1 import { randomUUID
} from
'node:crypto'
2 import { performance
} from
'node:perf_hooks'
3 import { existsSync
} from
'node:fs'
4 import { type TransferListItem
} from
'node:worker_threads'
7 PromiseResponseWrapper
,
9 } from
'../utility-types'
12 DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
,
21 updateMeasurementStatistics
23 import { KillBehaviors
} from
'../worker/worker-options'
32 type TasksQueueOptions
42 type MeasurementStatisticsRequirements
,
44 WorkerChoiceStrategies
,
45 type WorkerChoiceStrategy
,
46 type WorkerChoiceStrategyOptions
47 } from
'./selection-strategies/selection-strategies-types'
48 import { WorkerChoiceStrategyContext
} from
'./selection-strategies/worker-choice-strategy-context'
49 import { version
} from
'./version'
50 import { WorkerNode
} from
'./worker-node'
53 * Base class that implements some shared logic for all poolifier pools.
55 * @typeParam Worker - Type of worker which manages this pool.
56 * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
57 * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
59 export abstract class AbstractPool
<
60 Worker
extends IWorker
,
63 > implements IPool
<Worker
, Data
, Response
> {
65 public readonly workerNodes
: Array<IWorkerNode
<Worker
, Data
>> = []
68 public readonly emitter
?: PoolEmitter
71 * The task execution response promise map:
72 * - `key`: The message id of each submitted task.
73 * - `value`: An object that contains the worker, the execution response promise resolve and reject callbacks.
75 * When we receive a message from the worker, we get a map entry with the promise resolve/reject bound to the message id.
77 protected promiseResponseMap
: Map
<string, PromiseResponseWrapper
<Response
>> =
78 new Map
<string, PromiseResponseWrapper
<Response
>>()
81 * Worker choice strategy context referencing a worker choice algorithm implementation.
83 protected workerChoiceStrategyContext
: WorkerChoiceStrategyContext
<
90 * Dynamic pool maximum size property placeholder.
92 protected readonly max
?: number
95 * Whether the pool is started or not.
97 private started
: boolean
99 * Whether the pool is starting or not.
101 private starting
: boolean
103 * The start timestamp of the pool.
105 private readonly startTimestamp
108 * Constructs a new poolifier pool.
110 * @param numberOfWorkers - Number of workers that this pool should manage.
111 * @param filePath - Path to the worker file.
112 * @param opts - Options for the pool.
115 protected readonly numberOfWorkers
: number,
116 protected readonly filePath
: string,
117 protected readonly opts
: PoolOptions
<Worker
>
119 if (!this.isMain()) {
121 'Cannot start a pool from a worker with the same type as the pool'
124 this.checkNumberOfWorkers(this.numberOfWorkers
)
125 this.checkFilePath(this.filePath
)
126 this.checkPoolOptions(this.opts
)
128 this.chooseWorkerNode
= this.chooseWorkerNode
.bind(this)
129 this.executeTask
= this.executeTask
.bind(this)
130 this.enqueueTask
= this.enqueueTask
.bind(this)
132 if (this.opts
.enableEvents
=== true) {
133 this.emitter
= new PoolEmitter()
135 this.workerChoiceStrategyContext
= new WorkerChoiceStrategyContext
<
141 this.opts
.workerChoiceStrategy
,
142 this.opts
.workerChoiceStrategyOptions
148 this.starting
= false
149 if (this.opts
.startWorkers
=== true) {
153 this.startTimestamp
= performance
.now()
156 private checkFilePath (filePath
: string): void {
159 typeof filePath
!== 'string' ||
160 (typeof filePath
=== 'string' && filePath
.trim().length
=== 0)
162 throw new Error('Please specify a file with a worker implementation')
164 if (!existsSync(filePath
)) {
165 throw new Error(`Cannot find the worker file '${filePath}'`)
169 private checkNumberOfWorkers (numberOfWorkers
: number): void {
170 if (numberOfWorkers
== null) {
172 'Cannot instantiate a pool without specifying the number of workers'
174 } else if (!Number.isSafeInteger(numberOfWorkers
)) {
176 'Cannot instantiate a pool with a non safe integer number of workers'
178 } else if (numberOfWorkers
< 0) {
179 throw new RangeError(
180 'Cannot instantiate a pool with a negative number of workers'
182 } else if (this.type === PoolTypes
.fixed
&& numberOfWorkers
=== 0) {
183 throw new RangeError('Cannot instantiate a fixed pool with zero worker')
187 protected checkDynamicPoolSize (min
: number, max
: number): void {
188 if (this.type === PoolTypes
.dynamic
) {
191 'Cannot instantiate a dynamic pool without specifying the maximum pool size'
193 } else if (!Number.isSafeInteger(max
)) {
195 'Cannot instantiate a dynamic pool with a non safe integer maximum pool size'
197 } else if (min
> max
) {
198 throw new RangeError(
