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
,
18 updateMeasurementStatistics
20 import { KillBehaviors
} from
'../worker/worker-options'
29 type TasksQueueOptions
39 type MeasurementStatisticsRequirements
,
41 WorkerChoiceStrategies
,
42 type WorkerChoiceStrategy
,
43 type WorkerChoiceStrategyOptions
44 } from
'./selection-strategies/selection-strategies-types'
45 import { WorkerChoiceStrategyContext
} from
'./selection-strategies/worker-choice-strategy-context'
46 import { version
} from
'./version'
47 import { WorkerNode
} from
'./worker-node'
50 * Base class that implements some shared logic for all poolifier pools.
52 * @typeParam Worker - Type of worker which manages this pool.
53 * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
54 * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
56 export abstract class AbstractPool
<
57 Worker
extends IWorker
,
60 > implements IPool
<Worker
, Data
, Response
> {
62 public readonly workerNodes
: Array<IWorkerNode
<Worker
, Data
>> = []
65 public readonly emitter
?: PoolEmitter
68 * The task execution response promise map.
70 * - `key`: The message id of each submitted task.
71 * - `value`: An object that contains the worker, the execution response promise resolve and reject callbacks.
73 * When we receive a message from the worker, we get a map entry with the promise resolve/reject bound to the message id.
75 protected promiseResponseMap
: Map
<string, PromiseResponseWrapper
<Response
>> =
76 new Map
<string, PromiseResponseWrapper
<Response
>>()
79 * Worker choice strategy context referencing a worker choice algorithm implementation.
81 protected workerChoiceStrategyContext
: WorkerChoiceStrategyContext
<
88 * Dynamic pool maximum size property placeholder.
90 protected readonly max
?: number
93 * Whether the pool is starting or not.
95 private readonly starting
: boolean
97 * The start timestamp of the pool.
99 private readonly startTimestamp
102 * Constructs a new poolifier pool.
104 * @param numberOfWorkers - Number of workers that this pool should manage.
105 * @param filePath - Path to the worker file.
106 * @param opts - Options for the pool.
109 protected readonly numberOfWorkers
: number,
110 protected readonly filePath
: string,
111 protected readonly opts
: PoolOptions
<Worker
>
113 if (!this.isMain()) {
115 'Cannot start a pool from a worker with the same type as the pool'
118 this.checkNumberOfWorkers(this.numberOfWorkers
)
119 this.checkFilePath(this.filePath
)
120 this.checkPoolOptions(this.opts
)
122 this.chooseWorkerNode
= this.chooseWorkerNode
.bind(this)
123 this.executeTask
= this.executeTask
.bind(this)
124 this.enqueueTask
= this.enqueueTask
.bind(this)
126 if (this.opts
.enableEvents
=== true) {
127 this.emitter
= new PoolEmitter()
129 this.workerChoiceStrategyContext
= new WorkerChoiceStrategyContext
<
135 this.opts
.workerChoiceStrategy
,
136 this.opts
.workerChoiceStrategyOptions
143 this.starting
= false
145 this.startTimestamp
= performance
.now()
148 private checkFilePath (filePath
: string): void {
151 typeof filePath
!== 'string' ||
152 (typeof filePath
=== 'string' && filePath
.trim().length
=== 0)
154 throw new Error('Please specify a file with a worker implementation')
156 if (!existsSync(filePath
)) {
157 throw new Error(`Cannot find the worker file '${filePath}'`)
161 private checkNumberOfWorkers (numberOfWorkers
: number): void {
162 if (numberOfWorkers
== null) {
164 'Cannot instantiate a pool without specifying the number of workers'
166 } else if (!Number.isSafeInteger(numberOfWorkers
)) {
168 'Cannot instantiate a pool with a non safe integer number of workers'
170 } else if (numberOfWorkers
< 0) {
171 throw new RangeError(
172 'Cannot instantiate a pool with a negative number of workers'
174 } else if (this.type === PoolTypes
.fixed
&& numberOfWorkers
=== 0) {
175 throw new RangeError('Cannot instantiate a fixed pool with zero worker')
179 protected checkDynamicPoolSize (min
: number, max
: number): void {
180 if (this.type === PoolTypes
.dynamic
) {
183 'Cannot instantiate a dynamic pool without specifying the maximum pool size'
185 } else if (!Number.isSafeInteger(max
)) {
187 'Cannot instantiate a dynamic pool with a non safe integer maximum pool size'
189 } else if (min
> max
) {
190 throw new RangeError(
191 'Cannot instantiate a dynamic pool with a maximum pool size inferior to the minimum pool size'
193 } else if (max
