README.md

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   6
   7 # Node.js Worker_Threads and Cluster Worker Pool
   8
   9 </div>
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  25 </div>
  26
  27 ## Why Poolifier?
  28
  29 Poolifier is used to perform CPU and/or I/O intensive tasks on Node.js servers, it implements worker pools using [worker_threads](https://nodejs.org/api/worker_threads.html) and [cluster](https://nodejs.org/api/cluster.html) Node.js modules.
  30 With poolifier you can improve your **performance** and resolve problems related to the event loop.
  31 Moreover you can execute your tasks using an API designed to improve the **developer experience**.
  32 Please consult our [general guidelines](#general-guidelines).
  33
  34 - Easy to use :white_check_mark:
  35 - Fixed and dynamic pool size :white_check_mark:
  36 - Easy switch from a pool type to another :white_check_mark:
  37 - Performance [benchmarks](./benchmarks/README.md) :white_check_mark:
  38 - No runtime dependencies :white_check_mark:
  39 - Proper integration with Node.js [async_hooks](https://nodejs.org/api/async_hooks.html) :white_check_mark:
  40 - Support for CommonJS, ESM and TypeScript :white_check_mark:
  41 - Support for [worker_threads](https://nodejs.org/api/worker_threads.html) and [cluster](https://nodejs.org/api/cluster.html) Node.js modules :white_check_mark:
  42 - Tasks distribution strategies :white_check_mark:
  43 - Lockless tasks queueing :white_check_mark:
  44 - Queued tasks rescheduling:
  45   - Task stealing on idle :white_check_mark:
  46   - Tasks stealing under back pressure :white_check_mark:
  47   - Tasks redistribution on worker error :white_check_mark:
  48 - Support for sync and async task function :white_check_mark:
  49 - Support for multiple task functions with per task function queuing priority and tasks distribution strategy :white_check_mark:
  50 - Support for task functions [CRUD](https://en.wikipedia.org/wiki/Create,_read,_update_and_delete) operations at runtime :white_check_mark:
  51 - General guidelines on pool choice :white_check_mark:
  52 - Error handling out of the box :white_check_mark:
  53 - Widely tested :white_check_mark:
  54 - Active community :white_check_mark:
  55 - Code quality [![Bugs](https://sonarcloud.io/api/project_badges/measure?project=poolifier_poolifier&metric=bugs)](https://sonarcloud.io/dashboard?id=poolifier_poolifier)
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  62
  63 ## Table of contents
  64
  65 - [Overview](#overview)
  66 - [Installation](#installation)
  67 - [Usage](#usage)
  68 - [Node.js versions](#nodejs-versions)
  69 - [API](#api)
  70 - [General guidelines](#general-guidelines)
  71 - [Worker choice strategies](#worker-choice-strategies)
  72 - [Contribute](#contribute)
  73 - [Team](#team)
  74 - [License](#license)
  75
  76 ## Overview
  77
  78 Poolifier contains two [worker_threads](https://nodejs.org/api/worker_threads.html#class-worker)/[cluster](https://nodejs.org/api/cluster.html#cluster_class_worker) worker pool implementations, you don't have to deal with [worker_threads](https://nodejs.org/api/worker_threads.html)/[cluster](https://nodejs.org/api/cluster.html) complexity.
  79 The first implementation is a fixed worker pool, with a defined number of workers that are started at creation time and will be reused.
  80 The second implementation is a dynamic worker pool, with a number of worker started at creation time (these workers will be always active and reused) and other workers created when the load will increase (with an upper limit, these workers will be reused when active), the newly created workers will be stopped after a configurable period of inactivity.
