README.md

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   6
   7 # Node.js Worker_Threads and Cluster Worker Pool
   8
   9 </div>
  10
  11 <div align="center">
  12
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  26 </div>
  27
  28 ## Why Poolifier?
  29
  30 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.
  31 With poolifier you can improve your **performance** and resolve problems related to the event loop.
  32 Moreover you can execute your tasks using an API designed to improve the **developer experience**.
  33 Please consult our [general guidelines](#general-guidelines).
  34
  35 - Easy to use :white_check_mark:
  36 - Fixed and dynamic pool size :white_check_mark:
  37 - Easy switch from a pool type to another :white_check_mark:
  38 - Performance [benchmarks](./benchmarks/README.md) :white_check_mark:
  39 - No runtime dependencies :white_check_mark:
  40 - Proper integration with Node.js [async_hooks](https://nodejs.org/api/async_hooks.html) :white_check_mark:
  41 - Support for CommonJS, ESM and TypeScript :white_check_mark:
  42 - 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:
  43 - Tasks distribution strategies :white_check_mark:
  44 - Lockless tasks queueing :white_check_mark:
  45 - Queued tasks rescheduling:
  46   - Task stealing on idle :white_check_mark:
  47   - Tasks stealing under back pressure :white_check_mark:
  48   - Tasks redistribution on worker error :white_check_mark:
  49 - Support for sync and async task function :white_check_mark:
  50 - Support for multiple task functions with per task function queuing priority and tasks distribution strategy :white_check_mark:
  51 - Support for task functions [CRUD](https://en.wikipedia.org/wiki/Create,_read,_update_and_delete) operations at runtime :white_check_mark:
  52 - General guidelines on pool choice :white_check_mark:
  53 - Error handling out of the box :white_check_mark:
  54 - Widely tested :white_check_mark:
  55 - Active community :white_check_mark:
  56 - 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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  63
  64 ## Table of contents
  65
  66 - [Overview](#overview)
  67 - [Installation](#installation)
  68 - [Usage](#usage)
  69 - [Node.js versions](#nodejs-versions)
  70 - [API](#api)
  71 - [General guidelines](#general-guidelines)
  72 - [Worker choice strategies](#worker-choice-strategies)
  73 - [Contribute](#contribute)
  74 - [Team](#team)
  75 - [License](#license)
  76
  77 ## Overview
  78
  79 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.
  80 The first implementation is a fixed worker pool, with a defined number of workers that are started at creation time and will be reused.
  81 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.
  82 You have to implement your worker by extending the _ThreadWorker_ or _ClusterWorker_ class.
  83
  84 ## Installation
  85
  86 ### npmjs
  87
  88 ```shell
  89 npm install poolifier --save
  90 ```
  91
  92 ### JSR
  93
  94 ```shell
  95 npx jsr add @poolifier/poolifier
  96 ```
  97
  98 ## Usage
  99
 100 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_:
 101
 102 ```js
 103 import { ThreadWorker } from 'poolifier'
 104
 105 function yourFunction(data) {
 106   // this will be executed in the worker thread,
 107   // the data will be received by using the execute method
 108   return { ok: 1 }
 109 }
 110
 111 module.exports = new ThreadWorker(yourFunction, {
 112   maxInactiveTime: 60000
 113 })
 114 ```
 115
 116 Instantiate your pool based on your needs :
 117
 118 ```js
 119 import { DynamicThreadPool, FixedThreadPool, PoolEvents, availableParallelism } from 'poolifier'
 120
 121 // a fixed worker_threads pool
 122 const pool = new FixedThreadPool(availableParallelism(), './yourWorker.js', {
 123   onlineHandler: () => console.info('worker is online'),
 124   errorHandler: e => console.error(e)
 125 })
 126
 127 pool.emitter?.on(PoolEvents.ready, () => console.info('Pool is ready'))
 128 pool.emitter?.on(PoolEvents.busy, () => console.info('Pool is busy'))
 129
 130 // or a dynamic worker_threads pool
 131 const pool = new DynamicThreadPool(Math.floor(availableParallelism() / 2), availableParallelism(), './yourWorker.js', {
 132   onlineHandler: () => console.info('worker is online'),
 133   errorHandler: e => console.error(e)
 134 })
 135
 136 pool.emitter?.on(PoolEvents.full, () => console.info('Pool is full'))
 137 pool.emitter?.on(PoolEvents.ready, () => console.info('Pool is ready'))
 138 pool.emitter?.on(PoolEvents.busy, () => console.info('Pool is busy'))
 139
 140 // the execute method signature is the same for both implementations,
 141 // so you can easily switch from one to another
 142 pool
 143   .execute()
 144   .then(res => {
 145     console.info(res)
 146   })
 147   .catch(err => {
 148     console.error(err)
 149   })
 150 ```
 151
 152 You can do the same with the classes _ClusterWorker_, _FixedClusterPool_ and _DynamicClusterPool_.
 153
 154 **See [examples](./examples/) for more details**:
 155
 156 - [Javascript](./examples/javascript/)
 157 - [Typescript](./examples/typescript/)
 158   - [HTTP client pool](./examples/typescript/http-client-pool/)
 159   - [SMTP client pool](./examples/typescript/smtp-client-pool/)
 160   - [HTTP server pool](./examples/typescript/http-server-pool/)
 161     - [Express worker_threads pool](./examples/typescript/http-server-pool/express-worker_threads/)
 162     - [Express cluster pool](./examples/typescript/http-server-pool/express-cluster/)
 163     - [Express hybrid pool](./examples/typescript/http-server-pool/express-hybrid/)
 164     - [Fastify worker_threads pool](./examples/typescript/http-server-pool/fastify-worker_threads/)
 165     - [Fastify cluster pool](./examples/typescript/http-server-pool/fastify-cluster/)
 166     - [Fastify hybrid pool](./examples/typescript/http-server-pool/fastify-hybrid/)
 167   - [WebSocket server pool](./examples/typescript/websocket-server-pool/)
 168     - [ws worker_threads pool](./examples/typescript/websocket-server-pool/ws-worker_threads/)
 169     - [ws cluster pool](./examples/typescript/websocket-server-pool/ws-cluster/)
 170     - [ws hybrid pool](./examples/typescript/websocket-server-pool/ws-hybrid/)
 171
 172 Remember that workers can only send and receive structured-cloneable data.
 173
 174 ## Node.js versions
 175
 176 Node.js versions >= 18.x.x are supported.
 177
 178 ## [API](./docs/api.md)
 179
 180 ## [General guidelines](./docs/general-guidelines.md)
 181
 182 ## [Worker choice strategies](./docs/worker-choice-strategies.md)
 183
 184 ## Contribute
 185
 186 Choose your task [here](https://github.com/orgs/poolifier/projects/1), propose an idea, a fix, an improvement.
 187
 188 See [CONTRIBUTING](./CONTRIBUTING.md) guidelines.
 189
 190 ## Team
 191
 192 **Creator/Owner:**
 193
 194 - [**Alessandro Pio Ardizio**](https://github.com/pioardi)
 195
 196 **Maintainers:**
 197
 198 - [**Jérôme Benoit**](https://github.com/jerome-benoit)
 199
 200 **Contributors:**
 201
 202 - [**Shinigami92**](https://github.com/Shinigami92)
 203
 204 ## License
 205
 206 [MIT](./LICENSE)