199 'Cannot instantiate a dynamic pool with a maximum pool size inferior to the minimum pool size'
201 } else if (max
=== 0) {
202 throw new RangeError(
203 'Cannot instantiate a dynamic pool with a maximum pool size equal to zero'
205 } else if (min
=== max
) {
206 throw new RangeError(
207 'Cannot instantiate a dynamic pool with a minimum pool size equal to the maximum pool size. Use a fixed pool instead'
213 private checkPoolOptions (opts
: PoolOptions
<Worker
>): void {
214 if (isPlainObject(opts
)) {
215 this.opts
.startWorkers
= opts
.startWorkers
?? true
216 this.opts
.workerChoiceStrategy
=
217 opts
.workerChoiceStrategy
?? WorkerChoiceStrategies
.ROUND_ROBIN
218 this.checkValidWorkerChoiceStrategy(this.opts
.workerChoiceStrategy
)
219 this.opts
.workerChoiceStrategyOptions
= {
220 ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
,
221 ...opts
.workerChoiceStrategyOptions
223 this.checkValidWorkerChoiceStrategyOptions(
224 this.opts
.workerChoiceStrategyOptions
226 this.opts
.restartWorkerOnError
= opts
.restartWorkerOnError
?? true
227 this.opts
.enableEvents
= opts
.enableEvents
?? true
228 this.opts
.enableTasksQueue
= opts
.enableTasksQueue
?? false
229 if (this.opts
.enableTasksQueue
) {
230 this.checkValidTasksQueueOptions(
231 opts
.tasksQueueOptions
as TasksQueueOptions
233 this.opts
.tasksQueueOptions
= this.buildTasksQueueOptions(
234 opts
.tasksQueueOptions
as TasksQueueOptions
238 throw new TypeError('Invalid pool options: must be a plain object')
242 private checkValidWorkerChoiceStrategy (
243 workerChoiceStrategy
: WorkerChoiceStrategy
245 if (!Object.values(WorkerChoiceStrategies
).includes(workerChoiceStrategy
)) {
247 `Invalid worker choice strategy '${workerChoiceStrategy}'`
252 private checkValidWorkerChoiceStrategyOptions (
253 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
255 if (!isPlainObject(workerChoiceStrategyOptions
)) {
257 'Invalid worker choice strategy options: must be a plain object'
261 workerChoiceStrategyOptions
.retries
!= null &&
262 !Number.isSafeInteger(workerChoiceStrategyOptions
.retries
)
265 'Invalid worker choice strategy options: retries must be an integer'
269 workerChoiceStrategyOptions
.retries
!= null &&
270 workerChoiceStrategyOptions
.retries
< 0
272 throw new RangeError(
273 `Invalid worker choice strategy options: retries '${workerChoiceStrategyOptions.retries}' must be greater or equal than zero`
277 workerChoiceStrategyOptions
.weights
!= null &&
278 Object.keys(workerChoiceStrategyOptions
.weights
).length
!== this.maxSize
281 'Invalid worker choice strategy options: must have a weight for each worker node'
285 workerChoiceStrategyOptions
.measurement
!= null &&
286 !Object.values(Measurements
).includes(
287 workerChoiceStrategyOptions
.measurement
291 `Invalid worker choice strategy options: invalid measurement '${workerChoiceStrategyOptions.measurement}'`
296 private checkValidTasksQueueOptions (
297 tasksQueueOptions
: TasksQueueOptions
299 if (tasksQueueOptions
!= null && !isPlainObject(tasksQueueOptions
)) {
300 throw new TypeError('Invalid tasks queue options: must be a plain object')
303 tasksQueueOptions
?.concurrency
!= null &&
304 !Number.isSafeInteger(tasksQueueOptions
?.concurrency
)
307 'Invalid worker node tasks concurrency: must be an integer'
311 tasksQueueOptions
?.concurrency
!= null &&
312 tasksQueueOptions
?.concurrency
<= 0
314 throw new RangeError(
315 `Invalid worker node tasks concurrency: ${tasksQueueOptions?.concurrency} is a negative integer or zero`
319 tasksQueueOptions
?.size
!= null &&
320 !Number.isSafeInteger(tasksQueueOptions
?.size
)
323 'Invalid worker node tasks queue size: must be an integer'
326 if (tasksQueueOptions
?.size
!= null && tasksQueueOptions
?.size
<= 0) {
327 throw new RangeError(
328 `Invalid worker node tasks queue size: ${tasksQueueOptions?.size} is a negative integer or zero`
334 public get
info (): PoolInfo
{
339 started
: this.started
,
341 strategy
: this.opts
.workerChoiceStrategy
as WorkerChoiceStrategy
,
342 minSize
: this.minSize
,
343 maxSize
: this.maxSize
,
344 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
345 .runTime
.aggregate
&&
346 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
347 .waitTime
.aggregate
&& { utilization
: round(this.utilization
) }),
348 workerNodes
: this.workerNodes
.length
,
349 idleWorkerNodes
: this.workerNodes
.reduce(
350 (accumulator
, workerNode
) =>
351 workerNode
.usage
.tasks
.executing
=== 0
356 busyWorkerNodes
: this.workerNodes
.reduce(
357 (accumulator
, workerNode
) =>
358 workerNode
.usage
.tasks
.executing
> 0 ? accumulator
+ 1 : accumulator
,
361 executedTasks
: this.workerNodes
.reduce(
362 (accumulator
