zeromq-lpclient

ZeroMQ Reliable Request-Reply Lazy Pirate Pattern - client module

Don't know what this is? See the 0MQ Guide.

Usage

Use in conjunction with Lazy Pirate Server or Paranoid Pirate Queue and Paranoid Pirate Worker.

Make sure you have 0MQ installed on your machine first (ie. the C libraries). For OS X you can do this:

$ brew install --universal zeromq

On Ubuntu:

$ sudo apt-get -y install libzmq3-dev

Then you should be able to install NPM modules that depend upon the 0MQ libs (like this one).

Lazy Pirate example

lpclient.js (taken from https://github.com/lukebond/zeromq-lpclient/blob/master/example/example.js):

var LPClient = require('../index');

var lpc = new LPClient({url: 'tcp://127.0.0.1:9000', timeout: 2500});

lpc.on('message', function (message) {
  console.log(Date.now() + ' - Got work:', message.toString('utf8'));
  setTimeout(function () {
    lpc.ready();
  }, 100);
});
lpc.ready();

lpserver.js (taken from https://github.com/lukebond/zeromq-lpserver/blob/master/example/example.js):

var LPServer = require('../index');

function workerFn(cb) {
  console.log(Date.now() + ' - Got a request for work');
  return cb(JSON.stringify({lpserver: 'pretending to do work'}));
}

var lps = new LPServer({url: 'tcp://127.0.0.1:9000'}, workerFn);

lps.on('error', function (error) {
  console.log('error', error);
  process.exit(1);
});

Run both of these together in two different terminals and you should get output like this:

$ node lpclient
1406654717202 - Got work: {"lpserver":"pretending to do work"}
1406654717305 - Got work: {"lpserver":"pretending to do work"}
1406654717405 - Got work: {"lpserver":"pretending to do work"}
1406654717507 - Got work: {"lpserver":"pretending to do work"}
1406654717608 - Got work: {"lpserver":"pretending to do work"}
1406654717709 - Got work: {"lpserver":"pretending to do work"}
1406654717810 - Got work: {"lpserver":"pretending to do work"}
1406654717912 - Got work: {"lpserver":"pretending to do work"}
1406654718014 - Got work: {"lpserver":"pretending to do work"}

$ node lpserver
1406654716237 - Got a request for work
1406654717191 - Got a request for work
1406654717305 - Got a request for work
1406654717405 - Got a request for work
1406654717507 - Got a request for work
1406654717607 - Got a request for work
1406654717708 - Got a request for work
1406654717810 - Got a request for work
1406654717912 - Got a request for work
1406654718013 - Got a request for work

Paranoid Pirate example

For Paranoid Pirate we need three components- the Lazy Pirate client, Paranoid Pirate queue and Paranoid Pirate worker.

ppqueue.js (taken from https://github.com/lukebond/zeromq-ppqueue/blob/master/example/example.js):

var PPQueue = require('../index');
var ppq = new PPQueue({backendUrl: 'tcp://127.0.0.1:9001', frontendUrl: 'tcp://127.0.0.1:9000'});

ppworker.js (taken from https://github.com/lukebond/zeromq-ppworker/blob/master/example/example.js):

var PPWorker = require('../index');

function workerFn(cb) {
  console.log(Date.now() + ' - Got a request for work');
  return cb(JSON.stringify({ppworker: 'pretending to do work'}));
}

var ppw = new PPWorker({url: 'tcp://127.0.0.1:9001'}, workerFn);

Run all three together in different terminals and you should get output like this:

$ node lpclient
1406655819662 - Got work: {"ppworker":"pretending to do work"}
1406655819766 - Got work: {"ppworker":"pretending to do work"}
1406655819867 - Got work: {"ppworker":"pretending to do work"}
1406655819969 - Got work: {"ppworker":"pretending to do work"}
1406655820071 - Got work: {"ppworker":"pretending to do work"}
1406655820172 - Got work: {"ppworker":"pretending to do work"}
1406655820273 - Got work: {"ppworker":"pretending to do work"}
1406655820374 - Got work: {"ppworker":"pretending to do work"}
1406655820476 - Got work: {"ppworker":"pretending to do work"}

$ node ppqueue

(no output)

$ node ppworker
1406655819650 - Got a request for work
1406655819765 - Got a request for work
1406655819867 - Got a request for work
1406655819969 - Got a request for work
1406655820071 - Got a request for work
1406655820172 - Got a request for work
1406655820272 - Got a request for work
1406655820374 - Got a request for work
1406655820476 - Got a request for work

The Paranoid Pirate queue is routing the request-reply pairs between the client and the worker.

Tests

A bit thin on the ground at the moment, but there is an integration test in the ppqueue project that tests Lazy Pirate client, Paranoid Pirate queue and Paranoid Pirate worker together.

Licence

MIT