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 * Whether the pool is starting or not.
90 private readonly starting
: boolean
92 * The start timestamp of the pool.
94 private readonly startTimestamp
97 * Constructs a new poolifier pool.
99 * @param numberOfWorkers - Number of workers that this pool should manage.
100 * @param filePath - Path to the worker file.
101 * @param opts - Options for the pool.
104 protected readonly numberOfWorkers
: number,
105 protected readonly filePath
: string,
106 protected readonly opts
: PoolOptions
<Worker
>
108 if (!this.isMain()) {
110 'Cannot start a pool from a worker with the same type as the pool'
113 this.checkNumberOfWorkers(this.numberOfWorkers
)
114 this.checkFilePath(this.filePath
)
115 this.checkPoolOptions(this.opts
)
117 this.chooseWorkerNode
= this.chooseWorkerNode
.bind(this)
118 this.executeTask
= this.executeTask
.bind(this)
119 this.enqueueTask
= this.enqueueTask
.bind(this)
120 this.dequeueTask
= this.dequeueTask
.bind(this)
121 this.checkAndEmitEvents
= this.checkAndEmitEvents
.bind(this)
123 if (this.opts
.enableEvents
=== true) {
124 this.emitter
= new PoolEmitter()
126 this.workerChoiceStrategyContext
= new WorkerChoiceStrategyContext
<
132 this.opts
.workerChoiceStrategy
,
133 this.opts
.workerChoiceStrategyOptions
140 this.starting
= false
142 this.startTimestamp
= performance
.now()
145 private checkFilePath (filePath
: string): void {
148 typeof filePath
!== 'string' ||
149 (typeof filePath
=== 'string' && filePath
.trim().length
=== 0)
151 throw new Error('Please specify a file with a worker implementation')
153 if (!existsSync(filePath
)) {
154 throw new Error(`Cannot find the worker file '${filePath}'`)
158 private checkNumberOfWorkers (numberOfWorkers
: number): void {
159 if (numberOfWorkers
== null) {
161 'Cannot instantiate a pool without specifying the number of workers'
163 } else if (!Number.isSafeInteger(numberOfWorkers
)) {
165 'Cannot instantiate a pool with a non safe integer number of workers'
167 } else if (numberOfWorkers
< 0) {
168 throw new RangeError(
169 'Cannot instantiate a pool with a negative number of workers'
171 } else if (this.type === PoolTypes
.fixed
&& numberOfWorkers
=== 0) {
172 throw new RangeError('Cannot instantiate a fixed pool with zero worker')
176 protected checkDynamicPoolSize (min
: number, max
: number): void {
177 if (this.type === PoolTypes
.dynamic
) {
180 'Cannot instantiate a dynamic pool without specifying the maximum pool size'
182 } else if (!Number.isSafeInteger(max
)) {
184 'Cannot instantiate a dynamic pool with a non safe integer maximum pool size'
186 } else if (min
> max
) {
187 throw new RangeError(
188 'Cannot instantiate a dynamic pool with a maximum pool size inferior to the minimum pool size'
190 } else if (max
=== 0) {
191 throw new RangeError(
192 'Cannot instantiate a dynamic pool with a maximum pool size equal to zero'
194 } else if (min
=== max
) {
195 throw new RangeError(
196 'Cannot instantiate a dynamic pool with a minimum pool size equal to the maximum pool size. Use a fixed pool instead'
202 private checkPoolOptions (opts
: PoolOptions
<Worker
>): void {
203 if (isPlainObject(opts
)) {
204 this.opts
.workerChoiceStrategy
=
205 opts
.workerChoiceStrategy
?? WorkerChoiceStrategies
.ROUND_ROBIN
206 this.checkValidWorkerChoiceStrategy(this.opts
.workerChoiceStrategy
)
207 this.opts
.workerChoiceStrategyOptions
=
208 opts
.workerChoiceStrategyOptions
??
