docs: refine tasks concurrency task queue options description
[poolifier.git] / src / pools / pool.ts
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2845f2a5 1import { EventEmitter } from 'node:events'
7d91a8cd 2import { type TransferListItem } from 'node:worker_threads'
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3import type {
4 ErrorHandler,
5 ExitHandler,
50e66724 6 IWorker,
4b628b48 7 IWorkerNode,
bdaf31cd 8 MessageHandler,
c4855468 9 OnlineHandler,
4b628b48 10 WorkerType
f06e48d8 11} from './worker'
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12import type {
13 WorkerChoiceStrategy,
14 WorkerChoiceStrategyOptions
15} from './selection-strategies/selection-strategies-types'
bdaf31cd 16
c4855468 17/**
6b27d407 18 * Enumeration of pool types.
c4855468 19 */
6b27d407 20export const PoolTypes = Object.freeze({
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21 /**
22 * Fixed pool type.
23 */
6b27d407 24 fixed: 'fixed',
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25 /**
26 * Dynamic pool type.
27 */
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28 dynamic: 'dynamic'
29} as const)
30
31/**
32 * Pool type.
33 */
34export type PoolType = keyof typeof PoolTypes
c4855468 35
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36/**
37 * Pool events emitter.
38 */
2845f2a5 39export class PoolEmitter extends EventEmitter {}
b4904890 40
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41/**
42 * Enumeration of pool events.
43 */
44export const PoolEvents = Object.freeze({
2431bdb4 45 ready: 'ready',
1f68cede 46 busy: 'busy',
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47 full: 'full',
48 destroy: 'destroy',
91ee39ed 49 error: 'error',
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50 taskError: 'taskError',
51 backPressure: 'backPressure'
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52} as const)
53
54/**
55 * Pool event.
56 */
57export type PoolEvent = keyof typeof PoolEvents
58
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59/**
60 * Pool information.
61 */
62export interface PoolInfo {
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63 readonly version: string
64 readonly type: PoolType
65 readonly worker: WorkerType
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66 readonly ready: boolean
67 readonly strategy: WorkerChoiceStrategy
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68 readonly minSize: number
69 readonly maxSize: number
aa9eede8 70 /** Pool utilization. */
4b628b48 71 readonly utilization?: number
01a59f3c 72 /** Pool total worker nodes. */
4b628b48 73 readonly workerNodes: number
01a59f3c 74 /** Pool idle worker nodes. */
4b628b48 75 readonly idleWorkerNodes: number
01a59f3c 76 /** Pool busy worker nodes. */
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77 readonly busyWorkerNodes: number
78 readonly executedTasks: number
79 readonly executingTasks: number
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80 readonly queuedTasks?: number
81 readonly maxQueuedTasks?: number
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82 readonly failedTasks: number
83 readonly runTime?: {
84 readonly minimum: number
85 readonly maximum: number
86 readonly average: number
87 readonly median?: number
1dcf8b7b 88 }
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89 readonly waitTime?: {
90 readonly minimum: number
91 readonly maximum: number
92 readonly average: number
93 readonly median?: number
1dcf8b7b 94 }
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95}
96
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97/**
98 * Worker tasks queue options.
99 */
100export interface TasksQueueOptions {
101 /**
102 * Maximum number of tasks that can be executed concurrently on a worker.
103 *
104 * @defaultValue 1
105 */
eb7bf744 106 readonly concurrency?: number
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107}
108
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109/**
110 * Options for a poolifier pool.
c319c66b 111 *
d480d708 112 * @typeParam Worker - Type of worker.
bdaf31cd 113 */
50e66724 114export interface PoolOptions<Worker extends IWorker> {
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115 /**
116 * A function that will listen for online event on each worker.
117 */
118 onlineHandler?: OnlineHandler<Worker>
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119 /**
120 * A function that will listen for message event on each worker.
121 */
122 messageHandler?: MessageHandler<Worker>
123 /**
124 * A function that will listen for error event on each worker.
125 */
126 errorHandler?: ErrorHandler<Worker>
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127 /**
128 * A function that will listen for exit event on each worker.
129 */
130 exitHandler?: ExitHandler<Worker>
131 /**
46e857ca 132 * The worker choice strategy to use in this pool.
d29bce7c 133 *
95ec6006 134 * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
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135 */
136 workerChoiceStrategy?: WorkerChoiceStrategy
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137 /**
138 * The worker choice strategy options.
139 */
140 workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
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141 /**
142 * Restart worker on error.
