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 WorkerNodeEventCallback,
  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 implements IWorkerNode<Worker, Data> {
  33   /** @inheritdoc */
  34   public readonly worker: Worker
  35   /** @inheritdoc */
  36   public readonly info: WorkerInfo
  37   /** @inheritdoc */
  38   public usage: WorkerUsage
  39   /** @inheritdoc */
  40   public strategyData?: StrategyData
  41   /** @inheritdoc */
  42   public messageChannel?: MessageChannel
  43   /** @inheritdoc */
  44   public tasksQueueBackPressureSize: number
  45   /** @inheritdoc */
  46   public onBackPressure?: WorkerNodeEventCallback
  47   /** @inheritdoc */
  48   public onEmptyQueue?: WorkerNodeEventCallback
  49   private readonly tasksQueue: Deque<Task<Data>>
  50   private onBackPressureStarted: boolean
  51   private onEmptyQueueCount: number
  52   private readonly taskFunctionsUsage: Map<string, WorkerUsage>
  53
  54   /**
  55    * Constructs a new worker node.
  56    *
  57    * @param worker - The worker.
  58    * @param tasksQueueBackPressureSize - The tasks queue back pressure size.
  59    */
  60   constructor (worker: Worker, tasksQueueBackPressureSize: number) {
  61     checkWorkerNodeArguments<Worker>(worker, tasksQueueBackPressureSize)
  62     this.worker = worker
  63     this.info = this.initWorkerInfo(worker)
  64     this.usage = this.initWorkerUsage()
  65     if (this.info.type === WorkerTypes.thread) {
  66       this.messageChannel = new MessageChannel()
  67     }
  68     this.tasksQueueBackPressureSize = tasksQueueBackPressureSize
  69     this.tasksQueue = new Deque<Task<Data>>()
  70     this.onBackPressureStarted = false
  71     this.onEmptyQueueCount = 0
  72     this.taskFunctionsUsage = new Map<string, WorkerUsage>()
  73   }
  74
  75   /** @inheritdoc */
  76   public tasksQueueSize (): number {
  77     return this.tasksQueue.size
  78   }
  79
  80   /** @inheritdoc */
  81   public enqueueTask (task: Task<Data>): number {
  82     const tasksQueueSize = this.tasksQueue.push(task)
  83     if (
  84       this.onBackPressure != null &&
  85       this.hasBackPressure() &&
  86       !this.onBackPressureStarted
  87     ) {
  88       this.onBackPressureStarted = true
  89       this.onBackPressure(this.info.id as number)
  90       this.onBackPressureStarted = false
  91     }
  92     return tasksQueueSize
  93   }
  94
  95   /** @inheritdoc */
  96   public unshiftTask (task: Task<Data>): number {
  97     const tasksQueueSize = this.tasksQueue.unshift(task)
  98     if (
  99       this.onBackPressure != null &&
 100       this.hasBackPressure() &&
 101       !this.onBackPressureStarted
 102     ) {
 103       this.onBackPressureStarted = true
 104       this.onBackPressure(this.info.id as number)
 105       this.onBackPressureStarted = false
 106     }
 107     return tasksQueueSize
 108   }
 109
 110   /** @inheritdoc */
 111   public dequeueTask (): Task<Data> | undefined {
 112     const task = this.tasksQueue.shift()
 113     if (
 114       this.onEmptyQueue != null &&
 115       this.tasksQueue.size === 0 &&
 116       this.onEmptyQueueCount === 0
 117     ) {
 118       this.startOnEmptyQueue().catch(EMPTY_FUNCTION)
 119     }
 120     return task
 121   }
 122
 123   /** @inheritdoc */
 124   public popTask (): Task<Data> | undefined {
 125     const task = this.tasksQueue.pop()
 126     if (
 127       this.onEmptyQueue != null &&
 128       this.tasksQueue.size === 0 &&
 129       this.onEmptyQueueCount === 0
 130     ) {
 131       this.startOnEmptyQueue().catch(EMPTY_FUNCTION)
 132     }
 133     return task
 134   }
 135
 136   /** @inheritdoc */
 137   public clearTasksQueue (): void {
 138     this.tasksQueue.clear()
 139   }
 140
 141   /** @inheritdoc */
 142   public hasBackPressure (): boolean {
 143     return this.tasksQueue.size >= this.tasksQueueBackPressureSize
 144   }
 145
 146   /** @inheritdoc */
 147   public resetUsage (): void {
 148     this.usage = this.initWorkerUsage()
 149     this.taskFunctionsUsage.clear()
 150   }
 151
 152   /** @inheritdoc */
 153   public closeChannel (): void {
 154     if (this.messageChannel != null) {
 155       this.messageChannel?.port1.unref()
