README.md

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   4
   5 <h2 align="center">Node Thread Pool and Cluster Pool :arrow_double_up: :on:</h2>
   6
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  28 </p>
  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-guidance).
  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 guidance 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:
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  59
  60 ## Contents
  61
  62 <h3 align="center">
  63   <a href="#overview">Overview</a>
  64   <span> · </span>
  65   <a href="#installation">Installation</a>
  66   <span> · </span>
  67   <a href="#usage">Usage</a>
  68   <span> · </span>
  69   <a href="#node-versions">Node versions</a>
  70   <span> · </span>
  71   <a href="#api">API</a>
  72   <span> · </span>
  73   <a href="#general-guidance">General guidance</a>
  74   <span> · </span>
  75   <a href="#contribute">Contribute</a>
  76   <span> · </span>
  77   <a href="#team">Team</a>
  78   <span> · </span>
  79   <a href="#license">License</a>
  80 </h3>
  81
  82 ## Overview
  83
  84 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.
  85 The first implementation is a fixed worker pool, with a defined number of workers that are started at creation time and will be reused.
  86 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.
  87 You have to implement your worker by extending the _ThreadWorker_ or _ClusterWorker_ class.
  88
  89 ## Installation
  90
  91 ```shell
  92 npm install poolifier --save
  93 ```
  94
  95 ## Usage
  96
  97 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_:
  98
  99 ```js
 100 'use strict'
 101 const { ThreadWorker } = require('poolifier')
 102
 103 function yourFunction(data) {
 104   // this will be executed in the worker thread,
 105   // the data will be received by using the execute method
 106   return { ok: 1 }
 107 }
 108
 109 module.exports = new ThreadWorker(yourFunction, {
 110   maxInactiveTime: 60000
 111 })
 112 ```
 113
 114 Instantiate your pool based on your needs :
 115
 116 ```js
 117 'use strict'
 118 const { DynamicThreadPool, FixedThreadPool, PoolEvents, availableParallelism } = require('poolifier')
 119
 120 // a fixed worker_threads pool
 121 const pool = new FixedThreadPool(availableParallelism(), './yourWorker.js', {
 122   errorHandler: e => console.error(e),
 123   onlineHandler: () => console.info('worker is online')
 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   errorHandler: e => console.error(e),
 132   onlineHandler: () => console.info('worker is online')
 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 easy 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/) folder for more details (in particular if you want to use a pool with [multiple task functions](./examples/multiFunctionExample.js))**.
 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](https://poolifier.github.io/poolifier/)
 162
 163 [**API Details**](./docs/api-details.md)
 164
 165 ## General Guideline
 166
 167 For general guidelines, please refer to [this document](./docs/general-guidelines.md)
 168
 169 ## Contribute
 170
 171 Choose your task here [2.6.x](https://github.com/orgs/poolifier/projects/1), propose an idea, a fix, an improvement.
 172
 173 See [CONTRIBUTING](CONTRIBUTING.md) guidelines.
 174
 175 ## Team
 176
 177 **Creator/Owner:**
 178
 179 - [**Alessandro Pio Ardizio**](https://github.com/pioardi)
 180
 181 **_Contributors_**
 182
 183 - [**Shinigami92**](https://github.com/Shinigami92)
 184 - [**Jérôme Benoit**](https://github.com/jerome-benoit)
 185
 186 ## License
 187
 188 [MIT](./LICENSE)