=== 0) {
194 throw new RangeError(
195 'Cannot instantiate a dynamic pool with a maximum pool size equal to zero'
197 } else if (min
=== max
) {
198 throw new RangeError(
199 'Cannot instantiate a dynamic pool with a minimum pool size equal to the maximum pool size. Use a fixed pool instead'
205 private checkPoolOptions (opts
: PoolOptions
<Worker
>): void {
206 if (isPlainObject(opts
)) {
207 this.opts
.workerChoiceStrategy
=
208 opts
.workerChoiceStrategy
?? WorkerChoiceStrategies
.ROUND_ROBIN
209 this.checkValidWorkerChoiceStrategy(this.opts
.workerChoiceStrategy
)
210 this.opts
.workerChoiceStrategyOptions
= {
211 ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
,
212 ...opts
.workerChoiceStrategyOptions
214 this.checkValidWorkerChoiceStrategyOptions(
215 this.opts
.workerChoiceStrategyOptions
217 this.opts
.restartWorkerOnError
= opts
.restartWorkerOnError
?? true
218 this.opts
.enableEvents
= opts
.enableEvents
?? true
219 this.opts
.enableTasksQueue
= opts
.enableTasksQueue
?? false
220 if (this.opts
.enableTasksQueue
) {
221 this.checkValidTasksQueueOptions(
222 opts
.tasksQueueOptions
as TasksQueueOptions
224 this.opts
.tasksQueueOptions
= this.buildTasksQueueOptions(
225 opts
.tasksQueueOptions
as TasksQueueOptions
229 throw new TypeError('Invalid pool options: must be a plain object')
233 private checkValidWorkerChoiceStrategy (
234 workerChoiceStrategy
: WorkerChoiceStrategy
236 if (!Object.values(WorkerChoiceStrategies
).includes(workerChoiceStrategy
)) {
238 `Invalid worker choice strategy '${workerChoiceStrategy}'`
243 private checkValidWorkerChoiceStrategyOptions (
244 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
246 if (!isPlainObject(workerChoiceStrategyOptions
)) {
248 'Invalid worker choice strategy options: must be a plain object'
252 workerChoiceStrategyOptions
.choiceRetries
!= null &&
253 !Number.isSafeInteger(workerChoiceStrategyOptions
.choiceRetries
)
256 'Invalid worker choice strategy options: choice retries must be an integer'
260 workerChoiceStrategyOptions
.choiceRetries
!= null &&
261 workerChoiceStrategyOptions
.choiceRetries
<= 0
263 throw new RangeError(
264 `Invalid worker choice strategy options: choice retries '${workerChoiceStrategyOptions.choiceRetries}' must be greater than zero`
268 workerChoiceStrategyOptions
.weights
!= null &&
269 Object.keys(workerChoiceStrategyOptions
.weights
).length
!== this.maxSize
272 'Invalid worker choice strategy options: must have a weight for each worker node'
276 workerChoiceStrategyOptions
.measurement
!= null &&
277 !Object.values(Measurements
).includes(
278 workerChoiceStrategyOptions
.measurement
282 `Invalid worker choice strategy options: invalid measurement '${workerChoiceStrategyOptions.measurement}'`
287 private checkValidTasksQueueOptions (
288 tasksQueueOptions
: TasksQueueOptions
290 if (tasksQueueOptions
!= null && !isPlainObject(tasksQueueOptions
)) {
291 throw new TypeError('Invalid tasks queue options: must be a plain object')
294 tasksQueueOptions
?.concurrency
!= null &&
295 !Number.isSafeInteger(tasksQueueOptions
.concurrency
)
298 'Invalid worker tasks concurrency: must be an integer'
302 tasksQueueOptions
?.concurrency
!= null &&
303 tasksQueueOptions
.concurrency
<= 0
306 `Invalid worker tasks concurrency: ${tasksQueueOptions.concurrency} is a negative integer or zero`
311 private startPool (): void {
313 this.workerNodes
.reduce(
314 (accumulator
, workerNode
) =>
315 !workerNode
.info
.dynamic
? accumulator
+ 1 : accumulator
,
317 ) < this.numberOfWorkers
319 this.createAndSetupWorkerNode()
324 public get
info (): PoolInfo
{
330 strategy
: this.opts
.workerChoiceStrategy
as WorkerChoiceStrategy
,
331 minSize
: this.minSize
,
332 maxSize
: this.maxSize
,
333 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
334 .runTime
.aggregate
&&
335 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
336 .waitTime
.aggregate
&& { utilization
: round(this.utilization
) }),
337 workerNodes
: this.workerNodes
.length
,
338 idleWorkerNodes
: this.workerNodes
.reduce(
339 (accumulator
, workerNode
) =>
340 workerNode
.usage
.tasks
.executing
=== 0
345 busyWorkerNodes
: this.workerNodes
.reduce(
346 (accumulator
, workerNode
) =>
347 workerNode
.usage
.tasks
.executing
> 0 ? accumulator
+ 1 : accumulator
,
350 executedTasks
: this.workerNodes
.reduce(
351 (accumulator
, workerNode
) =>
352 accumulator
+ workerNode
.usage
.tasks
