socket-redis

socket-redis is a WebSocket pub/sub server and client, exposing an API over Redis (allowing you to use WebSocket functionality in your application using a Redis client).

About

socket-redis starts a WebSocket server (SockJS) where clients can connect to, and subscribe to multiple channels. The server will let you consume client-related events like message, subscribe and unsubscribe on a Redis pub/sub channel socket-redis-up. Additionally it will subscribe to another pub/sub channel socket-redis-down where you can send messages to all clients in a channel.

When specifying multiple --socket-ports the script will spawn a child process for each port. This is provided as a simple way to make use of all your CPU cores.

Server

Installation & Configuration

Package is available through npm registry:

npm install socket-redis [-g]
socket-redis.js --redis-host=my-redis

Or as a Docker image:

docker run cargomedia/socket-redis ./bin/socket-redis.js --redis-host=my-redis

See also the provided docker-compose.yml for reference.

Available options:

• --redis-host Specify host of redis server. Defaults to localhost.
• --redis-port Specify port. Default 6379
• --redis-pass Specify password if needed
• --socket-ports Comma separated public ports which SockJS workers will listen on. Defaults to 8090.
• --log-dir Directory where log is stored. Script will try to create directory if needed. Defaults to null which means it will output to stdout.
• --sockjs-client-url Specify custom url for sockjs-client library.
• --status-port Specify port for http status requests. It should not be publicly accesible. Defaults to 8085
• --status-secret Specify secret token to allow/deny http status requests (optional).
• --ssl-key Specify ssl private key file. Combine with ssl-cert option.
• --ssl-cert Specify ssl public certificate file. Combine with ssl-key option. Append CA-chain within this file.
• --ssl-pfx Specify ssl pfx file (key + cert). Overrides ssl-key and ssl-cert options.
• --ssl-passphrase Specify file containing the ssl passphrase.

Redis API

Messages published to redis pub/sub channel socket-redis-up:

• {type: "subscribe", data: {channel: <channel>, clientKey: <clientKey>, data: <subscribe-data>}}
• {type: "unsubscribe", data: {channel: <channel>, clientKey: <clientKey>}}
• {type: "message", data: {clientKey: <clientKey>, data: <data>}}

Messages consumed on redis pub/sub channel socket-redis-down:

• {type: "publish", data: {channel: <channel>, event: <event>, data: <data>}}

For example you could publish messages using Redis CLI:

redis-cli 'publish' 'socket-redis-down' '{"type":"publish", "data": {"channel":"<channel>", "event":"<event>", "data":"<data>"}}'

HTTP status API

Server also answers http status requests (on port 8085 by default).

A JSON representation of all current subscribers is returned on /:

$ curl 'http://localhost:8085/'

{<channel>: {
	"subscribers": {
		<clientKey>: {
			"clientKey": <clientKey>,
			"subscribeStamp": <subscribe-stamp>,
			"data": {}
		}
	}
}

A Prometheus scraping endpoint is responding on /metrics:

$ curl 'http://localhost:8085/metrics' 

# HELP socketredis_channels_total Number of channels
# TYPE socketredis_channels_total gauge
socketredis_channels_total 30

# HELP socketredis_subscribers_total Number of subscribers
# TYPE socketredis_subscribers_total gauge
socketredis_subscribers_total 90

Client

Building

Client is written as a node module. If you want to access it as a global variable in browser then you need to browserify client/index.js. It will be exposed under SocketRedis. Also it requires a global variable SockJS that contains sockjs client.

browserify --standalone SocketRedis ./client/index.js -o ./client/socket-redis.js

Installation

Include the SockJS and socket-redis client libraries in your html file:

<script src="http://cdn.sockjs.org/sockjs-0.3.min.js"></script>
<script src="./client/socket-redis.js"></script>

Example

To receive messages from the server create a new SocketRedis instance and subscribe to some channels:

var socketRedis = new SocketRedis('http://example.com:8090');
socketRedis.onopen = function() {
	socketRedis.subscribe('channel-name', null, {foo: 'bar'}, function(event, data) {
		console.log('New event `' + event + '` on channel `channel-name`:', data);
	});

	socketRedis.unsubscribe('channel-name');
};
socketRedis.open();

To publish messages to a channel from the client:

socketRedis.publish('channel-name', 'event-name', {foo: 'bar'});

(The event name will be prefixed with client- and thus become client-event-name.)

To send messages to the server:

socketRedis.send({foo: 'bar'});

Development

Install dependencies:

npm install

Build the docker image:

docker-compose build

Running Tests

docker-compose run --rm --volume $(pwd):/opt/socket-redis socket-redis ./script/test.sh

Running the Server

docker-compose run --volume $(pwd):/opt/socket-redis --service-ports socket-redis

Releasing new Versions

1. Update package.json with a new version
2. Push a new git tag with the updated package.json
3. The Travis build should deploy to NPM automatically

If it doesn't work you could release it manually with:

npm publish https://github.com/cargomedia/socket-redis/archive/<GitTagWithUpdatedPackageJson>.tar.gz