  81 You have to implement your worker by extending the _ThreadWorker_ or _ClusterWorker_ class.
  82
  83 ## Installation
  84
  85 ### npmjs
  86
  87 ```shell
  88 npm install poolifier --save
  89 ```
  90
  91 ### JSR
  92
  93 ```shell
  94 npx jsr add @poolifier/poolifier
  95 ```
  96
  97 ## Usage
  98
  99 You can implement a poolifier [worker_threads](https://nodejs.org/api/worker_threads.html#class-worker) worker in a simple way by extending the class _ThreadWorker_:
 100
 101 ```js
 102 import { ThreadWorker } from 'poolifier'
 103
 104 function yourFunction(data) {
 105   // this will be executed in the worker thread,
 106   // the data will be received by using the execute method
 107   return { ok: 1 }
 108 }
 109
 110 module.exports = new ThreadWorker(yourFunction, {
 111   maxInactiveTime: 60000
 112 })
 113 ```
 114
 115 Instantiate your pool based on your needs :
 116
 117 ```js
 118 import { DynamicThreadPool, FixedThreadPool, PoolEvents, availableParallelism } from 'poolifier'
 119
 120 // a fixed worker_threads pool
 121 const pool = new FixedThreadPool(availableParallelism(), './yourWorker.js', {
 122   onlineHandler: () => console.info('worker is online'),
 123   errorHandler: e => console.error(e)
 124 })
 125
 126 pool.emitter?.on(PoolEvents.ready, () => console.info('Pool is ready'))
 127 pool.emitter?.on(PoolEvents.busy, () => console.info('Pool is busy'))
 128
 129 // or a dynamic worker_threads pool
 130 const pool = new DynamicThreadPool(Math.floor(availableParallelism() / 2), availableParallelism(), './yourWorker.js', {
 131   onlineHandler: () => console.info('worker is online'),
 132   errorHandler: e => console.error(e)
 133 })
 134
 135 pool.emitter?.on(PoolEvents.full, () => console.info('Pool is full'))
 136 pool.emitter?.on(PoolEvents.ready, () => console.info('Pool is ready'))
 137 pool.emitter?.on(PoolEvents.busy, () => console.info('Pool is busy'))
 138
 139 // the execute method signature is the same for both implementations,
 140 // so you can easily switch from one to another
 141 pool
 142   .execute()
 143   .then(res => {
 144     console.info(res)
 145   })
 146   .catch(err => {
 147     console.error(err)
 148   })
 149 ```
 150
 151 You can do the same with the classes _ClusterWorker_, _FixedClusterPool_ and _DynamicClusterPool_.
 152
 153 **See [examples](./examples/) for more details**:
 154
 155 - [Javascript](./examples/javascript/)
 156 - [Typescript](./examples/typescript/)
 157   - [HTTP client pool](./examples/typescript/http-client-pool/)
 158   - [SMTP client pool](./examples/typescript/smtp-client-pool/)
 159   - [HTTP server pool](./examples/typescript/http-server-pool/)
 160     - [Express worker_threads pool](./examples/typescript/http-server-pool/express-worker_threads/)
 161     - [Express cluster pool](./examples/typescript/http-server-pool/express-cluster/)
 162     - [Express hybrid pool](./examples/typescript/http-server-pool/express-hybrid/)
 163     - [Fastify worker_threads pool](./examples/typescript/http-server-pool/fastify-worker_threads/)
 164     - [Fastify cluster pool](./examples/typescript/http-server-pool/fastify-cluster/)
 165     - [Fastify hybrid pool](./examples/typescript/http-server-pool/fastify-hybrid/)
 166   - [WebSocket server pool](./examples/typescript/websocket-server-pool/)
 167     - [ws worker_threads pool](./examples/typescript/websocket-server-pool/ws-worker_threads/)
 168     - [ws cluster pool](./examples/typescript/websocket-server-pool/ws-cluster/)
 169     - [ws hybrid pool](./examples/typescript/websocket-server-pool/ws-hybrid/)
 170
 171 Remember that workers can only send and receive structured-cloneable data.
 172
 173 ## Node.js versions
 174
 175 Node.js versions >= 18.x.x are supported.
 176
 177 ## [API](./docs/api.md)
 178
 179 ## [General guidelines](./docs/general-guidelines.md)
 180
 181 ## [Worker choice strategies](./docs/worker-choice-strategies.md)
 182
 183 ## Contribute
 184
 185 Choose your task [here](https://github.com/orgs/poolifier/projects/1), propose an idea, a fix, an improvement.
 186
 187 See [CONTRIBUTING](./CONTRIBUTING.md) guidelines.
 188
 189 ## Team
 190
 191 **Creator/Owner:**
 192
 193 - [**Alessandro Pio Ardizio**](https://github.com/pioardi)
 194
 195 **Maintainers:**
 196
 197 - [**Jérôme Benoit**](https://github.com/jerome-benoit)
 198
 199 **Contributors:**
 200
 201 - [**Shinigami92**](https://github.com/Shinigami92)
 202
 203 ## License
 204
 205 [MIT](./LICENSE)