, workerNode
) =>
363 accumulator
+ workerNode
.usage
.tasks
.executed
,
366 executingTasks
: this.workerNodes
.reduce(
367 (accumulator
, workerNode
) =>
368 accumulator
+ workerNode
.usage
.tasks
.executing
,
371 ...(this.opts
.enableTasksQueue
=== true && {
372 queuedTasks
: this.workerNodes
.reduce(
373 (accumulator
, workerNode
) =>
374 accumulator
+ workerNode
.usage
.tasks
.queued
,
378 ...(this.opts
.enableTasksQueue
=== true && {
379 maxQueuedTasks
: this.workerNodes
.reduce(
380 (accumulator
, workerNode
) =>
381 accumulator
+ (workerNode
.usage
.tasks
?.maxQueued
?? 0),
385 ...(this.opts
.enableTasksQueue
=== true && {
386 backPressure
: this.hasBackPressure()
388 ...(this.opts
.enableTasksQueue
=== true && {
389 stolenTasks
: this.workerNodes
.reduce(
390 (accumulator
, workerNode
) =>
391 accumulator
+ workerNode
.usage
.tasks
.stolen
,
395 failedTasks
: this.workerNodes
.reduce(
396 (accumulator
, workerNode
) =>
397 accumulator
+ workerNode
.usage
.tasks
.failed
,
400 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
401 .runTime
.aggregate
&& {
405 ...this.workerNodes
.map(
406 workerNode
=> workerNode
.usage
.runTime
?.minimum
?? Infinity
412 ...this.workerNodes
.map(
413 workerNode
=> workerNode
.usage
.runTime
?.maximum
?? -Infinity
417 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
418 .runTime
.average
&& {
421 this.workerNodes
.reduce
<number[]>(
422 (accumulator
, workerNode
) =>
423 accumulator
.concat(workerNode
.usage
.runTime
.history
),
429 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
433 this.workerNodes
.reduce
<number[]>(
434 (accumulator
, workerNode
) =>
435 accumulator
.concat(workerNode
.usage
.runTime
.history
),
443 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
444 .waitTime
.aggregate
&& {
448 ...this.workerNodes
.map(
449 workerNode
=> workerNode
.usage
.waitTime
?.minimum
?? Infinity
455 ...this.workerNodes
.map(
456 workerNode
=> workerNode
.usage
.waitTime
?.maximum
?? -Infinity
460 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
461 .waitTime
.average
&& {
464 this.workerNodes
.reduce
<number[]>(
465 (accumulator
, workerNode
) =>
466 accumulator
.concat(workerNode
.usage
.waitTime
.history
),
472 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
473 .waitTime
.median
&& {
476 this.workerNodes
.reduce
<number[]>(
477 (accumulator
, workerNode
) =>
478 accumulator
.concat(workerNode
.usage
.waitTime
.history
),
490 * The pool readiness boolean status.
492 private get
ready (): boolean {
494 this.workerNodes
.reduce(
495 (accumulator
, workerNode
) =>
496 !workerNode
.info
.dynamic
&& workerNode
.info
.ready
505 * The approximate pool utilization.
507 * @returns The pool utilization.
509 private get
utilization (): number {
510 const poolTimeCapacity
=
511 (performance
.now() - this.startTimestamp
) * this.maxSize
512 const totalTasksRunTime
= this.workerNodes
.reduce(
513 (accumulator
, workerNode
) =>
514 accumulator
+ (workerNode
.usage
.runTime
?.aggregate
?? 0),
517 const totalTasksWaitTime
= this.workerNodes
.reduce(
518 (accumulator
, workerNode
) =>
519 accumulator
+ (workerNode
.usage
.waitTime
?.aggregate
?? 0),
522 return (totalTasksRunTime
+ totalTasksWaitTime
) / poolTimeCapacity
528 * If it is `'dynamic'`, it provides the `max` property.
530 protected abstract get
type (): PoolType
535 protected abstract get
worker (): WorkerType
538 * The pool minimum size.
540 protected get
minSize (): number {
541 return this.numberOfWorkers
545 * The pool maximum size.
547 protected get
maxSize (): number {
548 return this.max
?? this.numberOfWorkers
552 * Checks if the worker id sent in the received message from a worker is valid.
554 * @param message - The received message.
555 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the worker id is invalid.
557 private checkMessageWorkerId (message
: MessageValue
<Response
>): void {
558 if (message
.workerId
== null) {
559 throw new Error('Worker message received without worker id')
561 message
.workerId
!= null &&
562 this.getWorkerNodeKeyByWorkerId(message
.workerId
) === -1
565 `Worker message received from unknown worker '${message.workerId}'`
571 * Gets the given worker its worker node key.
573 * @param worker - The worker.
574 * @returns The worker node key if found in the pool worker nodes, `-1` otherwise.
576 private getWorkerNodeKeyByWorker (worker
: Worker
): number {
577 return this.workerNodes
.findIndex(
578 workerNode
=> workerNode
.worker
=== worker
583 * Gets the worker node key given its worker id.
585 * @param workerId - The worker id.
586 * @returns The worker node key if the worker id is found in the pool worker nodes, `-1` otherwise.
