+ protected readonly pool: IPool<Worker, Data, Response>,
+ protected opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
+ ) {
+ this.opts = { ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS, ...opts }
+ this.choose = this.choose.bind(this)
+ }
+
+ protected setTaskStatisticsRequirements (
+ opts: WorkerChoiceStrategyOptions
+ ): void {
+ this.toggleMedianMeasurementStatisticsRequirements(
+ this.taskStatisticsRequirements.runTime,
+ opts.runTime?.median as boolean
+ )
+ this.toggleMedianMeasurementStatisticsRequirements(
+ this.taskStatisticsRequirements.waitTime,
+ opts.waitTime?.median as boolean
+ )
+ this.toggleMedianMeasurementStatisticsRequirements(
+ this.taskStatisticsRequirements.elu,
+ opts.elu?.median as boolean
+ )
+ }
+
+ private toggleMedianMeasurementStatisticsRequirements (
+ measurementStatisticsRequirements: MeasurementStatisticsRequirements,
+ toggleMedian: boolean
+ ): void {
+ if (measurementStatisticsRequirements.average && toggleMedian) {
+ measurementStatisticsRequirements.average = false
+ measurementStatisticsRequirements.median = toggleMedian
+ }
+ if (measurementStatisticsRequirements.median && !toggleMedian) {
+ measurementStatisticsRequirements.average = true
+ measurementStatisticsRequirements.median = toggleMedian
+ }
+ }
+
+ protected resetWorkerNodeKeyProperties (): void {
+ this.nextWorkerNodeKey = 0
+ this.previousWorkerNodeKey = 0
+ }
+
+ /** @inheritDoc */
+ public abstract reset (): boolean
+
+ /** @inheritDoc */
+ public abstract update (workerNodeKey: number): boolean
+
+ /** @inheritDoc */
+ public abstract choose (): number | undefined
+
+ /** @inheritDoc */
+ public abstract remove (workerNodeKey: number): boolean
+
+ /** @inheritDoc */
+ public setOptions (opts: WorkerChoiceStrategyOptions): void {
+ this.opts = { ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS, ...opts }
+ this.setTaskStatisticsRequirements(this.opts)
+ }
+
+ /**
+ * Whether the worker node is ready or not.
+ *
+ * @param workerNodeKey - The worker node key.
+ * @returns Whether the worker node is ready or not.
+ */
+ private isWorkerNodeReady (workerNodeKey: number): boolean {
+ return this.pool.workerNodes[workerNodeKey].info.ready
+ }
+
+ /**
+ * Whether the worker node has back pressure or not (i.e. its tasks queue is full).
+ *
+ * @param workerNodeKey - The worker node key.
+ * @returns `true` if the worker node has back pressure, `false` otherwise.
+ */
+ private hasWorkerNodeBackPressure (workerNodeKey: number): boolean {
+ return this.pool.hasWorkerNodeBackPressure(workerNodeKey)
+ }
+
+ /**
+ * Whether the worker node is eligible or not.
+ * A worker node is eligible if it is ready and does not have back pressure.
+ *
+ * @param workerNodeKey - The worker node key.
+ * @returns `true` if the worker node is eligible, `false` otherwise.
+ * @see {@link isWorkerNodeReady}
+ * @see {@link hasWorkerNodeBackPressure}
+ */
+ protected isWorkerNodeEligible (workerNodeKey: number): boolean {
+ return (
+ this.isWorkerNodeReady(workerNodeKey) &&
+ !this.hasWorkerNodeBackPressure(workerNodeKey)
+ )
+ }
+
+ /**
+ * Gets the worker node task runtime.
+ * If the task statistics require the average runtime, the average runtime is returned.
+ * If the task statistics require the median runtime , the median runtime is returned.
+ *
+ * @param workerNodeKey - The worker node key.
+ * @returns The worker node task runtime.
+ */
+ protected getWorkerNodeTaskRunTime (workerNodeKey: number): number {
+ return this.taskStatisticsRequirements.runTime.median
+ ? this.pool.workerNodes[workerNodeKey].usage.runTime.median ?? 0
+ : this.pool.workerNodes[workerNodeKey].usage.runTime.average ?? 0
+ }
+
+ /**
+ * Gets the worker node task wait time.
+ * If the task statistics require the average wait time, the average wait time is returned.
+ * If the task statistics require the median wait time, the median wait time is returned.
+ *
+ * @param workerNodeKey - The worker node key.
+ * @returns The worker node task wait time.
+ */
+ protected getWorkerNodeTaskWaitTime (workerNodeKey: number): number {
+ return this.taskStatisticsRequirements.waitTime.median
+ ? this.pool.workerNodes[workerNodeKey].usage.waitTime.median ?? 0
+ : this.pool.workerNodes[workerNodeKey].usage.waitTime.average ?? 0
+ }
+
+ /**
+ * Gets the worker node task ELU.
+ * If the task statistics require the average ELU, the average ELU is returned.
+ * If the task statistics require the median ELU, the median ELU is returned.
+ *
+ * @param workerNodeKey - The worker node key.
+ * @returns The worker node task ELU.
+ */
+ protected getWorkerNodeTaskElu (workerNodeKey: number): number {
+ return this.taskStatisticsRequirements.elu.median
+ ? this.pool.workerNodes[workerNodeKey].usage.elu.active.median ?? 0
+ : this.pool.workerNodes[workerNodeKey].usage.elu.active.average ?? 0
+ }
+
+ /**
+ * Sets safely the previous worker node key.
+ *
+ * @param workerNodeKey - The worker node key.
+ */
+ protected setPreviousWorkerNodeKey (workerNodeKey: number | undefined): void {
+ this.previousWorkerNodeKey = workerNodeKey ?? this.previousWorkerNodeKey
+ }
+
+ /**
+ * Check the next worker node eligibility.
+ */
+ protected checkNextWorkerNodeEligibility (): void {
+ if (!this.isWorkerNodeEligible(this.nextWorkerNodeKey as number)) {
+ this.nextWorkerNodeKey = undefined
+ }
+ }