1 import crypto from
'node:crypto'
2 import type { MessageValue
, PromiseResponseWrapper
} from
'../utility-types'
3 import { EMPTY_FUNCTION
} from
'../utils'
4 import { KillBehaviors
, isKillBehavior
} from
'../worker/worker-options'
5 import type { PoolOptions
} from
'./pool'
6 import { PoolEmitter
} from
'./pool'
7 import type { IPoolInternal
, TasksUsage
, WorkerType
} from
'./pool-internal'
8 import { PoolType
} from
'./pool-internal'
9 import type { IPoolWorker
} from
'./pool-worker'
11 WorkerChoiceStrategies
,
12 type WorkerChoiceStrategy
13 } from
'./selection-strategies/selection-strategies-types'
14 import { WorkerChoiceStrategyContext
} from
'./selection-strategies/worker-choice-strategy-context'
17 * Base class that implements some shared logic for all poolifier pools.
19 * @typeParam Worker - Type of worker which manages this pool.
20 * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
21 * @typeParam Response - Type of response of execution. This can only be serializable data.
23 export abstract class AbstractPool
<
24 Worker
extends IPoolWorker
,
27 > implements IPoolInternal
<Worker
, Data
, Response
> {
29 public readonly workers
: Array<WorkerType
<Worker
>> = []
32 public readonly emitter
?: PoolEmitter
35 * The promise response map.
37 * - `key`: The message id of each submitted task.
38 * - `value`: An object that contains the worker, the promise resolve and reject callbacks.
40 * When we receive a message from the worker we get a map entry with the promise resolve/reject bound to the message.
42 protected promiseResponseMap
: Map
<
44 PromiseResponseWrapper
<Worker
, Response
>
45 > = new Map
<string, PromiseResponseWrapper
<Worker
, Response
>>()
48 * Worker choice strategy context referencing a worker choice algorithm implementation.
50 * Default to a round robin algorithm.
52 protected workerChoiceStrategyContext
: WorkerChoiceStrategyContext
<
59 * Constructs a new poolifier pool.
61 * @param numberOfWorkers - Number of workers that this pool should manage.
62 * @param filePath - Path to the worker-file.
63 * @param opts - Options for the pool.
66 public readonly numberOfWorkers
: number,
67 public readonly filePath
: string,
68 public readonly opts
: PoolOptions
<Worker
>
71 throw new Error('Cannot start a pool from a worker!')
73 this.checkNumberOfWorkers(this.numberOfWorkers
)
74 this.checkFilePath(this.filePath
)
75 this.checkPoolOptions(this.opts
)
77 this.chooseWorker
.bind(this)
78 this.internalExecute
.bind(this)
79 this.checkAndEmitFull
.bind(this)
80 this.checkAndEmitBusy
.bind(this)
81 this.sendToWorker
.bind(this)
85 for (let i
= 1; i
<= this.numberOfWorkers
; i
++) {
86 this.createAndSetupWorker()
89 if (this.opts
.enableEvents
=== true) {
90 this.emitter
= new PoolEmitter()
92 this.workerChoiceStrategyContext
= new WorkerChoiceStrategyContext
<
96 >(this, this.opts
.workerChoiceStrategy
)
99 private checkFilePath (filePath
: string): void {
102 (typeof filePath
=== 'string' && filePath
.trim().length
=== 0)
104 throw new Error('Please specify a file with a worker implementation')
108 private checkNumberOfWorkers (numberOfWorkers
: number): void {
109 if (numberOfWorkers
== null) {
111 'Cannot instantiate a pool without specifying the number of workers'
113 } else if (!Number.isSafeInteger(numberOfWorkers
)) {
115 'Cannot instantiate a pool with a non integer number of workers'
117 } else if (numberOfWorkers
< 0) {
118 throw new RangeError(
119 'Cannot instantiate a pool with a negative number of workers'
121 } else if (this.type === PoolType
.FIXED
&& numberOfWorkers
=== 0) {
122 throw new Error('Cannot instantiate a fixed pool with no worker')
126 private checkPoolOptions (opts
: PoolOptions
<Worker
>): void {
127 this.opts
.workerChoiceStrategy
=
128 opts
.workerChoiceStrategy
?? WorkerChoiceStrategies
.ROUND_ROBIN
130 !Object.values(WorkerChoiceStrategies
).includes(
131 this.opts
.workerChoiceStrategy
135 `Invalid worker choice strategy '${this.opts.workerChoiceStrategy}'`
138 this.opts
.enableEvents
= opts
.enableEvents
?? true
142 public abstract get
type (): PoolType
145 * Number of tasks concurrently running in the pool.