209 DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
210 this.checkValidWorkerChoiceStrategyOptions(
211 this.opts
.workerChoiceStrategyOptions
213 this.opts
.restartWorkerOnError
= opts
.restartWorkerOnError
?? true
214 this.opts
.enableEvents
= opts
.enableEvents
?? true
215 this.opts
.enableTasksQueue
= opts
.enableTasksQueue
?? false
216 if (this.opts
.enableTasksQueue
) {
217 this.checkValidTasksQueueOptions(
218 opts
.tasksQueueOptions
as TasksQueueOptions
220 this.opts
.tasksQueueOptions
= this.buildTasksQueueOptions(
221 opts
.tasksQueueOptions
as TasksQueueOptions
225 throw new TypeError('Invalid pool options: must be a plain object')
229 private checkValidWorkerChoiceStrategy (
230 workerChoiceStrategy
: WorkerChoiceStrategy
232 if (!Object.values(WorkerChoiceStrategies
).includes(workerChoiceStrategy
)) {
234 `Invalid worker choice strategy '${workerChoiceStrategy}'`
239 private checkValidWorkerChoiceStrategyOptions (
240 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
242 if (!isPlainObject(workerChoiceStrategyOptions
)) {
244 'Invalid worker choice strategy options: must be a plain object'
248 workerChoiceStrategyOptions
.weights
!= null &&
249 Object.keys(workerChoiceStrategyOptions
.weights
).length
!== this.maxSize
252 'Invalid worker choice strategy options: must have a weight for each worker node'
256 workerChoiceStrategyOptions
.measurement
!= null &&
257 !Object.values(Measurements
).includes(
258 workerChoiceStrategyOptions
.measurement
262 `Invalid worker choice strategy options: invalid measurement '${workerChoiceStrategyOptions.measurement}'`
267 private checkValidTasksQueueOptions (
268 tasksQueueOptions
: TasksQueueOptions
270 if (tasksQueueOptions
!= null && !isPlainObject(tasksQueueOptions
)) {
271 throw new TypeError('Invalid tasks queue options: must be a plain object')
274 tasksQueueOptions
?.concurrency
!= null &&
275 !Number.isSafeInteger(tasksQueueOptions
.concurrency
)
278 'Invalid worker tasks concurrency: must be an integer'
282 tasksQueueOptions
?.concurrency
!= null &&
283 tasksQueueOptions
.concurrency
<= 0
286 `Invalid worker tasks concurrency '${tasksQueueOptions.concurrency}'`
291 private startPool (): void {
293 this.workerNodes
.reduce(
294 (accumulator
, workerNode
) =>
295 !workerNode
.info
.dynamic
? accumulator
+ 1 : accumulator
,
297 ) < this.numberOfWorkers
299 this.createAndSetupWorkerNode()
304 public get
info (): PoolInfo
{
310 strategy
: this.opts
.workerChoiceStrategy
as WorkerChoiceStrategy
,
311 minSize
: this.minSize
,
312 maxSize
: this.maxSize
,
313 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
314 .runTime
.aggregate
&&
315 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
316 .waitTime
.aggregate
&& { utilization
: round(this.utilization
) }),
317 workerNodes
: this.workerNodes
.length
,
318 idleWorkerNodes
: this.workerNodes
.reduce(
319 (accumulator
, workerNode
) =>
320 workerNode
.usage
.tasks
.executing
=== 0
325 busyWorkerNodes
: this.workerNodes
.reduce(
326 (accumulator
, workerNode
) =>
327 workerNode
.usage
.tasks
.executing
> 0 ? accumulator
+ 1 : accumulator
,
330 executedTasks
: this.workerNodes
.reduce(
331 (accumulator
, workerNode
) =>
332 accumulator
+ workerNode
.usage
.tasks
.executed
,
335 executingTasks
: this.workerNodes
.reduce(
336 (accumulator
, workerNode
) =>
337 accumulator
+ workerNode
.usage
.tasks
.executing
,
340 ...(this.opts
.enableTasksQueue
=== true && {
341 queuedTasks
: this.workerNodes
.reduce(
342 (accumulator
, workerNode
) =>
343 accumulator
+ workerNode
.usage
.tasks
.queued
,
347 ...(this.opts
.enableTasksQueue
=== true && {
348 maxQueuedTasks
: this.workerNodes
.reduce(
349 (accumulator
, workerNode
) =>
350 accumulator
+ (workerNode
.usage
.tasks
?.maxQueued
?? 0),
354 failedTasks
: this.workerNodes
.reduce(
355 (accumulator
, workerNode
) =>
356 accumulator
+ workerNode
.usage
.tasks
.failed
,
359 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
360 .runTime
.aggregate
&& {
364 ...this.workerNodes
.map(
365 (workerNode
) => workerNode
.usage
.runTime
?.minimum
?? Infinity
371 ...this.workerNodes
.map(
372 (workerNode
) => workerNode
.usage
.runTime
?.maximum
?? -Infinity
377 this.workerNodes
.reduce(
378 (accumulator
, workerNode
) =>
379 accumulator
+ (workerNode
.usage
.runTime
?.aggregate
?? 0),
382 this.workerNodes
.reduce(
383 (accumulator
, workerNode
) =>
384 accumulator
+ (workerNode
.usage
.tasks
?.executed
?? 0),
388 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
392 this.workerNodes
.map(
393 (workerNode
) => workerNode
.usage
.runTime
?.median
?? 0
400 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
401 .waitTime
.aggregate
&& {
405 ...this.workerNodes
.map(
406 (workerNode
) => workerNode
.usage
.waitTime
?.minimum
?? Infinity
412 ...this.workerNodes
.map(
413 (workerNode
) => workerNode
.usage
.waitTime
?.maximum
?? -Infinity
418 this.workerNodes
.reduce(
419 (accumulator
, workerNode
) =>
420 accumulator
+ (workerNode
.usage
.waitTime
?.aggregate
?? 0),
423 this.workerNodes
.reduce(
424 (accumulator
, workerNode
) =>
425 accumulator
+ (workerNode
.usage
.tasks
?.executed
?? 0),
429 ...(this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
430 .waitTime
.median
&& {
433 this.workerNodes
.map(
434 (workerNode
) => workerNode
.usage
.waitTime
?.median
?? 0
445 * The pool readiness boolean status.