588 private getWorkerNodeKeyByWorkerId (workerId
: number): number {
589 return this.workerNodes
.findIndex(
590 workerNode
=> workerNode
.info
.id
=== workerId
595 public setWorkerChoiceStrategy (
596 workerChoiceStrategy
: WorkerChoiceStrategy
,
597 workerChoiceStrategyOptions
?: WorkerChoiceStrategyOptions
599 this.checkValidWorkerChoiceStrategy(workerChoiceStrategy
)
600 this.opts
.workerChoiceStrategy
= workerChoiceStrategy
601 this.workerChoiceStrategyContext
.setWorkerChoiceStrategy(
602 this.opts
.workerChoiceStrategy
604 if (workerChoiceStrategyOptions
!= null) {
605 this.setWorkerChoiceStrategyOptions(workerChoiceStrategyOptions
)
607 for (const [workerNodeKey
, workerNode
] of this.workerNodes
.entries()) {
608 workerNode
.resetUsage()
609 this.sendStatisticsMessageToWorker(workerNodeKey
)
614 public setWorkerChoiceStrategyOptions (
615 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
617 this.checkValidWorkerChoiceStrategyOptions(workerChoiceStrategyOptions
)
618 this.opts
.workerChoiceStrategyOptions
= {
619 ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
,
620 ...workerChoiceStrategyOptions
622 this.workerChoiceStrategyContext
.setOptions(
623 this.opts
.workerChoiceStrategyOptions
628 public enableTasksQueue (
630 tasksQueueOptions
?: TasksQueueOptions
632 if (this.opts
.enableTasksQueue
=== true && !enable
) {
633 this.flushTasksQueues()
635 this.opts
.enableTasksQueue
= enable
636 this.setTasksQueueOptions(tasksQueueOptions
as TasksQueueOptions
)
640 public setTasksQueueOptions (tasksQueueOptions
: TasksQueueOptions
): void {
641 if (this.opts
.enableTasksQueue
=== true) {
642 this.checkValidTasksQueueOptions(tasksQueueOptions
)
643 this.opts
.tasksQueueOptions
=
644 this.buildTasksQueueOptions(tasksQueueOptions
)
645 this.setTasksQueueSize(this.opts
.tasksQueueOptions
.size
as number)
646 } else if (this.opts
.tasksQueueOptions
!= null) {
647 delete this.opts
.tasksQueueOptions
651 private setTasksQueueSize (size
: number): void {
652 for (const workerNode
of this.workerNodes
) {
653 workerNode
.tasksQueueBackPressureSize
= size
657 private buildTasksQueueOptions (
658 tasksQueueOptions
: TasksQueueOptions
659 ): TasksQueueOptions
{
662 size
: Math.pow(this.maxSize
, 2),
665 tasksStealingOnBackPressure
: true
672 * Whether the pool is full or not.
674 * The pool filling boolean status.
676 protected get
full (): boolean {
677 return this.workerNodes
.length
>= this.maxSize
681 * Whether the pool is busy or not.
683 * The pool busyness boolean status.
685 protected abstract get
busy (): boolean
688 * Whether worker nodes are executing concurrently their tasks quota or not.
690 * @returns Worker nodes busyness boolean status.
692 protected internalBusy (): boolean {
693 if (this.opts
.enableTasksQueue
=== true) {
695 this.workerNodes
.findIndex(
697 workerNode
.info
.ready
&&
698 workerNode
.usage
.tasks
.executing
<
699 (this.opts
.tasksQueueOptions
?.concurrency
as number)
704 this.workerNodes
.findIndex(
706 workerNode
.info
.ready
&& workerNode
.usage
.tasks
.executing
=== 0
712 public listTaskFunctions (): string[] {
713 for (const workerNode
of this.workerNodes
) {
715 Array.isArray(workerNode
.info
.taskFunctions
) &&
716 workerNode
.info
.taskFunctions
.length
> 0
718 return workerNode
.info
.taskFunctions
724 private shallExecuteTask (workerNodeKey
: number): boolean {
726 this.tasksQueueSize(workerNodeKey
) === 0 &&
727 this.workerNodes
[workerNodeKey
].usage
.tasks
.executing
<
728 (this.opts
.tasksQueueOptions
?.concurrency
as number)
733 public async execute (
736 transferList
?: TransferListItem
[]
737 ): Promise
<Response
> {
738 return await new Promise
<Response
>((resolve
, reject
) => {
740 reject(new Error('Cannot execute a task on not started pool'))
743 if (name
!= null && typeof name
!== 'string') {
744 reject(new TypeError('name argument must be a string'))
749 typeof name
=== 'string' &&
750 name
.trim().length
=== 0
752 reject(new TypeError('name argument must not be an empty string'))
755 if (transferList
!= null && !Array.isArray(transferList
)) {
756 reject(new TypeError('transferList argument must be an array'))
759 const timestamp
= performance
.now()
760 const workerNodeKey
= this.chooseWorkerNode()
761 const task
: Task
<Data
> = {
762 name
: name
?? DEFAULT_TASK_NAME
,
763 // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
764 data
: data
?? ({} as Data
),
767 workerId
: this.getWorkerInfo(workerNodeKey
).id
as number,
770 this.promiseResponseMap
.set(task
.taskId
as string, {
776 this.opts
.enableTasksQueue
=== false ||
777 (this.opts
.enableTasksQueue
=== true &&
778 this.shallExecuteTask(workerNodeKey
))
780 this.executeTask(workerNodeKey
, task
)
782 this.enqueueTask(workerNodeKey
, task
)
788 public start (): void {
791 this.workerNodes
.reduce(
792 (accumulator
, workerNode
) =>
793 !workerNode
.info
.dynamic
? accumulator
+ 1 : accumulator
,
795 ) < this.numberOfWorkers
797 this.createAndSetupWorkerNode()
799 this.starting
= false
804 public async destroy (): Promise
<void> {
806 this.workerNodes
.map(async (_
, workerNodeKey
) => {
807 await this.destroyWorkerNode(workerNodeKey
)
810 this.emitter
?.emit(PoolEvents
.destroy
, this.info
)
814 protected async sendKillMessageToWorker (
815 workerNodeKey
: number,
818 await new Promise
<void>((resolve
, reject
) => {
819 this.registerWorkerMessageListener(workerNodeKey
, message
=> {
820 if (message
.kill
=== 'success') {
822 } else if (message
.kill
=== 'failure') {
823 reject(new Error(`Worker ${workerId} kill message handling failed`))
826 this.sendToWorker(workerNodeKey
, { kill
: true, workerId
})
831 * Terminates the worker node given its worker node key.
833 * @param workerNodeKey - The worker node key.
835 protected abstract destroyWorkerNode (workerNodeKey
: number): Promise
<void>
838 * Setup hook to execute code before worker nodes are created in the abstract constructor.
