src/pools/selection-strategies/round-robin-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 next worker in a round robin fashion.
  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 RoundRobinWorkerChoiceStrategy<
  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 roundRobinNextWorkerNodeKey (): number | undefined {
  32     this.nextWorkerNodeKey =
  33       this.nextWorkerNodeKey === this.pool.workerNodes.length - 1
  34         ? 0
  35         : (this.nextWorkerNodeKey ?? this.previousWorkerNodeKey) + 1
  36     return this.nextWorkerNodeKey
  37   }
  38
  39   /** @inheritDoc */
  40   public choose (): number | undefined {
  41     const chosenWorkerNodeKey = this.nextWorkerNodeKey
  42     this.setPreviousWorkerNodeKey(chosenWorkerNodeKey)
  43     this.roundRobinNextWorkerNodeKey()
  44     this.checkNextWorkerNodeKey()
  45     return chosenWorkerNodeKey
  46   }
  47
  48   /** @inheritDoc */
  49   public remove (workerNodeKey: number): boolean {
  50     if (this.pool.workerNodes.length === 0) {
  51       this.reset()
  52       return true
  53     }
  54     if (
  55       this.nextWorkerNodeKey === workerNodeKey &&
  56       this.nextWorkerNodeKey > this.pool.workerNodes.length - 1
  57     ) {
  58       this.nextWorkerNodeKey = this.pool.workerNodes.length - 1
  59     }
  60     if (
  61       this.previousWorkerNodeKey === workerNodeKey &&
  62       this.previousWorkerNodeKey > this.pool.workerNodes.length - 1
  63     ) {
  64       this.previousWorkerNodeKey = this.pool.workerNodes.length - 1
  65     }
  66     return true
  67   }
  68
  69   /** @inheritDoc */
  70   public reset (): boolean {
  71     this.resetWorkerNodeKeyProperties()
  72     return true
  73   }
  74
  75   /** @inheritDoc */
  76   public update (): boolean {
  77     return true
  78   }
  79 }