1 import { AsyncResource
} from
'node:async_hooks'
2 import type { Worker
} from
'node:cluster'
3 import type { MessagePort
} from
'node:worker_threads'
4 import { performance
} from
'node:perf_hooks'
9 } from
'../utility-types'
10 import { EMPTY_FUNCTION
, isPlainObject
} from
'../utils'
15 } from
'./worker-options'
21 } from
'./worker-functions'
23 const DEFAULT_FUNCTION_NAME
= 'default'
24 const DEFAULT_MAX_INACTIVE_TIME
= 60000
25 const DEFAULT_KILL_BEHAVIOR
: KillBehavior
= KillBehaviors
.SOFT
28 * Base class that implements some shared logic for all poolifier workers.
30 * @typeParam MainWorker - Type of main worker.
31 * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
32 * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
34 export abstract class AbstractWorker
<
35 MainWorker
extends Worker
| MessagePort
,
38 > extends AsyncResource
{
42 protected abstract id
: number
44 * Task function(s) processed by the worker when the pool's `execution` function is invoked.
46 protected taskFunctions
!: Map
<string, WorkerFunction
<Data
, Response
>>
48 * Timestamp of the last task processed by this worker.
50 protected lastTaskTimestamp
!: number
52 * Performance statistics computation requirements.
54 protected statistics
!: WorkerStatistics
56 * Handler id of the `aliveInterval` worker alive check.
58 protected readonly aliveInterval
?: NodeJS
.Timeout
60 * Constructs a new poolifier worker.
62 * @param type - The type of async event.
63 * @param isMain - Whether this is the main worker or not.
64 * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
65 * @param mainWorker - Reference to main worker.
66 * @param opts - Options for the worker.
70 protected readonly isMain
: boolean,
72 | WorkerFunction
<Data
, Response
>
73 | TaskFunctions
<Data
, Response
>,
74 protected readonly mainWorker
: MainWorker
,
75 protected readonly opts
: WorkerOptions
= {
77 * The kill behavior option on this worker or its default value.
79 killBehavior
: DEFAULT_KILL_BEHAVIOR
,
81 * The maximum time to keep this worker alive while idle.
82 * The pool automatically checks and terminates this worker when the time expires.
84 maxInactiveTime
: DEFAULT_MAX_INACTIVE_TIME
88 this.checkWorkerOptions(this.opts
)
89 this.checkTaskFunctions(taskFunctions
)
91 this.lastTaskTimestamp
= performance
.now()
92 this.aliveInterval
= setInterval(
93 this.checkAlive
.bind(this),
94 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
) / 2
96 this.checkAlive
.bind(this)()
97 this.mainWorker
?.on('message', this.messageListener
.bind(this))
101 private checkWorkerOptions (opts
: WorkerOptions
): void {
102 this.opts
.killBehavior
= opts
.killBehavior
?? DEFAULT_KILL_BEHAVIOR
103 this.opts
.maxInactiveTime
=
104 opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
105 delete this.opts
.async
109 * Checks if the `taskFunctions` parameter is passed to the constructor.
111 * @param taskFunctions - The task function(s) parameter that should be checked.
113 private checkTaskFunctions (
115 | WorkerFunction
<Data
, Response
>
116 | TaskFunctions
<Data
, Response
>
118 if (taskFunctions
== null) {
119 throw new Error('taskFunctions parameter is mandatory')
121 this.taskFunctions
= new Map
<string, WorkerFunction
<Data
, Response
>>()
122 if (typeof taskFunctions
=== 'function') {
123 this.taskFunctions
.set(DEFAULT_FUNCTION_NAME
, taskFunctions
.bind(this))
124 } else if (isPlainObject(taskFunctions
)) {
125 let firstEntry
= true
126 for (const [name
, fn
] of Object.entries(taskFunctions
)) {
127 if (typeof fn
!== 'function') {
129 'A taskFunctions parameter object value is not a function'
132 this.taskFunctions
.set(name
, fn
.bind(this))
134 this.taskFunctions
.set(DEFAULT_FUNCTION_NAME
, fn
.bind(this))
139 throw new Error('taskFunctions parameter object is empty')
143 'taskFunctions parameter is not a function or a plain object'
149 * Worker message listener.