843 protected setupHook (): void {
844 /* Intentionally empty */
848 * Should return whether the worker is the main worker or not.
850 protected abstract isMain (): boolean
853 * Hook executed before the worker task execution.
856 * @param workerNodeKey - The worker node key.
857 * @param task - The task to execute.
859 protected beforeTaskExecutionHook (
860 workerNodeKey
: number,
863 if (this.workerNodes
[workerNodeKey
]?.usage
!= null) {
864 const workerUsage
= this.workerNodes
[workerNodeKey
].usage
865 ++workerUsage
.tasks
.executing
866 this.updateWaitTimeWorkerUsage(workerUsage
, task
)
869 this.shallUpdateTaskFunctionWorkerUsage(workerNodeKey
) &&
870 this.workerNodes
[workerNodeKey
].getTaskFunctionWorkerUsage(
874 const taskFunctionWorkerUsage
= this.workerNodes
[
876 ].getTaskFunctionWorkerUsage(task
.name
as string) as WorkerUsage
877 ++taskFunctionWorkerUsage
.tasks
.executing
878 this.updateWaitTimeWorkerUsage(taskFunctionWorkerUsage
, task
)
883 * Hook executed after the worker task execution.
886 * @param workerNodeKey - The worker node key.
887 * @param message - The received message.
889 protected afterTaskExecutionHook (
890 workerNodeKey
: number,
891 message
: MessageValue
<Response
>
893 if (this.workerNodes
[workerNodeKey
]?.usage
!= null) {
894 const workerUsage
= this.workerNodes
[workerNodeKey
].usage
895 this.updateTaskStatisticsWorkerUsage(workerUsage
, message
)
896 this.updateRunTimeWorkerUsage(workerUsage
, message
)
897 this.updateEluWorkerUsage(workerUsage
, message
)
900 this.shallUpdateTaskFunctionWorkerUsage(workerNodeKey
) &&
901 this.workerNodes
[workerNodeKey
].getTaskFunctionWorkerUsage(
902 message
.taskPerformance
?.name
as string
905 const taskFunctionWorkerUsage
= this.workerNodes
[
907 ].getTaskFunctionWorkerUsage(
908 message
.taskPerformance
?.name
as string
910 this.updateTaskStatisticsWorkerUsage(taskFunctionWorkerUsage
, message
)
911 this.updateRunTimeWorkerUsage(taskFunctionWorkerUsage
, message
)
912 this.updateEluWorkerUsage(taskFunctionWorkerUsage
, message
)
917 * Whether the worker node shall update its task function worker usage or not.
919 * @param workerNodeKey - The worker node key.
920 * @returns `true` if the worker node shall update its task function worker usage, `false` otherwise.
922 private shallUpdateTaskFunctionWorkerUsage (workerNodeKey
: number): boolean {
923 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
925 workerInfo
!= null &&
926 Array.isArray(workerInfo
.taskFunctions
) &&
927 workerInfo
.taskFunctions
.length
> 2
931 private updateTaskStatisticsWorkerUsage (
932 workerUsage
: WorkerUsage
,
933 message
: MessageValue
<Response
>
935 const workerTaskStatistics
= workerUsage
.tasks
937 workerTaskStatistics
.executing
!= null &&
938 workerTaskStatistics
.executing
> 0
940 --workerTaskStatistics
.executing
942 if (message
.taskError
== null) {
943 ++workerTaskStatistics
.executed
945 ++workerTaskStatistics
.failed
949 private updateRunTimeWorkerUsage (
950 workerUsage
: WorkerUsage
,
951 message
: MessageValue
<Response
>
953 if (message
.taskError
!= null) {
956 updateMeasurementStatistics(
958 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().runTime
,
959 message
.taskPerformance
?.runTime
?? 0
963 private updateWaitTimeWorkerUsage (
964 workerUsage
: WorkerUsage
,
967 const timestamp
= performance
.now()
968 const taskWaitTime
= timestamp
- (task
.timestamp
?? timestamp
)
969 updateMeasurementStatistics(
970 workerUsage
.waitTime
,
971 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().waitTime
,
976 private updateEluWorkerUsage (
977 workerUsage
: WorkerUsage
,
978 message
: MessageValue
<Response
>
980 if (message
.taskError
!= null) {
983 const eluTaskStatisticsRequirements
: MeasurementStatisticsRequirements
=
984 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().elu
985 updateMeasurementStatistics(
986 workerUsage
.elu
.active
,
987 eluTaskStatisticsRequirements
,
988 message
.taskPerformance
?.elu
?.active
?? 0
990 updateMeasurementStatistics(
991 workerUsage
.elu
.idle
,
992 eluTaskStatisticsRequirements
,
993 message
.taskPerformance
?.elu
?.idle
?? 0
995 if (eluTaskStatisticsRequirements
.aggregate
) {
996 if (message
.taskPerformance
?.elu
!= null) {
997 if (workerUsage
.elu
.utilization
!= null) {
998 workerUsage
.elu
.utilization
=
999 (workerUsage
.elu
.utilization
+
1000 message
.taskPerformance
.elu
.utilization
) /
1003 workerUsage
.elu
.utilization
= message
.taskPerformance
.elu
.utilization
1010 * Chooses a worker node for the next task.
1012 * The default worker choice strategy uses a round robin algorithm to distribute the tasks.
1014 * @returns The chosen worker node key
1016 private chooseWorkerNode (): number {
1017 if (this.shallCreateDynamicWorker()) {
1018 const workerNodeKey
= this.createAndSetupDynamicWorkerNode()
1020 this.workerChoiceStrategyContext
.getStrategyPolicy().dynamicWorkerUsage
1022 return workerNodeKey
1025 return this.workerChoiceStrategyContext
.execute()
1029 * Conditions for dynamic worker creation.
