src/pools/selection-strategies/round-robin-worker-choice-strategy.ts

   1 import type { IWorker } from '../worker'
   2 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy'
   3 import type { IWorkerChoiceStrategy } from './selection-strategies-types'
   4
   5 /**
   6  * Selects the next worker in a round robin fashion.
   7  *
   8  * @typeParam Worker - Type of worker which manages the strategy.
   9  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  10  * @typeParam Response - Type of response of execution. This can only be serializable data.
  11  */
  12 export class RoundRobinWorkerChoiceStrategy<
  13     Worker extends IWorker,
  14     Data = unknown,
  15     Response = unknown
  16   >
  17   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
  18   implements IWorkerChoiceStrategy {
  19   /**
  20    * Id of the next worker node.
  21    */
  22   private nextWorkerNodeId: number = 0
  23
  24   /** @inheritDoc */
  25   public reset (): boolean {
  26     this.nextWorkerNodeId = 0
  27     return true
  28   }
  29
  30   /** @inheritDoc */
  31   public choose (): number {
  32     const chosenWorkerNodeKey = this.nextWorkerNodeId
  33     this.nextWorkerNodeId =
  34       this.nextWorkerNodeId === this.pool.workerNodes.length - 1
  35         ? 0
  36         : this.nextWorkerNodeId + 1
  37     return chosenWorkerNodeKey
  38   }
  39
  40   /** @inheritDoc */
  41   public remove (workerNodeKey: number): boolean {
  42     if (this.nextWorkerNodeId === workerNodeKey) {
  43       if (this.pool.workerNodes.length === 0) {
  44         this.nextWorkerNodeId = 0
  45       } else {
  46         this.nextWorkerNodeId =
  47           this.nextWorkerNodeId > this.pool.workerNodes.length - 1
  48             ? this.pool.workerNodes.length - 1
  49             : this.nextWorkerNodeId
  50       }
  51     }
  52     return true
  53   }
  54 }