Commit | Line | Data |
---|---|---|
be0676b3 APA |
1 | import type { |
2 | MessageValue, | |
3 | PromiseWorkerResponseWrapper | |
4 | } from '../utility-types' | |
a35560ba S |
5 | import type { IPoolInternal } from './pool-internal' |
6 | import { PoolEmitter } from './pool-internal' | |
7 | import type { WorkerChoiceStrategy } from './selection-strategies' | |
8 | import { | |
9 | WorkerChoiceStrategies, | |
10 | WorkerChoiceStrategyContext | |
11 | } from './selection-strategies' | |
c97c7edb | 12 | |
c510fea7 APA |
13 | /** |
14 | * An intentional empty function. | |
15 | */ | |
a35560ba S |
16 | const EMPTY_FUNCTION: () => void = () => { |
17 | /* Intentionally empty */ | |
c510fea7 APA |
18 | } |
19 | ||
729c563d S |
20 | /** |
21 | * Callback invoked if the worker raised an error. | |
22 | */ | |
c97c7edb | 23 | export type ErrorHandler<Worker> = (this: Worker, e: Error) => void |
729c563d S |
24 | |
25 | /** | |
26 | * Callback invoked when the worker has started successfully. | |
27 | */ | |
c97c7edb | 28 | export type OnlineHandler<Worker> = (this: Worker) => void |
729c563d S |
29 | |
30 | /** | |
31 | * Callback invoked when the worker exits successfully. | |
32 | */ | |
c97c7edb S |
33 | export type ExitHandler<Worker> = (this: Worker, code: number) => void |
34 | ||
729c563d S |
35 | /** |
36 | * Basic interface that describes the minimum required implementation of listener events for a pool-worker. | |
37 | */ | |
c97c7edb | 38 | export interface IWorker { |
3832ad95 S |
39 | /** |
40 | * Register a listener to the error event. | |
41 | * | |
42 | * @param event `'error'`. | |
43 | * @param handler The error handler. | |
44 | */ | |
c97c7edb | 45 | on(event: 'error', handler: ErrorHandler<this>): void |
3832ad95 S |
46 | /** |
47 | * Register a listener to the online event. | |
48 | * | |
49 | * @param event `'online'`. | |
50 | * @param handler The online handler. | |
51 | */ | |
c97c7edb | 52 | on(event: 'online', handler: OnlineHandler<this>): void |
3832ad95 S |
53 | /** |
54 | * Register a listener to the exit event. | |
55 | * | |
56 | * @param event `'exit'`. | |
57 | * @param handler The exit handler. | |
58 | */ | |
c97c7edb | 59 | on(event: 'exit', handler: ExitHandler<this>): void |
3832ad95 S |
60 | /** |
61 | * Register a listener to the exit event that will only performed once. | |
62 | * | |
63 | * @param event `'exit'`. | |
64 | * @param handler The exit handler. | |
65 | */ | |
45dbbb14 | 66 | once(event: 'exit', handler: ExitHandler<this>): void |
c97c7edb S |
67 | } |
68 | ||
729c563d S |
69 | /** |
70 | * Options for a poolifier pool. | |
71 | */ | |
c97c7edb S |
72 | export interface PoolOptions<Worker> { |
73 | /** | |
74 | * A function that will listen for error event on each worker. | |
75 | */ | |
76 | errorHandler?: ErrorHandler<Worker> | |
77 | /** | |
78 | * A function that will listen for online event on each worker. | |
79 | */ | |
80 | onlineHandler?: OnlineHandler<Worker> | |
81 | /** | |
82 | * A function that will listen for exit event on each worker. | |
83 | */ | |
84 | exitHandler?: ExitHandler<Worker> | |
85 | /** | |
729c563d S |
86 | * This is just to avoid non-useful warning messages. |
87 | * | |
88 | * Will be used to set `maxListeners` on event emitters (workers are event emitters). | |
c97c7edb S |
89 | * |
90 | * @default 1000 | |
729c563d | 91 | * @see [Node events emitter.setMaxListeners(n)](https://nodejs.org/api/events.html#events_emitter_setmaxlisteners_n) |
c97c7edb S |
92 | */ |
93 | maxTasks?: number | |
a35560ba S |
94 | /** |
95 | * The work choice strategy to use in this pool. | |
96 | */ | |
97 | workerChoiceStrategy?: WorkerChoiceStrategy | |
c97c7edb S |
98 | } |
99 | ||
729c563d S |
100 | /** |