1031 * @returns Whether to create a dynamic worker or not.
1033 private shallCreateDynamicWorker (): boolean {
1034 return this.type === PoolTypes
.dynamic
&& !this.full
&& this.internalBusy()
1038 * Sends a message to worker given its worker node key.
1040 * @param workerNodeKey - The worker node key.
1041 * @param message - The message.
1042 * @param transferList - The optional array of transferable objects.
1044 protected abstract sendToWorker (
1045 workerNodeKey
: number,
1046 message
: MessageValue
<Data
>,
1047 transferList
?: TransferListItem
[]
1051 * Creates a new worker.
1053 * @returns Newly created worker.
1055 protected abstract createWorker (): Worker
1058 * Creates a new, completely set up worker node.
1060 * @returns New, completely set up worker node key.
1062 protected createAndSetupWorkerNode (): number {
1063 const worker
= this.createWorker()
1065 worker
.on('online', this.opts
.onlineHandler
?? EMPTY_FUNCTION
)
1066 worker
.on('message', this.opts
.messageHandler
?? EMPTY_FUNCTION
)
1067 worker
.on('error', this.opts
.errorHandler
?? EMPTY_FUNCTION
)
1068 worker
.on('error', error
=> {
1069 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1070 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
1071 workerInfo
.ready
= false
1072 this.workerNodes
[workerNodeKey
].closeChannel()
1073 this.emitter
?.emit(PoolEvents
.error
, error
)
1075 this.opts
.restartWorkerOnError
=== true &&
1079 if (workerInfo
.dynamic
) {
1080 this.createAndSetupDynamicWorkerNode()
1082 this.createAndSetupWorkerNode()
1085 if (this.opts
.enableTasksQueue
=== true) {
1086 this.redistributeQueuedTasks(workerNodeKey
)
1089 worker
.on('exit', this.opts
.exitHandler
?? EMPTY_FUNCTION
)
1090 worker
.once('exit', () => {
1091 this.removeWorkerNode(worker
)
1094 const workerNodeKey
= this.addWorkerNode(worker
)
1096 this.afterWorkerNodeSetup(workerNodeKey
)
1098 return workerNodeKey
1102 * Creates a new, completely set up dynamic worker node.
1104 * @returns New, completely set up dynamic worker node key.
1106 protected createAndSetupDynamicWorkerNode (): number {
1107 const workerNodeKey
= this.createAndSetupWorkerNode()
1108 this.registerWorkerMessageListener(workerNodeKey
, message
=> {
1109 const localWorkerNodeKey
= this.getWorkerNodeKeyByWorkerId(
1112 const workerUsage
= this.workerNodes
[localWorkerNodeKey
].usage
1113 // Kill message received from worker
1115 isKillBehavior(KillBehaviors
.HARD
, message
.kill
) ||
1116 (isKillBehavior(KillBehaviors
.SOFT
, message
.kill
) &&
1117 ((this.opts
.enableTasksQueue
=== false &&
1118 workerUsage
.tasks
.executing
=== 0) ||
1119 (this.opts
.enableTasksQueue
=== true &&
1120 workerUsage
.tasks
.executing
=== 0 &&
1121 this.tasksQueueSize(localWorkerNodeKey
) === 0)))
1123 this.destroyWorkerNode(localWorkerNodeKey
).catch(error
=> {
1124 this.emitter
?.emit(PoolEvents
.error
, error
)
1128 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
1129 this.sendToWorker(workerNodeKey
, {
1131 workerId
: workerInfo
.id
as number
1133 workerInfo
.dynamic
= true
1135 this.workerChoiceStrategyContext
.getStrategyPolicy().dynamicWorkerReady
||
1136 this.workerChoiceStrategyContext
.getStrategyPolicy().dynamicWorkerUsage
1138 workerInfo
.ready
= true
1140 this.checkAndEmitDynamicWorkerCreationEvents()
1141 return workerNodeKey
1145 * Registers a listener callback on the worker given its worker node key.
1147 * @param workerNodeKey - The worker node key.
1148 * @param listener - The message listener callback.
1150 protected abstract registerWorkerMessageListener
<
1151 Message
extends Data
| Response
1153 workerNodeKey
: number,
1154 listener
: (message
: MessageValue
<Message
>) => void
1158 * Method hooked up after a worker node has been newly created.
1159 * Can be overridden.
1161 * @param workerNodeKey - The newly created worker node key.
1163 protected afterWorkerNodeSetup (workerNodeKey
: number): void {
1164 // Listen to worker messages.
1165 this.registerWorkerMessageListener(workerNodeKey
, this.workerListener())
1166 // Send the startup message to worker.
1167 this.sendStartupMessageToWorker(workerNodeKey
)
1168 // Send the statistics message to worker.
1169 this.sendStatisticsMessageToWorker(workerNodeKey
)
1170 if (this.opts
.enableTasksQueue
=== true) {
1171 if (this.opts
.tasksQueueOptions
?.taskStealing
=== true) {
1172 this.workerNodes
[workerNodeKey
].onEmptyQueue
=
1173 this.taskStealingOnEmptyQueue
.bind(this)
1175 if (this.opts
.tasksQueueOptions
?.tasksStealingOnBackPressure
=== true) {
1176 this.workerNodes
[workerNodeKey
].onBackPressure
=
1177 this.tasksStealingOnBackPressure
.bind(this)
1183 * Sends the startup message to worker given its worker node key.
