src/pools/pool.ts

   1 import type { ClusterSettings } from 'node:cluster'
   2 import type { EventEmitterAsyncResource } from 'node:events'
   3 import type { TransferListItem, WorkerOptions } from 'node:worker_threads'
   4
   5 import type { TaskFunctionProperties } from '../utility-types.js'
   6 import type {
   7   TaskFunction,
   8   TaskFunctionObject
   9 } from '../worker/task-functions.js'
  10 import type {
  11   WorkerChoiceStrategy,
  12   WorkerChoiceStrategyOptions
  13 } from './selection-strategies/selection-strategies-types.js'
  14 import type {
  15   ErrorHandler,
  16   ExitHandler,
  17   IWorker,
  18   IWorkerNode,
  19   MessageHandler,
  20   OnlineHandler,
  21   WorkerType
  22 } from './worker.js'
  23
  24 /**
  25  * Enumeration of pool types.
  26  */
  27 export const PoolTypes: Readonly<{
  28   fixed: 'fixed'
  29   dynamic: 'dynamic'
  30 }> = Object.freeze({
  31   /**
  32    * Fixed pool type.
  33    */
  34   fixed: 'fixed',
  35   /**
  36    * Dynamic pool type.
  37    */
  38   dynamic: 'dynamic'
  39 } as const)
  40
  41 /**
  42  * Pool type.
  43  */
  44 export type PoolType = keyof typeof PoolTypes
  45
  46 /**
  47  * Enumeration of pool events.
  48  */
  49 export const PoolEvents: Readonly<{
  50   ready: 'ready'
  51   busy: 'busy'
  52   full: 'full'
  53   empty: 'empty'
  54   destroy: 'destroy'
  55   error: 'error'
  56   taskError: 'taskError'
  57   backPressure: 'backPressure'
  58 }> = Object.freeze({
  59   ready: 'ready',
  60   busy: 'busy',
  61   full: 'full',
  62   empty: 'empty',
  63   destroy: 'destroy',
  64   error: 'error',
  65   taskError: 'taskError',
  66   backPressure: 'backPressure'
  67 } as const)
  68
  69 /**
  70  * Pool event.
  71  */
  72 export type PoolEvent = keyof typeof PoolEvents
  73
  74 /**
  75  * Pool information.
  76  */
  77 export interface PoolInfo {
  78   readonly version: string
  79   readonly type: PoolType
  80   readonly worker: WorkerType
  81   readonly started: boolean
  82   readonly ready: boolean
  83   readonly defaultStrategy: WorkerChoiceStrategy
  84   readonly strategyRetries: number
  85   readonly minSize: number
  86   readonly maxSize: number
  87   /** Pool utilization. */
  88   readonly utilization?: number
  89   /** Pool total worker nodes. */
  90   readonly workerNodes: number
  91   /** Pool stealing worker nodes. */
  92   readonly stealingWorkerNodes?: number
  93   /** Pool idle worker nodes. */
  94   readonly idleWorkerNodes: number
  95   /** Pool busy worker nodes. */
  96   readonly busyWorkerNodes: number
  97   readonly executedTasks: number
  98   readonly executingTasks: number
  99   readonly queuedTasks?: number
 100   readonly maxQueuedTasks?: number
 101   readonly backPressure?: boolean
 102   readonly stolenTasks?: number
 103   readonly failedTasks: number
 104   readonly runTime?: {
 105     readonly minimum: number
 106     readonly maximum: number
 107     readonly average?: number
 108     readonly median?: number
 109   }
 110   readonly waitTime?: {
 111     readonly minimum: number
 112     readonly maximum: number
 113     readonly average?: number
 114     readonly median?: number
 115   }
 116   readonly elu?: {
 117     idle: {
 118       readonly minimum: number
 119       readonly maximum: number
 120       readonly average?: number
 121       readonly median?: number
 122     }
 123     active: {
 124       readonly minimum: number
 125       readonly maximum: number
 126       readonly average?: number
 127       readonly median?: number
 128     }
 129   }
 130 }
 131
 132 /**
 133  * Worker node tasks queue options.
 134  */
 135 export interface TasksQueueOptions {
 136   /**
 137    * Maximum tasks queue size per worker node flagging it as back pressured.
