1 import { EventEmitter
} from
'node:events'
2 import { type TransferListItem
} from
'node:worker_threads'
3 import type { TaskFunction
} from
'../worker/task-functions'
15 WorkerChoiceStrategyOptions
16 } from
'./selection-strategies/selection-strategies-types'
19 * Enumeration of pool types.
21 export const PoolTypes
= Object.freeze({
35 export type PoolType
= keyof
typeof PoolTypes
38 * Pool events emitter.
40 export class PoolEmitter
extends EventEmitter
{}
43 * Enumeration of pool events.
45 export const PoolEvents
= Object.freeze({
51 taskError
: 'taskError',
52 backPressure
: 'backPressure'
58 export type PoolEvent
= keyof
typeof PoolEvents
63 export interface PoolInfo
{
64 readonly version
: string
65 readonly type: PoolType
66 readonly worker
: WorkerType
67 readonly started
: boolean
68 readonly ready
: boolean
69 readonly strategy
: WorkerChoiceStrategy
70 readonly minSize
: number
71 readonly maxSize
: number
72 /** Pool utilization. */
73 readonly utilization
?: number
74 /** Pool total worker nodes. */
75 readonly workerNodes
: number
76 /** Pool idle worker nodes. */
77 readonly idleWorkerNodes
: number
78 /** Pool busy worker nodes. */
79 readonly busyWorkerNodes
: number
80 readonly executedTasks
: number
81 readonly executingTasks
: number
82 readonly queuedTasks
?: number
83 readonly maxQueuedTasks
?: number
84 readonly backPressure
?: boolean
85 readonly stolenTasks
?: number
86 readonly failedTasks
: number
88 readonly minimum
: number
89 readonly maximum
: number
90 readonly average
?: number
91 readonly median
?: number
94 readonly minimum
: number
95 readonly maximum
: number
96 readonly average
?: number
97 readonly median
?: number
102 * Worker node tasks queue options.
104 export interface TasksQueueOptions
{
106 * Maximum tasks queue size per worker node flagging it as back pressured.
108 * @defaultValue (pool maximum size)^2
110 readonly size
?: number
112 * Maximum number of tasks that can be executed concurrently on a worker node.
116 readonly concurrency
?: number
118 * Whether to enable task stealing.
122 readonly taskStealing
?: boolean
124 * Whether to enable tasks stealing on back pressure.
128 readonly tasksStealingOnBackPressure
?: boolean
132 * Options for a poolifier pool.
134 * @typeParam Worker - Type of worker.
136 export interface PoolOptions
<Worker
extends IWorker
> {
138 * A function that will listen for online event on each worker.
140 onlineHandler
?: OnlineHandler
<Worker
>
142 * A function that will listen for message event on each worker.
144 messageHandler
?: MessageHandler
<Worker
>
146 * A function that will listen for error event on each worker.
148 errorHandler
?: ErrorHandler
<Worker
>
150 * A function that will listen for exit event on each worker.
152 exitHandler
?: ExitHandler
<Worker
>
154 * Whether to start the minimum number of workers at pool initialization.
158 startWorkers
?: boolean
160 * The worker choice strategy to use in this pool.
162 * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
164 workerChoiceStrategy
?: WorkerChoiceStrategy
166 * The worker choice strategy options.
168 workerChoiceStrategyOptions
?: WorkerChoiceStrategyOptions
170 * Restart worker on error.
172 restartWorkerOnError
?: boolean
174 * Pool events emission.
178 enableEvents
?: boolean
180 * Pool worker node tasks queue.
182 * @defaultValue false
184 enableTasksQueue
?: boolean
186 * Pool worker node tasks queue options.
188 tasksQueueOptions
?: TasksQueueOptions
192 * Contract definition for a poolifier pool.
194 * @typeParam Worker - Type of worker which manages this pool.
195 * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
196 * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
198 export interface IPool
<
199 Worker
extends IWorker
,
206 readonly info
: PoolInfo
212 readonly workerNodes
: Array<IWorkerNode
<Worker
, Data
>>
214 * Whether the worker node has back pressure (i.e. its tasks queue is full).
216 * @param workerNodeKey - The worker node key.
217 * @returns `true` if the worker node has back pressure, `false` otherwise.
220 readonly hasWorkerNodeBackPressure
: (workerNodeKey
: number) => boolean
222 * Emitter on which events can be listened to.
224 * Events that can currently be listened to:
226 * - `'ready'`: Emitted when the number of workers created in the pool has reached the minimum size expected and are ready.
227 * - `'busy'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are executing concurrently their tasks quota.
228 * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
229 * - `'destroy'`: Emitted when the pool is destroyed.
230 * - `'error'`: Emitted when an uncaught error occurs.
231 * - `'taskError'`: Emitted when an error occurs while executing a task.
232 * - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size \>= maximum queue size).
234 readonly emitter
?: PoolEmitter
236 * Executes the specified function in the worker constructor with the task data input parameter.
238 * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
239 * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
240 * @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.
241 * @returns Promise that will be fulfilled when the task is completed.
246 transferList
?: TransferListItem
[]
247 ) => Promise
<Response
>
249 * Starts the minimum number of workers in this pool.
251 readonly start
: () => void
253 * Terminates all workers in this pool.
255 readonly destroy
: () => Promise
<void>
257 * Whether the specified task function exists in this pool.
259 * @param name - The name of the task function.
260 * @returns `true` if the task function exists, `false` otherwise.
262 readonly hasTaskFunction
: (name
: string) => boolean
264 * Adds a task function to this pool.
265 * If a task function with the same name already exists, it will be overwritten.
267 * @param name - The name of the task function.
268 * @param taskFunction - The task function.
269 * @returns `true` if the task function was added, `false` otherwise.
271 readonly addTaskFunction
: (
273 taskFunction
: TaskFunction
<Data
, Response
>
274 ) => Promise
<boolean>
276 * Removes a task function from this pool.
278 * @param name - The name of the task function.
279 * @returns `true` if the task function was removed, `false` otherwise.
281 readonly removeTaskFunction
: (name
: string) => Promise
<boolean>
283 * Lists the names of task function available in this pool.
285 * @returns The names of task function available in this pool.
287 readonly listTaskFunctionNames
: () => string[]
289 * Sets the default task function in this pool.
291 * @param name - The name of the task function.
292 * @returns `true` if the default task function was set, `false` otherwise.
294 readonly setDefaultTaskFunction
: (name
: string) => Promise
<boolean>
296 * Sets the worker choice strategy in this pool.
298 * @param workerChoiceStrategy - The worker choice strategy.
299 * @param workerChoiceStrategyOptions - The worker choice strategy options.
301 readonly setWorkerChoiceStrategy
: (
302 workerChoiceStrategy
: WorkerChoiceStrategy
,
303 workerChoiceStrategyOptions
?: WorkerChoiceStrategyOptions
306 * Sets the worker choice strategy options in this pool.
308 * @param workerChoiceStrategyOptions - The worker choice strategy options.
310 readonly setWorkerChoiceStrategyOptions
: (
311 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
314 * Enables/disables the worker node tasks queue in this pool.
316 * @param enable - Whether to enable or disable the worker node tasks queue.
317 * @param tasksQueueOptions - The worker node tasks queue options.
319 readonly enableTasksQueue
: (
321 tasksQueueOptions
?: TasksQueueOptions
324 * Sets the worker node tasks queue options in this pool.
326 * @param tasksQueueOptions - The worker node tasks queue options.
328 readonly setTasksQueueOptions
: (tasksQueueOptions
: TasksQueueOptions
) => void