1185 * @param workerNodeKey - The worker node key.
1187 protected abstract sendStartupMessageToWorker (workerNodeKey
: number): void
1190 * Sends the statistics message to worker given its worker node key.
1192 * @param workerNodeKey - The worker node key.
1194 private sendStatisticsMessageToWorker (workerNodeKey
: number): void {
1195 this.sendToWorker(workerNodeKey
, {
1198 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
1200 elu
: this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
1203 workerId
: this.getWorkerInfo(workerNodeKey
).id
as number
1207 private redistributeQueuedTasks (workerNodeKey
: number): void {
1208 while (this.tasksQueueSize(workerNodeKey
) > 0) {
1209 const destinationWorkerNodeKey
= this.workerNodes
.reduce(
1210 (minWorkerNodeKey
, workerNode
, workerNodeKey
, workerNodes
) => {
1211 return workerNode
.info
.ready
&&
1212 workerNode
.usage
.tasks
.queued
<
1213 workerNodes
[minWorkerNodeKey
].usage
.tasks
.queued
1219 const destinationWorkerNode
= this.workerNodes
[destinationWorkerNodeKey
]
1221 ...(this.dequeueTask(workerNodeKey
) as Task
<Data
>),
1222 workerId
: destinationWorkerNode
.info
.id
as number
1224 if (this.shallExecuteTask(destinationWorkerNodeKey
)) {
1225 this.executeTask(destinationWorkerNodeKey
, task
)
1227 this.enqueueTask(destinationWorkerNodeKey
, task
)
1232 private updateTaskStolenStatisticsWorkerUsage (
1233 workerNodeKey
: number,
1236 const workerNode
= this.workerNodes
[workerNodeKey
]
1237 if (workerNode
?.usage
!= null) {
1238 ++workerNode
.usage
.tasks
.stolen
1241 this.shallUpdateTaskFunctionWorkerUsage(workerNodeKey
) &&
1242 workerNode
.getTaskFunctionWorkerUsage(taskName
) != null
1244 const taskFunctionWorkerUsage
= workerNode
.getTaskFunctionWorkerUsage(
1247 ++taskFunctionWorkerUsage
.tasks
.stolen
1251 private taskStealingOnEmptyQueue (workerId
: number): void {
1252 const destinationWorkerNodeKey
= this.getWorkerNodeKeyByWorkerId(workerId
)
1253 const destinationWorkerNode
= this.workerNodes
[destinationWorkerNodeKey
]
1254 const workerNodes
= this.workerNodes
1257 (workerNodeA
, workerNodeB
) =>
1258 workerNodeB
.usage
.tasks
.queued
- workerNodeA
.usage
.tasks
.queued
1260 const sourceWorkerNode
= workerNodes
.find(
1262 workerNode
.info
.ready
&&
1263 workerNode
.info
.id
!== workerId
&&
1264 workerNode
.usage
.tasks
.queued
> 0
1266 if (sourceWorkerNode
!= null) {
1268 ...(sourceWorkerNode
.popTask() as Task
<Data
>),
1269 workerId
: destinationWorkerNode
.info
.id
as number
1271 if (this.shallExecuteTask(destinationWorkerNodeKey
)) {
1272 this.executeTask(destinationWorkerNodeKey
, task
)
1274 this.enqueueTask(destinationWorkerNodeKey
, task
)
1276 this.updateTaskStolenStatisticsWorkerUsage(
1277 destinationWorkerNodeKey
,
1283 private tasksStealingOnBackPressure (workerId
: number): void {
1284 const sizeOffset
= 1
1285 if ((this.opts
.tasksQueueOptions
?.size
as number) <= sizeOffset
) {
1288 const sourceWorkerNode
=
1289 this.workerNodes
[this.getWorkerNodeKeyByWorkerId(workerId
)]
1290 const workerNodes
= this.workerNodes
1293 (workerNodeA
, workerNodeB
) =>
1294 workerNodeA
.usage
.tasks
.queued
- workerNodeB
.usage
.tasks
.queued
1296 for (const [workerNodeKey
, workerNode
] of workerNodes
.entries()) {
1298 sourceWorkerNode
.usage
.tasks
.queued
> 0 &&
1299 workerNode
.info
.ready
&&
1300 workerNode
.info
.id
!== workerId
&&
1301 workerNode
.usage
.tasks
.queued
<
1302 (this.opts
.tasksQueueOptions
?.size
as number) - sizeOffset
1305 ...(sourceWorkerNode
.popTask() as Task
<Data
>),
1306 workerId
: workerNode
.info
.id
as number
1308 if (this.shallExecuteTask(workerNodeKey
)) {
1309 this.executeTask(workerNodeKey
, task
)
1311 this.enqueueTask(workerNodeKey
, task
)
1313 this.updateTaskStolenStatisticsWorkerUsage(
1322 * This method is the listener registered for each worker message.
1324 * @returns The listener function to execute when a message is received from a worker.
