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 [async_hooks](https://nodejs.org/api/async_hooks.html) :white_check_mark:
  43 - Support 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 multiple task functions :white_check_mark:
  46 - Support sync and async task functions :white_check_mark:
  47 - Tasks distribution strategies :white_check_mark:
  48 - General guidelines on pool choice :white_check_mark:
  49 - Error handling out of the box :white_check_mark:
  50 - Widely tested :white_check_mark:
  51 - Active community :white_check_mark:
  52 - 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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  59
  60 ## Table of contents
  61
  62 - [Overview](#overview)
  63 - [Installation](#installation)
  64 - [Usage](#usage)
  65 - [Node versions](#node-versions)
  66 - [API](#api)
  67 - [General guidelines](#general-guidelines)
  68 - [Worker choice strategies](#worker-choice-strategies)
  69 - [Contribute](#contribute)
  70 - [Team](#team)
  71 - [License](#license)
  72
  73 ## Overview
  74
  75 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.
  76 The first implementation is a fixed worker pool, with a defined number of workers that are started at creation time and will be reused.
  77 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.
  78 You have to implement your worker by extending the _ThreadWorker_ or _ClusterWorker_ class.
  79
  80 ## Installation
  81
  82 ```shell
  83 npm install poolifier --save
  84 ```
  85
  86 ## Usage
  87
  88 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_:
  89
  90 ```js
  91 'use strict'
  92 const { ThreadWorker } = require('poolifier')
  93
  94 function yourFunction(data) {
  95   // this will be executed in the worker thread,
  96   // the data will be received by using the execute method
  97   return { ok: 1 }
  98 }
  99
 100 module.exports = new ThreadWorker(yourFunction, {
 101   maxInactiveTime: 60000
 102 })
 103 ```
 104
 105 Instantiate your pool based on your needs :
 106
 107 ```js
 108 'use strict'
 109 const { DynamicThreadPool, FixedThreadPool, PoolEvents, availableParallelism } = require('poolifier')
 110
 111 // a fixed worker_threads pool
 112 const pool = new FixedThreadPool(availableParallelism(), './yourWorker.js', {
 113   errorHandler: e => console.error(e),
 114   onlineHandler: () => console.info('worker is online')
 115 })
 116
 117 pool.emitter.on(PoolEvents.ready, () => console.info('Pool is ready'))
 118 pool.emitter.on(PoolEvents.busy, () => console.info('Pool is busy'))
 119
 120 // or a dynamic worker_threads pool
 121 const pool = new DynamicThreadPool(Math.floor(availableParallelism() / 2), availableParallelism(), './yourWorker.js', {
 122   errorHandler: e => console.error(e),
 123   onlineHandler: () => console.info('worker is online')
 124 })
 125
 126 pool.emitter.on(PoolEvents.full, () => console.info('Pool is full'))
 127 pool.emitter.on(PoolEvents.ready, () => console.info('Pool is ready'))
 128 pool.emitter.on(PoolEvents.busy, () => console.info('Pool is busy'))
 129
 130 // the execute method signature is the same for both implementations,
 131 // so you can easy switch from one to another
 132 pool
 133   .execute()
 134   .then(res => {
 135     console.info(res)
 136   })
 137   .catch(err => {
 138     console.error(err)
 139   })
 140 ```
 141
 142 You can do the same with the classes _ClusterWorker_, _FixedClusterPool_ and _DynamicClusterPool_.
 143
 144 **See [examples](./examples/) folder for more details**:
 145
 146 - [Javascript](./examples/javascript/)
 147 - [Typescript](./examples/typescript/)
 148   - [HTTP client pool](./examples/typescript/http-client-pool/)
 149   - [HTTP server pool](./examples/typescript/http-server-pool/)
 150     - [Express](./examples/typescript/http-server-pool/express/)
 151     - [Fastify](./examples/typescript/http-server-pool/fastify/)
 152   - [Websocket server pool](./examples/typescript/websocket-server-pool/)
 153     - [ws](./examples/typescript/websocket-server-pool/ws/)
 154
 155 Remember that workers can only send and receive structured-cloneable data.
 156
 157 ## Node versions
 158
 159 Node versions >= 16.14.x are supported.
 160
 161 ## [API](./docs/api.md)
 162
 163 ## [General guidelines](./docs/general-guidelines.md)
 164
 165 ## [Worker choice strategies](./docs/worker-choice-strategies.md)
 166
 167 ## Contribute
 168
 169 Choose your task here [2.6.x](https://github.com/orgs/poolifier/projects/1), propose an idea, a fix, an improvement.
 170
 171 See [CONTRIBUTING](CONTRIBUTING.md) guidelines.
 172
 173 ## Team
 174
 175 **Creator/Owner:**
 176
 177 - [**Alessandro Pio Ardizio**](https://github.com/pioardi)
 178
 179 **_Contributors_**
 180
 181 - [**Shinigami92**](https://github.com/Shinigami92)
 182 - [**Jérôme Benoit**](https://github.com/jerome-benoit)
 183
 184 ## License
 185
 186 [MIT](./LICENSE)