447 private get
ready (): boolean {
449 this.workerNodes
.reduce(
450 (accumulator
, workerNode
) =>
451 !workerNode
.info
.dynamic
&& workerNode
.info
.ready
460 * The approximate pool utilization.
462 * @returns The pool utilization.
464 private get
utilization (): number {
465 const poolTimeCapacity
=
466 (performance
.now() - this.startTimestamp
) * this.maxSize
467 const totalTasksRunTime
= this.workerNodes
.reduce(
468 (accumulator
, workerNode
) =>
469 accumulator
+ (workerNode
.usage
.runTime
?.aggregate
?? 0),
472 const totalTasksWaitTime
= this.workerNodes
.reduce(
473 (accumulator
, workerNode
) =>
474 accumulator
+ (workerNode
.usage
.waitTime
?.aggregate
?? 0),
477 return (totalTasksRunTime
+ totalTasksWaitTime
) / poolTimeCapacity
483 * If it is `'dynamic'`, it provides the `max` property.
485 protected abstract get
type (): PoolType
490 protected abstract get
worker (): WorkerType
493 * The pool minimum size.
495 protected abstract get
minSize (): number
498 * The pool maximum size.
500 protected abstract get
maxSize (): number
503 * Checks if the worker id sent in the received message from a worker is valid.
505 * @param message - The received message.
506 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the worker id is invalid.
508 private checkMessageWorkerId (message
: MessageValue
<Response
>): void {
509 if (message
.workerId
== null) {
510 throw new Error('Worker message received without worker id')
512 message
.workerId
!= null &&
513 this.getWorkerNodeKeyByWorkerId(message
.workerId
) === -1
516 `Worker message received from unknown worker '${message.workerId}'`
522 * Gets the given worker its worker node key.
524 * @param worker - The worker.
525 * @returns The worker node key if found in the pool worker nodes, `-1` otherwise.
527 private getWorkerNodeKeyByWorker (worker
: Worker
): number {
528 return this.workerNodes
.findIndex(
529 (workerNode
) => workerNode
.worker
=== worker
534 * Gets the worker node key given its worker id.
536 * @param workerId - The worker id.
537 * @returns The worker node key if the worker id is found in the pool worker nodes, `-1` otherwise.
