         failed: 0
 269       },
 270       runTime: {
 271         history: new CircularArray<number>()
 272       },
 273       waitTime: {
 274         history: new CircularArray<number>()
 275       },
 276       elu: {
 277         idle: {
 278           history: new CircularArray<number>()
 279         },
 280         active: {
 281           history: new CircularArray<number>()
 282         }
 283       }
 284     }
 285   }
 286 }