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 | } | |
c510fea7 | 165 | this.checkFilePath(this.filePath) |
c97c7edb S |
166 | this.setupHook() |
167 | ||
5c5a1fb7 | 168 | for (let i = 1; i <= this.numberOfWorkers; i++) { |
280c2a77 | 169 | this.createAndSetupWorker() |
c97c7edb S |
170 | } |
171 | ||
172 | this.emitter = new PoolEmitter() | |
a35560ba S |
173 | this.workerChoiceStrategyContext = new WorkerChoiceStrategyContext( |
174 | this, | |
175 | opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN | |
176 | ) | |
c97c7edb S |
177 | } |
178 | ||
a35560ba | 179 | private checkFilePath (filePath: string): void { |
c510fea7 APA |
180 | if (!filePath) { |
181 | throw new Error('Please specify a file with a worker implementation') | |
182 | } | |
183 | } | |
184 | ||
a35560ba S |
185 | /** @inheritdoc */ |
186 | public isDynamic (): boolean { | |
187 | return false | |
188 | } | |
189 | ||
190 | /** @inheritdoc */ | |
191 | public setWorkerChoiceStrategy ( | |
192 | workerChoiceStrategy: WorkerChoiceStrategy | |
193 | ): void { | |
194 | this.workerChoiceStrategyContext.setWorkerChoiceStrategy( | |
195 | workerChoiceStrategy | |
196 | ) | |
197 | } | |
198 | ||
199 | /** @inheritdoc */ | |
280c2a77 S |
200 | public execute (data: Data): Promise<Response> { |
201 | // Configure worker to handle message with the specified task | |
202 | const worker = this.chooseWorker() | |
203 | this.increaseWorkersTask(worker) | |
204 | const messageId = ++this.nextMessageId | |
205 | const res = this.internalExecute(worker, messageId) | |
206 | this.sendToWorker(worker, { data: data || ({} as Data), id: messageId }) | |
207 | return res | |
208 | } | |
c97c7edb | 209 | |
a35560ba | 210 | /** @inheritdoc */ |
c97c7edb | 211 | public async destroy (): Promise<void> { |
45dbbb14 | 212 | await Promise.all(this.workers.map(worker => this.destroyWorker(worker))) |
c97c7edb S |
213 | } |
214 | ||
a35560ba S |
215 | /** @inheritdoc */ |
216 | public abstract destroyWorker (worker: Worker): void | Promise<void> | |
c97c7edb | 217 | |
729c563d | 218 | /** |
280c2a77 S |
219 | * Setup hook that can be overridden by a Poolifier pool implementation |
220 | * to run code before workers are created in the abstract constructor. | |
729c563d | 221 | */ |
280c2a77 S |
222 | protected setupHook (): void { |
223 | // Can be overridden | |
224 | } | |
c97c7edb | 225 | |
729c563d | 226 | /** |
280c2a77 S |
227 | * Should return whether the worker is the main worker or not. |
228 | */ | |
229 | protected abstract isMain (): boolean | |
230 | ||
231 | /** | |
232 | * Increase the number of tasks that the given workers has done. | |
729c563d | 233 | * |
f416c098 | 234 | * @param worker Worker whose tasks are increased. |
729c563d | 235 | */ |
280c2a77 | 236 | protected increaseWorkersTask (worker: Worker): void { |
f416c098 | 237 | this.stepWorkerNumberOfTasks(worker, 1) |
c97c7edb S |
238 | } |
239 | ||
c01733f1 | 240 | /** |
d63d3be3 | 241 | * Decrease the number of tasks that the given workers has done. |
c01733f1 | 242 | * |
f416c098 | 243 | * @param worker Worker whose tasks are decreased. |
c01733f1 | 244 | */ |
245 | protected decreaseWorkersTasks (worker: Worker): void { | |
f416c098 JB |
246 | this.stepWorkerNumberOfTasks(worker, -1) |
247 | } | |
248 | ||
249 | /** | |
250 | * Step the number of tasks that the given workers has done. | |
251 | * | |
252 | * @param worker Worker whose tasks are set. | |
253 | * @param step Worker number of tasks step. | |
254 | */ | |
a35560ba | 255 | private stepWorkerNumberOfTasks (worker: Worker, step: number): void { |
d63d3be3 | 256 | const numberOfTasksInProgress = this.tasks.get(worker) |
257 | if (numberOfTasksInProgress !== undefined) { | |
f416c098 | 258 | this.tasks.set(worker, numberOfTasksInProgress + step) |
c01733f1 | 259 | } else { |
260 | throw Error('Worker could not be found in tasks map') | |
261 | } | |