.executed
,
355 executingTasks
: this.workerNodes
.reduce(
356 (accumulator
, workerNode
) =>
357 accumulator
+ workerNode
.usage
.tasks
.executing
,
360 ...(this.opts
.enableTasksQueue
=== true && {
361 queuedTasks
: this.workerNodes
.reduce(
362 (accumulator
, workerNode
) =>
363 accumulator
+ workerNode
.usage
.tasks
.queued
,
367 ...(this.opts
.enableTasksQueue
=== true && {
368 maxQueuedTasks
: this.workerNodes
.reduce(
369 (accumulator
, workerNode
) =>
370 accumulator
+ (workerNode
.usage
.tasks
?.maxQueued
?? 0),
374 ...(this.opts
.enableTasksQueue
=== true && {
375 backPressure
: this.hasBackPressure()
377 failedTasks
: this.workerNodes
.reduce(
378 (accumulator
, workerNode
) =>
379 accumulator
+ workerNode
.usage
.tasks
.failed
,
382 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
383 .runTime
.aggregate
&& {
387 ...this.workerNodes
.map(
388 (workerNode
) => workerNode
.usage
.runTime
?.minimum
?? Infinity
394 ...this.workerNodes
.map(
395 (workerNode
) => workerNode
.usage
.runTime
?.maximum
?? -Infinity
400 this.workerNodes
.reduce(
401 (accumulator
, workerNode
) =>
402 accumulator
+ (workerNode
.usage
.runTime
?.aggregate
?? 0),
405 this.workerNodes
.reduce(
406 (accumulator
, workerNode
) =>
407 accumulator
+ (workerNode
.usage
.tasks
?.executed
?? 0),
411 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
415 this.workerNodes
.map(
416 (workerNode
) => workerNode
.usage
.runTime
?.median
?? 0
423 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
424 .waitTime
.aggregate
&& {
428 ...this.workerNodes
.map(
429 (workerNode
) => workerNode
.usage
.waitTime
?.minimum
?? Infinity
435 ...this.workerNodes
.map(
436 (workerNode
) => workerNode
.usage
.waitTime
?.maximum
?? -Infinity
441 this.workerNodes
.reduce(
442 (accumulator
, workerNode
) =>
443 accumulator
+ (workerNode
.usage
.waitTime
?.aggregate
?? 0),
446 this.workerNodes
.reduce(
447 (accumulator
, workerNode
) =>
448 accumulator
+ (workerNode
.usage
.tasks
?.executed
?? 0),
452 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
453 .waitTime
.median
&& {
456 this.workerNodes
.map(
457 (workerNode
) => workerNode
.usage
.waitTime
?.median
?? 0
468 * The pool readiness boolean status.
470 private get
ready (): boolean {
472 this.workerNodes
.reduce(
473 (accumulator
, workerNode
) =>
474 !workerNode
.info
.dynamic
&& workerNode
.info
.ready
483 * The approximate pool utilization.
485 * @returns The pool utilization.
487 private get
utilization (): number {
488 const poolTimeCapacity
=
489 (performance
.now() - this.startTimestamp
) * this.maxSize
490 const totalTasksRunTime
= this.workerNodes
.reduce(
491 (accumulator
, workerNode
) =>
492 accumulator
+ (workerNode
.usage
.runTime
?.aggregate
?? 0),
495 const totalTasksWaitTime
= this.workerNodes
.reduce(
496 (accumulator
, workerNode
) =>
497 accumulator
+ (workerNode
.usage
.waitTime
?.aggregate
?? 0),
500 return (totalTasksRunTime
+ totalTasksWaitTime
) / poolTimeCapacity
506 * If it is `'dynamic'`, it provides the `max` property.
508 protected abstract get
type (): PoolType
513 protected abstract get
worker (): WorkerType
516 * The pool minimum size.
518 protected get
minSize (): number {
519 return this.numberOfWorkers
523 * The pool maximum size.
525 protected get
maxSize (): number {
526 return this.max
?? this.numberOfWorkers
530 * Checks if the worker id sent in the received message from a worker is valid.
532 * @param message - The received message.
533 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the worker id is invalid.
535 private checkMessageWorkerId (message
: MessageValue
<Response
>): void {
536 if (message
.workerId
== null) {
537 throw new Error('Worker message received without worker id')
539 message
.workerId
!= null &&
540 this.getWorkerNodeKeyByWorkerId(message
.workerId
) === -1
543 `Worker message received from unknown worker '${message.workerId}'`
549 * Gets the given worker its worker node key.
551 * @param worker - The worker.
552 * @returns The worker node key if found in the pool worker nodes, `-1` otherwise.
554 private getWorkerNodeKeyByWorker (worker
: Worker
): number {
555 return this.workerNodes
.findIndex(
556 (workerNode
) => workerNode
.worker
=== worker
561 * Gets the worker node key given its worker id.
563 * @param workerId - The worker id.
564 * @returns The worker node key if the worker id is found in the pool worker nodes, `-1` otherwise.
