README.md

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   5 <h1 align="center">Node.js Worker_Threads and Cluster Worker Pool</h1>
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  29
  30 ## Why Poolifier?
  31
  32 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.
  33 With poolifier you can improve your **performance** and resolve problems related to the event loop.
  34 Moreover you can execute your tasks using an API designed to improve the **developer experience**.
  35 Please consult our [general guidelines](#general-guidelines).
  36
  37 - Easy to use :white_check_mark:
  38 - Performance [benchmarks](./benchmarks/README.md) :white_check_mark:
  39 - Fixed and dynamic pool size :white_check_mark:
  40 - Easy switch from a pool type to another :white_check_mark:
  41 - No runtime dependencies :white_check_mark:
  42 - Proper integration with Node.js [async_hooks](https://nodejs.org/api/async_hooks.html) :white_check_mark:
  43 - Support for CommonJS, ESM, and TypeScript :white_check_mark:
  44 - 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:
  45 - Support for multiple task functions :white_check_mark:
  46 - Support for sync and async task functions :white_check_mark:
  47 - Tasks distribution strategies :white_check_mark:
  48 - Lockless tasks queueing :white_check_mark:
  49 - General guidelines on pool choice :white_check_mark:
  50 - Error handling out of the box :white_check_mark:
  51 - Widely tested :white_check_mark:
  52 - Active community :white_check_mark:
  53 - Code quality [![Bugs](https://sonarcloud.io/api/project_badges/measure?project=pioardi_poolifier&metric=bugs)](https://sonarcloud.io/dashboard?id=pioardi_poolifier)
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  60
  61 ## Table of contents
  62
  63 - [Overview](#overview)
  64 - [Installation](#installation)
  65 - [Usage](#usage)
  66 - [Node.js versions](#nodejs-versions)
  67 - [API](#api)
  68 - [General guidelines](#general-guidelines)
  69 - [Worker choice strategies](#worker-choice-strategies)
  70 - [Contribute](#contribute)
  71 - [Team](#team)
  72 - [License](#license)
  73
  74 ## Overview
  75
  76 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.
  77 The first implementation is a fixed worker pool, with a defined number of workers that are started at creation time and will be reused.
  78 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 new created workers will be stopped after a configurable period of inactivity.
  79 You have to implement your worker by extending the _ThreadWorker_ or _ClusterWorker_ class.
  80
  81 ## Installation
  82
  83 ```shell
  84 npm install poolifier --save
  85 ```
  86
  87 ## Usage
  88
  89 You can implement a [worker_threads](https://nodejs.org/api/worker_threads.html#class-worker) worker in a simple way by extending the class _ThreadWorker_:
  90
  91 ```js
  92 'use strict'
  93 const { ThreadWorker } = require('poolifier')
  94
  95 function yourFunction(data) {
  96   // this will be executed in the worker thread,
  97   // the data will be received by using the execute method
  98   return { ok: 1 }
  99 }
 100
 101 module.exports = new ThreadWorker(yourFunction, {
 102   maxInactiveTime: 60000
 103 })
 104 ```
 105
 106 Instantiate your pool based on your needs :
 107
 108 ```js
 109 'use strict'
 110 const { DynamicThreadPool, FixedThreadPool, PoolEvents, availableParallelism } = require('poolifier')
 111
 112 // a fixed worker_threads pool
 113 const pool = new FixedThreadPool(availableParallelism(), './yourWorker.js', {
 114   errorHandler: (e) => console.error(e),
 115   onlineHandler: () => console.info('worker is online')
 116 })
 117
 118 pool.emitter.on(PoolEvents.ready, () => console.info('Pool is ready'))
 119 pool.emitter.on(PoolEvents.busy, () => console.info('Pool is busy'))
 120
 121 // or a dynamic worker_threads pool
 122 const pool = new DynamicThreadPool(Math.floor(availableParallelism() / 2), availableParallelism(), './yourWorker.js', {
 123   errorHandler: (e) => console.error(e),
 124   onlineHandler: () => console.info('worker is online')
 125 })
 126
 127 pool.emitter.on(PoolEvents.full, () => console.info('Pool is full'))
 128 pool.emitter.on(PoolEvents.ready, () => console.info('Pool is ready'))
 129 pool.emitter.on(PoolEvents.busy, () => console.info('Pool is busy'))
 130
 131 // the execute method signature is the same for both implementations,
 132 // so you can easily switch from one to another
 133 pool
 134   .execute()
 135   .then((res) => {
 136     console.info(res)
 137   })
 138   .catch((err) => {
 139     console.error(err)
 140   })
 141 ```
 142
 143 You can do the same with the classes _ClusterWorker_, _FixedClusterPool_ and _DynamicClusterPool_.
 144
 145 **See [examples](./examples/) for more details**:
 146
 147 - [Javascript](./examples/javascript/)
 148 - [Typescript](./examples/typescript/)
 149   - [HTTP client pool](./examples/typescript/http-client-pool/)
 150   - [SMTP client pool](./examples/typescript/smtp-client-pool/)
 151   - [HTTP server pool](./examples/typescript/http-server-pool/)
 152     - [Express worker_threads pool](./examples/typescript/http-server-pool/express-worker_threads/)
 153     - [Express cluster pool](./examples/typescript/http-server-pool/express-cluster/)
 154     - [Express hybrid pool](./examples/typescript/http-server-pool/express-hybrid/)
 155     - [Fastify worker_threads pool](./examples/typescript/http-server-pool/fastify-worker_threads/)
 156     - [Fastify cluster pool](./examples/typescript/http-server-pool/fastify-cluster/)
 157     - [Fastify hybrid pool](./examples/typescript/http-server-pool/fastify-hybrid/)
 158   - [WebSocket server pool](./examples/typescript/websocket-server-pool/)
 159     - [ws worker_threads pool](./examples/typescript/websocket-server-pool/ws-worker_threads/)
 160     - [ws cluster pool](./examples/typescript/websocket-server-pool/ws-cluster/)
 161     - [ws hybrid pool](./examples/typescript/websocket-server-pool/ws-hybrid/)
 162
 163 Remember that workers can only send and receive structured-cloneable data.
 164
 165 ## Node.js versions
 166
 167 Node.js versions >= 16.14.x are supported.
 168
 169 ## [API](./docs/api.md)
 170
 171 ## [General guidelines](./docs/general-guidelines.md)
 172
 173 ## [Worker choice strategies](./docs/worker-choice-strategies.md)
 174
 175 ## Contribute
 176
 177 Choose your task here [2.6.x](https://github.com/orgs/poolifier/projects/1), propose an idea, a fix, an improvement.
 178
 179 See [CONTRIBUTING](CONTRIBUTING.md) guidelines.
 180
 181 ## Team
 182
 183 **Creator/Owner:**
 184
 185 - [**Alessandro Pio Ardizio**](https://github.com/pioardi)
 186
 187 **_Contributors_**
 188
 189 - [**Shinigami92**](https://github.com/Shinigami92)
 190 - [**Jérôme Benoit**](https://github.com/jerome-benoit)
 191
 192 ## License
 193
 194 [MIT](./LICENSE)