 138    *
 139    * @defaultValue (pool maximum size)^2
 140    */
 141   readonly size?: number
 142   /**
 143    * Maximum number of tasks that can be executed concurrently on a worker node.
 144    *
 145    * @defaultValue 1
 146    */
 147   readonly concurrency?: number
 148   /**
 149    * Whether to enable task stealing on idle.
 150    *
 151    * @defaultValue true
 152    */
 153   readonly taskStealing?: boolean
 154   /**
 155    * Whether to enable tasks stealing under back pressure.
 156    *
 157    * @defaultValue false
 158    */
 159   readonly tasksStealingOnBackPressure?: boolean
 160   /**
 161    * Queued tasks finished timeout in milliseconds at worker node termination.
 162    *
 163    * @defaultValue 2000
 164    */
 165   readonly tasksFinishedTimeout?: number
 166 }
 167
 168 /**
 169  * Options for a poolifier pool.
 170  *
 171  * @typeParam Worker - Type of worker.
 172  */
 173 export interface PoolOptions<Worker extends IWorker> {
 174   /**
 175    * A function that will listen for online event on each worker.
 176    *
 177    * @defaultValue `() => {}`
 178    */
 179   onlineHandler?: OnlineHandler<Worker>
 180   /**
 181    * A function that will listen for message event on each worker.
 182    *
 183    * @defaultValue `() => {}`
 184    */
 185   messageHandler?: MessageHandler<Worker>
 186   /**
 187    * A function that will listen for error event on each worker.
 188    *
 189    * @defaultValue `() => {}`
 190    */
 191   errorHandler?: ErrorHandler<Worker>
 192   /**
 193    * A function that will listen for exit event on each worker.
 194    *
 195    * @defaultValue `() => {}`
 196    */
 197   exitHandler?: ExitHandler<Worker>
 198   /**
 199    * Whether to start the minimum number of workers at pool initialization.
 200    *
 201    * @defaultValue true
 202    */
 203   startWorkers?: boolean
 204   /**
 205    * The default worker choice strategy to use in this pool.
 206    *
 207    * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
 208    */
 209   workerChoiceStrategy?: WorkerChoiceStrategy
 210   /**
 211    * The worker choice strategy options.
 212    */
 213   workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 214   /**
 215    * Restart worker on error.
 216    */
 217   restartWorkerOnError?: boolean
 218   /**
 219    * Pool events integrated with async resource emission.
 220    *
 221    * @defaultValue true
 222    */
 223   enableEvents?: boolean
 224   /**
 225    * Pool worker node tasks queue.
 226    *
 227    * @defaultValue false
 228    */
 229   enableTasksQueue?: boolean
 230   /**
 231    * Pool worker node tasks queue options.
 232    */
 233   tasksQueueOptions?: TasksQueueOptions
 234   /**
 235    * Worker options.
 236    *
 237    * @see https://nodejs.org/api/worker_threads.html#new-workerfilename-options
 238    */
 239   workerOptions?: WorkerOptions
 240   /**
 241    * Key/value pairs to add to worker process environment.
 242    *
 243    * @see https://nodejs.org/api/cluster.html#cluster_cluster_fork_env
 244    */
 245   env?: Record<string, unknown>
 246   /**
 247    * Cluster settings.
 248    *
 249    * @see https://nodejs.org/api/cluster.html#cluster_cluster_settings
 250    */
 251   settings?: ClusterSettings
 252 }
 253
 254 /**
 255  * Contract definition for a poolifier pool.
 256  *
 257  * @typeParam Worker - Type of worker which manages this pool.
 258  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 259  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
 260  */
 261 export interface IPool<
 262   Worker extends IWorker,
 263   Data = unknown,
 264   Response = unknown
 265 > {
 266   /**
 267    * Pool information.
 268    */
 269   readonly info: PoolInfo
 270   /**
 271    * Pool worker nodes.
 272    *
 273    * @internal
 274    */
 275   readonly workerNodes: Array<IWorkerNode<Worker, Data>>
 276   /**
 277    * Pool event emitter integrated with async resource.
 278    * The async tracking tooling identifier is `poolifier:<PoolType>-<WorkerType>-pool`.
 279    *
 280    * Events that can currently be listened to:
 281    *
 282    * - `'ready'`: Emitted when the number of workers created in the pool has reached the minimum size expected and are ready. If the pool is dynamic with a minimum number of workers is set to zero, this event is emitted when at least one dynamic worker is ready.