566 private getWorkerNodeKeyByWorkerId (workerId
: number): number {
567 return this.workerNodes
.findIndex(
568 (workerNode
) => workerNode
.info
.id
=== workerId
573 public setWorkerChoiceStrategy (
574 workerChoiceStrategy
: WorkerChoiceStrategy
,
575 workerChoiceStrategyOptions
?: WorkerChoiceStrategyOptions
577 this.checkValidWorkerChoiceStrategy(workerChoiceStrategy
)
578 this.opts
.workerChoiceStrategy
= workerChoiceStrategy
579 this.workerChoiceStrategyContext
.setWorkerChoiceStrategy(
580 this.opts
.workerChoiceStrategy
582 if (workerChoiceStrategyOptions
!= null) {
583 this.setWorkerChoiceStrategyOptions(workerChoiceStrategyOptions
)
585 for (const [workerNodeKey
, workerNode
] of this.workerNodes
.entries()) {
586 workerNode
.resetUsage()
587 this.sendStatisticsMessageToWorker(workerNodeKey
)
592 public setWorkerChoiceStrategyOptions (
593 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
595 this.checkValidWorkerChoiceStrategyOptions(workerChoiceStrategyOptions
)
596 this.opts
.workerChoiceStrategyOptions
= {
597 ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
,
598 ...workerChoiceStrategyOptions
600 this.workerChoiceStrategyContext
.setOptions(
601 this.opts
.workerChoiceStrategyOptions
606 public enableTasksQueue (
608 tasksQueueOptions
?: TasksQueueOptions
610 if (this.opts
.enableTasksQueue
=== true && !enable
) {
611 this.flushTasksQueues()
613 this.opts
.enableTasksQueue
= enable
614 this.setTasksQueueOptions(tasksQueueOptions
as TasksQueueOptions
)
618 public setTasksQueueOptions (tasksQueueOptions
: TasksQueueOptions
): void {
619 if (this.opts
.enableTasksQueue
=== true) {
620 this.checkValidTasksQueueOptions(tasksQueueOptions
)
621 this.opts
.tasksQueueOptions
=
622 this.buildTasksQueueOptions(tasksQueueOptions
)
623 } else if (this.opts
.tasksQueueOptions
!= null) {
624 delete this.opts
.tasksQueueOptions
628 private buildTasksQueueOptions (
629 tasksQueueOptions
: TasksQueueOptions
630 ): TasksQueueOptions
{
632 concurrency
: tasksQueueOptions
?.concurrency
?? 1
637 * Whether the pool is full or not.
639 * The pool filling boolean status.
641 protected get
full (): boolean {
642 return this.workerNodes
.length
>= this.maxSize
646 * Whether the pool is busy or not.
648 * The pool busyness boolean status.
650 protected abstract get
busy (): boolean
653 * Whether worker nodes are executing concurrently their tasks quota or not.
655 * @returns Worker nodes busyness boolean status.
657 protected internalBusy (): boolean {
658 if (this.opts
.enableTasksQueue
=== true) {
660 this.workerNodes
.findIndex(
662 workerNode
.info
.ready
&&
663 workerNode
.usage
.tasks
.executing
<
664 (this.opts
.tasksQueueOptions
?.concurrency
as number)
669 this.workerNodes
.findIndex(
671 workerNode
.info
.ready
&& workerNode
.usage
.tasks
.executing
=== 0
678 public listTaskFunctions (): string[] {
679 for (const workerNode
of this.workerNodes
) {
681 Array.isArray(workerNode
.info
.taskFunctions
) &&
682 workerNode
.info
.taskFunctions
.length
> 0
684 return workerNode
.info
.taskFunctions
691 public async execute (
694 transferList
?: TransferListItem
[]
695 ): Promise
<Response
> {
696 return await new Promise
<Response
>((resolve
, reject
) => {
697 if (name
!= null && typeof name
!== 'string') {
698 reject(new TypeError('name argument must be a string'))
702 typeof name
=== 'string' &&
703 name
.trim().length
=== 0
705 reject(new TypeError('name argument must not be an empty string'))
707 if (transferList
!= null && !Array.isArray(transferList
)) {
708 reject(new TypeError('transferList argument must be an array'))
710 const timestamp
= performance
.now()
711 const workerNodeKey
= this.chooseWorkerNode()
712 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
715 Array.isArray(workerInfo
.taskFunctions
) &&
716 !workerInfo
.taskFunctions
.includes(name
)
719 new Error(`Task function '${name}' is not registered in the pool`)
722 const task
: Task
<Data
> = {
723 name
: name
?? DEFAULT_TASK_NAME
,
724 // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
725 data
: data
?? ({} as Data
),
728 workerId
: workerInfo
.id
as number,
731 this.promiseResponseMap
.set(task
.taskId
as string, {
737 this.opts
.enableTasksQueue
=== false ||
738 (this.opts
.enableTasksQueue
=== true &&
739 this.workerNodes
[workerNodeKey
].usage
.tasks
.executing
<
740 (this.opts
.tasksQueueOptions
?.concurrency
as number))
742 this.executeTask(workerNodeKey
, task
)
744 this.enqueueTask(workerNodeKey
, task
)
750 public async destroy (): Promise
<void> {
752 this.workerNodes
.map(async (_
, workerNodeKey
) => {
753 await this.destroyWorkerNode(workerNodeKey
)
756 this.emitter
?.emit(PoolEvents
.destroy
, this.info
)
759 protected async sendKillMessageToWorker (
760 workerNodeKey
: number,
763 await new Promise
<void>((resolve
, reject
) => {
764 this.registerWorkerMessageListener(workerNodeKey
, (message
) => {
765 if (message
.kill
=== 'success') {
767 } else if (message
.kill
=== 'failure') {
768 reject(new Error(`Worker ${workerId} kill message handling failed`))
771 this.sendToWorker(workerNodeKey
, { kill
: true, workerId
})
776 * Terminates the worker node given its worker node key.
