zmq-json-pub.js
A node.js module for publishing JSON messages via 0MQ (ZeroMQ)
Install 0MQ
On a Mac:
$ brew install zmq
To verify the installation
$ man zmq
See zeromq.org
Install zmq-json-pub in your project
$ npm init
$ npm install zmq-json-pub --save
Usage
The complete project can be found in the examples/demo folder.
This example shows how to create a simple app that publishes a heartbeat JSON message every 3 seconds. The example JSON is completely arbitrary. You can specify your own JSON format.
File: examples/demo/config.js
var config = {};
config.endpoint = "tcp://*:5431";
config.interval = 3000; // micro seconds
module.exports = config;
File: examples/demo/index.js
"use strict";
var ZmqJsonPub = require('zmq-json-pub'),
config = require('./config'),
pub = new ZmqJsonPub();
pub.publish(config.endpoint);
let data = {
type: "heartbeat",
status: "OK",
message: 'service is running',
timestamp: Date.now()
}
function heartbeat() {
data.timestamp = Date.now();
console.log("sending heartbeat at " + new Date(data.timestamp));
pub.send(data, function(err) {
if (err) {
console.log(err);
return;
}
});
setTimeout(heartbeat, config.interval);
}
console.log("Sending heartbeat every " + config.interval / 1000 + " seconds")
setTimeout(heartbeat, config.interval);
/*
Handle termination can close pub.
*/
// terminator === the termination handler.
function terminator(sig) {
if (typeof sig === "string") {
console.log('%s: Received %s - terminating Node server ...',
Date(Date.now()), sig);
console.log("Closing publisher before exit");
pub.close();
process.exit(1);
}
console.log('%s: Node server stopped.', Date(Date.now()) );
}
// Process on exit and signals.
process.on('exit', function() { terminator(); });
['SIGHUP', 'SIGINT', 'SIGQUIT', 'SIGILL', 'SIGTRAP', 'SIGABRT', 'SIGBUS',
'SIGFPE', 'SIGUSR1', 'SIGSEGV', 'SIGUSR2', 'SIGPIPE', 'SIGTERM'
].forEach(function(element, index, array) {
process.on(element, function() { terminator(element); });
});
To run:
$ node index.js
To stop press Ctrl-C.
Tests
Tests assume that mocha has been installed globally. If not execute the following:
$ npm install -g mocha
Run the tests from the projects root folder in one of the following ways:
$ mocha --recursive --timeout 20000
Or
$ npm test
Or if you feel like kickin' it old skool:
make test
Testing by Version
To run the tests for each version (currently there is only one version (v0001)):
$ mocha --timeout 5000 --recursive test/v0001/*test.js
The tests generate log files in a logs/ folder under the projects root folder.
Repo(s)
Contributing
In lieu of a formal style guide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.
Version History
Version 0.1.2 release notes
- Wrapped send call in setTimeout
- Added sendDelay property (in micro seconds)
Version 0.1.1 release notes
- Updated example to use published module
Version 0.1.0 release notes
- Initial release