539 private getWorkerNodeKeyByWorkerId (workerId
: number): number {
540 return this.workerNodes
.findIndex(
541 (workerNode
) => workerNode
.info
.id
=== workerId
546 public setWorkerChoiceStrategy (
547 workerChoiceStrategy
: WorkerChoiceStrategy
,
548 workerChoiceStrategyOptions
?: WorkerChoiceStrategyOptions
550 this.checkValidWorkerChoiceStrategy(workerChoiceStrategy
)
551 this.opts
.workerChoiceStrategy
= workerChoiceStrategy
552 this.workerChoiceStrategyContext
.setWorkerChoiceStrategy(
553 this.opts
.workerChoiceStrategy
555 if (workerChoiceStrategyOptions
!= null) {
556 this.setWorkerChoiceStrategyOptions(workerChoiceStrategyOptions
)
558 for (const [workerNodeKey
, workerNode
] of this.workerNodes
.entries()) {
559 workerNode
.resetUsage()
560 this.sendStatisticsMessageToWorker(workerNodeKey
)
565 public setWorkerChoiceStrategyOptions (
566 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
568 this.checkValidWorkerChoiceStrategyOptions(workerChoiceStrategyOptions
)
569 this.opts
.workerChoiceStrategyOptions
= workerChoiceStrategyOptions
570 this.workerChoiceStrategyContext
.setOptions(
571 this.opts
.workerChoiceStrategyOptions
576 public enableTasksQueue (
578 tasksQueueOptions
?: TasksQueueOptions
580 if (this.opts
.enableTasksQueue
=== true && !enable
) {
581 this.flushTasksQueues()
583 this.opts
.enableTasksQueue
= enable
584 this.setTasksQueueOptions(tasksQueueOptions
as TasksQueueOptions
)
588 public setTasksQueueOptions (tasksQueueOptions
: TasksQueueOptions
): void {
589 if (this.opts
.enableTasksQueue
=== true) {
590 this.checkValidTasksQueueOptions(tasksQueueOptions
)
591 this.opts
.tasksQueueOptions
=
592 this.buildTasksQueueOptions(tasksQueueOptions
)
593 } else if (this.opts
.tasksQueueOptions
!= null) {
594 delete this.opts
.tasksQueueOptions
598 private buildTasksQueueOptions (
599 tasksQueueOptions
: TasksQueueOptions
600 ): TasksQueueOptions
{
602 concurrency
: tasksQueueOptions
?.concurrency
?? 1
607 * Whether the pool is full or not.
609 * The pool filling boolean status.
611 protected get
full (): boolean {
612 return this.workerNodes
.length
>= this.maxSize
616 * Whether the pool is busy or not.
618 * The pool busyness boolean status.
620 protected abstract get
busy (): boolean
623 * Whether worker nodes are executing concurrently their tasks quota or not.
625 * @returns Worker nodes busyness boolean status.
627 protected internalBusy (): boolean {
628 if (this.opts
.enableTasksQueue
=== true) {
630 this.workerNodes
.findIndex(
632 workerNode
.info
.ready
&&
633 workerNode
.usage
.tasks
.executing
<
634 (this.opts
.tasksQueueOptions
?.concurrency
as number)
639 this.workerNodes
.findIndex(
641 workerNode
.info
.ready
&& workerNode
.usage
.tasks
.executing
=== 0
648 public listTaskFunctions (): string[] {
649 for (const workerNode
of this.workerNodes
) {
651 Array.isArray(workerNode
.info
.taskFunctions
) &&
652 workerNode
.info
.taskFunctions
.length
> 0
654 return workerNode
.info
.taskFunctions
661 public async execute (
664 transferList
?: TransferListItem
[]
665 ): Promise
<Response
> {
666 return await new Promise
<Response
>((resolve
, reject
) => {
667 if (name
!= null && typeof name
!== 'string') {
668 reject(new TypeError('name argument must be a string'))
672 typeof name
=== 'string' &&
673 name
.trim().length
=== 0
675 reject(new TypeError('name argument must not be an empty string'))
677 if (transferList
!= null && !Array.isArray(transferList
)) {
678 reject(new TypeError('transferList argument must be an array'))
680 const timestamp
= performance
.now()
681 const workerNodeKey
= this.chooseWorkerNode()
682 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
685 Array.isArray(workerInfo
.taskFunctions
) &&
686 !workerInfo
.taskFunctions
.includes(name
)
689 new Error(`Task function '${name}' is not registered in the pool`)
692 const task
: Task
<Data
> = {
693 name
: name
?? DEFAULT_TASK_NAME
,
694 // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
695 data
: data
?? ({} as Data
),
698 workerId
: workerInfo
.id
as number,
701 this.promiseResponseMap
.set(task
.taskId
as string, {
707 this.opts
.enableTasksQueue
=== false ||
708 (this.opts
.enableTasksQueue
=== true &&
709 this.workerNodes
[workerNodeKey
].usage
.tasks
.executing
<
710 (this.opts
.tasksQueueOptions
?.concurrency
as number))
712 this.executeTask(workerNodeKey
, task
)
714 this.enqueueTask(workerNodeKey
, task
)
716 this.checkAndEmitEvents()
721 public async destroy (): Promise
<void> {
723 this.workerNodes
.map(async (_
, workerNodeKey
) => {
724 await this.destroyWorkerNode(workerNodeKey
)
727 this.emitter
?.emit(PoolEvents
.destroy
)
730 protected async sendKillMessageToWorker (
731 workerNodeKey
: number,
734 await new Promise
<void>((resolve
, reject
) => {
735 this.registerWorkerMessageListener(workerNodeKey
, (message
) => {
736 if (message
.kill
=== 'success') {
738 } else if (message
.kill
=== 'failure') {
739 reject(new Error(`Worker ${workerId} kill message handling failed`))
742 this.sendToWorker(workerNodeKey
, { kill
: true, workerId
})
747 * Terminates the worker node given its worker node key.