778 * @param workerNodeKey - The worker node key.
780 protected abstract destroyWorkerNode (workerNodeKey
: number): Promise
<void>
783 * Setup hook to execute code before worker nodes are created in the abstract constructor.
788 protected setupHook (): void {
789 // Intentionally empty
793 * Should return whether the worker is the main worker or not.
795 protected abstract isMain (): boolean
798 * Hook executed before the worker task execution.
801 * @param workerNodeKey - The worker node key.
802 * @param task - The task to execute.
804 protected beforeTaskExecutionHook (
805 workerNodeKey
: number,
808 const workerUsage
= this.workerNodes
[workerNodeKey
].usage
809 ++workerUsage
.tasks
.executing
810 this.updateWaitTimeWorkerUsage(workerUsage
, task
)
811 if (this.shallUpdateTaskFunctionWorkerUsage(workerNodeKey
)) {
812 const taskFunctionWorkerUsage
= this.workerNodes
[
814 ].getTaskFunctionWorkerUsage(task
.name
as string) as WorkerUsage
815 ++taskFunctionWorkerUsage
.tasks
.executing
816 this.updateWaitTimeWorkerUsage(taskFunctionWorkerUsage
, task
)
821 * Hook executed after the worker task execution.
824 * @param workerNodeKey - The worker node key.
825 * @param message - The received message.
827 protected afterTaskExecutionHook (
828 workerNodeKey
: number,
829 message
: MessageValue
<Response
>
831 const workerUsage
= this.workerNodes
[workerNodeKey
].usage
832 this.updateTaskStatisticsWorkerUsage(workerUsage
, message
)
833 this.updateRunTimeWorkerUsage(workerUsage
, message
)
834 this.updateEluWorkerUsage(workerUsage
, message
)
835 if (this.shallUpdateTaskFunctionWorkerUsage(workerNodeKey
)) {
836 const taskFunctionWorkerUsage
= this.workerNodes
[
838 ].getTaskFunctionWorkerUsage(
839 message
.taskPerformance
?.name
?? DEFAULT_TASK_NAME
841 this.updateTaskStatisticsWorkerUsage(taskFunctionWorkerUsage
, message
)
842 this.updateRunTimeWorkerUsage(taskFunctionWorkerUsage
, message
)
843 this.updateEluWorkerUsage(taskFunctionWorkerUsage
, message
)
848 * Whether the worker node shall update its task function worker usage or not.
850 * @param workerNodeKey - The worker node key.
851 * @returns `true` if the worker node shall update its task function worker usage, `false` otherwise.
