README.md

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   6
   7 # Node.js Worker_Threads and Cluster Worker Pool
   8
   9 </div>
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  24 </div>
  25
  26 ## Why Poolifier?
  27
  28 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.
  29 With poolifier you can improve your **performance** and resolve problems related to the event loop.
  30 Moreover you can execute your tasks using an API designed to improve the **developer experience**.
  31 Please consult our [general guidelines](#general-guidelines).
  32
  33 - Easy to use :white_check_mark:
  34 - Fixed and dynamic pool size :white_check_mark:
  35 - Easy switch from a pool type to another :white_check_mark:
  36 - Performance [benchmarks](./benchmarks/README.md) :white_check_mark:
  37 - No runtime dependencies :white_check_mark:
  38 - Proper integration with Node.js [async_hooks](https://nodejs.org/api/async_hooks.html) :white_check_mark:
  39 - Support for CommonJS, ESM, and TypeScript :white_check_mark:
  40 - 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:
  41 - Support for multiple task functions :white_check_mark:
  42 - Support for task functions [CRUD](https://en.wikipedia.org/wiki/Create,_read,_update_and_delete) operations at runtime :white_check_mark:
  43 - Support for sync and async task functions :white_check_mark:
  44 - Tasks distribution strategies :white_check_mark:
  45 - Lockless tasks queueing :white_check_mark:
  46 - Queued tasks rescheduling:
  47   - Task stealing :white_check_mark:
  48   - Tasks stealing under back pressure :white_check_mark:
  49   - Tasks redistribution on worker error :white_check_mark:
  50 - General guidelines on pool choice :white_check_mark:
  51 - Error handling out of the box :white_check_mark:
  52 - Widely tested :white_check_mark:
  53 - Active community :white_check_mark:
  54 - 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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  61
  62 ## Table of contents
  63
  64 - [Overview](#overview)
  65 - [Installation](#installation)
  66 - [Usage](#usage)
  67 - [Node.js versions](#nodejs-versions)
  68 - [API](#api)
  69 - [General guidelines](#general-guidelines)
  70 - [Worker choice strategies](#worker-choice-strategies)
  71 - [Contribute](#contribute)
  72 - [Team](#team)
  73 - [License](#license)
  74
  75 ## Overview
  76
  77 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.
  78 The first implementation is a fixed worker pool, with a defined number of workers that are started at creation time and will be reused.
  79 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.
  80 You have to implement your worker by extending the _ThreadWorker_ or _ClusterWorker_ class.
  81
  82 ## Installation
  83
  84 ```shell
  85 npm install poolifier --save
  86 ```
  87
  88 ## Usage
  89
  90 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_:
  91
  92 ```js
  93 'use strict'
  94 const { ThreadWorker } = require('poolifier')
  95
  96 function yourFunction(data) {
  97   // this will be executed in the worker thread,
  98   // the data will be received by using the execute method
  99   return { ok: 1 }
 100 }
 101
 102 module.exports = new ThreadWorker(yourFunction, {
 103   maxInactiveTime: 60000
 104 })
 105 ```
 106
 107 Instantiate your pool based on your needs :
 108
 109 ```js
 110 'use strict'
 111 const { DynamicThreadPool, FixedThreadPool, PoolEvents, availableParallelism } = require('poolifier')
 112
 113 // a fixed worker_threads pool
 114 const pool = new FixedThreadPool(availableParallelism(), './yourWorker.js', {
 115   errorHandler: (e) => console.error(e),
 116   onlineHandler: () => console.info('worker is online')
 117 })
 118
 119 pool.emitter.on(PoolEvents.ready, () => console.info('Pool is ready'))
 120 pool.emitter.on(PoolEvents.busy, () => console.info('Pool is busy'))
 121
 122 // or a dynamic worker_threads pool
 123 const pool = new DynamicThreadPool(Math.floor(availableParallelism() / 2), availableParallelism(), './yourWorker.js', {
 124   errorHandler: (e) => console.error(e),
 125   onlineHandler: () => console.info('worker is online')
 126 })
 127
 128 pool.emitter.on(PoolEvents.full, () => console.info('Pool is full'))
 129 pool.emitter.on(PoolEvents.ready, () => console.info('Pool is ready'))
 130 pool.emitter.on(PoolEvents.busy, () => console.info('Pool is busy'))
 131
 132 // the execute method signature is the same for both implementations,
 133 // so you can easily switch from one to another
 134 pool
 135   .execute()
 136   .then((res) => {
 137     console.info(res)
 138   })
 139   .catch((err) => {
 140     console.error(err)
 141   })
 142 ```
 143
 144 You can do the same with the classes _ClusterWorker_, _FixedClusterPool_ and _DynamicClusterPool_.
 145
 146 **See [examples](./examples/) for more details**:
 147
 148 - [Javascript](./examples/javascript/)
 149 - [Typescript](./examples/typescript/)
 150   - [HTTP client pool](./examples/typescript/http-client-pool/)
 151   - [SMTP client pool](./examples/typescript/smtp-client-pool/)
 152   - [HTTP server pool](./examples/typescript/http-server-pool/)
 153     - [Express worker_threads pool](./examples/typescript/http-server-pool/express-worker_threads/)
 154     - [Express cluster pool](./examples/typescript/http-server-pool/express-cluster/)
 155     - [Express hybrid pool](./examples/typescript/http-server-pool/express-hybrid/)
 156     - [Fastify worker_threads pool](./examples/typescript/http-server-pool/fastify-worker_threads/)
 157     - [Fastify cluster pool](./examples/typescript/http-server-pool/fastify-cluster/)
 158     - [Fastify hybrid pool](./examples/typescript/http-server-pool/fastify-hybrid/)
 159   - [WebSocket server pool](./examples/typescript/websocket-server-pool/)
 160     - [ws worker_threads pool](./examples/typescript/websocket-server-pool/ws-worker_threads/)
 161     - [ws cluster pool](./examples/typescript/websocket-server-pool/ws-cluster/)
 162     - [ws hybrid pool](./examples/typescript/websocket-server-pool/ws-hybrid/)
 163
 164 Remember that workers can only send and receive structured-cloneable data.
 165
 166 ## Node.js versions
 167
 168 Node.js versions >= 16.14.x are supported.
 169
 170 ## [API](./docs/api.md)
 171
 172 ## [General guidelines](./docs/general-guidelines.md)
 173
 174 ## [Worker choice strategies](./docs/worker-choice-strategies.md)
 175
 176 ## Contribute
 177
 178 Choose your task [here](https://github.com/orgs/poolifier/projects/1), propose an idea, a fix, an improvement.
 179
 180 See [CONTRIBUTING](./CONTRIBUTING.md) guidelines.
 181
 182 ## Team
 183
 184 **Creator/Owner:**
 185
 186 - [**Alessandro Pio Ardizio**](https://github.com/pioardi)
 187
 188 **Maintainers:**
 189
 190 - [**Jérôme Benoit**](https://github.com/jerome-benoit)
 191
 192 **Contributors:**
 193
 194 - [**Shinigami92**](https://github.com/Shinigami92)
 195
 196 ## License
 197
 198 [MIT](./LICENSE)