147 private get
numberOfRunningTasks (): number {
148 return this.promiseResponseMap
.size
152 * Gets the given worker key.
154 * @param worker - The worker.
155 * @returns The worker key if the worker is found in the pool, `-1` otherwise.
157 private getWorkerKey (worker
: Worker
): number {
158 return this.workers
.findIndex(workerItem
=> workerItem
.worker
=== worker
)
162 public setWorkerChoiceStrategy (
163 workerChoiceStrategy
: WorkerChoiceStrategy
165 this.opts
.workerChoiceStrategy
= workerChoiceStrategy
166 for (const [index
, workerItem
] of this.workers
.entries()) {
167 this.setWorker(index
, workerItem
.worker
, {
175 this.workerChoiceStrategyContext
.setWorkerChoiceStrategy(
181 public abstract get
full (): boolean
184 public abstract get
busy (): boolean
186 protected internalBusy (): boolean {
188 this.numberOfRunningTasks
>= this.numberOfWorkers
&&
189 this.findFreeWorkerKey() === -1
194 public findFreeWorkerKey (): number {
195 return this.workers
.findIndex(workerItem
=> {
196 return workerItem
.tasksUsage
.running
=== 0
201 public async execute (data
: Data
): Promise
<Response
> {
202 const [workerKey
, worker
] = this.chooseWorker()
203 const messageId
= crypto
.randomUUID()
204 const res
= this.internalExecute(workerKey
, worker
, messageId
)
205 this.checkAndEmitFull()
206 this.checkAndEmitBusy()
207 this.sendToWorker(worker
, {
208 // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
209 data
: data
?? ({} as Data
),
212 // eslint-disable-next-line @typescript-eslint/return-await
217 public async destroy (): Promise
<void> {
219 this.workers
.map(async workerItem
=> {
220 await this.destroyWorker(workerItem
.worker
)
226 * Shutdowns given worker in the pool.
228 * @param worker - A worker within `workers`.
230 protected abstract destroyWorker (worker
: Worker
): void | Promise
<void>
233 * Setup hook that can be overridden by a Poolifier pool implementation
234 * to run code before workers are created in the abstract constructor.
239 protected setupHook (): void {
240 // Intentionally empty
244 * Should return whether the worker is the main worker or not.
246 protected abstract isMain (): boolean
249 * Hook executed before the worker task promise resolution.
252 * @param workerKey - The worker key.
254 protected beforePromiseResponseHook (workerKey
: number): void {
255 ++this.workers
[workerKey
].tasksUsage
.running
259 * Hook executed after the worker task promise resolution.
262 * @param worker - The worker.
263 * @param message - The received message.
265 protected afterPromiseResponseHook (
267 message
: MessageValue
<Response
>
269 const workerTasksUsage
= this.getWorkerTasksUsage(worker
) as TasksUsage
270 --workerTasksUsage
.running
271 ++workerTasksUsage
.run
272 if (message
.error
!= null) {
273 ++workerTasksUsage
.error
275 if (this.workerChoiceStrategyContext
.getRequiredStatistics().runTime
) {
276 workerTasksUsage
.runTime
+= message
.taskRunTime
?? 0
278 this.workerChoiceStrategyContext
.getRequiredStatistics().avgRunTime
&&
279 workerTasksUsage
.run
!== 0
281 workerTasksUsage
.avgRunTime
=
282 workerTasksUsage
.runTime
/ workerTasksUsage
.run
288 * Chooses a worker for the next task.
290 * The default uses a round robin algorithm to distribute the load.
292 * @returns [worker key, worker].
294 protected chooseWorker (): [number, Worker
] {
295 let workerKey
: number
297 this.type === PoolType
.DYNAMIC
&&
299 this.findFreeWorkerKey() === -1
301 const createdWorker
= this.createAndSetupWorker()
302 this.registerWorkerMessageListener(createdWorker
, message
=> {
304 isKillBehavior(KillBehaviors
.HARD
, message
.kill
) ||
305 (message
.kill
!= null &&
306 this.getWorkerTasksUsage(createdWorker
)?.running
=== 0)
308 // Kill received from the worker, means that no new tasks are submitted to that worker for a while ( > maxInactiveTime)
309 void this.destroyWorker(createdWorker
)
312 workerKey
= this.getWorkerKey(createdWorker
)
314 workerKey
= this.workerChoiceStrategyContext
.execute()
316 return [workerKey
, this.workers
[workerKey
].worker
]
320 * Sends a message to the given worker.