853 private shallUpdateTaskFunctionWorkerUsage (workerNodeKey
: number): boolean {
854 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
856 Array.isArray(workerInfo
.taskFunctions
) &&
857 workerInfo
.taskFunctions
.length
> 2
861 private updateTaskStatisticsWorkerUsage (
862 workerUsage
: WorkerUsage
,
863 message
: MessageValue
<Response
>
865 const workerTaskStatistics
= workerUsage
.tasks
867 workerTaskStatistics
.executing
!= null &&
868 workerTaskStatistics
.executing
> 0
870 --workerTaskStatistics
.executing
872 workerTaskStatistics
.executing
!= null &&
873 workerTaskStatistics
.executing
< 0
876 'Worker usage statistic for tasks executing cannot be negative'
879 if (message
.taskError
== null) {
880 ++workerTaskStatistics
.executed
882 ++workerTaskStatistics
.failed
886 private updateRunTimeWorkerUsage (
887 workerUsage
: WorkerUsage
,
888 message
: MessageValue
<Response
>
890 updateMeasurementStatistics(
892 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().runTime
,
893 message
.taskPerformance
?.runTime
?? 0,
894 workerUsage
.tasks
.executed
898 private updateWaitTimeWorkerUsage (
899 workerUsage
: WorkerUsage
,
902 const timestamp
= performance
.now()
903 const taskWaitTime
= timestamp
- (task
.timestamp
?? timestamp
)
904 updateMeasurementStatistics(
905 workerUsage
.waitTime
,
906 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().waitTime
,
908 workerUsage
.tasks
.executed
912 private updateEluWorkerUsage (
913 workerUsage
: WorkerUsage
,
914 message
: MessageValue
<Response
>
916 const eluTaskStatisticsRequirements
: MeasurementStatisticsRequirements
=
917 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().elu
918 updateMeasurementStatistics(
919 workerUsage
.elu
.active
,
920 eluTaskStatisticsRequirements
,
921 message
.taskPerformance
?.elu
?.active
?? 0,
922 workerUsage
.tasks
.executed
924 updateMeasurementStatistics(
925 workerUsage
.elu
.idle
,
926 eluTaskStatisticsRequirements
,
927 message
.taskPerformance
?.elu
?.idle
?? 0,
928 workerUsage
.tasks
.executed
930 if (eluTaskStatisticsRequirements
.aggregate
) {
931 if (message
.taskPerformance
?.elu
!= null) {
932 if (workerUsage
.elu
.utilization
!= null) {
933 workerUsage
.elu
.utilization
=
934 (workerUsage
.elu
.utilization
+
935 message
.taskPerformance
.elu
.utilization
) /
938 workerUsage
.elu
.utilization
= message
.taskPerformance
.elu
.utilization
945 * Chooses a worker node for the next task.
947 * The default worker choice strategy uses a round robin algorithm to distribute the tasks.
949 * @returns The chosen worker node key
951 private chooseWorkerNode (): number {
952 if (this.shallCreateDynamicWorker()) {
953 const workerNodeKey
= this.createAndSetupDynamicWorkerNode()
955 this.workerChoiceStrategyContext
.getStrategyPolicy().dynamicWorkerUsage
960 return this.workerChoiceStrategyContext
.execute()
964 * Conditions for dynamic worker creation.
966 * @returns Whether to create a dynamic worker or not.
968 private shallCreateDynamicWorker (): boolean {
969 return this.type === PoolTypes
.dynamic
&& !this.full
&& this.internalBusy()
973 * Sends a message to worker given its worker node key.
975 * @param workerNodeKey - The worker node key.
976 * @param message - The message.
977 * @param transferList - The optional array of transferable objects.
979 protected abstract sendToWorker (
980 workerNodeKey
: number,
981 message
: MessageValue
<Data
>,
982 transferList
?: TransferListItem
[]
986 * Creates a new worker.
988 * @returns Newly created worker.
990 protected abstract createWorker (): Worker
993 * Creates a new, completely set up worker node.
995 * @returns New, completely set up worker node key.
997 protected createAndSetupWorkerNode (): number {
998 const worker
= this.createWorker()
1000 worker
.on('online', this.opts
.onlineHandler
?? EMPTY_FUNCTION
)
1001 worker
.on('message', this.opts
.messageHandler
?? EMPTY_FUNCTION
)
1002 worker
.on('error', this.opts
.errorHandler
?? EMPTY_FUNCTION
)
1003 worker
.on('error', (error
) => {
1004 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1005 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
1006 workerInfo
.ready
= false
1007 this.workerNodes
[workerNodeKey
].closeChannel()
1008 this.emitter
?.emit(PoolEvents
.error
, error
)
1009 if (this.opts
.restartWorkerOnError
=== true && !this.starting
) {
1010 if (workerInfo
.dynamic
) {
1011 this.createAndSetupDynamicWorkerNode()
1013 this.createAndSetupWorkerNode()
1016 if (this.opts
.enableTasksQueue
=== true) {
1017 this.redistributeQueuedTasks(workerNodeKey
)
1020 worker
.on('exit', this.opts
.exitHandler
?? EMPTY_FUNCTION
)
1021 worker
.once('exit', () => {
1022 this.removeWorkerNode(worker
)
1025 const workerNodeKey
= this.addWorkerNode(worker
)
1027 this.afterWorkerNodeSetup(workerNodeKey
)
1029 return workerNodeKey
1033 * Creates a new, completely set up dynamic worker node.
1035 * @returns New, completely set up dynamic worker node key.
