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     utilization: {
 130       readonly average?: number
 131       readonly median?: number
 132     }
 133   }
 134 }
 135
 136 /**
 137  * Worker node tasks queue options.
 138  */
 139 export interface TasksQueueOptions {
 140   /**
 141    * Maximum tasks queue size per worker node flagging it as back pressured.
 142    * @defaultValue (pool maximum size)^2
 143    */
 144   readonly size?: number
 145   /**
 146    * Maximum number of tasks that can be executed concurrently on a worker node.
 147    * @defaultValue 1
 148    */
 149   readonly concurrency?: number
 150   /**
 151    * Whether to enable task stealing on idle.
 152    * @defaultValue true
 153    */
 154   readonly taskStealing?: boolean
 155   /**
 156    * Whether to enable tasks stealing under back pressure.
 157    * @defaultValue false
 158    */
 159   readonly tasksStealingOnBackPressure?: boolean
 160   /**
 161    * Queued tasks finished timeout in milliseconds at worker node termination.
 162    * @defaultValue 2000
 163    */
 164   readonly tasksFinishedTimeout?: number
 165 }
 166
 167 /**
 168  * Options for a poolifier pool.
 169  * @typeParam Worker - Type of worker.
 170  */
 171 export interface PoolOptions<Worker extends IWorker> {
 172   /**
 173    * A function that will listen for online event on each worker.
 174    * @defaultValue `() => {}`
 175    */
 176   onlineHandler?: OnlineHandler<Worker>
 177   /**
 178    * A function that will listen for message event on each worker.
 179    * @defaultValue `() => {}`
 180    */
 181   messageHandler?: MessageHandler<Worker>
 182   /**
 183    * A function that will listen for error event on each worker.
 184    * @defaultValue `() => {}`
 185    */
 186   errorHandler?: ErrorHandler<Worker>
 187   /**
 188    * A function that will listen for exit event on each worker.
 189    * @defaultValue `() => {}`
 190    */
 191   exitHandler?: ExitHandler<Worker>
 192   /**
 193    * Whether to start the minimum number of workers at pool initialization.
 194    * @defaultValue true
 195    */
 196   startWorkers?: boolean
 197   /**
 198    * The default worker choice strategy to use in this pool.
 199    * @defaultValue WorkerChoiceStrategies.ROUND_ROBIN
 200    */
 201   workerChoiceStrategy?: WorkerChoiceStrategy
 202   /**
 203    * The worker choice strategy options.
 204    */
 205   workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 206   /**
 207    * Restart worker on error.
 208    */
 209   restartWorkerOnError?: boolean
 210   /**
 211    * Pool events integrated with async resource emission.
 212    * @defaultValue true
 213    */
 214   enableEvents?: boolean
 215   /**
 216    * Pool worker node tasks queue.
 217    * @defaultValue false
 218    */
 219   enableTasksQueue?: boolean
 220   /**
 221    * Pool worker node tasks queue options.
 222    */
 223   tasksQueueOptions?: TasksQueueOptions
 224   /**
 225    * Worker options.
 226    * @see https://nodejs.org/api/worker_threads.html#new-workerfilename-options
 227    */
 228   workerOptions?: WorkerOptions
 229   /**
 230    * Key/value pairs to add to worker process environment.
 231    * @see https://nodejs.org/api/cluster.html#cluster_cluster_fork_env
 232    */
 233   env?: Record<string, unknown>
 234   /**
 235    * Cluster settings.
 236    * @see https://nodejs.org/api/cluster.html#cluster_cluster_settings
 237    */
 238   settings?: ClusterSettings
 239 }
 240
 241 /**
 242  * Contract definition for a poolifier pool.
 243  * @typeParam Worker - Type of worker which manages this pool.
 244  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
 245  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
 246  */
 247 export interface IPool<
 248   Worker extends IWorker,
 249   Data = unknown,
 250   Response = unknown
 251 > {
 252   /**
 253    * Pool information.
 254    */
 255   readonly info: PoolInfo
 256   /**
 257    * Pool worker nodes.
 258    * @internal
 259    */
 260   readonly workerNodes: IWorkerNode<Worker, Data>[]
 261   /**
 262    * Pool event emitter integrated with async resource.