262 | } | |
263 | ||
729c563d S |
264 | /** |
265 | * Removes the given worker from the pool. | |
266 | * | |
267 | * @param worker Worker that will be removed. | |
268 | */ | |
f2fdaa86 JB |
269 | protected removeWorker (worker: Worker): void { |
270 | // Clean worker from data structure | |
271 | const workerIndex = this.workers.indexOf(worker) | |
272 | this.workers.splice(workerIndex, 1) | |
273 | this.tasks.delete(worker) | |
274 | } | |
275 | ||
280c2a77 S |
276 | /** |
277 | * Choose a worker for the next task. | |
278 | * | |
279 | * The default implementation uses a round robin algorithm to distribute the load. | |
280 | * | |
281 | * @returns Worker. | |
282 | */ | |
283 | protected chooseWorker (): Worker { | |
a35560ba | 284 | return this.workerChoiceStrategyContext.execute() |
c97c7edb S |
285 | } |
286 | ||
280c2a77 S |
287 | /** |
288 | * Send a message to the given worker. | |
289 | * | |
290 | * @param worker The worker which should receive the message. | |
291 | * @param message The message. | |
292 | */ | |
293 | protected abstract sendToWorker ( | |
294 | worker: Worker, | |
295 | message: MessageValue<Data> | |
296 | ): void | |
297 | ||
a35560ba S |
298 | /** @inheritdoc */ |
299 | public abstract registerWorkerMessageListener< | |
4f7fa42a S |
300 | Message extends Data | Response |
301 | > (worker: Worker, listener: (message: MessageValue<Message>) => void): void | |
c97c7edb | 302 | |
280c2a77 S |
303 | protected internalExecute ( |
304 | worker: Worker, | |
305 | messageId: number | |
306 | ): Promise<Response> { | |
be0676b3 APA |
307 | return new Promise<Response>((resolve, reject) => { |
308 | this.promiseMap.set(messageId, { resolve, reject, worker }) | |
c97c7edb S |
309 | }) |
310 | } | |
311 | ||
729c563d S |
312 | /** |
313 | * Returns a newly created worker. | |
314 | */ | |
280c2a77 | 315 | protected abstract createWorker (): Worker |
c97c7edb | 316 | |
729c563d S |
317 | /** |
318 | * Function that can be hooked up when a worker has been newly created and moved to the workers registry. | |
319 | * | |
320 | * Can be used to update the `maxListeners` or binding the `main-worker`<->`worker` connection if not bind by default. | |
321 | * | |
322 | * @param worker The newly created worker. | |
323 | */ | |
280c2a77 | 324 | protected abstract afterWorkerSetup (worker: Worker): void |
c97c7edb | 325 | |
a35560ba S |
326 | /** @inheritdoc */ |
327 | public createAndSetupWorker (): Worker { | |
280c2a77 S |
328 | const worker: Worker = this.createWorker() |
329 | ||
a35560ba S |
330 | worker.on('error', this.opts.errorHandler ?? EMPTY_FUNCTION) |
331 | worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION) | |
332 | worker.on('exit', this.opts.exitHandler ?? EMPTY_FUNCTION) | |
45dbbb14 | 333 | worker.once('exit', () => this.removeWorker(worker)) |
280c2a77 | 334 | |
c97c7edb | 335 | this.workers.push(worker) |
280c2a77 S |
336 | |
337 | // Init tasks map | |
c97c7edb | 338 | this.tasks.set(worker, 0) |
280c2a77 S |
339 | |
340 | this.afterWorkerSetup(worker) | |
341 | ||
c97c7edb S |
342 | return worker |
343 | } | |
be0676b3 APA |
344 | |
345 | /** | |
346 | * This function is the listener registered for each worker. | |
347 | * | |
348 | * @returns The listener function to execute when a message is sent from a worker. | |
349 | */ | |
350 | protected workerListener (): (message: MessageValue<Response>) => void { | |
351 | const listener: (message: MessageValue<Response>) => void = message => { | |
352 | if (message.id) { | |
353 | const value = this.promiseMap.get(message.id) | |
354 | if (value) { | |
355 | this.decreaseWorkersTasks(value.worker) | |
356 | if (message.error) value.reject(message.error) | |
357 | else value.resolve(message.data as Response) | |
358 | this.promiseMap.delete(message.id) | |
359 | } | |
360 | } | |
361 | } | |
362 | return listener | |
363 | } | |
c97c7edb | 364 | } |