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

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