src/pools/worker-node.ts

   1 import { EventEmitter } from 'node:events'
   2 import { MessageChannel } from 'node:worker_threads'
   3
   4 import { CircularArray } from '../circular-array.js'
   5 import { PriorityQueue } from '../priority-queue.js'
   6 import type { Task } from '../utility-types.js'
   7 import { DEFAULT_TASK_NAME } from '../utils.js'
   8 import {
   9   checkWorkerNodeArguments,
  10   createWorker,
  11   getWorkerId,
  12   getWorkerType
  13 } from './utils.js'
  14 import {
  15   type EventHandler,
  16   type IWorker,
  17   type IWorkerNode,
  18   type StrategyData,
  19   type WorkerInfo,
  20   type WorkerNodeOptions,
  21   type WorkerType,
  22   WorkerTypes,
  23   type WorkerUsage
  24 } from './worker.js'
  25
  26 /**
  27  * Worker node.
  28  *
  29  * @typeParam Worker - Type of worker.
  30  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  31  */
  32 export class WorkerNode<Worker extends IWorker, Data = unknown>
  33   extends EventEmitter
  34   implements IWorkerNode<Worker, Data> {
  35   /** @inheritdoc */
  36   public readonly worker: Worker
  37   /** @inheritdoc */
  38   public readonly info: WorkerInfo
  39   /** @inheritdoc */
  40   public usage: WorkerUsage
  41   /** @inheritdoc */
  42   public strategyData?: StrategyData
  43   /** @inheritdoc */
  44   public messageChannel?: MessageChannel
  45   /** @inheritdoc */
  46   public tasksQueueBackPressureSize: number
  47   private readonly tasksQueue: PriorityQueue<Task<Data>>
  48   private onBackPressureStarted: boolean
  49   private readonly taskFunctionsUsage: Map<string, WorkerUsage>
  50
  51   /**
  52    * Constructs a new worker node.
  53    *
  54    * @param type - The worker type.
  55    * @param filePath - Path to the worker file.
  56    * @param opts - The worker node options.
  57    */
  58   constructor (type: WorkerType, filePath: string, opts: WorkerNodeOptions) {
  59     super()
  60     checkWorkerNodeArguments(type, filePath, opts)
  61     this.worker = createWorker<Worker>(type, filePath, {
  62       env: opts.env,
  63       workerOptions: opts.workerOptions
  64     })
  65     this.info = this.initWorkerInfo(this.worker)
  66     this.usage = this.initWorkerUsage()
  67     if (this.info.type === WorkerTypes.thread) {
  68       this.messageChannel = new MessageChannel()
  69     }
  70     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  71     this.tasksQueueBackPressureSize = opts.tasksQueueBackPressureSize!
  72     this.tasksQueue = new PriorityQueue<Task<Data>>(opts.tasksQueueBucketSize)
  73     this.onBackPressureStarted = false
  74     this.taskFunctionsUsage = new Map<string, WorkerUsage>()
  75   }
  76
  77   /** @inheritdoc */
  78   public tasksQueueSize (): number {
  79     return this.tasksQueue.size
  80   }
  81
  82   /** @inheritdoc */
  83   public enqueueTask (task: Task<Data>): number {
  84     const tasksQueueSize = this.tasksQueue.enqueue(task, task.priority)
  85     if (this.hasBackPressure() && !this.onBackPressureStarted) {
  86       this.onBackPressureStarted = true
  87       this.emit('backPressure', { workerId: this.info.id })
  88       this.onBackPressureStarted = false
  89     }
  90     return tasksQueueSize
  91   }
  92
  93   /** @inheritdoc */
  94   public dequeueTask (bucket?: number): Task<Data> | undefined {
  95     return this.tasksQueue.dequeue(bucket)
  96   }
  97
  98   /** @inheritdoc */
  99   public dequeueLastBucketTask (): Task<Data> | undefined {
 100     // Start from the last empty or partially filled bucket
 101     return this.tasksQueue.dequeue(this.tasksQueue.buckets + 1)
 102   }
 103
 104   /** @inheritdoc */
 105   public clearTasksQueue (): void {
 106     this.tasksQueue.clear()
 107   }
 108
 109   /** @inheritdoc */
 110   public hasBackPressure (): boolean {
 111     return this.tasksQueue.size >= this.tasksQueueBackPressureSize
 112   }
 113
 114   /** @inheritdoc */
 115   public async terminate (): Promise<void> {
 116     const waitWorkerExit = new Promise<void>(resolve => {
 117       this.registerOnceWorkerEventHandler('exit', () => {
 118         resolve()
 119       })
 120     })
 121     this.closeMessageChannel()
 122     this.removeAllListeners()
 123     switch (this.info.type) {
 124       case WorkerTypes.thread:
 125         this.worker.unref?.()
 126         await this.worker.terminate?.()
 127         break
 128       case WorkerTypes.cluster:
 129         this.registerOnceWorkerEventHandler('disconnect', () => {
 130           this.worker.kill?.()
 131         })
 132         this.worker.disconnect?.()
 133         break
 134     }
 135     await waitWorkerExit
