Commit | Line | Data |
---|---|---|
987e0026 | 1 | # Node Thread Pool :arrow_double_up: :on: |
34a572eb | 2 | [![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com) |
103df814 | 3 | [![Dependabot](https://badgen.net/dependabot/dependabot/dependabot-core/?icon=dependabot)](https://badgen.net/dependabot/dependabot/dependabot-core/?icon=dependabot) |
e7752b74 | 4 | [![Actions Status](https://github.com/pioardi/node-pool/workflows/NodeCI/badge.svg)](https://github.com/pioardi/node-pool/actions) |
754c89d2 | 5 | [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) |
106744f7 | 6 | [![NODEP](https://img.shields.io/static/v1?label=dependencies&message=no%20dependencies&color=brightgreen |
7 | )](https://img.shields.io/static/v1?label=dependencies&message=no%20dependencies&color=brightgreen | |
8 | ) | |
b4b2dc8b | 9 | |
34a572eb | 10 | <h2>Contents </h2> |
11 | <h3 align="center"> | |
12 | <a href="#installation">Installation</a> | |
13 | <span> · </span> | |
14 | <a href="#usage">Usage</a> | |
15 | <span> · </span> | |
16 | <a href="#api">API</a> | |
17 | <span> · </span> | |
48211d04 APA |
18 | <a href="#cyp">Choose a pool</a> |
19 | <span> · </span> | |
34a572eb | 20 | <a href="#contribute">Contribute</a> |
21 | <span> · </span> | |
22 | <a href="#nv">Compatibility</a> | |
23 | <span> · </span> | |
24 | <a href="#license">License</a> | |
25 | </h3> | |
26 | ||
f349ea72 | 27 | <h2> Overview </h2> |
1a4ec243 | 28 | Node pool contains two <a href="https://nodejs.org/api/worker_threads.html#worker_threads_worker_threads">worker-threads </a> pool implementations , you don' t have to deal with worker-threads complexity. <br> |
755f08b3 | 29 | The first implementation is a static thread pool , with a defined number of threads that are started at creation time and will be reused.<br> |
106744f7 | 30 | The second implementation is a dynamic thread pool with a number of threads started at creation time ( these threads will be always active and reused) and other threads created when the load will increase ( with an upper limit, these threads will be reused when active ), the new created threads will be stopped after a configurable period of inactivity. <br> |
34a572eb | 31 | You have to implement your worker extending the ThreadWorker class<br> |
32 | <h2 id="installation">Installation</h2> | |
13031992 | 33 | |
1a4ec243 | 34 | ``` |
ba2be357 | 35 | npm install node-thread-pool --save |
1a4ec243 | 36 | ``` |
34a572eb | 37 | <h2 id="usage">Usage</h2> |
1a4ec243 APA |
38 | |
39 | You can implement a worker in a simple way , extending the class ThreadWorker : | |
40 | ||
41 | ```js | |
42 | 'use strict' | |
43 | const { ThreadWorker } = require('node-pool') | |
44 | ||
106744f7 | 45 | function yourFunction (data) { |
46 | // this will be executed in the worker thread, | |
47 | // the data will be received by using the execute method | |
48 | return { ok: 1 } | |
49 | } | |
50 | ||
1a4ec243 APA |
51 | class MyWorker extends ThreadWorker { |
52 | constructor () { | |
106744f7 | 53 | super(yourFunction, { maxInactiveTime: 1000 * 60}) |
1a4ec243 APA |
54 | } |
55 | } | |
56 | module.exports = new MyWorker() | |
57 | ``` | |
58 | ||
59 | Instantiate your pool based on your needed : | |
60 | ||
61 | ```js | |
62 | 'use strict' | |
34a572eb | 63 | const { FixedThreadPool, DynamicThreadPool } = require('node-pool') |
1a4ec243 APA |
64 | |
65 | // a fixed thread pool | |
66 | const pool = new FixedThreadPool(15, | |
106744f7 | 67 | './yourWorker.js', |
68 | { errorHandler: (e) => console.error(e), onlineHandler: () => console.log('worker is online') }) | |
1a4ec243 APA |
69 | |
70 | // or a dynamic thread pool | |
71 | const pool = new DynamicThreadPool(10, 100, | |
106744f7 | 72 | './yourWorker.js', |
73 | { errorHandler: (e) => console.error(e), onlineHandler: () => console.log('worker is online') }) | |
74 | ||
1a4ec243 APA |
75 | pool.emitter.on('FullPool', () => console.log('Pool is full')) |
76 | ||
77 | // the execute method signature is the same for both implementations, | |
78 | // so you can easy switch from one to another | |
79 | pool.execute({}).then(res => { | |
80 | console.log(res) | |
