build(deps-dev): bump @types/node
[poolifier.git] / src / utils.ts
1 import * as os from 'node:os'
2 import { getRandomValues, randomInt } from 'node:crypto'
3 import { Worker as ClusterWorker } from 'node:cluster'
4 import { Worker as ThreadWorker } from 'node:worker_threads'
5 import { cpus } from 'node:os'
6 import type {
7 MeasurementStatisticsRequirements,
8 WorkerChoiceStrategyOptions
9 } from './pools/selection-strategies/selection-strategies-types.js'
10 import type { KillBehavior } from './worker/worker-options.js'
11 import { type IWorker, type WorkerType, WorkerTypes } from './pools/worker.js'
12 import type { IPool } from './pools/pool.js'
13
14 /**
15 * Default task name.
16 */
17 export const DEFAULT_TASK_NAME = 'default'
18
19 /**
20 * An intentional empty function.
21 */
22 export const EMPTY_FUNCTION: () => void = Object.freeze(() => {
23 /* Intentionally empty */
24 })
25
26 /**
27 * Default measurement statistics requirements.
28 */
29 export const DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS: MeasurementStatisticsRequirements =
30 {
31 aggregate: false,
32 average: false,
33 median: false
34 }
35
36 /**
37 * Returns safe host OS optimized estimate of the default amount of parallelism a pool should use.
38 * Always returns a value greater than zero.
39 *
40 * @returns The host OS optimized maximum pool size.
41 */
42 export const availableParallelism = (): number => {
43 let availableParallelism = 1
44 try {
45 availableParallelism = os.availableParallelism()
46 } catch {
47 const cpus = os.cpus()
48 if (Array.isArray(cpus) && cpus.length > 0) {
49 availableParallelism = cpus.length
50 }
51 }
52 return availableParallelism
53 }
54
55 /**
56 * Returns the worker type of the given worker.
57 *
58 * @param worker - The worker to get the type of.
59 * @returns The worker type of the given worker.
60 * @internal
61 */
62 export const getWorkerType = (worker: IWorker): WorkerType | undefined => {
63 if (worker instanceof ThreadWorker) {
64 return WorkerTypes.thread
65 } else if (worker instanceof ClusterWorker) {
66 return WorkerTypes.cluster
67 }
68 }
69
70 /**
71 * Returns the worker id of the given worker.
72 *
73 * @param worker - The worker to get the id of.
74 * @returns The worker id of the given worker.
75 * @internal
76 */
77 export const getWorkerId = (worker: IWorker): number | undefined => {
78 if (worker instanceof ThreadWorker) {
79 return worker.threadId
80 } else if (worker instanceof ClusterWorker) {
81 return worker.id
82 }
83 }
84
85 /**
86 * Sleeps for the given amount of milliseconds.
87 *
88 * @param ms - The amount of milliseconds to sleep.
89 * @returns A promise that resolves after the given amount of milliseconds.
90 * @internal
91 */
92 export const sleep = async (ms: number): Promise<void> => {
93 await new Promise(resolve => {
94 setTimeout(resolve, ms)
95 })
96 }
97
98 /**
99 * Computes the retry delay in milliseconds using an exponential back off algorithm.
100 *
101 * @param retryNumber - The number of retries that have already been attempted
102 * @param delayFactor - The base delay factor in milliseconds
103 * @returns Delay in milliseconds
104 * @internal
105 */
106 export const exponentialDelay = (
107 retryNumber = 0,
108 delayFactor = 100
109 ): number => {
110 const delay = Math.pow(2, retryNumber) * delayFactor
111 const randomSum = delay * 0.2 * secureRandom() // 0-20% of the delay
112 return delay + randomSum
113 }
114
115 /**
116 * Computes the average of the given data set.
117 *
118 * @param dataSet - Data set.
119 * @returns The average of the given data set.
120 * @internal
121 */
122 export const average = (dataSet: number[]): number => {
123 if (Array.isArray(dataSet) && dataSet.length === 0) {
124 return 0
125 }
126 if (Array.isArray(dataSet) && dataSet.length === 1) {
127 return dataSet[0]
128 }
129 return (
130 dataSet.reduce((accumulator, number) => accumulator + number, 0) /
131 dataSet.length
132 )
133 }
134
135 /**
136 * Computes the median of the given data set.
137 *
138 * @param dataSet - Data set.
139 * @returns The median of the given data set.
140 * @internal
141 */
142 export const median = (dataSet: number[]): number => {
143 if (Array.isArray(dataSet) && dataSet.length === 0) {
144 return 0
145 }
146 if (Array.isArray(dataSet) && dataSet.length === 1) {
147 return dataSet[0]
148 }
149 const sortedDataSet = dataSet.slice().sort((a, b) => a - b)
150 return (
151 (sortedDataSet[(sortedDataSet.length - 1) >> 1] +
152 sortedDataSet[sortedDataSet.length >> 1]) /
153 2
154 )
155 }
156
157 /**
158 * Rounds the given number to the given scale.
159 * The rounding is done using the "round half away from zero" method.
160 *
161 * @param num - The number to round.
162 * @param scale - The scale to round to.
163 * @returns The rounded number.
164 * @internal
165 */
166 export const round = (num: number, scale = 2): number => {
167 const rounder = Math.pow(10, scale)
168 return Math.round(num * rounder * (1 + Number.EPSILON)) / rounder
169 }
170
171 /**
172 * Is the given object a plain object?
173 *
174 * @param obj - The object to check.
175 * @returns `true` if the given object is a plain object, `false` otherwise.