749 * @param workerNodeKey - The worker node key.
751 protected abstract destroyWorkerNode (workerNodeKey
: number): Promise
<void>
754 * Setup hook to execute code before worker nodes are created in the abstract constructor.
759 protected setupHook (): void {
760 // Intentionally empty
764 * Should return whether the worker is the main worker or not.
766 protected abstract isMain (): boolean
769 * Hook executed before the worker task execution.
772 * @param workerNodeKey - The worker node key.
773 * @param task - The task to execute.
775 protected beforeTaskExecutionHook (
776 workerNodeKey
: number,
779 const workerUsage
= this.workerNodes
[workerNodeKey
].usage
780 ++workerUsage
.tasks
.executing
781 this.updateWaitTimeWorkerUsage(workerUsage
, task
)
782 if (this.canUpdateTaskWorkerUsage(workerNodeKey
)) {
783 const taskWorkerUsage
= this.workerNodes
[
785 ].getTaskWorkerUsage(task
.name
as string) as WorkerUsage
786 ++taskWorkerUsage
.tasks
.executing
787 this.updateWaitTimeWorkerUsage(taskWorkerUsage
, task
)
792 * Hook executed after the worker task execution.
795 * @param workerNodeKey - The worker node key.
796 * @param message - The received message.
798 protected afterTaskExecutionHook (
799 workerNodeKey
: number,
800 message
: MessageValue
<Response
>
802 const workerUsage
= this.workerNodes
[workerNodeKey
].usage
803 this.updateTaskStatisticsWorkerUsage(workerUsage
, message
)
804 this.updateRunTimeWorkerUsage(workerUsage
, message
)
805 this.updateEluWorkerUsage(workerUsage
, message
)
806 if (this.canUpdateTaskWorkerUsage(workerNodeKey
)) {
807 const taskWorkerUsage
= this.workerNodes
[
809 ].getTaskWorkerUsage(
810 message
.taskPerformance
?.name
?? DEFAULT_TASK_NAME
812 this.updateTaskStatisticsWorkerUsage(taskWorkerUsage
, message
)
813 this.updateRunTimeWorkerUsage(taskWorkerUsage
, message
)
814 this.updateEluWorkerUsage(taskWorkerUsage
, message
)
818 private canUpdateTaskWorkerUsage (workerNodeKey
: number): boolean {
819 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
821 Array.isArray(workerInfo
.taskFunctions
) &&
822 workerInfo
.taskFunctions
.length
> 1
826 private updateTaskStatisticsWorkerUsage (
827 workerUsage
: WorkerUsage
,
828 message
: MessageValue
<Response
>
830 const workerTaskStatistics
= workerUsage
.tasks
831 --workerTaskStatistics
.executing
832 if (message
.taskError
== null) {
833 ++workerTaskStatistics
.executed
835 ++workerTaskStatistics
.failed
839 private updateRunTimeWorkerUsage (
840 workerUsage
: WorkerUsage
,
841 message
: MessageValue
<Response
>
843 updateMeasurementStatistics(
845 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().runTime
,
846 message
.taskPerformance
?.runTime
?? 0,
847 workerUsage
.tasks
.executed
851 private updateWaitTimeWorkerUsage (
852 workerUsage
: WorkerUsage
,
855 const timestamp
= performance
.now()
856 const taskWaitTime
= timestamp
- (task
.timestamp
?? timestamp
)
857 updateMeasurementStatistics(
858 workerUsage
.waitTime
,
859 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().waitTime
,
861 workerUsage
.tasks
.executed
865 private updateEluWorkerUsage (
866 workerUsage
: WorkerUsage
,
867 message
: MessageValue
<Response
>
869 const eluTaskStatisticsRequirements
: MeasurementStatisticsRequirements
=
870 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements().elu
871 updateMeasurementStatistics(
872 workerUsage
.elu
.active
,
873 eluTaskStatisticsRequirements
,
874 message
.taskPerformance
?.elu
?.active
?? 0,
875 workerUsage
.tasks
.executed
877 updateMeasurementStatistics(
878 workerUsage
.elu
.idle
,
879 eluTaskStatisticsRequirements
,
880 message
.taskPerformance
?.elu
?.idle
?? 0,
881 workerUsage
.tasks
.executed
883 if (eluTaskStatisticsRequirements
.aggregate
) {
884 if (message
.taskPerformance
?.elu
!= null) {
885 if (workerUsage
.elu
.utilization
!= null) {
886 workerUsage
.elu
.utilization
=
887 (workerUsage
.elu
.utilization
+
888 message
.taskPerformance
.elu
.utilization
) /
891 workerUsage
.elu
.utilization
= message
.taskPerformance
.elu
.utilization
898 * Chooses a worker node for the next task.
