-import type { WorkerChoiceStrategyOptions } from './pools/selection-strategies/selection-strategies-types'
+import * as os from 'node:os'
+import { getRandomValues, randomInt } from 'node:crypto'
+import { Worker as ClusterWorker } from 'node:cluster'
+import { Worker as ThreadWorker } from 'node:worker_threads'
+import { cpus } from 'node:os'
+import type {
+ MeasurementStatisticsRequirements,
+ WorkerChoiceStrategyOptions
+} from './pools/selection-strategies/selection-strategies-types.js'
+import type { KillBehavior } from './worker/worker-options.js'
+import { type IWorker, type WorkerType, WorkerTypes } from './pools/worker.js'
+import type { IPool } from './pools/pool.js'
+
+/**
+ * Default task name.
+ */
+export const DEFAULT_TASK_NAME = 'default'
/**
* An intentional empty function.
})
/**
- * Default worker choice strategy options.
+ * Default measurement statistics requirements.
*/
-export const DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS: WorkerChoiceStrategyOptions =
+export const DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS: MeasurementStatisticsRequirements =
{
- medRunTime: false
+ aggregate: false,
+ average: false,
+ median: false
+ }
+
+/**
+ * Returns safe host OS optimized estimate of the default amount of parallelism a pool should use.
+ * Always returns a value greater than zero.
+ *
+ * @returns The host OS optimized maximum pool size.
+ */
+export const availableParallelism = (): number => {
+ let availableParallelism = 1
+ try {
+ availableParallelism = os.availableParallelism()
+ } catch {
+ const cpus = os.cpus()
+ if (Array.isArray(cpus) && cpus.length > 0) {
+ availableParallelism = cpus.length
+ }
+ }
+ return availableParallelism
+}
+
+/**
+ * Returns the worker type of the given worker.
+ *
+ * @param worker - The worker to get the type of.
+ * @returns The worker type of the given worker.
+ * @internal
+ */
+export const getWorkerType = (worker: IWorker): WorkerType | undefined => {
+ if (worker instanceof ThreadWorker) {
+ return WorkerTypes.thread
+ } else if (worker instanceof ClusterWorker) {
+ return WorkerTypes.cluster
+ }
+}
+
+/**
+ * Returns the worker id of the given worker.
+ *
+ * @param worker - The worker to get the id of.
+ * @returns The worker id of the given worker.
+ * @internal
+ */
+export const getWorkerId = (worker: IWorker): number | undefined => {
+ if (worker instanceof ThreadWorker) {
+ return worker.threadId
+ } else if (worker instanceof ClusterWorker) {
+ return worker.id
}
+}
/**
- * Compute the median of the given data set.
+ * Sleeps for the given amount of milliseconds.
+ *
+ * @param ms - The amount of milliseconds to sleep.
+ * @returns A promise that resolves after the given amount of milliseconds.
+ * @internal
+ */
+export const sleep = async (ms: number): Promise<void> => {
+ await new Promise(resolve => {
+ setTimeout(resolve, ms)
+ })
+}
+
+/**
+ * Computes the retry delay in milliseconds using an exponential back off algorithm.
+ *
+ * @param retryNumber - The number of retries that have already been attempted
+ * @param delayFactor - The base delay factor in milliseconds
+ * @returns Delay in milliseconds
+ * @internal
+ */
+export const exponentialDelay = (
+ retryNumber = 0,
+ delayFactor = 100
+): number => {
+ const delay = Math.pow(2, retryNumber) * delayFactor
+ const randomSum = delay * 0.2 * secureRandom() // 0-20% of the delay
+ return delay + randomSum
+}
+
+/**
+ * Computes the average of the given data set.
+ *
+ * @param dataSet - Data set.
+ * @returns The average of the given data set.
+ * @internal
+ */
+export const average = (dataSet: number[]): number => {
+ if (Array.isArray(dataSet) && dataSet.length === 0) {
+ return 0
+ }
+ if (Array.isArray(dataSet) && dataSet.length === 1) {
+ return dataSet[0]
+ }
+ return (
+ dataSet.reduce((accumulator, number) => accumulator + number, 0) /
+ dataSet.length
+ )
+}
+
+/**
+ * Computes the median of the given data set.
*
* @param dataSet - Data set.
* @returns The median of the given data set.
+ * @internal
*/
export const median = (dataSet: number[]): number => {
+ if (Array.isArray(dataSet) && dataSet.length === 0) {
+ return 0
+ }
if (Array.isArray(dataSet) && dataSet.length === 1) {
return dataSet[0]
}
const sortedDataSet = dataSet.slice().sort((a, b) => a - b)
- const middleIndex = Math.floor(sortedDataSet.length / 2)
- if (sortedDataSet.length % 2 === 0) {
- return sortedDataSet[middleIndex / 2]
- }
- return (sortedDataSet[middleIndex - 1] + sortedDataSet[middleIndex]) / 2
+ return (
+ (sortedDataSet[(sortedDataSet.length - 1) >> 1] +
+ sortedDataSet[sortedDataSet.length >> 1]) /
+ 2
+ )
}
+/**
+ * Rounds the given number to the given scale.
+ * The rounding is done using the "round half away from zero" method.
+ *
+ * @param num - The number to round.
+ * @param scale - The scale to round to.
+ * @returns The rounded number.
+ * @internal
+ */
+export const round = (num: number, scale = 2): number => {
+ const rounder = Math.pow(10, scale)
+ return Math.round(num * rounder * (1 + Number.EPSILON)) / rounder
+}
+
+/**
+ * Is the given object a plain object?