151 * @param message - Message received.
153 protected messageListener (message
: MessageValue
<Data
, Data
>): void {
154 if (message
.id
!= null && message
.data
!= null) {
155 // Task message received
156 const fn
= this.getTaskFunction(message
.name
)
157 if (fn
?.constructor
.name
=== 'AsyncFunction') {
158 this.runInAsyncScope(this.runAsync
.bind(this), this, fn
, message
)
160 this.runInAsyncScope(this.runSync
.bind(this), this, fn
, message
)
162 } else if (message
.statistics
!= null) {
163 // Statistics message received
164 this.statistics
= message
.statistics
165 } else if (message
.kill
!= null) {
166 // Kill message received
167 this.aliveInterval
!= null && clearInterval(this.aliveInterval
)
173 * Returns the main worker.
175 * @returns Reference to the main worker.
177 protected getMainWorker (): MainWorker
{
178 if (this.mainWorker
== null) {
179 throw new Error('Main worker not set')
181 return this.mainWorker
185 * Sends a message to the main worker.
187 * @param message - The response message.
189 protected abstract sendToMainWorker (
190 message
: MessageValue
<Response
, Data
>
194 * Checks if the worker should be terminated, because its living too long.
196 protected checkAlive (): void {
198 performance
.now() - this.lastTaskTimestamp
>
199 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
)
201 this.sendToMainWorker({ kill
: this.opts
.killBehavior
})
206 * Handles an error and convert it to a string so it can be sent back to the main worker.
208 * @param e - The error raised by the worker.
209 * @returns Message of the error.
211 protected handleError (e
: Error | string): string {
216 * Runs the given function synchronously.
218 * @param fn - Function that will be executed.
219 * @param message - Input data for the given function.
222 fn
: WorkerSyncFunction
<Data
, Response
>,
223 message
: MessageValue
<Data
>
226 let taskPerformance
= this.beginTaskPerformance()
227 const res
= fn(message
.data
)
228 taskPerformance
= this.endTaskPerformance(taskPerformance
)
229 this.sendToMainWorker({
236 const err
= this.handleError(e
as Error)
237 this.sendToMainWorker({
246 !this.isMain
&& (this.lastTaskTimestamp
= performance
.now())
251 * Runs the given function asynchronously.
253 * @param fn - Function that will be executed.
254 * @param message - Input data for the given function.
257 fn
: WorkerAsyncFunction
<Data
, Response
>,
258 message
: MessageValue
<Data
>
260 let taskPerformance
= this.beginTaskPerformance()
263 taskPerformance
= this.endTaskPerformance(taskPerformance
)
264 this.sendToMainWorker({
273 const err
= this.handleError(e
as Error)
274 this.sendToMainWorker({
284 !this.isMain
&& (this.lastTaskTimestamp
= performance
.now())
286 .catch(EMPTY_FUNCTION
)
290 * Gets the task function in the given scope.
292 * @param name - Name of the function that will be returned.
294 private getTaskFunction (name
?: string): WorkerFunction
<Data
, Response
> {
295 name
= name
?? DEFAULT_FUNCTION_NAME
296 const fn
= this.taskFunctions
.get(name
)
298 throw new Error(`Task function '${name}' not found`)
303 private beginTaskPerformance (): TaskPerformance
{
304 this.checkStatistics()
306 timestamp
: performance
.now(),
307 ...(this.statistics
.elu
&& { elu
: performance
.eventLoopUtilization() })
311 private endTaskPerformance (
312 taskPerformance
: TaskPerformance
314 this.checkStatistics()
317 ...(this.statistics
.runTime
&& {
318 runTime
: performance
.now() - taskPerformance
.timestamp
320 ...(this.statistics
.elu
&& {
321 elu
: performance
.eventLoopUtilization(taskPerformance
.elu
)
326 private checkStatistics (): void {
327 if (this.statistics
== null) {
328 throw new Error('Performance statistics computation requirements not set')