101 | * Base class containing some shared logic for all poolifier pools. | |
102 | * | |
103 | * @template Worker Type of worker which manages this pool. | |
deb85c12 JB |
104 | * @template Data Type of data sent to the worker. This can only be serializable data. |
105 | * @template Response Type of response of execution. This can only be serializable data. | |
729c563d | 106 | */ |
c97c7edb S |
107 | export abstract class AbstractPool< |
108 | Worker extends IWorker, | |
d3c8a1a8 S |
109 | Data = unknown, |
110 | Response = unknown | |
a35560ba | 111 | > implements IPoolInternal<Worker, Data, Response> { |
be0676b3 APA |
112 | /** |
113 | * The promise map. | |
114 | * | |
115 | * - `key`: This is the message ID of each submitted task. | |
116 | * - `value`: An object that contains the worker, the resolve function and the reject function. | |
117 | * | |
118 | * When we receive a message from the worker we get a map entry and resolve/reject the promise based on the message. | |
119 | */ | |
120 | protected promiseMap: Map< | |
121 | number, | |
122 | PromiseWorkerResponseWrapper<Worker, Response> | |
123 | > = new Map<number, PromiseWorkerResponseWrapper<Worker, Response>>() | |
124 | ||
a35560ba | 125 | /** @inheritdoc */ |
c97c7edb | 126 | public readonly workers: Worker[] = [] |
729c563d | 127 | |
a35560ba | 128 | /** @inheritdoc */ |
c97c7edb S |
129 | public readonly tasks: Map<Worker, number> = new Map<Worker, number>() |
130 | ||
a35560ba | 131 | /** @inheritdoc */ |
c97c7edb S |
132 | public readonly emitter: PoolEmitter |
133 | ||
729c563d S |
134 | /** |
135 | * ID of the next message. | |
136 | */ | |
280c2a77 | 137 | protected nextMessageId: number = 0 |
c97c7edb | 138 | |
a35560ba S |
139 | /** |
140 | * Worker choice strategy instance implementing the worker choice algorithm. | |
141 | * | |
142 | * Default to a strategy implementing a round robin algorithm. | |
143 | */ | |
144 | protected workerChoiceStrategyContext: WorkerChoiceStrategyContext< | |
145 | Worker, | |
146 | Data, | |
147 | Response | |
148 | > | |
149 | ||
729c563d S |
150 | /** |
151 | * Constructs a new poolifier pool. | |
152 | * | |
5c5a1fb7 | 153 | * @param numberOfWorkers Number of workers that this pool should manage. |
729c563d S |
154 | * @param filePath Path to the worker-file. |
155 | * @param opts Options for the pool. Default: `{ maxTasks: 1000 }` | |
156 | */ | |
c97c7edb | 157 | public constructor ( |
5c5a1fb7 | 158 | public readonly numberOfWorkers: number, |
c97c7edb S |
159 | public readonly filePath: string, |
160 | public readonly opts: PoolOptions<Worker> = { maxTasks: 1000 } | |
161 | ) { | |
162 | if (!this.isMain()) { | |
163 | throw new Error('Cannot start a pool from a worker!') | |
164 | } | |
8d3782fa | 165 | this.checkNumberOfWorkers(this.numberOfWorkers) |
c510fea7 | 166 | this.checkFilePath(this.filePath) |
c97c7edb S |
167 | this.setupHook() |
168 | ||
5c5a1fb7 | 169 | for (let i = 1; i <= this.numberOfWorkers; i++) { |
280c2a77 | 170 | this.createAndSetupWorker() |
c97c7edb S |
171 | } |
172 | ||
173 | this.emitter = new PoolEmitter() | |
a35560ba S |
174 | this.workerChoiceStrategyContext = new WorkerChoiceStrategyContext( |
175 | this, | |
176 | opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN | |
177 | ) | |
c97c7edb S |
178 | } |
179 | ||
a35560ba | 180 | private checkFilePath (filePath: string): void { |
c510fea7 APA |
181 | if (!filePath) { |
182 | throw new Error('Please specify a file with a worker implementation') | |
183 | } | |
184 | } | |
185 | ||
8d3782fa JB |
186 | private checkNumberOfWorkers (numberOfWorkers: number): void { |
187 | if (numberOfWorkers == null) { | |
188 | throw new Error( | |
189 | 'Cannot instantiate a pool without specifying the number of workers' | |
190 | ) | |