900 * The default worker choice strategy uses a round robin algorithm to distribute the tasks.
902 * @returns The chosen worker node key
904 private chooseWorkerNode (): number {
905 if (this.shallCreateDynamicWorker()) {
906 const workerNodeKey
= this.createAndSetupDynamicWorkerNode()
908 this.workerChoiceStrategyContext
.getStrategyPolicy().useDynamicWorker
913 return this.workerChoiceStrategyContext
.execute()
917 * Conditions for dynamic worker creation.
919 * @returns Whether to create a dynamic worker or not.
921 private shallCreateDynamicWorker (): boolean {
922 return this.type === PoolTypes
.dynamic
&& !this.full
&& this.internalBusy()
926 * Sends a message to worker given its worker node key.
928 * @param workerNodeKey - The worker node key.
929 * @param message - The message.
930 * @param transferList - The optional array of transferable objects.
932 protected abstract sendToWorker (
933 workerNodeKey
: number,
934 message
: MessageValue
<Data
>,
935 transferList
?: TransferListItem
[]
939 * Creates a new worker.
941 * @returns Newly created worker.
943 protected abstract createWorker (): Worker
946 * Creates a new, completely set up worker node.
948 * @returns New, completely set up worker node key.
950 protected createAndSetupWorkerNode (): number {
951 const worker
= this.createWorker()
953 worker
.on('online', this.opts
.onlineHandler
?? EMPTY_FUNCTION
)
954 worker
.on('message', this.opts
.messageHandler
?? EMPTY_FUNCTION
)
955 worker
.on('error', this.opts
.errorHandler
?? EMPTY_FUNCTION
)
956 worker
.on('error', (error
) => {
957 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
958 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
959 workerInfo
.ready
= false
960 this.workerNodes
[workerNodeKey
].closeChannel()
961 this.emitter
?.emit(PoolEvents
.error
, error
)
962 if (this.opts
.restartWorkerOnError
=== true && !this.starting
) {
963 if (workerInfo
.dynamic
) {
964 this.createAndSetupDynamicWorkerNode()
966 this.createAndSetupWorkerNode()
969 if (this.opts
.enableTasksQueue
=== true) {
970 this.redistributeQueuedTasks(workerNodeKey
)
973 worker
.on('exit', this.opts
.exitHandler
?? EMPTY_FUNCTION
)
974 worker
.once('exit', () => {
975 this.removeWorkerNode(worker
)
978 const workerNodeKey
= this.addWorkerNode(worker
)
980 this.afterWorkerNodeSetup(workerNodeKey
)
986 * Creates a new, completely set up dynamic worker node.
988 * @returns New, completely set up dynamic worker node key.
990 protected createAndSetupDynamicWorkerNode (): number {
991 const workerNodeKey
= this.createAndSetupWorkerNode()
992 this.registerWorkerMessageListener(workerNodeKey
, (message
) => {
993 const localWorkerNodeKey
= this.getWorkerNodeKeyByWorkerId(
996 const workerUsage
= this.workerNodes
[localWorkerNodeKey
].usage
997 // Kill message received from worker
999 isKillBehavior(KillBehaviors
.HARD
, message
.kill
) ||
1000 (isKillBehavior(KillBehaviors
.SOFT
, message
.kill
) &&
1001 ((this.opts
.enableTasksQueue
=== false &&
1002 workerUsage
.tasks
.executing
=== 0) ||
1003 (this.opts
.enableTasksQueue
=== true &&
1004 workerUsage
.tasks
.executing
=== 0 &&
1005 this.tasksQueueSize(localWorkerNodeKey
) === 0)))
1007 this.destroyWorkerNode(localWorkerNodeKey
).catch((error
) => {
1008 this.emitter
?.emit(PoolEvents
.error
, error
)
1012 const workerInfo
= this.getWorkerInfo(workerNodeKey
)
1013 this.sendToWorker(workerNodeKey
, {
1015 workerId
: workerInfo
.id
as number
1017 workerInfo
.dynamic
= true
1018 if (this.workerChoiceStrategyContext
.getStrategyPolicy().useDynamicWorker
) {
1019 workerInfo
.ready
= true
1021 return workerNodeKey
1025 * Registers a listener callback on the worker given its worker node key.