 263    * The async tracking tooling identifier is `poolifier:<PoolType>-<WorkerType>-pool`.
 264    *
 265    * Events that can currently be listened to:
 266    *
 267    * - `'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.
 268    * - `'busy'`: Emitted when the number of workers created in the pool has reached the maximum size expected and are executing concurrently their tasks quota.
 269    * - `'full'`: Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
 270    * - `'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.
 271    * - `'destroy'`: Emitted when the pool is destroyed.
 272    * - `'error'`: Emitted when an uncaught error occurs.
 273    * - `'taskError'`: Emitted when an error occurs while executing a task.
 274    * - `'backPressure'`: Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size \>= maximum queue size).
 275    */
 276   readonly emitter?: EventEmitterAsyncResource
 277   /**
 278    * Executes the specified function in the worker constructor with the task data input parameter.
 279    * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
 280    * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
 281    * @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.
 282    * @returns Promise that will be fulfilled when the task is completed.
 283    */
 284   readonly execute: (
 285     data?: Data,
 286     name?: string,
 287     transferList?: readonly TransferListItem[]
 288   ) => Promise<Response>
 289   /**
 290    * Starts the minimum number of workers in this pool.
 291    */
 292   readonly start: () => void
 293   /**
 294    * Terminates all workers in this pool.
 295    */
 296   readonly destroy: () => Promise<void>
 297   /**
 298    * Whether the specified task function exists in this pool.
 299    * @param name - The name of the task function.
 300    * @returns `true` if the task function exists, `false` otherwise.
 301    */
 302   readonly hasTaskFunction: (name: string) => boolean
 303   /**
 304    * Adds a task function to this pool.
 305    * If a task function with the same name already exists, it will be overwritten.
 306    * @param name - The name of the task function.
 307    * @param fn - The task function.
 308    * @returns `true` if the task function was added, `false` otherwise.
 309    * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
 310    * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `fn` parameter is not a function or task function object.
 311    */
 312   readonly addTaskFunction: (
 313     name: string,
 314     fn: TaskFunction<Data, Response> | TaskFunctionObject<Data, Response>
 315   ) => Promise<boolean>
 316   /**
 317    * Removes a task function from this pool.
 318    * @param name - The name of the task function.
 319    * @returns `true` if the task function was removed, `false` otherwise.
 320    */
 321   readonly removeTaskFunction: (name: string) => Promise<boolean>
 322   /**
 323    * Lists the properties of task functions available in this pool.
 324    * @returns The properties of task functions available in this pool.
 325    */
 326   readonly listTaskFunctionsProperties: () => TaskFunctionProperties[]
 327   /**
 328    * Sets the default task function in this pool.
 329    * @param name - The name of the task function.
 330    * @returns `true` if the default task function was set, `false` otherwise.
 331    */
 332   readonly setDefaultTaskFunction: (name: string) => Promise<boolean>
 333   /**
 334    * Sets the default worker choice strategy in this pool.
 335    * @param workerChoiceStrategy - The default worker choice strategy.
 336    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 337    */
 338   readonly setWorkerChoiceStrategy: (
 339     workerChoiceStrategy: WorkerChoiceStrategy,
 340     workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
 341   ) => void
 342   /**
 343    * Sets the worker choice strategy options in this pool.
 344    * @param workerChoiceStrategyOptions - The worker choice strategy options.
 345    * @returns `true` if the worker choice strategy options were set, `false` otherwise.
 346    */
 347   readonly setWorkerChoiceStrategyOptions: (
 348     workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
 349   ) => boolean
 350   /**
 351    * Enables/disables the worker node tasks queue in this pool.
 352    * @param enable - Whether to enable or disable the worker node tasks queue.
 353    * @param tasksQueueOptions - The worker node tasks queue options.
 354    */
 355   readonly enableTasksQueue: (
 356     enable: boolean,
 357     tasksQueueOptions?: TasksQueueOptions
 358   ) => void
 359   /**
 360    * Sets the worker node tasks queue options in this pool.
 361    * @param tasksQueueOptions - The worker node tasks queue options.
 362    */
 363   readonly setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
 364 }