191 | } else if (!Number.isSafeInteger(numberOfWorkers)) { | |
192 | throw new Error( | |
193 | 'Cannot instantiate a pool with a non integer number of workers' | |
194 | ) | |
195 | } else if (numberOfWorkers < 0) { | |
196 | throw new Error( | |
197 | 'Cannot instantiate a pool with a negative number of workers' | |
198 | ) | |
199 | } else if (!this.isDynamic() && numberOfWorkers === 0) { | |
200 | throw new Error('Cannot instantiate a fixed pool with no worker') | |
201 | } | |
202 | } | |
203 | ||
a35560ba S |
204 | /** @inheritdoc */ |
205 | public isDynamic (): boolean { | |
206 | return false | |
207 | } | |
208 | ||
209 | /** @inheritdoc */ | |
210 | public setWorkerChoiceStrategy ( | |
211 | workerChoiceStrategy: WorkerChoiceStrategy | |
212 | ): void { | |
213 | this.workerChoiceStrategyContext.setWorkerChoiceStrategy( | |
214 | workerChoiceStrategy | |
215 | ) | |
216 | } | |
217 | ||
218 | /** @inheritdoc */ | |
280c2a77 S |
219 | public execute (data: Data): Promise<Response> { |
220 | // Configure worker to handle message with the specified task | |
221 | const worker = this.chooseWorker() | |
222 | this.increaseWorkersTask(worker) | |
223 | const messageId = ++this.nextMessageId | |
224 | const res = this.internalExecute(worker, messageId) | |
225 | this.sendToWorker(worker, { data: data || ({} as Data), id: messageId }) | |
226 | return res | |
227 | } | |
c97c7edb | 228 | |
a35560ba | 229 | /** @inheritdoc */ |
c97c7edb | 230 | public async destroy (): Promise<void> { |
45dbbb14 | 231 | await Promise.all(this.workers.map(worker => this.destroyWorker(worker))) |
c97c7edb S |
232 | } |
233 | ||
a35560ba S |
234 | /** @inheritdoc */ |
235 | public abstract destroyWorker (worker: Worker): void | Promise<void> | |
c97c7edb | 236 | |
729c563d | 237 | /** |
280c2a77 S |
238 | * Setup hook that can be overridden by a Poolifier pool implementation |
239 | * to run code before workers are created in the abstract constructor. | |
729c563d | 240 | */ |
280c2a77 S |
241 | protected setupHook (): void { |
242 | // Can be overridden | |
243 | } | |
c97c7edb | 244 | |
729c563d | 245 | /** |
280c2a77 S |
246 | * Should return whether the worker is the main worker or not. |
247 | */ | |
248 | protected abstract isMain (): boolean | |
249 | ||
250 | /** | |
251 | * Increase the number of tasks that the given workers has done. | |
729c563d | 252 | * |
f416c098 | 253 | * @param worker Worker whose tasks are increased. |
729c563d | 254 | */ |
280c2a77 | 255 | protected increaseWorkersTask (worker: Worker): void { |
f416c098 | 256 | this.stepWorkerNumberOfTasks(worker, 1) |
c97c7edb S |
257 | } |
258 | ||
c01733f1 | 259 | /** |
d63d3be3 | 260 | * Decrease the number of tasks that the given workers has done. |
c01733f1 | 261 | * |
f416c098 | 262 | * @param worker Worker whose tasks are decreased. |
c01733f1 | 263 | */ |
264 | protected decreaseWorkersTasks (worker: Worker): void { | |
f416c098 JB |
265 | this.stepWorkerNumberOfTasks(worker, -1) |
266 | } | |
267 | ||
268 | /** | |
269 | * Step the number of tasks that the given workers has done. | |
270 | * | |
271 | * @param worker Worker whose tasks are set. | |
272 | * @param step Worker number of tasks step. | |
273 | */ | |
a35560ba | 274 | private stepWorkerNumberOfTasks (worker: Worker, step: number): void { |
d63d3be3 | 275 | const numberOfTasksInProgress = this.tasks.get(worker) |
276 | if (numberOfTasksInProgress !== undefined) { | |
f416c098 | 277 | this.tasks.set(worker, numberOfTasksInProgress + step) |
c01733f1 | 278 | } else { |
279 | throw Error('Worker could not be found in tasks map') | |
280 | } | |
281 | } | |
282 | ||
729c563d S |
283 | /** |
284 | * Removes the given worker from the pool. | |
285 | * | |
286 | * @param worker Worker that will be removed. | |