143 */
144 restartWorkerOnError?: boolean
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145 /**
146 * Pool events emission.
147 *
38e795c1 148 * @defaultValue true
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149 */
150 enableEvents?: boolean
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151 /**
152 * Pool worker tasks queue.
153 *
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154 * @defaultValue false
155 */
156 enableTasksQueue?: boolean
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157 /**
158 * Pool worker tasks queue options.
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159 */
160 tasksQueueOptions?: TasksQueueOptions
bdaf31cd 161}
a35560ba 162
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163/**
164 * Contract definition for a poolifier pool.
165 *
c4855468 166 * @typeParam Worker - Type of worker which manages this pool.
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167 * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
168 * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
729c563d 169 */
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170export interface IPool<
171 Worker extends IWorker,
172 Data = unknown,
173 Response = unknown
174> {
08f3f44c 175 /**
6b27d407 176 * Pool information.
08f3f44c 177 */
6b27d407 178 readonly info: PoolInfo
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179 /**
180 * Pool worker nodes.
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181 *
182 * @internal
c4855468 183 */
4b628b48 184 readonly workerNodes: Array<IWorkerNode<Worker, Data>>
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185 /**
186 * Whether the worker node has back pressure (i.e. its tasks queue is full).
187 *
188 * @param workerNodeKey - The worker node key.
189 * @returns `true` if the worker node has back pressure, `false` otherwise.
9768f49f 190 * @internal
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191 */
192 readonly hasWorkerNodeBackPressure: (workerNodeKey: number) => boolean
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193 /**
194 * Emitter on which events can be listened to.
195 *
196 * Events that can currently be listened to:
197 *
d5024c00 198 * - `'ready'`: Emitted when the number of workers created in the pool has reached the minimum size expected and are ready.
2431bdb4 199 * - `'busy'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are executing at least one task.
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200 * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
201 * - '`destroy`': Emitted when the pool is destroyed.
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202 * - `'error'`: Emitted when an uncaught error occurs.
203 * - `'taskError'`: Emitted when an error occurs while executing a task.
9e844245 204 * - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full).
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205 */
206 readonly emitter?: PoolEmitter
729c563d 207 /**
61aa11a6 208 * Executes the specified function in the worker constructor with the task data input parameter.
729c563d 209 *
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210 * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
211 * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
212 * @param transferList - An optional array of transferable objects to transfer ownership of. Ownership of the transferred objects is given to the pool's worker_threads worker and they should not be used in the main thread afterwards.
ef41a6e6 213 * @returns Promise that will be fulfilled when the task is completed.
729c563d 214 */
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215 readonly execute: (
216 data?: Data,
217 name?: string,
218 transferList?: TransferListItem[]
219 ) => Promise<Response>
280c2a77 220 /**
aa9eede8 221 * Terminates all workers in this pool.
280c2a77 222 */
4b628b48 223 readonly destroy: () => Promise<void>
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224 /**
225 * Lists the names of task function available in this pool.
226 *
227 * @returns The names of task function available in this pool.
228 */
229 readonly listTaskFunctions: () => string[]
a35560ba 230 /**
bdede008 231 * Sets the worker choice strategy in this pool.
a35560ba 232 *
38e795c1 233 * @param workerChoiceStrategy - The worker choice strategy.
59219cbb 234 * @param workerChoiceStrategyOptions - The worker choice strategy options.
a35560ba 235 */
4b628b48 236 readonly setWorkerChoiceStrategy: (
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237 workerChoiceStrategy: WorkerChoiceStrategy,
238 workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
239 ) => void
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240 /**
241 * Sets the worker choice strategy options in this pool.
242 *
243 * @param workerChoiceStrategyOptions - The worker choice strategy options.
244 */
4b628b48 245 readonly setWorkerChoiceStrategyOptions: (
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246 workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
247 ) => void
248 /**
249 * Enables/disables the worker tasks queue in this pool.
250 *
251 * @param enable - Whether to enable or disable the worker tasks queue.
252 * @param tasksQueueOptions - The worker tasks queue options.
253 */
4b628b48 254 readonly enableTasksQueue: (
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255 enable: boolean,
256 tasksQueueOptions?: TasksQueueOptions
257 ) => void
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258 /**
259 * Sets the worker tasks queue options in this pool.
260 *
261 * @param tasksQueueOptions - The worker tasks queue options.
262 */
4b628b48 263 readonly setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
c97c7edb 264}