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 APA |
5 | [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) |
6 | ||
b4b2dc8b | 7 | |
34a572eb | 8 | <h2>Contents </h2> |
9 | <h3 align="center"> | |
10 | <a href="#installation">Installation</a> | |
11 | <span> · </span> | |
12 | <a href="#usage">Usage</a> | |
13 | <span> · </span> | |
14 | <a href="#api">API</a> | |
15 | <span> · </span> | |
48211d04 APA |
16 | <a href="#cyp">Choose a pool</a> |
17 | <span> · </span> | |
34a572eb | 18 | <a href="#contribute">Contribute</a> |
19 | <span> · </span> | |
20 | <a href="#nv">Compatibility</a> | |
21 | <span> · </span> | |
22 | <a href="#license">License</a> | |
23 | </h3> | |
24 | ||
f349ea72 | 25 | <h2> Overview </h2> |
1a4ec243 | 26 | 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 APA |
27 | 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> |
28 | 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 ), the new created threads will be stopped after a configurable period of inactivity. <br> | |
34a572eb | 29 | You have to implement your worker extending the ThreadWorker class<br> |
30 | <h2 id="installation">Installation</h2> | |
13031992 | 31 | |
1a4ec243 | 32 | ``` |
ba2be357 | 33 | npm install node-thread-pool --save |
1a4ec243 | 34 | ``` |
34a572eb | 35 | <h2 id="usage">Usage</h2> |
1a4ec243 APA |
36 | |
37 | You can implement a worker in a simple way , extending the class ThreadWorker : | |
38 | ||
39 | ```js | |
40 | 'use strict' | |
41 | const { ThreadWorker } = require('node-pool') | |
42 | ||
43 | class MyWorker extends ThreadWorker { | |
44 | constructor () { | |
45 | super((data) => { | |
34a572eb | 46 | // this will be executed in the worker thread, |
47 | // the data will be received by using the execute method | |
1a4ec243 | 48 | return { ok: 1 } |
34a572eb | 49 | }, { maxInactiveTime: 1000 * 60}) |
1a4ec243 APA |
50 | } |
51 | } | |
52 | module.exports = new MyWorker() | |
53 | ``` | |
54 | ||
55 | Instantiate your pool based on your needed : | |
56 | ||
57 | ```js | |
58 | 'use strict' | |
34a572eb | 59 | const { FixedThreadPool, DynamicThreadPool } = require('node-pool') |
1a4ec243 APA |
60 | |
61 | // a fixed thread pool | |
62 | const pool = new FixedThreadPool(15, | |
63 | './yourWorker.js') | |
64 | ||
65 | // or a dynamic thread pool | |
66 | const pool = new DynamicThreadPool(10, 100, | |
67 | './yourWorker.js') | |
68 | pool.emitter.on('FullPool', () => console.log('Pool is full')) | |
69 | ||
70 | // the execute method signature is the same for both implementations, | |
71 | // so you can easy switch from one to another | |
72 | pool.execute({}).then(res => { | |
73 | console.log(res) | |
74 | }).catch .... | |
75 | ||
76 | ``` | |
77 | ||
28b6da3e | 78 | <strong> See examples folder for more details.</strong> |
1a4ec243 | 79 | |
34a572eb | 80 | <h2 id="nv">Node versions</h2> |
81 | ||
ab1526e9 | 82 | You can use node version 10.x with --experimental-worker flag, or you can use an higher version (i.e 12.x) <br> |
1a4ec243 | 83 | |
34a572eb | 84 | <h2 id="api">API</h2> |
85 | ||
86 | ### `pool = new FixedThreadPool(numThreads, filePath, opts)` | |
87 | `numThreads` (mandatory) Num of threads for this worker pool <br> | |
88 | `filePath` (mandatory) Path to a file with a worker implementation <br> | |
89 | `opts` (optional) An object with these properties : | |
90 | - `errorHandler` - A function that will listen for error event on each worker thread | |
91 | - `onlineHandler` - A function that will listen for online event on each worker thread | |
92 | - `exitHandler` - A function that will listen for exit event on each worker thread | |
93 | - `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) | |
94 | ||
95 | ### `pool = new DynamicThreadPool(min, max, filePath, opts)` | |
96 | `min` (mandatory) Same as FixedThreadPool numThreads , this number of threads will be always active <br> | |
97 | `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> | |
98 | `filePath` (mandatory) Same as FixedThreadPool <br> | |
99 | `opts` (optional) Same as FixedThreadPool <br> | |
100 | ||
101 | ### `pool.execute(data)` | |
102 | Execute method is available on both pool implementations ( return type : Promise): <br> | |
103 | `data` (mandatory) An object that you want to pass to your worker implementation <br> | |
104 | ||
105 | ### `pool.destroy()` | |
106 | Destroy method is available on both pool implementations.<br> | |
107 | This method will call the terminate method on each worker. | |
108 | ||
109 | ||
110 | ### `class YourWorker extends ThreadWorker` | |
111 | `fn` (mandatory) The function that you want to execute on the worker thread <br> | |
112 | `opts` (optional) An object with these properties : | |
113 | - `maxInactiveTime` - Max time to wait tasks to work on ( in ms) , after this period the new worker threads will die. | |
114 | ||
48211d04 APA |
115 | <h2 id="cyp">Choose your pool</h2> |
116 | Performance is one of the main target of these thread pool implementation, we want to have a strong focus on this.<br> | |
117 | We already have a bench folder where you can find some comparisons. | |
118 | 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> | |
119 | 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> | |
120 | 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> | |
121 | 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 requests, this is the advantage to use the DynamicThreadPool. <br> | |
122 | But in general , <strong>always profile your application </strong> | |
123 | ||
34a572eb | 124 | <h2 id="contribute">Contribute</h2> |
125 | ||
126 | See guidelines [CONTRIBUTING](./.github/CONTRIBUTING.md) | |
1a4ec243 | 127 | |
1a4ec243 | 128 | |
34a572eb | 129 | <h2 id="license">License</h2> |
1a4ec243 | 130 | |
9507c1d4 | 131 | [MIT](./LICENSE) |
1a4ec243 | 132 |