287 | */ | |
f2fdaa86 JB |
288 | protected removeWorker (worker: Worker): void { |
289 | // Clean worker from data structure | |
290 | const workerIndex = this.workers.indexOf(worker) | |
291 | this.workers.splice(workerIndex, 1) | |
292 | this.tasks.delete(worker) | |
293 | } | |
294 | ||
280c2a77 S |
295 | /** |
296 | * Choose a worker for the next task. | |
297 | * | |
298 | * The default implementation uses a round robin algorithm to distribute the load. | |
299 | * | |
300 | * @returns Worker. | |
301 | */ | |
302 | protected chooseWorker (): Worker { | |
a35560ba | 303 | return this.workerChoiceStrategyContext.execute() |
c97c7edb S |
304 | } |
305 | ||
280c2a77 S |
306 | /** |
307 | * Send a message to the given worker. | |
308 | * | |
309 | * @param worker The worker which should receive the message. | |
310 | * @param message The message. | |
311 | */ | |
312 | protected abstract sendToWorker ( | |
313 | worker: Worker, | |
314 | message: MessageValue<Data> | |
315 | ): void | |
316 | ||
a35560ba S |
317 | /** @inheritdoc */ |
318 | public abstract registerWorkerMessageListener< | |
4f7fa42a S |
319 | Message extends Data | Response |
320 | > (worker: Worker, listener: (message: MessageValue<Message>) => void): void | |
c97c7edb | 321 | |
280c2a77 S |
322 | protected internalExecute ( |
323 | worker: Worker, | |
324 | messageId: number | |
325 | ): Promise<Response> { | |
be0676b3 APA |
326 | return new Promise<Response>((resolve, reject) => { |
327 | this.promiseMap.set(messageId, { resolve, reject, worker }) | |
c97c7edb S |
328 | }) |
329 | } | |
330 | ||
729c563d S |
331 | /** |
332 | * Returns a newly created worker. | |
333 | */ | |
280c2a77 | 334 | protected abstract createWorker (): Worker |
c97c7edb | 335 | |
729c563d S |
336 | /** |
337 | * Function that can be hooked up when a worker has been newly created and moved to the workers registry. | |
338 | * | |
339 | * Can be used to update the `maxListeners` or binding the `main-worker`<->`worker` connection if not bind by default. | |
340 | * | |
341 | * @param worker The newly created worker. | |
342 | */ | |
280c2a77 | 343 | protected abstract afterWorkerSetup (worker: Worker): void |
c97c7edb | 344 | |
a35560ba S |
345 | /** @inheritdoc */ |
346 | public createAndSetupWorker (): Worker { | |
280c2a77 S |
347 | const worker: Worker = this.createWorker() |
348 | ||
a35560ba S |
349 | worker.on('error', this.opts.errorHandler ?? EMPTY_FUNCTION) |
350 | worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION) | |
351 | worker.on('exit', this.opts.exitHandler ?? EMPTY_FUNCTION) | |
45dbbb14 | 352 | worker.once('exit', () => this.removeWorker(worker)) |
280c2a77 | 353 | |
c97c7edb | 354 | this.workers.push(worker) |
280c2a77 S |
355 | |
356 | // Init tasks map | |
c97c7edb | 357 | this.tasks.set(worker, 0) |
280c2a77 S |
358 | |
359 | this.afterWorkerSetup(worker) | |
360 | ||
c97c7edb S |
361 | return worker |
362 | } | |
be0676b3 APA |
363 | |
364 | /** | |
365 | * This function is the listener registered for each worker. | |
366 | * | |
367 | * @returns The listener function to execute when a message is sent from a worker. | |
368 | */ | |
369 | protected workerListener (): (message: MessageValue<Response>) => void { | |
370 | const listener: (message: MessageValue<Response>) => void = message => { | |
371 | if (message.id) { | |
372 | const value = this.promiseMap.get(message.id) | |
373 | if (value) { | |
374 | this.decreaseWorkersTasks(value.worker) | |
375 | if (message.error) value.reject(message.error) | |
376 | else value.resolve(message.data as Response) | |
377 | this.promiseMap.delete(message.id) | |
378 | } | |
379 | } | |
380 | } | |
381 | return listener | |
382 | } | |
c97c7edb | 383 | } |