81 | }).catch .... | |
82 | ||
83 | ``` | |
84 | ||
106744f7 | 85 | <strong> See examples folder for more details ( in particular if you want to use a pool for [multiple functions](./examples/multiFunctionExample.js) ).</strong> |
1a4ec243 | 86 | |
34a572eb | 87 | <h2 id="nv">Node versions</h2> |
88 | ||
ab1526e9 | 89 | You can use node version 10.x with --experimental-worker flag, or you can use an higher version (i.e 12.x) <br> |
1a4ec243 | 90 | |
34a572eb | 91 | <h2 id="api">API</h2> |
92 | ||
93 | ### `pool = new FixedThreadPool(numThreads, filePath, opts)` | |
94 | `numThreads` (mandatory) Num of threads for this worker pool <br> | |
95 | `filePath` (mandatory) Path to a file with a worker implementation <br> | |
96 | `opts` (optional) An object with these properties : | |
97 | - `errorHandler` - A function that will listen for error event on each worker thread | |
98 | - `onlineHandler` - A function that will listen for online event on each worker thread | |
99 | - `exitHandler` - A function that will listen for exit event on each worker thread | |
100 | - `maxTasks` - This is just to avoid not useful warnings message, is used to set <a href="https://nodejs.org/dist/latest-v12.x/docs/api/events.html#events_emitter_setmaxlisteners_n">maxListeners</a> on event emitters ( workers are event emitters) | |
101 | ||
102 | ### `pool = new DynamicThreadPool(min, max, filePath, opts)` | |
103 | `min` (mandatory) Same as FixedThreadPool numThreads , this number of threads will be always active <br> | |
104 | `max` (mandatory) Max number of workers that this pool can contain, the new created threads will die after a threshold ( default is 1 minute , you can override it in your worker implementation). <br> | |
105 | `filePath` (mandatory) Same as FixedThreadPool <br> | |
106 | `opts` (optional) Same as FixedThreadPool <br> | |
107 | ||
108 | ### `pool.execute(data)` | |
109 | Execute method is available on both pool implementations ( return type : Promise): <br> | |
110 | `data` (mandatory) An object that you want to pass to your worker implementation <br> | |
111 | ||
112 | ### `pool.destroy()` | |
113 | Destroy method is available on both pool implementations.<br> | |
114 | This method will call the terminate method on each worker. | |
115 | ||
116 | ||
117 | ### `class YourWorker extends ThreadWorker` | |
118 | `fn` (mandatory) The function that you want to execute on the worker thread <br> | |
119 | `opts` (optional) An object with these properties : | |
120 | - `maxInactiveTime` - Max time to wait tasks to work on ( in ms) , after this period the new worker threads will die. | |
121 | ||
48211d04 | 122 | <h2 id="cyp">Choose your pool</h2> |
106744f7 | 123 | Performance is one of the main target of these thread pool implementations, we want to have a strong focus on this.<br> |
48211d04 APA |
124 | We already have a bench folder where you can find some comparisons. |
125 | To choose your pool consider that with a FixedThreadPool or a DynamicThreadPool ( in this case is important the min parameter passed to the constructor) your application memory footprint will increase . <br> | |
106744f7 | 126 | Increasing the memory footprint, your application will be ready to accept more CPU bound tasks, but during idle time your application will consume more memory. <br> |
48211d04 | 127 | One good choose from my point of view is to profile your application using Fixed/Dynamic thread pool , and to see your application metrics when you increase/decrease the num of threads. <br> |
106744f7 | 128 | For example you could keep the memory footprint low choosing a DynamicThreadPool with 5 threads, and allow to create new threads until 50/100 when needed, this is the advantage to use the DynamicThreadPool. <br> |
48211d04 APA |
129 | But in general , <strong>always profile your application </strong> |
130 | ||
34a572eb | 131 | <h2 id="contribute">Contribute</h2> |
132 | ||
133 | See guidelines [CONTRIBUTING](./.github/CONTRIBUTING.md) | |
1a4ec243 | 134 | |
1a4ec243 | 135 | |
34a572eb | 136 | <h2 id="license">License</h2> |
1a4ec243 | 137 | |
9507c1d4 | 138 | [MIT](./LICENSE) |
1a4ec243 | 139 |