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 onIdleWorkerNodeCount: 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.onIdleWorkerNodeCount = 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.isIdle() && this.onIdleWorkerNodeCount === 0) {
 112       this.startOnIdleWorkerNode().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.isIdle() && this.onIdleWorkerNodeCount === 0) {
 121       this.startOnIdleWorkerNode().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 startOnIdleWorkerNode (): Promise<void> {
 183     if (
 184       this.onIdleWorkerNodeCount > 0 &&
 185       (this.usage.tasks.executing > 0 || this.tasksQueue.size > 0)
 186     ) {
 187       this.onIdleWorkerNodeCount = 0
 188       return
 189     }
 190     ++this.onIdleWorkerNodeCount
 191     this.dispatchEvent(
 192       new CustomEvent<WorkerNodeEventDetail>('idleWorkerNode', {
 193         detail: { workerId: this.info.id as number }
 194       })
 195     )
 196     await sleep(exponentialDelay(this.onIdleWorkerNodeCount))
 197     await this.startOnIdleWorkerNode()
 198   }
 199
 200   private isIdle (): boolean {
 201     return this.usage.tasks.executing === 0 && this.tasksQueue.size === 0
 202   }
 203
 204   private initWorkerInfo (worker: Worker): WorkerInfo {
 205     return {
 206       id: getWorkerId(worker),
 207       type: getWorkerType(worker) as WorkerType,
 208       dynamic: false,
 209       ready: false
 210     }
 211   }
 212
 213   private initWorkerUsage (): WorkerUsage {
 214     const getTasksQueueSize = (): number => {
 215       return this.tasksQueue.size
 216     }
 217     const getTasksQueueMaxSize = (): number => {
 218       return this.tasksQueue.maxSize
 219     }
 220     return {
 221       tasks: {
 222         executed: 0,
 223         executing: 0,
 224         get queued (): number {
 225           return getTasksQueueSize()
 226         },
 227         get maxQueued (): number {
 228           return getTasksQueueMaxSize()
 229         },
 230         stolen: 0,
 231         failed: 0
 232       },
 233       runTime: {
 234         history: new CircularArray<number>()
 235       },
 236       waitTime: {
 237         history: new CircularArray<number>()
 238       },
 239       elu: {
 240         idle: {
 241           history: new CircularArray<number>()
 242         },
 243         active: {
 244           history: new CircularArray<number>()
 245         }
 246       }
 247     }
 248   }
 249
 250   private initTaskFunctionWorkerUsage (name: string): WorkerUsage {
 251     const getTaskFunctionQueueSize = (): number => {
 252       let taskFunctionQueueSize = 0
 253       for (const task of this.tasksQueue) {
 254         if (
 255           (task.name === DEFAULT_TASK_NAME &&
 256             name === (this.info.taskFunctionNames as string[])[1]) ||
 257           (task.name !== DEFAULT_TASK_NAME && name === task.name)
 258         ) {
 259           ++taskFunctionQueueSize
 260         }
 261       }
 262       return taskFunctionQueueSize
 263     }
 264     return {
 265       tasks: {
 266         executed: 0,
 267         executing: 0,
 268         get queued (): number {
 269           return getTaskFunctionQueueSize()
 270         },
 271         stolen: 0,
 272         failed: 0
 273       },
 274       runTime: {
 275         history: new CircularArray<number>()
 276       },
 277       waitTime: {
 278         history: new CircularArray<number>()
 279       },
 280       elu: {
 281         idle: {
 282           history: new CircularArray<number>()
 283         },
 284         active: {
 285           history: new CircularArray<number>()
 286         }
 287       }
 288     }
 289   }
 290 }