 283    * - `'busy'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are executing concurrently their tasks quota.
 284    * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
 285    * - `'empty'`: Emitted when the pool is dynamic with a minimum number of workers set to zero and the number of workers has reached the minimum size expected.
 286    * - `'destroy'`: Emitted when the pool is destroyed.
 287    * - `'error'`: Emitted when an uncaught error occurs.
 288    * - `'taskError'`: Emitted when an error occurs while executing a task.
 289    * - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size \>= maximum queue size).
 290    */
 291   readonly emitter?: EventEmitterAsyncResource
 292   /**
 293    * Executes the specified function in the worker constructor with the task data input parameter.
 294    *
 295    * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
 296    * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
 297    * @param transferList - An optional array of transferable objects to transfer ownership of. Ownership of the transferred objects is given to the chosen pool's worker_threads worker and they should not be used in the main thread afterwards.
 298    * @returns Promise that will be fulfilled when the task is completed.
 299    */
 300   readonly execute: (
 301     data?: Data,
 302     name?: string,
 303     transferList?: readonly TransferListItem[]
 304   ) => Promise<Response>
 305   /**
 306    * Starts the minimum number of workers in this pool.
 307    */
 308   readonly start: () => void
 309   /**
 310    * Terminates all workers in this pool.
 311    */
 312   readonly destroy: () => Promise<void>
 313   /**
 314    * Whether the specified task function exists in this pool.
 315    *
 316    * @param name - The name of the task function.
 317    * @returns `true` if the task function exists, `false` otherwise.
 318    */
 319   readonly hasTaskFunction: (name: string) => boolean
 320   /**
 321    * Adds a task function to this pool.
 322    * If a task function with the same name already exists, it will be overwritten.
 323    *
 324    * @param name - The name of the task function.
 325    * @param fn - The task function.
 326    * @returns `true` if the task function was added, `false` otherwise.
 327    * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
 328    * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `fn` parameter is not a function or task function object.
 329    */
 330   readonly addTaskFunction: (
 331     name: string,
 332     fn: TaskFunction<Data, Response> | TaskFunctionObject<Data, Response>
 333   ) => Promise<boolean>
 334   /**
 335    * Removes a task function from this pool.
 336    *
 337    * @param name - The name of the task function.
 338    * @returns `true` if the task function was removed, `false` otherwise.
 339    */
 340   readonly removeTaskFunction: (name: string) => Promise<boolean>
 341   /**
 342    * Lists the properties of task functions available in this pool.
 343    *
 344    * @returns The properties of task functions available in this pool.
 345    */
 346   readonly listTaskFunctionsProperties: () => TaskFunctionProperties[]
 347   /**
 348    * Sets the default task function in this pool.
 349    *
 350    * @param name - The name of the task function.
 351    * @returns `true` if the default task function was set, `false` otherwise.
 352    */
 353   readonly setDefaultTaskFunction: (name: string) => Promise<boolean>
 354   /**
 355    * Sets the default worker choice strategy in this pool.
 356    *
 357    * @param workerChoiceStrategy - The default worker choice strategy.
 358    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 359    */
 360   readonly setWorkerChoiceStrategy: (
 361     workerChoiceStrategy: WorkerChoiceStrategy,
 362     workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 363   ) => void
 364   /**
 365    * Sets the worker choice strategy options in this pool.
 366    *
 367    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 368    * @returns `true` if the worker choice strategy options were set, `false` otherwise.
 369    */
 370   readonly setWorkerChoiceStrategyOptions: (
 371     workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
 372   ) => boolean
 373   /**
 374    * Enables/disables the worker node tasks queue in this pool.
 375    *
 376    * @param enable - Whether to enable or disable the worker node tasks queue.
 377    * @param tasksQueueOptions - The worker node tasks queue options.
 378    */
 379   readonly enableTasksQueue: (
 380     enable: boolean,
 381     tasksQueueOptions?: TasksQueueOptions
 382   ) => void
 383   /**
 384    * Sets the worker node tasks queue options in this pool.
 385    *
 386    * @param tasksQueueOptions - The worker node tasks queue options.
 387    */
 388   readonly setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
 389 }