1326 protected workerListener (): (message
: MessageValue
<Response
>) => void {
1328 this.checkMessageWorkerId(message
)
1329 if (message
.ready
!= null && message
.taskFunctions
!= null) {
1330 // Worker ready response received from worker
1331 this.handleWorkerReadyResponse(message
)
1332 } else if (message
.taskId
!= null) {
1333 // Task execution response received from worker
1334 this.handleTaskExecutionResponse(message
)
1335 } else if (message
.taskFunctions
!= null) {
1336 // Task functions message received from worker
1338 this.getWorkerNodeKeyByWorkerId(message
.workerId
)
1339 ).taskFunctions
= message
.taskFunctions
1344 private handleWorkerReadyResponse (message
: MessageValue
<Response
>): void {
1345 if (message
.ready
=== false) {
1346 throw new Error(`Worker ${message.workerId} failed to initialize`)
1348 const workerInfo
= this.getWorkerInfo(
1349 this.getWorkerNodeKeyByWorkerId(message
.workerId
)
1351 workerInfo
.ready
= message
.ready
as boolean
1352 workerInfo
.taskFunctions
= message
.taskFunctions
1353 if (this.emitter
!= null && this.ready
) {
1354 this.emitter
.emit(PoolEvents
.ready
, this.info
)
1358 private handleTaskExecutionResponse (message
: MessageValue
<Response
>): void {
1359 const { taskId
, taskError
, data
} = message
1360 const promiseResponse
= this.promiseResponseMap
.get(taskId
as string)
1361 if (promiseResponse
!= null) {
1362 if (taskError
!= null) {
1363 this.emitter
?.emit(PoolEvents
.taskError
, taskError
)
1364 promiseResponse
.reject(taskError
.message
)
1366 promiseResponse
.resolve(data
as Response
)
1368 const workerNodeKey
= promiseResponse
.workerNodeKey
1369 this.afterTaskExecutionHook(workerNodeKey
, message
)
1370 this.workerChoiceStrategyContext
.update(workerNodeKey
)
1371 this.promiseResponseMap
.delete(taskId
as string)
1373 this.opts
.enableTasksQueue
=== true &&
1374 this.tasksQueueSize(workerNodeKey
) > 0 &&
1375 this.workerNodes
[workerNodeKey
].usage
.tasks
.executing
<
1376 (this.opts
.tasksQueueOptions
?.concurrency
as number)
1380 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1386 private checkAndEmitTaskExecutionEvents (): void {
1388 this.emitter
?.emit(PoolEvents
.busy
, this.info
)
1392 private checkAndEmitTaskQueuingEvents (): void {
1393 if (this.hasBackPressure()) {
1394 this.emitter
?.emit(PoolEvents
.backPressure
, this.info
)
1398 private checkAndEmitDynamicWorkerCreationEvents (): void {
1399 if (this.type === PoolTypes
.dynamic
) {
1401 this.emitter
?.emit(PoolEvents
.full
, this.info
)
1407 * Gets the worker information given its worker node key.
1409 * @param workerNodeKey - The worker node key.
1410 * @returns The worker information.
1412 protected getWorkerInfo (workerNodeKey
: number): WorkerInfo
{
1413 return this.workerNodes
[workerNodeKey
].info
1417 * Adds the given worker in the pool worker nodes.
1419 * @param worker - The worker.
1420 * @returns The added worker node key.
1421 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the added worker node is not found.
1423 private addWorkerNode (worker
: Worker
): number {
1424 const workerNode
= new WorkerNode
<Worker
, Data
>(
1426 this.opts
.tasksQueueOptions
?.size
?? Math.pow(this.maxSize
, 2)
1428 // Flag the worker node as ready at pool startup.
1429 if (this.starting
) {
1430 workerNode
.info
.ready
= true
1432 this.workerNodes
.push(workerNode
)
1433 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1434 if (workerNodeKey
=== -1) {
1435 throw new Error('Worker added not found in worker nodes')
1437 return workerNodeKey
1441 * Removes the given worker from the pool worker nodes.
1443 * @param worker - The worker.
1445 private removeWorkerNode (worker
: Worker
): void {
1446 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1447 if (workerNodeKey
!== -1) {
1448 this.workerNodes
.splice(workerNodeKey
, 1)
1449 this.workerChoiceStrategyContext
.remove(workerNodeKey
)
1454 public hasWorkerNodeBackPressure (workerNodeKey
: number): boolean {
1456 this.opts
.enableTasksQueue
=== true &&
1457 this.workerNodes
[workerNodeKey
].hasBackPressure()
1461 private hasBackPressure (): boolean {
1463 this.opts
.enableTasksQueue
=== true &&
1464 this.workerNodes
.findIndex(
1465 workerNode
=> !workerNode
.hasBackPressure()
1471 * Executes the given task on the worker given its worker node key.
1473 * @param workerNodeKey - The worker node key.
1474 * @param task - The task to execute.
1476 private executeTask (workerNodeKey
: number, task
: Task
<Data
>): void {
1477 this.beforeTaskExecutionHook(workerNodeKey
, task
)
1478 this.sendToWorker(workerNodeKey
, task
, task
.transferList
)
1479 this.checkAndEmitTaskExecutionEvents()
1482 private enqueueTask (workerNodeKey
: number, task
: Task
<Data
>): number {
1483 const tasksQueueSize
= this.workerNodes
[workerNodeKey
].enqueueTask(task
)
1484 this.checkAndEmitTaskQueuingEvents()
1485 return tasksQueueSize
1488 private dequeueTask (workerNodeKey
: number): Task
<Data
> | undefined {
1489 return this.workerNodes
[workerNodeKey
].dequeueTask()
1492 private tasksQueueSize (workerNodeKey
: number): number {
1493 return this.workerNodes
[workerNodeKey
].tasksQueueSize()
1496 protected flushTasksQueue (workerNodeKey
: number): void {
1497 while (this.tasksQueueSize(workerNodeKey
) > 0) {
1500 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1503 this.workerNodes
[workerNodeKey
].clearTasksQueue()
1506 private flushTasksQueues (): void {
1507 for (const [workerNodeKey
] of this.workerNodes
.entries()) {
1508 this.flushTasksQueue(workerNodeKey
)