1027 * @param workerNodeKey - The worker node key.
1028 * @param listener - The message listener callback.
1030 protected abstract registerWorkerMessageListener
<
1031 Message
extends Data
| Response
1033 workerNodeKey
: number,
1034 listener
: (message
: MessageValue
<Message
>) => void
1038 * Method hooked up after a worker node has been newly created.
1039 * Can be overridden.
1041 * @param workerNodeKey - The newly created worker node key.
1043 protected afterWorkerNodeSetup (workerNodeKey
: number): void {
1044 // Listen to worker messages.
1045 this.registerWorkerMessageListener(workerNodeKey
, this.workerListener())
1046 // Send the startup message to worker.
1047 this.sendStartupMessageToWorker(workerNodeKey
)
1048 // Send the statistics message to worker.
1049 this.sendStatisticsMessageToWorker(workerNodeKey
)
1053 * Sends the startup message to worker given its worker node key.
1055 * @param workerNodeKey - The worker node key.
1057 protected abstract sendStartupMessageToWorker (workerNodeKey
: number): void
1060 * Sends the statistics message to worker given its worker node key.
1062 * @param workerNodeKey - The worker node key.
1064 private sendStatisticsMessageToWorker (workerNodeKey
: number): void {
1065 this.sendToWorker(workerNodeKey
, {
1068 this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
1070 elu
: this.workerChoiceStrategyContext
.getTaskStatisticsRequirements()
1073 workerId
: this.getWorkerInfo(workerNodeKey
).id
as number
1077 private redistributeQueuedTasks (workerNodeKey
: number): void {
1078 while (this.tasksQueueSize(workerNodeKey
) > 0) {
1079 let targetWorkerNodeKey
: number = workerNodeKey
1080 let minQueuedTasks
= Infinity
1081 let executeTask
= false
1082 for (const [workerNodeId
, workerNode
] of this.workerNodes
.entries()) {
1083 const workerInfo
= this.getWorkerInfo(workerNodeId
)
1085 workerNodeId
!== workerNodeKey
&&
1087 workerNode
.usage
.tasks
.queued
=== 0
1090 this.workerNodes
[workerNodeId
].usage
.tasks
.executing
<
1091 (this.opts
.tasksQueueOptions
?.concurrency
as number)
1095 targetWorkerNodeKey
= workerNodeId
1099 workerNodeId
!== workerNodeKey
&&
1101 workerNode
.usage
.tasks
.queued
< minQueuedTasks
1103 minQueuedTasks
= workerNode
.usage
.tasks
.queued
1104 targetWorkerNodeKey
= workerNodeId
1109 targetWorkerNodeKey
,
1110 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1114 targetWorkerNodeKey
,
1115 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1122 * This method is the listener registered for each worker message.
1124 * @returns The listener function to execute when a message is received from a worker.
1126 protected workerListener (): (message
: MessageValue
<Response
>) => void {
1127 return (message
) => {
1128 this.checkMessageWorkerId(message
)
1129 if (message
.ready
!= null && message
.taskFunctions
!= null) {
1130 // Worker ready response received from worker
1131 this.handleWorkerReadyResponse(message
)
1132 } else if (message
.taskId
!= null) {
1133 // Task execution response received from worker
1134 this.handleTaskExecutionResponse(message
)
1135 } else if (message
.taskFunctions
!= null) {
1136 // Task functions message received from worker
1138 this.getWorkerNodeKeyByWorkerId(message
.workerId
)
1139 ).taskFunctions
= message
.taskFunctions
1144 private handleWorkerReadyResponse (message
: MessageValue
<Response
>): void {
1145 if (message
.ready
=== false) {
1146 throw new Error(`Worker ${message.workerId} failed to initialize`)
1148 const workerInfo
= this.getWorkerInfo(
1149 this.getWorkerNodeKeyByWorkerId(message
.workerId
)
1151 workerInfo
.ready
= message
.ready
as boolean
1152 workerInfo
.taskFunctions
= message
.taskFunctions
1153 if (this.emitter
!= null && this.ready
) {
1154 this.emitter
.emit(PoolEvents
.ready
, this.info
)
1158 private handleTaskExecutionResponse (message
: MessageValue
<Response
>): void {
1159 const { taskId
, taskError
, data
} = message
1160 const promiseResponse
= this.promiseResponseMap
.get(taskId
as string)
1161 if (promiseResponse
!= null) {
1162 if (taskError
!= null) {
1163 this.emitter
?.emit(PoolEvents
.taskError
, taskError
)
1164 promiseResponse
.reject(taskError
.message
)
1166 promiseResponse
.resolve(data
as Response
)
1168 const workerNodeKey
= promiseResponse
.workerNodeKey
1169 this.afterTaskExecutionHook(workerNodeKey
, message
)
1170 this.promiseResponseMap
.delete(taskId
as string)
1172 this.opts
.enableTasksQueue
=== true &&
1173 this.tasksQueueSize(workerNodeKey
) > 0 &&
1174 this.workerNodes
[workerNodeKey
].usage
.tasks
.executing
<
1175 (this.opts
.tasksQueueOptions
?.concurrency
as number)
1179 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1182 this.workerChoiceStrategyContext
.update(workerNodeKey
)
1186 private checkAndEmitEvents (): void {
1187 if (this.emitter
!= null) {
1189 this.emitter
.emit(PoolEvents
.busy
, this.info
)
1191 if (this.type === PoolTypes
.dynamic
&& this.full
) {
1192 this.emitter
.emit(PoolEvents
.full
, this.info
)
1198 * Gets the worker information given its worker node key.
