1 import { AsyncResource
} from
'node:async_hooks'
2 import type { MessagePort
} from
'node:worker_threads'
3 import { performance
} from
'node:perf_hooks'
8 } from
'../utility-types'
9 import { EMPTY_FUNCTION
, isPlainObject
} from
'../utils'
14 } from
'./worker-options'
20 } from
'./worker-functions'
22 const DEFAULT_FUNCTION_NAME
= 'default'
23 const DEFAULT_MAX_INACTIVE_TIME
= 60000
24 const DEFAULT_KILL_BEHAVIOR
: KillBehavior
= KillBehaviors
.SOFT
27 * Base class that implements some shared logic for all poolifier workers.
29 * @typeParam MainWorker - Type of main worker.
30 * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
31 * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
33 export abstract class AbstractWorker
<
34 MainWorker
extends NodeJS
.Process
| MessagePort
,
37 > extends AsyncResource
{
39 * Task function(s) processed by the worker when the pool's `execution` function is invoked.
41 protected taskFunctions
!: Map
<string, WorkerFunction
<Data
, Response
>>
43 * Timestamp of the last task processed by this worker.
45 protected lastTaskTimestamp
!: number
47 * Performance statistics computation requirements.
49 protected statistics
!: WorkerStatistics
51 * Handler id of the `aliveInterval` worker alive check.
53 protected readonly aliveInterval
?: NodeJS
.Timeout
55 * Constructs a new poolifier worker.
57 * @param type - The type of async event.
58 * @param isMain - Whether this is the main worker or not.
59 * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
60 * @param mainWorker - Reference to main worker.
61 * @param opts - Options for the worker.
65 protected readonly isMain
: boolean,
67 | WorkerFunction
<Data
, Response
>
68 | TaskFunctions
<Data
, Response
>,
69 protected mainWorker
: MainWorker
,
70 protected readonly opts
: WorkerOptions
= {
72 * The kill behavior option on this worker or its default value.
74 killBehavior
: DEFAULT_KILL_BEHAVIOR
,
76 * The maximum time to keep this worker alive while idle.
77 * The pool automatically checks and terminates this worker when the time expires.
79 maxInactiveTime
: DEFAULT_MAX_INACTIVE_TIME
83 this.checkWorkerOptions(this.opts
)
84 this.checkTaskFunctions(taskFunctions
)
86 this.lastTaskTimestamp
= performance
.now()
87 this.aliveInterval
= setInterval(
88 this.checkAlive
.bind(this),
89 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
) / 2
91 this.checkAlive
.bind(this)()
93 this.mainWorker
?.on('message', this.messageListener
.bind(this))
96 private checkWorkerOptions (opts
: WorkerOptions
): void {
97 this.opts
.killBehavior
= opts
.killBehavior
?? DEFAULT_KILL_BEHAVIOR
98 this.opts
.maxInactiveTime
=
99 opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
100 delete this.opts
.async
104 * Checks if the `taskFunctions` parameter is passed to the constructor.
106 * @param taskFunctions - The task function(s) parameter that should be checked.
108 private checkTaskFunctions (
110 | WorkerFunction
<Data
, Response
>
111 | TaskFunctions
<Data
, Response
>
113 if (taskFunctions
== null) {
114 throw new Error('taskFunctions parameter is mandatory')
116 this.taskFunctions
= new Map
<string, WorkerFunction
<Data
, Response
>>()
117 if (typeof taskFunctions
=== 'function') {
118 this.taskFunctions
.set(DEFAULT_FUNCTION_NAME
, taskFunctions
.bind(this))
119 } else if (isPlainObject(taskFunctions
)) {
120 let firstEntry
= true
121 for (const [name
, fn
] of Object.entries(taskFunctions
)) {
122 if (typeof fn
!== 'function') {
124 'A taskFunctions parameter object value is not a function'
127 this.taskFunctions
.set(name
, fn
.bind(this))
129 this.taskFunctions
.set(DEFAULT_FUNCTION_NAME
, fn
.bind(this))
134 throw new Error('taskFunctions parameter object is empty')
138 'taskFunctions parameter is not a function or a plain object'
144 * Worker message listener.
146 * @param message - Message received.
148 protected messageListener (
149 message
: MessageValue
<Data
, Data
, MainWorker
>
151 if (message
.id
!= null && message
.data
!= null) {
152 // Task message received
153 const fn
= this.getTaskFunction(message
.name
)
154 if (fn
?.constructor
.name
=== 'AsyncFunction') {
155 this.runInAsyncScope(this.runAsync
.bind(this), this, fn
, message
)
157 this.runInAsyncScope(this.runSync
.bind(this), this, fn
, message
)
159 } else if (message
.parent != null) {
160 // Main worker reference message received
161 this.mainWorker
= message
.parent
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({
235 const err
= this.handleError(e
as Error)
236 this.sendToMainWorker({
244 !this.isMain
&& (this.lastTaskTimestamp
= performance
.now())
249 * Runs the given function asynchronously.
251 * @param fn - Function that will be executed.
252 * @param message - Input data for the given function.
255 fn
: WorkerAsyncFunction
<Data
, Response
>,
256 message
: MessageValue
<Data
>
258 let taskPerformance
= this.beginTaskPerformance()
261 taskPerformance
= this.endTaskPerformance(taskPerformance
)
262 this.sendToMainWorker({
270 const err
= this.handleError(e
as Error)
271 this.sendToMainWorker({
280 !this.isMain
&& (this.lastTaskTimestamp
= performance
.now())
282 .catch(EMPTY_FUNCTION
)
286 * Gets the task function in the given scope.
288 * @param name - Name of the function that will be returned.
290 private getTaskFunction (name
?: string): WorkerFunction
<Data
, Response
> {
291 name
= name
?? DEFAULT_FUNCTION_NAME
292 const fn
= this.taskFunctions
.get(name
)
294 throw new Error(`Task function '${name}' not found`)
299 private beginTaskPerformance (): TaskPerformance
{
300 this.checkStatistics()
302 timestamp
: performance
.now(),
303 ...(this.statistics
.elu
&& { elu
: performance
.eventLoopUtilization() })
307 private endTaskPerformance (
308 taskPerformance
: TaskPerformance
310 this.checkStatistics()
313 ...(this.statistics
.runTime
&& {
314 runTime
: performance
.now() - taskPerformance
.timestamp
316 ...(this.statistics
.elu
&& {
317 elu
: performance
.eventLoopUtilization(taskPerformance
.elu
)
322 private checkStatistics (): void {
323 if (this.statistics
== null) {
324 throw new Error('Performance statistics computation requirements not set')