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