1200 * @param workerNodeKey - The worker node key.
1201 * @returns The worker information.
1203 protected getWorkerInfo (workerNodeKey
: number): WorkerInfo
{
1204 return this.workerNodes
[workerNodeKey
].info
1208 * Adds the given worker in the pool worker nodes.
1210 * @param worker - The worker.
1211 * @returns The added worker node key.
1212 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the added worker node is not found.
1214 private addWorkerNode (worker
: Worker
): number {
1215 const workerNode
= new WorkerNode
<Worker
, Data
>(
1220 // Flag the worker node as ready at pool startup.
1221 if (this.starting
) {
1222 workerNode
.info
.ready
= true
1224 this.workerNodes
.push(workerNode
)
1225 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1226 if (workerNodeKey
=== -1) {
1227 throw new Error('Worker node added not found')
1229 return workerNodeKey
1233 * Removes the given worker from the pool worker nodes.
1235 * @param worker - The worker.
1237 private removeWorkerNode (worker
: Worker
): void {
1238 const workerNodeKey
= this.getWorkerNodeKeyByWorker(worker
)
1239 if (workerNodeKey
!== -1) {
1240 this.workerNodes
.splice(workerNodeKey
, 1)
1241 this.workerChoiceStrategyContext
.remove(workerNodeKey
)
1246 public hasWorkerNodeBackPressure (workerNodeKey
: number): boolean {
1248 this.opts
.enableTasksQueue
=== true &&
1249 this.workerNodes
[workerNodeKey
].hasBackPressure()
1257 * Executes the given task on the worker given its worker node key.
1259 * @param workerNodeKey - The worker node key.
1260 * @param task - The task to execute.
1262 private executeTask (workerNodeKey
: number, task
: Task
<Data
>): void {
1263 this.beforeTaskExecutionHook(workerNodeKey
, task
)
1264 this.sendToWorker(workerNodeKey
, task
, task
.transferList
)
1267 private enqueueTask (workerNodeKey
: number, task
: Task
<Data
>): number {
1268 const tasksQueueSize
= this.workerNodes
[workerNodeKey
].enqueueTask(task
)
1269 if (this.hasWorkerNodeBackPressure(workerNodeKey
)) {
1270 this.emitter
?.emit(PoolEvents
.backPressure
, {
1271 workerId
: this.getWorkerInfo(workerNodeKey
).id
,
1275 return tasksQueueSize
1278 private dequeueTask (workerNodeKey
: number): Task
<Data
> | undefined {
1279 return this.workerNodes
[workerNodeKey
].dequeueTask()
1282 private tasksQueueSize (workerNodeKey
: number): number {
1283 return this.workerNodes
[workerNodeKey
].tasksQueueSize()
1286 protected flushTasksQueue (workerNodeKey
: number): void {
1287 while (this.tasksQueueSize(workerNodeKey
) > 0) {
1290 this.dequeueTask(workerNodeKey
) as Task
<Data
>
1293 this.workerNodes
[workerNodeKey
].clearTasksQueue()
1296 private flushTasksQueues (): void {
1297 for (const [workerNodeKey
] of this.workerNodes
.entries()) {
1298 this.flushTasksQueue(workerNodeKey
)