Merge branch 'master' of github.com:jerome-benoit/poolifier
[poolifier.git] / src / pools / pool.ts
1 import { EventEmitter } from 'node:events'
2 import { type TransferListItem } from 'node:worker_threads'
3 import type {
4 ErrorHandler,
5 ExitHandler,
6 IWorker,
7 IWorkerNode,
8 MessageHandler,
9 OnlineHandler,
10 WorkerType
11 } from './worker'
12 import type {
13 WorkerChoiceStrategy,
14 WorkerChoiceStrategyOptions
15 } from './selection-strategies/selection-strategies-types'
16
17 /**
18 * Enumeration of pool types.
19 */
20 export const PoolTypes = Object.freeze({
21 /**
22 * Fixed pool type.
23 */
24 fixed: 'fixed',
25 /**
26 * Dynamic pool type.
27 */
28 dynamic: 'dynamic'
29 } as const)
30
31 /**
32 * Pool type.
33 */
34 export type PoolType = keyof typeof PoolTypes
35
36 /**
37 * Pool events emitter.
38 */
39 export class PoolEmitter extends EventEmitter {}
40
41 /**
42 * Enumeration of pool events.
43 */
44 export const PoolEvents = Object.freeze({
45 ready: 'ready',
46 busy: 'busy',
47 full: 'full',
48 destroy: 'destroy',
49 error: 'error',
50 taskError: 'taskError',
51 backPressure: 'backPressure'
52 } as const)
53
54 /**
55 * Pool event.
56 */
57 export type PoolEvent = keyof typeof PoolEvents
58
59 /**
60 * Pool information.
61 */
62 export interface PoolInfo {
63 readonly version: string
64 readonly type: PoolType
65 readonly worker: WorkerType
66 readonly ready: boolean
67 readonly strategy: WorkerChoiceStrategy
68 readonly minSize: number
69 readonly maxSize: number
70 /** Pool utilization. */
71 readonly utilization?: number
72 /** Pool total worker nodes. */
73 readonly workerNodes: number
74 /** Pool idle worker nodes. */
75 readonly idleWorkerNodes: number
76 /** Pool busy worker nodes. */
77 readonly busyWorkerNodes: number
78 readonly executedTasks: number
79 readonly executingTasks: number
80 readonly queuedTasks?: number
81 readonly maxQueuedTasks?: number
82 readonly backPressure?: boolean
83 readonly stolenTasks?: number
84 readonly failedTasks: number
85 readonly runTime?: {
86 readonly minimum: number
87 readonly maximum: number
88 readonly average?: number
89 readonly median?: number
90 }
91 readonly waitTime?: {
92 readonly minimum: number
93 readonly maximum: number
94 readonly average?: number
95 readonly median?: number
96 }
97 }
98
99 /**
100 * Worker node tasks queue options.
101 */
102 export interface TasksQueueOptions {
103 /**
104 * Maximum tasks queue size per worker node flagging it as back pressured.
105 *
106 * @defaultValue (pool maximum size)^2
107 */
108 readonly size?: number
109 /**
110 * @deprecated Use `size` instead.
111 */
112 readonly queueMaxSize?: number
113 /**
114 * Maximum number of tasks that can be executed concurrently on a worker node.
115 *
116 * @defaultValue 1
117 */
118 readonly concurrency?: number
119 }
120
121 /**
122 * Options for a poolifier pool.
123 *
124 * @typeParam Worker - Type of worker.
125 */
126 export interface PoolOptions<Worker extends IWorker> {
127 /**
128 * A function that will listen for online event on each worker.
129 */
130 onlineHandler?: OnlineHandler<Worker>
131 /**
132 * A function that will listen for message event on each worker.
133 */
134 messageHandler?: MessageHandler<Worker>
135 /**
136 * A function that will listen for error event on each worker.
137 */
138 errorHandler?: ErrorHandler<Worker>
139 /**
140 * A function that will listen for exit event on each worker.
141 */
142 exitHandler?: ExitHandler<Worker>
143 /**
144 * The worker choice strategy to use in this pool.
