src/pools/selection-strategies/least-elu-worker-choice-strategy.ts

   1 import {
   2   DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
   3   DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
   4 } from '../../utils'
   5 import type { IPool } from '../pool'
   6 import type { IWorker } from '../worker'
   7 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy'
   8 import type {
   9   IWorkerChoiceStrategy,
  10   StrategyPolicy,
  11   TaskStatisticsRequirements,
  12   WorkerChoiceStrategyOptions
  13 } from './selection-strategies-types'
  14
  15 /**
  16  * Selects the worker with the least ELU.
  17  *
  18  * @typeParam Worker - Type of worker which manages the strategy.
  19  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  20  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
  21  */
  22 export class LeastEluWorkerChoiceStrategy<
  23     Worker extends IWorker,
  24     Data = unknown,
  25     Response = unknown
  26   >
  27   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
  28   implements IWorkerChoiceStrategy {
  29   /** @inheritDoc */
  30   public readonly strategyPolicy: StrategyPolicy = {
  31     dynamicWorkerUsage: false,
  32     dynamicWorkerReady: true
  33   }
  34
  35   /** @inheritDoc */
  36   public readonly taskStatisticsRequirements: TaskStatisticsRequirements = {
  37     runTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
  38     waitTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
  39     elu: {
  40       aggregate: true,
  41       average: false,
  42       median: false
  43     }
  44   }
  45
  46   /** @inheritDoc */
  47   public constructor (
  48     pool: IPool<Worker, Data, Response>,
  49     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  50   ) {
  51     super(pool, opts)
  52     this.setTaskStatisticsRequirements(this.opts)
  53   }
  54
  55   /** @inheritDoc */
  56   public reset (): boolean {
  57     return true
  58   }
  59
  60   /** @inheritDoc */
  61   public update (): boolean {
  62     return true
  63   }
  64
  65   /** @inheritDoc */
  66   public choose (): number | undefined {
  67     const chosenWorkerNodeKey = this.leastEluNextWorkerNodeKey()
  68     this.assignChosenWorkerNodeKey(chosenWorkerNodeKey)
  69     return this.nextWorkerNodeKey
  70   }
  71
  72   /** @inheritDoc */
  73   public remove (): boolean {
  74     return true
  75   }
  76
  77   private leastEluNextWorkerNodeKey (): number | undefined {
  78     let minWorkerElu = Infinity
  79     let chosenWorkerNodeKey: number | undefined
  80     for (const [workerNodeKey, workerNode] of this.pool.workerNodes.entries()) {
  81       const workerUsage = workerNode.usage
  82       const workerElu = workerUsage.elu?.active?.aggregate ?? 0
  83       if (this.isWorkerNodeEligible(workerNodeKey) && workerElu === 0) {
  84         chosenWorkerNodeKey = workerNodeKey
  85         break
  86       } else if (
  87         this.isWorkerNodeEligible(workerNodeKey) &&
  88         workerElu < minWorkerElu
  89       ) {
  90         minWorkerElu = workerElu
  91         chosenWorkerNodeKey = workerNodeKey
  92       }
  93     }
  94     return chosenWorkerNodeKey
  95   }
  96 }