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https://github.com/fent/clusterhub
Sync data in your cluster applications.
https://github.com/fent/clusterhub
cluster node
Last synced: about 1 month ago
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Sync data in your cluster applications.
- Host: GitHub
- URL: https://github.com/fent/clusterhub
- Owner: fent
- License: mit
- Created: 2012-02-12T04:10:00.000Z (over 12 years ago)
- Default Branch: master
- Last Pushed: 2020-07-03T19:12:11.000Z (about 4 years ago)
- Last Synced: 2024-07-20T01:15:11.314Z (about 2 months ago)
- Topics: cluster, node
- Language: JavaScript
- Homepage:
- Size: 104 KB
- Stars: 133
- Watchers: 9
- Forks: 7
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# clusterhub
An attempt at giving multi process node programs a simple and efficient way to share data.
[](http://travis-ci.org/fent/clusterhub)
[](https://david-dm.org/fent/clusterhub)
[](https://codecov.io/gh/fent/clusterhub)
# Usage
```js
const cluster = require('cluster');
const numCPUs = require('os').cpus().length;
const hub = require('clusterhub');
if (cluster.isMaster) {
// Fork workers.
for (let i = 0; i < numCPUs; i++) {
cluster.fork();
}
} else {
hub.on('event', (data) => {
// do something with `data`
});
// emit event to all workers
hub.emit('event', { foo: 'bar' });
}
```
# Features
* Efficient event emitter system. Clusterhub will not send an event to a process that isn't listening for it. Events from the same process of a listener will be emitted synchronously.
* In process database. Each hub has its own instance of a redis-like database powered by [EventVat][eventvat].
# Motive
Node.js is a perfect candidate to developing [Date Intensive Real-time Applications](http://video.nextconf.eu/video/1914374/nodejs-digs-dirt-about). Load balancing in these applications can become complicated when having to share data between processes.
A remote database can be an easy solution for this, but it's not the most optimal. Communicating with a local process is several times faster than opening remote requests from a database. And even if the database is hosted locally, the overhead of communicating with yet another program is lessened.
Note that this module is experimental. It currently works by using a process's internal messaging system.
## Made with Clusterhub
* [socket.io-clusterhub](https://github.com/fent/socket.io-clusterhub) - Sync data between multi-process socket.io applications.
* [clusterchat](https://github.com/fent/clusterchat) - A multi-process chat that shows off socket.io-clusterhub.
# API
### hub.createHub(id)
Clusterhub already comes with a default global hub. But you can use this if you want to create more.
### Hub#destroy()
Call to disable hub from emitting and receiving remote messages/commands.
Additionally, all functions from the regular [EventEmitter](http://nodejs.org/docs/latest/api/events.html#events.EventEmitter) are included. Plus a couple of extras.
### Hub#emitLocal(event, ...args)
Emit an event only to the current process.
### Hub#emitRemote(event, ...args)
Emit an event only to other worker processes and master. Or only to workers if the current process is the master.
```js
hub.on('remotehello', () => {
// Hello from another process.
});
hub.emitRemote('remotehello', { hello: 'there' });
```
All functions from [EventVat][eventvat] are included as well. Their returned value can be accessed by providing a callback as the last argument. Or optionally by its returned value if called by the master.
[eventvat]: https://github.com/hij1nx/EventVat
#### worker process
```js
hub.set('foo', 'bar', () => {
hub.get('foo', (val) => {
console.log(val === 'bar'); // true
});
});
```
#### master process
```js
let returnedVal = hub.incr('foo', (val) => {
// Can be given a callback for consistency.
console.log(val === 1); // true
});
// But since it's the master process it has direct access to the database.
console.log(returnedVal === 1); // true
```
# Install
npm install clusterhub
# Tests
Tests are written with [mocha](https://mochajs.org)
```bash
npm test
```