176 * @internal
177 */
178 export const isPlainObject = (obj: unknown): boolean =>
179 typeof obj === 'object' &&
180 obj !== null &&
181 obj.constructor === Object &&
182 Object.prototype.toString.call(obj) === '[object Object]'
183
184 /**
185 * Detects whether the given value is a kill behavior or not.
186 *
187 * @typeParam KB - Which specific KillBehavior type to test against.
188 * @param killBehavior - Which kind of kill behavior to detect.
189 * @param value - Any value.
190 * @returns `true` if `value` was strictly equals to `killBehavior`, otherwise `false`.
191 * @internal
192 */
193 export const isKillBehavior = <KB extends KillBehavior>(
194 killBehavior: KB,
195 value: unknown
196 ): value is KB => {
197 return value === killBehavior
198 }
199
200 /**
201 * Detects whether the given value is an asynchronous function or not.
202 *
203 * @param fn - Any value.
204 * @returns `true` if `fn` was an asynchronous function, otherwise `false`.
205 * @internal
206 */
207 export const isAsyncFunction = (
208 fn: unknown
209 ): fn is (...args: unknown[]) => Promise<unknown> => {
210 return typeof fn === 'function' && fn.constructor.name === 'AsyncFunction'
211 }
212
213 /**
214 * Generates a cryptographically secure random number in the [0,1[ range
215 *
216 * @returns A number in the [0,1[ range
217 * @internal
218 */
219 export const secureRandom = (): number => {
220 return getRandomValues(new Uint32Array(1))[0] / 0x100000000
221 }
222
223 /**
224 * Returns the minimum of the given numbers.
225 * If no numbers are given, `Infinity` is returned.
226 *
227 * @param args - The numbers to get the minimum of.
228 * @returns The minimum of the given numbers.
229 * @internal
230 */
231 export const min = (...args: number[]): number =>
232 args.reduce((minimum, num) => (minimum < num ? minimum : num), Infinity)
233
234 /**
235 * Returns the maximum of the given numbers.
236 * If no numbers are given, `-Infinity` is returned.
237 *
238 * @param args - The numbers to get the maximum of.
239 * @returns The maximum of the given numbers.
240 * @internal
241 */
242 export const max = (...args: number[]): number =>
243 args.reduce((maximum, num) => (maximum > num ? maximum : num), -Infinity)
244
245 /**
246 * Wraps a function so that it can only be called once.
247 *
248 * @param fn - The function to wrap.
249 * @param context - The context to bind the function to.
250 * @returns The wrapped function.
251 * @internal
252 */
253 // eslint-disable-next-line @typescript-eslint/no-explicit-any
254 export const once = <T, A extends any[], R>(
255 fn: (...args: A) => R,
256 context: T
257 ): ((...args: A) => R) => {
258 let result: R
259 return (...args: A) => {
260 // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
261 if (fn != null) {
262 result = fn.apply<T, A, R>(context, args)
263 ;(fn as unknown as undefined) = (context as unknown as undefined) =
264 undefined
265 }
266 return result
267 }
268 }
269
270 export const getWorkerChoiceStrategyRetries = <
271 Worker extends IWorker,
272 Data,
273 Response
274 >(
275 pool: IPool<Worker, Data, Response>,
276 opts?: WorkerChoiceStrategyOptions
277 ): number => {
278 return (
279 pool.info.maxSize +
280 Object.keys(opts?.weights ?? getDefaultWeights(pool.info.maxSize)).length
281 )
282 }
283
284 const clone = <T>(object: T): T => {
285 return structuredClone<T>(object)
286 }
287
288 export const buildWorkerChoiceStrategyOptions = <
289 Worker extends IWorker,
290 Data,
291 Response
292 >(
293 pool: IPool<Worker, Data, Response>,
294 opts?: WorkerChoiceStrategyOptions
295 ): WorkerChoiceStrategyOptions => {
296 opts = clone(opts ?? {})
297 opts.weights = opts.weights ?? getDefaultWeights(pool.info.maxSize)
298 return {
299 ...{
300 runTime: { median: false },
301 waitTime: { median: false },
302 elu: { median: false }
303 },
304 ...opts
305 }
306 }
307
308 const getDefaultWeights = (
309 poolMaxSize: number,
310 defaultWorkerWeight?: number
311 ): Record<number, number> => {
312 defaultWorkerWeight = defaultWorkerWeight ?? getDefaultWorkerWeight()
313 const weights: Record<number, number> = {}
314 for (let workerNodeKey = 0; workerNodeKey < poolMaxSize; workerNodeKey++) {
315 weights[workerNodeKey] = defaultWorkerWeight
316 }
317 return weights
318 }
319
320 const getDefaultWorkerWeight = (): number => {
321 const cpuSpeed = randomInt(500, 2500)
322 let cpusCycleTimeWeight = 0
323 for (const cpu of cpus()) {
324 // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
325 if (cpu.speed == null || cpu.speed === 0) {
326 cpu.speed =
327 // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
328 cpus().find(cpu => cpu.speed != null && cpu.speed !== 0)?.speed ??
329 cpuSpeed
330 }
331 // CPU estimated cycle time
332 const numberOfDigits = cpu.speed.toString().length - 1
333 const cpuCycleTime = 1 / (cpu.speed / Math.pow(10, numberOfDigits))
334 cpusCycleTimeWeight += cpuCycleTime * Math.pow(10, numberOfDigits)
335 }
336 return Math.round(cpusCycleTimeWeight / cpus().length)
337 }