145 *
146 * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
147 */
148 workerChoiceStrategy?: WorkerChoiceStrategy
149 /**
150 * The worker choice strategy options.
151 */
152 workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
153 /**
154 * Restart worker on error.
155 */
156 restartWorkerOnError?: boolean
157 /**
158 * Pool events emission.
159 *
160 * @defaultValue true
161 */
162 enableEvents?: boolean
163 /**
164 * Pool worker node tasks queue.
165 *
166 * @defaultValue false
167 */
168 enableTasksQueue?: boolean
169 /**
170 * Pool worker node tasks queue options.
171 */
172 tasksQueueOptions?: TasksQueueOptions
173 }
174
175 /**
176 * Contract definition for a poolifier pool.
177 *
178 * @typeParam Worker - Type of worker which manages this pool.
179 * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
180 * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
181 */
182 export interface IPool<
183 Worker extends IWorker,
184 Data = unknown,
185 Response = unknown
186 > {
187 /**
188 * Pool information.
189 */
190 readonly info: PoolInfo
191 /**
192 * Pool worker nodes.
193 *
194 * @internal
195 */
196 readonly workerNodes: Array<IWorkerNode<Worker, Data>>
197 /**
198 * Whether the worker node has back pressure (i.e. its tasks queue is full).
199 *
200 * @param workerNodeKey - The worker node key.
201 * @returns `true` if the worker node has back pressure, `false` otherwise.
202 * @internal
203 */
204 readonly hasWorkerNodeBackPressure: (workerNodeKey: number) => boolean
205 /**
206 * Emitter on which events can be listened to.
207 *
208 * Events that can currently be listened to:
209 *
210 * - `'ready'`: Emitted when the number of workers created in the pool has reached the minimum size expected and are ready.
211 * - `'busy'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are executing concurrently their tasks quota.
212 * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
213 * - `'destroy'`: Emitted when the pool is destroyed.
214 * - `'error'`: Emitted when an uncaught error occurs.
215 * - `'taskError'`: Emitted when an error occurs while executing a task.
216 * - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size \>= maximum queue size).
217 */
218 readonly emitter?: PoolEmitter
219 /**
220 * Executes the specified function in the worker constructor with the task data input parameter.
221 *
222 * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
223 * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
224 * @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.
225 * @returns Promise that will be fulfilled when the task is completed.
226 */
227 readonly execute: (
228 data?: Data,
229 name?: string,
230 transferList?: TransferListItem[]
231 ) => Promise<Response>
232 /**
233 * Terminates all workers in this pool.
234 */
235 readonly destroy: () => Promise<void>
236 /**
237 * Lists the names of task function available in this pool.
238 *
239 * @returns The names of task function available in this pool.
240 */
241 readonly listTaskFunctions: () => string[]
242 /**
243 * Sets the worker choice strategy in this pool.
244 *
245 * @param workerChoiceStrategy - The worker choice strategy.
246 * @param workerChoiceStrategyOptions - The worker choice strategy options.
247 */
248 readonly setWorkerChoiceStrategy: (
249 workerChoiceStrategy: WorkerChoiceStrategy,
250 workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
251 ) => void
252 /**
253 * Sets the worker choice strategy options in this pool.
254 *
255 * @param workerChoiceStrategyOptions - The worker choice strategy options.
256 */
257 readonly setWorkerChoiceStrategyOptions: (
258 workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
259 ) => void
260 /**
261 * Enables/disables the worker node tasks queue in this pool.
262 *
263 * @param enable - Whether to enable or disable the worker node tasks queue.
264 * @param tasksQueueOptions - The worker node tasks queue options.
265 */
266 readonly enableTasksQueue: (
267 enable: boolean,
268 tasksQueueOptions?: TasksQueueOptions
269 ) => void
270 /**
271 * Sets the worker node tasks queue options in this pool.
272 *
273 * @param tasksQueueOptions - The worker node tasks queue options.
274 */
275 readonly setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
276 }