+ *
+ * @param obj - The object to check.
+ * @returns `true` if the given object is a plain object, `false` otherwise.
+ * @internal
+ */
export const isPlainObject = (obj: unknown): boolean =>
typeof obj === 'object' &&
obj !== null &&
- obj?.constructor === Object &&
+ obj.constructor === Object &&
Object.prototype.toString.call(obj) === '[object Object]'
+
+/**
+ * Detects whether the given value is a kill behavior or not.
+ *
+ * @typeParam KB - Which specific KillBehavior type to test against.
+ * @param killBehavior - Which kind of kill behavior to detect.
+ * @param value - Any value.
+ * @returns `true` if `value` was strictly equals to `killBehavior`, otherwise `false`.
+ * @internal
+ */
+export const isKillBehavior = <KB extends KillBehavior>(
+ killBehavior: KB,
+ value: unknown
+): value is KB => {
+ return value === killBehavior
+}
+
+/**
+ * Detects whether the given value is an asynchronous function or not.
+ *
+ * @param fn - Any value.
+ * @returns `true` if `fn` was an asynchronous function, otherwise `false`.
+ * @internal
+ */
+export const isAsyncFunction = (
+ fn: unknown
+): fn is (...args: unknown[]) => Promise<unknown> => {
+ return typeof fn === 'function' && fn.constructor.name === 'AsyncFunction'
+}
+
+/**
+ * Generates a cryptographically secure random number in the [0,1[ range
+ *
+ * @returns A number in the [0,1[ range
+ * @internal
+ */
+export const secureRandom = (): number => {
+ return getRandomValues(new Uint32Array(1))[0] / 0x100000000
+}
+
+/**
+ * Returns the minimum of the given numbers.
+ * If no numbers are given, `Infinity` is returned.
+ *
+ * @param args - The numbers to get the minimum of.
+ * @returns The minimum of the given numbers.
+ * @internal
+ */
+export const min = (...args: number[]): number =>
+ args.reduce((minimum, num) => (minimum < num ? minimum : num), Infinity)
+
+/**
+ * Returns the maximum of the given numbers.
+ * If no numbers are given, `-Infinity` is returned.
+ *
+ * @param args - The numbers to get the maximum of.
+ * @returns The maximum of the given numbers.
+ * @internal
+ */
+export const max = (...args: number[]): number =>
+ args.reduce((maximum, num) => (maximum > num ? maximum : num), -Infinity)
+
+/**
+ * Wraps a function so that it can only be called once.
+ *
+ * @param fn - The function to wrap.
+ * @param context - The context to bind the function to.
+ * @returns The wrapped function.
+ * @internal
+ */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export const once = <T, A extends any[], R>(
+ fn: (...args: A) => R,
+ context: T
+): ((...args: A) => R) => {
+ let result: R
+ return (...args: A) => {
+ // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+ if (fn != null) {
+ result = fn.apply<T, A, R>(context, args)
+ ;(fn as unknown as undefined) = (context as unknown as undefined) =
+ undefined
+ }
+ return result
+ }
+}
+
+export const getWorkerChoiceStrategyRetries = <
+ Worker extends IWorker,
+ Data,
+ Response
+>(
+ pool: IPool<Worker, Data, Response>,
+ opts?: WorkerChoiceStrategyOptions
+ ): number => {
+ return (
+ pool.info.maxSize +
+ Object.keys(opts?.weights ?? getDefaultWeights(pool.info.maxSize)).length
+ )
+}
+
+const clone = <T>(object: T): T => {
+ return structuredClone<T>(object)
+}
+
+export const buildWorkerChoiceStrategyOptions = <
+ Worker extends IWorker,
+ Data,
+ Response
+>(
+ pool: IPool<Worker, Data, Response>,
+ opts?: WorkerChoiceStrategyOptions
+ ): WorkerChoiceStrategyOptions => {
+ opts = clone(opts ?? {})
+ opts.weights = opts.weights ?? getDefaultWeights(pool.info.maxSize)
+ return {
+ ...{
+ runTime: { median: false },
+ waitTime: { median: false },
+ elu: { median: false }
+ },
+ ...opts
+ }
+}
+
+const getDefaultWeights = (
+ poolMaxSize: number,
+ defaultWorkerWeight?: number
+): Record<number, number> => {
+ defaultWorkerWeight = defaultWorkerWeight ?? getDefaultWorkerWeight()
+ const weights: Record<number, number> = {}
+ for (let workerNodeKey = 0; workerNodeKey < poolMaxSize; workerNodeKey++) {
+ weights[workerNodeKey] = defaultWorkerWeight
+ }
+ return weights
+}
+
+const getDefaultWorkerWeight = (): number => {
+ const cpuSpeed = randomInt(500, 2500)
+ let cpusCycleTimeWeight = 0
+ for (const cpu of cpus()) {
+ // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+ if (cpu.speed == null || cpu.speed === 0) {
+ cpu.speed =
+ // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+ cpus().find(cpu => cpu.speed != null && cpu.speed !== 0)?.speed ??
+ cpuSpeed
+ }
+ // CPU estimated cycle time
+ const numberOfDigits = cpu.speed.toString().length - 1
+ const cpuCycleTime = 1 / (cpu.speed / Math.pow(10, numberOfDigits))
+ cpusCycleTimeWeight += cpuCycleTime * Math.pow(10, numberOfDigits)
+ }
+ return Math.round(cpusCycleTimeWeight / cpus().length)
+}