reduler - a redis-backed distributed task scheduler

Usage

var cluster = require('cluster');
var reduler = require('reduler');
var numCPUs = require('os').cpus().length;

reduler.connect();

if (cluster.isMaster) {
  for (var i = 0; i < numCPUs; ++i)
    cluster.fork();

  reduler.run();

  console.log((new Date()).toString() + ' adding...');
  reduler.add('multiply', [1, 2], {
    start: Date.now() + 10000
  }, function(err, id) {
    console.log((new Date()).toString() + ' added: multiply [1, 2]', err, id);
  });

  console.log((new Date()).toString() + ' adding...');
  reduler.add('multiply', [3, 4], {
    start: Date.now() + 3000,
    repeats: 2
  }, function(err, id) {
    console.log((new Date()).toString() + ' added: multiply [3, 4]', err, id);
  });
} else {
  var tasks = {
    'multiply': function (a, b) {
      console.log(a * b);
    }
  }
  reduler.worker(function(id, name, args) {
    console.log((new Date()).toString() + ' worker-' + cluster.worker.id, id, name, args);
    tasks[name].apply(null, args);
  });
}

Output:

Fri Nov 15 2013 14:23:38 GMT+0800 (CST) adding...
Fri Nov 15 2013 14:23:38 GMT+0800 (CST) adding...
Fri Nov 15 2013 14:23:38 GMT+0800 (CST) added: multiply [1, 2] null 5
Fri Nov 15 2013 14:23:38 GMT+0800 (CST) added: multiply [3, 4] null 6
Fri Nov 15 2013 14:23:41 GMT+0800 (CST) worker-1 6 multiply [ 3, 4 ]
12
Fri Nov 15 2013 14:23:48 GMT+0800 (CST) worker-2 5 multiply [ 1, 2 ]
2
Fri Nov 15 2013 14:24:41 GMT+0800 (CST) worker-1 6 multiply [ 3, 4 ]
12

API

reduler.connect([host], [port])

Default host 127.0.0.1, port 6379.

reduler.add(name, args, [options], [callback])

• name
• args
• options Object
  • start start date running the task, default is Date.now().
  • repeats default is 1, use 0 for unlimited.
  • period the time in milliseconds of repeat cycle, default 60000.
• callback Function
  The callback gets two arguments (err, id).

reduler.remove(id)

reduler.run()

The main loop handling tasks life cycle, there should have exactly one invocation.

reduler.worker(callback)

The worker can be invoked from a process other than the one calling reduler.run().
The callback gets three arguments (id, name, args), where name and args are the ones from reduler.add().