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   private leastUsedNextWorkerNodeKey (): number | undefined {
  32     return this.pool.workerNodes.reduce(
  33       (minWorkerNodeKey, workerNode, workerNodeKey, workerNodes) => {
  34         return this.isWorkerNodeReady(workerNodeKey) &&
  35           workerNode.usage.tasks.executing + workerNode.usage.tasks.queued <
  36             workerNodes[minWorkerNodeKey].usage.tasks.executing +
  37               workerNodes[minWorkerNodeKey].usage.tasks.queued
  38           ? workerNodeKey
  39           : minWorkerNodeKey
  40       },
  41       0
  42     )
  43   }
  44
  45   /** @inheritDoc */
  46   public choose (): number | undefined {
  47     this.setPreviousWorkerNodeKey(this.nextWorkerNodeKey)
  48     this.nextWorkerNodeKey = this.leastUsedNextWorkerNodeKey()
  49     return this.nextWorkerNodeKey
  50   }
  51
  52   /** @inheritDoc */
  53   public remove (): boolean {
  54     return true
  55   }
  56
  57   /** @inheritDoc */
  58   public reset (): boolean {
  59     return true
  60   }
  61
  62   /** @inheritDoc */
  63   public update (): boolean {
  64     return true
  65   }
  66 }