322 * @param worker - The worker which should receive the message.
323 * @param message - The message.
325 protected abstract sendToWorker (
327 message
: MessageValue
<Data
>
331 * Registers a listener callback on a given worker.
333 * @param worker - The worker which should register a listener.
334 * @param listener - The message listener callback.
336 protected abstract registerWorkerMessageListener
<
337 Message
extends Data
| Response
338 >(worker
: Worker
, listener
: (message
: MessageValue
<Message
>) => void): void
341 * Returns a newly created worker.
343 protected abstract createWorker (): Worker
346 * Function that can be hooked up when a worker has been newly created and moved to the workers registry.
348 * Can be used to update the `maxListeners` or binding the `main-worker`\<-\>`worker` connection if not bind by default.
350 * @param worker - The newly created worker.
353 protected abstract afterWorkerSetup (worker
: Worker
): void
356 * Creates a new worker for this pool and sets it up completely.
358 * @returns New, completely set up worker.
360 protected createAndSetupWorker (): Worker
{
361 const worker
= this.createWorker()
363 worker
.on('message', this.opts
.messageHandler
?? EMPTY_FUNCTION
)
364 worker
.on('error', this.opts
.errorHandler
?? EMPTY_FUNCTION
)
365 worker
.on('online', this.opts
.onlineHandler
?? EMPTY_FUNCTION
)
366 worker
.on('exit', this.opts
.exitHandler
?? EMPTY_FUNCTION
)
367 worker
.once('exit', () => {
368 this.removeWorker(worker
)
371 this.pushWorker(worker
, {
379 this.afterWorkerSetup(worker
)
385 * This function is the listener registered for each worker.
387 * @returns The listener function to execute when a message is received from a worker.
389 protected workerListener (): (message
: MessageValue
<Response
>) => void {
391 if (message
.id
!= null) {
392 const promiseResponse
= this.promiseResponseMap
.get(message
.id
)
393 if (promiseResponse
!= null) {
394 if (message
.error
!= null) {
395 promiseResponse
.reject(message
.error
)
397 promiseResponse
.resolve(message
.data
as Response
)
399 this.afterPromiseResponseHook(promiseResponse
.worker
, message
)
400 this.promiseResponseMap
.delete(message
.id
)
406 private async internalExecute (
410 ): Promise
<Response
> {
411 this.beforePromiseResponseHook(workerKey
)
412 return await new Promise
<Response
>((resolve
, reject
) => {
413 this.promiseResponseMap
.set(messageId
, { resolve
, reject
, worker
})
417 private checkAndEmitBusy (): void {
418 if (this.opts
.enableEvents
=== true && this.busy
) {
419 this.emitter
?.emit('busy')
423 private checkAndEmitFull (): void {
425 this.type === PoolType
.DYNAMIC
&&
426 this.opts
.enableEvents
=== true &&
429 this.emitter
?.emit('full')
434 * Gets the given worker tasks usage in the pool.
436 * @param worker - The worker.
437 * @returns The worker tasks usage.
439 private getWorkerTasksUsage (worker
: Worker
): TasksUsage
| undefined {
440 const workerKey
= this.getWorkerKey(worker
)
441 if (workerKey
!== -1) {
442 return this.workers
[workerKey
].tasksUsage
444 throw new Error('Worker could not be found in the pool')
448 * Pushes the given worker in the pool.
450 * @param worker - The worker.
451 * @param tasksUsage - The worker tasks usage.
453 private pushWorker (worker
: Worker
, tasksUsage
: TasksUsage
): void {
461 * Sets the given worker in the pool.
463 * @param workerKey - The worker key.
464 * @param worker - The worker.
465 * @param tasksUsage - The worker tasks usage.
470 tasksUsage
: TasksUsage
472 this.workers
[workerKey
] = {
479 * Removes the given worker from the pool.
481 * @param worker - The worker that will be removed.
483 protected removeWorker (worker
: Worker
): void {
484 const workerKey
= this.getWorkerKey(worker
)
485 this.workers
.splice(workerKey
, 1)
486 this.workerChoiceStrategyContext
.remove(workerKey
)