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

   1 import type { IPool } from '../pool.js'
   2 import type { IWorker } from '../worker.js'
   3 import type {
   4   IWorkerChoiceStrategy,
   5   WorkerChoiceStrategyOptions,
   6 } from './selection-strategies-types.js'
   7
   8 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy.js'
   9
  10 /**
  11  * Selects the least used worker.
  12  * @typeParam Worker - Type of worker which manages the strategy.
  13  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  14  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
  15  */
  16 export class LeastUsedWorkerChoiceStrategy<
  17     Worker extends IWorker,
  18     Data = unknown,
  19     Response = unknown
  20   >
  21   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
  22   implements IWorkerChoiceStrategy {
  23   /** @inheritDoc */
  24   public constructor (
  25     pool: IPool<Worker, Data, Response>,
  26     opts?: WorkerChoiceStrategyOptions
  27   ) {
  28     super(pool, opts)
  29   }
  30
  31   /** @inheritDoc */
  32   public choose (): number | undefined {
  33     this.setPreviousWorkerNodeKey(this.nextWorkerNodeKey)
  34     this.nextWorkerNodeKey = this.leastUsedNextWorkerNodeKey()
  35     return this.nextWorkerNodeKey
  36   }
  37
  38   /** @inheritDoc */
  39   public remove (): boolean {
  40     return true
  41   }
  42
  43   /** @inheritDoc */
  44   public reset (): boolean {
  45     return true
  46   }
  47
  48   /** @inheritDoc */
  49   public update (): boolean {
  50     return true
  51   }
  52
  53   private leastUsedNextWorkerNodeKey (): number | undefined {
  54     return this.pool.workerNodes.reduce(
  55       (minWorkerNodeKey, workerNode, workerNodeKey, workerNodes) => {
  56         return this.isWorkerNodeReady(workerNodeKey) &&
  57           workerNode.usage.tasks.executing + workerNode.usage.tasks.queued <
  58             workerNodes[minWorkerNodeKey].usage.tasks.executing +
  59               workerNodes[minWorkerNodeKey].usage.tasks.queued
  60           ? workerNodeKey
  61           : minWorkerNodeKey
  62       },
  63       0
  64     )
  65   }
  66 }