1 import { EventEmitter
} from
'node:events'
2 import { type TransferListItem
} from
'node:worker_threads'
14 WorkerChoiceStrategyOptions
15 } from
'./selection-strategies/selection-strategies-types'
18 * Enumeration of pool types.
20 export const PoolTypes
= Object.freeze({
34 export type PoolType
= keyof
typeof PoolTypes
37 * Pool events emitter.
39 export class PoolEmitter
extends EventEmitter
{}
42 * Enumeration of pool events.
44 export const PoolEvents
= Object.freeze({
50 taskError
: 'taskError',
51 backPressure
: 'backPressure'
57 export type PoolEvent
= keyof
typeof PoolEvents
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 failedTasks
: number
85 readonly minimum
: number
86 readonly maximum
: number
87 readonly average
: number
88 readonly median
?: number
91 readonly minimum
: number
92 readonly maximum
: number
93 readonly average
: number
94 readonly median
?: number
99 * Worker node tasks queue options.
101 export interface TasksQueueOptions
{
103 * Maximum tasks queue size per worker node flagging it as back pressured.
105 * @defaultValue (pool maximum size)^2
107 readonly size
?: number
109 * @deprecated Use `size` instead.
111 readonly queueMaxSize
?: number
113 * Maximum number of tasks that can be executed concurrently on a worker node.
117 readonly concurrency
?: number
121 * Options for a poolifier pool.
123 * @typeParam Worker - Type of worker.
125 export interface PoolOptions
<Worker
extends IWorker
> {
127 * A function that will listen for online event on each worker.
129 onlineHandler
?: OnlineHandler
<Worker
>
131 * A function that will listen for message event on each worker.
133 messageHandler
?: MessageHandler
<Worker
>
135 * A function that will listen for error event on each worker.
137 errorHandler
?: ErrorHandler
<Worker
>
139 * A function that will listen for exit event on each worker.
141 exitHandler
?: ExitHandler
<Worker
>
143 * The worker choice strategy to use in this pool.
145 * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
147 workerChoiceStrategy
?: WorkerChoiceStrategy
149 * The worker choice strategy options.
151 workerChoiceStrategyOptions
?: WorkerChoiceStrategyOptions
153 * Restart worker on error.
155 restartWorkerOnError
?: boolean
157 * Pool events emission.
161 enableEvents
?: boolean
163 * Pool worker node tasks queue.
165 * @defaultValue false
167 enableTasksQueue
?: boolean
169 * Pool worker node tasks queue options.
171 tasksQueueOptions
?: TasksQueueOptions
175 * Contract definition for a poolifier pool.
177 * @typeParam Worker - Type of worker which manages this pool.
178 * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
179 * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
181 export interface IPool
<
182 Worker
extends IWorker
,
189 readonly info
: PoolInfo
195 readonly workerNodes
: Array<IWorkerNode
<Worker
, Data
>>
197 * Whether the worker node has back pressure (i.e. its tasks queue is full).
199 * @param workerNodeKey - The worker node key.
200 * @returns `true` if the worker node has back pressure, `false` otherwise.
203 readonly hasWorkerNodeBackPressure
: (workerNodeKey
: number) => boolean
205 * Emitter on which events can be listened to.
207 * Events that can currently be listened to:
209 * - `'ready'`: Emitted when the number of workers created in the pool has reached the minimum size expected and are ready.
210 * - `'busy'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are executing at least one task.
211 * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
212 * - '`destroy`': Emitted when the pool is destroyed.
213 * - `'error'`: Emitted when an uncaught error occurs.
214 * - `'taskError'`: Emitted when an error occurs while executing a task.
215 * - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size \>= maximum queue size).
217 readonly emitter
?: PoolEmitter
219 * Executes the specified function in the worker constructor with the task data input parameter.
221 * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
222 * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
223 * @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.
224 * @returns Promise that will be fulfilled when the task is completed.
229 transferList
?: TransferListItem
[]
230 ) => Promise
<Response
>
232 * Terminates all workers in this pool.
234 readonly destroy
: () => Promise
<void>
236 * Lists the names of task function available in this pool.
238 * @returns The names of task function available in this pool.
240 readonly listTaskFunctions
: () => string[]
242 * Sets the worker choice strategy in this pool.
244 * @param workerChoiceStrategy - The worker choice strategy.
245 * @param workerChoiceStrategyOptions - The worker choice strategy options.
247 readonly setWorkerChoiceStrategy
: (
248 workerChoiceStrategy
: WorkerChoiceStrategy
,
249 workerChoiceStrategyOptions
?: WorkerChoiceStrategyOptions
252 * Sets the worker choice strategy options in this pool.
254 * @param workerChoiceStrategyOptions - The worker choice strategy options.
256 readonly setWorkerChoiceStrategyOptions
: (
257 workerChoiceStrategyOptions
: WorkerChoiceStrategyOptions
260 * Enables/disables the worker node tasks queue in this pool.
262 * @param enable - Whether to enable or disable the worker node tasks queue.
263 * @param tasksQueueOptions - The worker node tasks queue options.
265 readonly enableTasksQueue
: (
267 tasksQueueOptions
?: TasksQueueOptions
270 * Sets the worker node tasks queue options in this pool.
272 * @param tasksQueueOptions - The worker node tasks queue options.
274 readonly setTasksQueueOptions
: (tasksQueueOptions
: TasksQueueOptions
) => void