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

   1 import { DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS } from '../../utils'
   2 import type { IPool } from '../pool'
   3 import type { IWorker } from '../worker'
   4 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy'
   5 import type {
   6   IWorkerChoiceStrategy,
   7   StrategyPolicy,
   8   WorkerChoiceStrategyOptions
   9 } from './selection-strategies-types'
  10
  11 /**
  12  * Selects the next worker in a round robin fashion.
  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 serializable data.
  16  * @typeParam Response - Type of execution response. This can only be serializable data.
  17  */
  18 export class RoundRobinWorkerChoiceStrategy<
  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 strategyPolicy: StrategyPolicy = {
  27     useDynamicWorker: true
  28   }
  29
  30   /**
  31    * Id of the next worker node.
  32    */
  33   private nextWorkerNodeId: number = 0
  34
  35   /** @inheritDoc */
  36   public constructor (
  37     pool: IPool<Worker, Data, Response>,
  38     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  39   ) {
  40     super(pool, opts)
  41     this.setTaskStatisticsRequirements(this.opts)
  42   }
  43
  44   /** @inheritDoc */
  45   public reset (): boolean {
  46     this.nextWorkerNodeId = 0
  47     return true
  48   }
  49
  50   /** @inheritDoc */
  51   public update (): boolean {
  52     return true
  53   }
  54
  55   /** @inheritDoc */
  56   public choose (): number {
  57     const chosenWorkerNodeKey = this.nextWorkerNodeId
  58     this.nextWorkerNodeId =
  59       this.nextWorkerNodeId === this.pool.workerNodes.length - 1
  60         ? 0
  61         : this.nextWorkerNodeId + 1
  62     return chosenWorkerNodeKey
  63   }
  64
  65   /** @inheritDoc */
  66   public remove (workerNodeKey: number): boolean {
  67     if (this.nextWorkerNodeId === workerNodeKey) {
  68       if (this.pool.workerNodes.length === 0) {
  69         this.nextWorkerNodeId = 0
  70       } else if (this.nextWorkerNodeId > this.pool.workerNodes.length - 1) {
  71         this.nextWorkerNodeId = this.pool.workerNodes.length - 1
  72       }
  73     }
  74     return true
  75   }
  76 }