 156       this.messageChannel?.port2.unref()
 157       this.messageChannel?.port1.close()
 158       this.messageChannel?.port2.close()
 159       delete this.messageChannel
 160     }
 161   }
 162
 163   /** @inheritdoc */
 164   public getTaskFunctionWorkerUsage (name: string): WorkerUsage | undefined {
 165     if (!Array.isArray(this.info.taskFunctionNames)) {
 166       throw new Error(
 167         `Cannot get task function worker usage for task function name '${name}' when task function names list is not yet defined`
 168       )
 169     }
 170     if (
 171       Array.isArray(this.info.taskFunctionNames) &&
 172       this.info.taskFunctionNames.length < 3
 173     ) {
 174       throw new Error(
 175         `Cannot get task function worker usage for task function name '${name}' when task function names list has less than 3 elements`
 176       )
 177     }
 178     if (name === DEFAULT_TASK_NAME) {
 179       name = this.info.taskFunctionNames[1]
 180     }
 181     if (!this.taskFunctionsUsage.has(name)) {
 182       this.taskFunctionsUsage.set(name, this.initTaskFunctionWorkerUsage(name))
 183     }
 184     return this.taskFunctionsUsage.get(name)
 185   }
 186
 187   /** @inheritdoc */
 188   public deleteTaskFunctionWorkerUsage (name: string): boolean {
 189     return this.taskFunctionsUsage.delete(name)
 190   }
 191
 192   private async startOnEmptyQueue (): Promise<void> {
 193     if (
 194       this.onEmptyQueueCount > 0 &&
 195       (this.usage.tasks.executing > 0 || this.tasksQueue.size > 0)
 196     ) {
 197       this.onEmptyQueueCount = 0
 198       return
 199     }
 200     ++this.onEmptyQueueCount
 201     this.onEmptyQueue?.(this.info.id as number)
 202     await sleep(exponentialDelay(this.onEmptyQueueCount))
 203     await this.startOnEmptyQueue()
 204   }
 205
 206   private initWorkerInfo (worker: Worker): WorkerInfo {
 207     return {
 208       id: getWorkerId(worker),
 209       type: getWorkerType(worker) as WorkerType,
 210       dynamic: false,
 211       ready: false
 212     }
 213   }
 214
 215   private initWorkerUsage (): WorkerUsage {
 216     const getTasksQueueSize = (): number => {
 217       return this.tasksQueue.size
 218     }
 219     const getTasksQueueMaxSize = (): number => {
 220       return this.tasksQueue.maxSize
 221     }
 222     return {
 223       tasks: {
 224         executed: 0,
 225         executing: 0,
 226         get queued (): number {
 227           return getTasksQueueSize()
 228         },
 229         get maxQueued (): number {
 230           return getTasksQueueMaxSize()
 231         },
 232         stolen: 0,
 233         failed: 0
 234       },
 235       runTime: {
 236         history: new CircularArray()
 237       },
 238       waitTime: {
 239         history: new CircularArray()
 240       },
 241       elu: {
 242         idle: {
 243           history: new CircularArray()
 244         },
 245         active: {
 246           history: new CircularArray()
 247         }
 248       }
 249     }
 250   }
 251
 252   private initTaskFunctionWorkerUsage (name: string): WorkerUsage {
 253     const getTaskFunctionQueueSize = (): number => {
 254       let taskFunctionQueueSize = 0
 255       for (const task of this.tasksQueue) {
 256         if (
 257           (task.name === DEFAULT_TASK_NAME &&
 258             name === (this.info.taskFunctionNames as string[])[1]) ||
 259           (task.name !== DEFAULT_TASK_NAME && name === task.name)
 260         ) {
 261           ++taskFunctionQueueSize
 262         }
 263       }
 264       return taskFunctionQueueSize
 265     }
 266     return {
 267       tasks: {
 268         executed: 0,
 269         executing: 0,
 270         get queued (): number {
 271           return getTaskFunctionQueueSize()
 272         },
 273         stolen: 0,
 274         failed: 0
 275       },
 276       runTime: {
 277         history: new CircularArray()
 278       },
 279       waitTime: {
 280         history: new CircularArray()
 281       },
 282       elu: {
 283         idle: {
 284           history: new CircularArray()
 285         },
 286         active: {
 287           history: new CircularArray()
 288         }
 289       }
 290     }
 291   }
 292 }