 136   }
 137
 138   /** @inheritdoc */
 139   public registerWorkerEventHandler (
 140     event: string,
 141     handler: EventHandler<Worker>
 142   ): void {
 143     this.worker.on(event, handler)
 144   }
 145
 146   /** @inheritdoc */
 147   public registerOnceWorkerEventHandler (
 148     event: string,
 149     handler: EventHandler<Worker>
 150   ): void {
 151     this.worker.once(event, handler)
 152   }
 153
 154   /** @inheritdoc */
 155   public getTaskFunctionWorkerUsage (name: string): WorkerUsage | undefined {
 156     if (!Array.isArray(this.info.taskFunctionsProperties)) {
 157       throw new Error(
 158         `Cannot get task function worker usage for task function name '${name}' when task function properties list is not yet defined`
 159       )
 160     }
 161     if (
 162       Array.isArray(this.info.taskFunctionsProperties) &&
 163       this.info.taskFunctionsProperties.length < 3
 164     ) {
 165       throw new Error(
 166         `Cannot get task function worker usage for task function name '${name}' when task function properties list has less than 3 elements`
 167       )
 168     }
 169     if (name === DEFAULT_TASK_NAME) {
 170       name = this.info.taskFunctionsProperties[1].name
 171     }
 172     if (!this.taskFunctionsUsage.has(name)) {
 173       this.taskFunctionsUsage.set(name, this.initTaskFunctionWorkerUsage(name))
 174     }
 175     return this.taskFunctionsUsage.get(name)
 176   }
 177
 178   /** @inheritdoc */
 179   public deleteTaskFunctionWorkerUsage (name: string): boolean {
 180     return this.taskFunctionsUsage.delete(name)
 181   }
 182
 183   private closeMessageChannel (): void {
 184     if (this.messageChannel != null) {
 185       this.messageChannel.port1.unref()
 186       this.messageChannel.port2.unref()
 187       this.messageChannel.port1.close()
 188       this.messageChannel.port2.close()
 189       delete this.messageChannel
 190     }
 191   }
 192
 193   private initWorkerInfo (worker: Worker): WorkerInfo {
 194     return {
 195       id: getWorkerId(worker),
 196       // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 197       type: getWorkerType(worker)!,
 198       dynamic: false,
 199       ready: false,
 200       stealing: false
 201     }
 202   }
 203
 204   private initWorkerUsage (): WorkerUsage {
 205     const getTasksQueueSize = (): number => {
 206       return this.tasksQueue.size
 207     }
 208     const getTasksQueueMaxSize = (): number => {
 209       return this.tasksQueue.maxSize
 210     }
 211     return {
 212       tasks: {
 213         executed: 0,
 214         executing: 0,
 215         get queued (): number {
 216           return getTasksQueueSize()
 217         },
 218         get maxQueued (): number {
 219           return getTasksQueueMaxSize()
 220         },
 221         sequentiallyStolen: 0,
 222         stolen: 0,
 223         failed: 0
 224       },
 225       runTime: {
 226         history: new CircularArray<number>()
 227       },
 228       waitTime: {
 229         history: new CircularArray<number>()
 230       },
 231       elu: {
 232         idle: {
 233           history: new CircularArray<number>()
 234         },
 235         active: {
 236           history: new CircularArray<number>()
 237         }
 238       }
 239     }
 240   }
 241
 242   private initTaskFunctionWorkerUsage (name: string): WorkerUsage {
 243     const getTaskFunctionQueueSize = (): number => {
 244       let taskFunctionQueueSize = 0
 245       for (const task of this.tasksQueue) {
 246         if (
 247           (task.name === DEFAULT_TASK_NAME &&
 248             // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 249             name === this.info.taskFunctionsProperties![1].name) ||
 250           (task.name !== DEFAULT_TASK_NAME && name === task.name)
 251         ) {
 252           ++taskFunctionQueueSize
 253         }
 254       }
 255       return taskFunctionQueueSize
 256     }
 257     return {
 258       tasks: {
 259         executed: 0,
 260         executing: 0,
 261         get queued (): number {
 262           return getTaskFunctionQueueSize()
 263         },
 264         sequentiallyStolen: 0,
 265         stolen: 0,
 266         failed: 0
 267       },
 268       runTime: {
 269         history: new CircularArray<number>()
 270       },
 271       waitTime: {
 272         history: new CircularArray<number>()
 273       },
 274       elu: {
 275         idle: {
 276           history: new CircularArray<number>()
 277         },
 278         active: {
 279           history: new CircularArray<number>()
 280         }
 281       }
 282     }
 283   }
 284 }