https://github.com/jclem/clusterflock
a clustering server for node that speaks in signals
https://github.com/jclem/clusterflock
Last synced: about 1 year ago
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a clustering server for node that speaks in signals
- Host: GitHub
- URL: https://github.com/jclem/clusterflock
- Owner: jclem
- License: mit
- Created: 2014-03-03T00:48:38.000Z (over 12 years ago)
- Default Branch: master
- Last Pushed: 2014-10-27T18:05:23.000Z (over 11 years ago)
- Last Synced: 2025-04-10T17:31:09.036Z (about 1 year ago)
- Language: JavaScript
- Homepage: npmjs.org/package/clusterflock
- Size: 332 KB
- Stars: 9
- Watchers: 1
- Forks: 0
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
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README
# clusterflock [](https://travis-ci.org/jclem/clusterflock)
clusterflock is a simple clustering HTTP server for Node. It accepts a single request handler and a hash of options. The goal of clusterflock is to eliminate my own repeated need for a simple clustering server that implements graceful worker shutdown and re-forking of dead workers.
**This package is deprecated.** I wrote a much more well-tested version without the known bugs of clusterflock called [teamster](https://www.npmjs.org/package/teamster).
## Installation
```sh
$ npm install clusterflock --save
```
## Usage
By default, clusterflock will fork the number of workers equal to `os.cpus().length`. When it receives a `SIGINT` or `SIGTERM` signal, it will begin attempting to shut down gracefully by ceasing to receive requests and closing all servers after existing requests have been completed.
The simplest use case of clusterflock is to pass it a single request handler function:
```javascript
var clusterflock = require('clusterflock');
clusterflock(function (req, res) {
res.end('ok');
});
```
Since clusterflock essentially just calls `http.createServer` in the worker process, anything that can be normally passed to that function can be passed to the `clusterflock` main function, including [express](http://expressjs.com) apps:
```javascript
var clusterflock = require('clusterflock'),
express = require('express'),
app = express();
app.use(express.bodyParser()); // &c.
clusterflock(app);
```
### Worker Re-forking
When a worker disconnects, the master checks the value of its [`suicide`](http://nodejs.org/api/cluster.html#cluster_worker_suicide) attribute. If that value is true, master does nothing. If that value is not true (i.e. the worker died/was killed unintentionally), the master forks a new worker.
## Options
The `clusterflock` function accepts an options object:
```javascript
var clusterflock = require('clusterflock'),
app = require('./lib/app');
clusterflock(app, {
numWorkers: 1,
port : 3000,
timeout : 5000
});
```
Name | Type(s) | Default | Description
------------ | ------------------ | -------------------------- | ------------------
`numWorkers` | `Number` | `os.cpus().length` | number of worker processes to fork
`port` | `Number`, `String` | process.env.PORT || 5000 | port the workers will listen on
`timeout` | `Number` | `1000` | amount of time after receiving a graceful shutdown signal that the master will immediately kill workers
## Signals
clusterflock responds to signals. [heroku, for example](https://devcenter.heroku.com/articles/dynos#graceful-shutdown-with-sigterm), sends `SIGTERM` to stop and restart dynos, which will cause clusterflock to initiate a graceful shutdown. `SIGINT`, on the other hand, will force clusterflock to shut down immediately.
Signal | Behavior
--------- | --------------------------------------------------------
`SIGTTIN` | Fork an additonal worker
`SIGTTOU` | Disconnect the least-recently forked worker
`SIGINT` | Kill master process (and therefore workers) immediately.
`SIGTERM` | Forward myself `SIGQUIT`.
`SIGQUIT` | Attempt a graceful shutdown (stop serving requests, serve remaining requests, and shut down).
## Testing
To run the tests:
```sh
$ npm test
```
## Contributing
1. Fork it.
2. Create a branch (`git checkout -b my-clusterflock`)
3. Commit your changes (`git commit -am "add unicorns"`)
4. Push to the branch (`git push origin my-clusterflock`)
5. Open a [Pull Request](http://github.com/jclem/clusterflock/pulls)
## Meta
The photo in this readme is by Flickr user [Eugene Zemlyanskiy](http://www.flickr.com/photos/pictureperfectpose/81938785/). It has a [CC BY 2.0](http://creativecommons.org/licenses/by/2.0/) license.
## Thanks, Heroku
While I created and maintain this project, it was done while I was an employee
of [Heroku][heroku] on the Human Interfaces Team, and they were kind enough to
allow me to open source the work. Heroku is awesome.
[heroku]: https://www.heroku.com/home