1037 protected createAndSetupDynamicWorkerNode (): number {
1038 const workerNodeKey
= this.createAndSetupWorkerNode()
1039 this.registerWorkerMessageListener(workerNodeKey
, (message
) => {
1040 const localWorkerNodeKey
= this.getWorkerNodeKeyByWorkerId(
1043 const workerUsage
= this.workerNodes
[localWorkerNodeKey
].usage
1044 // Kill message received from worker
1046 isKillBehavior(KillBehaviors
.HARD
, message
.kill
) ||
1047 (isKillBehavior(KillBehaviors
.SOFT
, message
.kill
) &&
1048 ((this.opts
.enableTasksQueue
=== false &&
1049 workerUsage
.tasks
.executing
=== 0) ||
1050 (this.opts
.enableTasksQueue
=== true &&
1051 workerUsage
.tasks
.executing
=== 0 &&
1052 this.tasksQueueSize(localWorkerNodeKey
) === 0)))
1054 this.destroyWorkerNode(localWorkerNodeKey
).catch((error
) => {
1055 this.emitter
?.emit(PoolEvents
.error
, error
)
1059 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
1060 this.sendToWorker(workerNodeKey
, {
1062 workerId
: workerInfo
.id
as number
1064 workerInfo
.dynamic
= true
1066 this.workerChoiceStrategyContext
.getStrategyPolicy().dynamicWorkerReady
||
1067 this.workerChoiceStrategyContext
.getStrategyPolicy().dynamicWorkerUsage
1069 workerInfo
.ready
= true
1071 this.checkAndEmitDynamicWorkerCreationEvents()
1072 return workerNodeKey
1076 * Registers a listener callback on the worker given its worker node key.
1078 * @param workerNodeKey - The worker node key.
1079 * @param listener - The message listener callback.
1081 protected abstract registerWorkerMessageListener
<
1082 Message
extends Data
| Response
1084 workerNodeKey
: number,
1085 listener
: (message
: MessageValue
<Message
>) => void
1089 * Method hooked up after a worker node has been newly created.
1090 * Can be overridden.
1092 * @param workerNodeKey - The newly created worker node key.
1094 protected afterWorkerNodeSetup (workerNodeKey
: number): void {
1095 // Listen to worker messages.
1096 this.registerWorkerMessageListener(workerNodeKey
, this.workerListener())
1097 // Send the startup message to worker.
1098 this.sendStartupMessageToWorker(workerNodeKey
)
1099 // Send the statistics message to worker.
1100 this.sendStatisticsMessageToWorker(workerNodeKey
)
1104 * Sends the startup message to worker given its worker node key.
1106 * @param workerNodeKey - The worker node key.
1108 protected abstract sendStartupMessageToWorker (workerNodeKey
: number): void
1111 * Sends the statistics message to worker given its worker node key.
1113 * @param workerNodeKey - The worker node key.
1115 private sendStatisticsMessageToWorker (workerNodeKey
: number): void {
1116 this.sendToWorker(workerNodeKey
, {
1119 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
1121 elu
: this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
1124 workerId
: this.getWorkerInfo(workerNodeKey
).id
as number
1128 private redistributeQueuedTasks (workerNodeKey
: number): void {
1129 while (this.tasksQueueSize(workerNodeKey
) > 0) {
1130 let targetWorkerNodeKey
: number = workerNodeKey
1131 let minQueuedTasks
= Infinity
1132 let executeTask
= false
1133 for (const [workerNodeId
, workerNode
] of this.workerNodes
.entries()) {
1134 const workerInfo
= this.getWorkerInfo(workerNodeId
)
1136 workerNodeId
!== workerNodeKey
&&
1138 workerNode
.usage
.tasks
.queued
=== 0
1141 this.workerNodes
[workerNodeId
].usage
.tasks
.executing
<
1142 (this.opts
.tasksQueueOptions
?.concurrency
as number)
1146 targetWorkerNodeKey
= workerNodeId
1150 workerNodeId
!== workerNodeKey
&&
1152 workerNode
.usage
.tasks
.queued
< minQueuedTasks
1154 minQueuedTasks
= workerNode
.usage
.tasks
.queued
1155 targetWorkerNodeKey
= workerNodeId
1160 targetWorkerNodeKey
,
1161 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1165 targetWorkerNodeKey
,
1166 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1173 * This method is the listener registered for each worker message.
1175 * @returns The listener function to execute when a message is received from a worker.
1177 protected workerListener (): (message
: MessageValue
<Response
>) => void {
1178 return (message
) => {
1179 this.checkMessageWorkerId(message
)
1180 if (message
.ready
!= null && message
.taskFunctions
!= null) {
1181 // Worker ready response received from worker
1182 this.handleWorkerReadyResponse(message
)
1183 } else if (message
.taskId
!= null) {
1184 // Task execution response received from worker
1185 this.handleTaskExecutionResponse(message
)
1186 } else if (message
.taskFunctions
!= null) {
1187 // Task functions message received from worker
1189 this.getWorkerNodeKeyByWorkerId(message
.workerId
)
1190 ).taskFunctions
= message
.taskFunctions
1195 private handleWorkerReadyResponse (message
: MessageValue
<Response
>): void {
1196 if (message
.ready
=== false) {
1197 throw new Error(`Worker ${message.workerId} failed to initialize`)
1199 const workerInfo
= this.getWorkerInfo(
1200 this.getWorkerNodeKeyByWorkerId(message
.workerId
)
1202 workerInfo
.ready
= message
.ready
as boolean
1203 workerInfo
.taskFunctions
= message
.taskFunctions
1204 if (this.emitter
!= null && this.ready
) {
1205 this.emitter
.emit(PoolEvents
.ready
, this.info
)
1209 private handleTaskExecutionResponse (message
: MessageValue
<Response
>): void {
1210 const { taskId
, taskError
, data
} = message
1211 const promiseResponse
= this.promiseResponseMap
.get(taskId
as string)
1212 if (promiseResponse
!= null) {
1213 if (taskError
!= null) {
1214 this.emitter
?.emit(PoolEvents
.taskError
, taskError
)
1215 promiseResponse
.reject(taskError
.message
)
1217 promiseResponse
.resolve(data
as Response
)
1219 const workerNodeKey
= promiseResponse
.workerNodeKey
1220 this.afterTaskExecutionHook(workerNodeKey
, message
)
1221 this.promiseResponseMap
.delete(taskId
as string)
1223 this.opts
.enableTasksQueue
=== true &&
1224 this.tasksQueueSize(workerNodeKey
) > 0 &&
1225 this.workerNodes
[workerNodeKey
].usage
.tasks
.executing
<
1226 (this.opts
.tasksQueueOptions
?.concurrency
as number)
1230 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1233 this.workerChoiceStrategyContext
.update(workerNodeKey
)
1237 private checkAndEmitTaskExecutionEvents (): void {
1239 this.emitter
?.emit(PoolEvents
.busy
, this.info
)
1243 private checkAndEmitTaskQueuingEvents (): void {
1244 if (this.hasBackPressure()) {
1245 this.emitter
?.emit(PoolEvents
.backPressure
, this.info
)
1249 private checkAndEmitDynamicWorkerCreationEvents (): void {
1250 if (this.type === PoolTypes
.dynamic
) {
1252 this.emitter
?.emit(PoolEvents
.full
, this.info
)
1258 * Gets the worker information given its worker node key.
1260 * @param workerNodeKey - The worker node key.
1261 * @returns The worker information.
1263 protected getWorkerInfo (workerNodeKey
: number): WorkerInfo
{
1264 return this.workerNodes
[workerNodeKey
].info
1268 * Adds the given worker in the pool worker nodes.
1270 * @param worker - The worker.
1271 * @returns The added worker node key.
1272 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the added worker node is not found.
1274 private addWorkerNode (worker
: Worker
): number {
1275 const workerNode
= new WorkerNode
<Worker
, Data
>(
1280 // Flag the worker node as ready at pool startup.
1281 if (this.starting
) {
1282 workerNode
.info
.ready
= true
1284 this.workerNodes
.push(workerNode
)
1285 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1286 if (workerNodeKey
=== -1) {
1287 throw new Error('Worker node added not found')
1289 return workerNodeKey
1293 * Removes the given worker from the pool worker nodes.
1295 * @param worker - The worker.
1297 private removeWorkerNode (worker
: Worker
): void {
1298 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1299 if (workerNodeKey
!== -1) {
1300 this.workerNodes
.splice(workerNodeKey
, 1)
1301 this.workerChoiceStrategyContext
.remove(workerNodeKey
)
1306 public hasWorkerNodeBackPressure (workerNodeKey
: number): boolean {
1308 this.opts
.enableTasksQueue
=== true &&
1309 this.workerNodes
[workerNodeKey
].hasBackPressure()
1313 private hasBackPressure (): boolean {
1315 this.opts
.enableTasksQueue
=== true &&
1316 this.workerNodes
.findIndex(
1317 (workerNode
) => !workerNode
.hasBackPressure()
1323 * Executes the given task on the worker given its worker node key.
1325 * @param workerNodeKey - The worker node key.
1326 * @param task - The task to execute.
1328 private executeTask (workerNodeKey
: number, task
: Task
<Data
>): void {
1329 this.beforeTaskExecutionHook(workerNodeKey
, task
)
1330 this.sendToWorker(workerNodeKey
, task
, task
.transferList
)
1331 this.checkAndEmitTaskExecutionEvents()
1334 private enqueueTask (workerNodeKey
: number, task
: Task
<Data
>): number {
1335 const tasksQueueSize
= this.workerNodes
[workerNodeKey
].enqueueTask(task
)
1336 this.checkAndEmitTaskQueuingEvents()
1337 return tasksQueueSize
1340 private dequeueTask (workerNodeKey
: number): Task
<Data
> | undefined {
1341 return this.workerNodes
[workerNodeKey
].dequeueTask()
1344 private tasksQueueSize (workerNodeKey
: number): number {
1345 return this.workerNodes
[workerNodeKey
].tasksQueueSize()
1348 protected flushTasksQueue (workerNodeKey
: number): void {
1349 while (this.tasksQueueSize(workerNodeKey
) > 0) {
1352 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1355 this.workerNodes
[workerNodeKey
].clearTasksQueue()
1358 private flushTasksQueues (): void {
1359 for (const [workerNodeKey
] of this.workerNodes
.entries()) {
1360 this.flushTasksQueue(workerNodeKey
)