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spam

Simple Process Manager (SPaM)

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SPAM is a module for simple node.js process management, and wraps the cluster module.

Use

To install:

$ npm install spam

To create some processes, using the spawn method. This takes the following parameters:

  • Configuration object
    • number (number of processes to spawn, e.g. 4)
    • timeout (time in milliseconds to allow each spawn to occur, before timing out)
    • strategy (either 'series', or 'parallel', to spawn one at a time, or all together)
    • readyOn (what signal indicates the script is ready, 'ready' or 'listening' - default)
  • Callback when initialization of the module is complete
var spam = require('spam');
 
// to create 4 processes using the myscript.js script - ready on listen(), 
// created in parallel, with a timeout of 60 seconds 
spam.setScript('./myscript.js');
spam.spawn(
    {
        number: 4,
        timeout: 60000,
        strategy: 'parallel'
    }, function(err) {
            // callback occurs when all processes have declared they are working 
            // or a timeout occurs 
            if (err) {
                console.log('oops');
            }
});
 
// to create 2 processes callback is called when 'ready' message sent, not on 'listen' 
// created in series, with no timeout 
spam.spawn(
    {
        number: 2,
        timeout: 0,
        strategy: 'serial',
        readyOn: 'ready'
    },  function(err) {
            // callback occurs when all processes have declared they are working 
            // or a timeout occurs 
            if (err) {
                console.log('oops');
            }
});

If you want to log what's going on in SPAM

spam.on('log', function(message) {
    // do some logging 
    console.log('SPAM: ' + message);
});

If you want to gracefully restart all the processes, by starting a new worker before killing the old worker, do this with the restart method.

// graceful restart of all the processes 
spam.restart({ strategy: 'series' }, function(err) {
    if (err) {
        console.log('oops');
    }
});

To stop all the processes:

// stop all 
spam.stop(function() {
    console.log('stop initiated')
});

NOTE: The scripts that are run, either need to run server.listen() or emit a specific 'ready' message. If they do not do this, then SPAM will assume they've not started and time them out. You can emit a 'ready' message using a convenience function or explicitly using process.send();

// using the signal module 
var signal = require('spam').signal;
signal.ready();
 
// using the process.send method 
process.send({ cmd: 'ready'});

Tests

To run the npm unit tests, install development dependencies and run tests with 'npm test' or 'make'.

cd node_modules/spam
$ npm install
$ npm test

If you contribute to the project, tests are written in mocha, using should.js or the node.js assert module.

Coverage can be measured using the node-jscoverage project. After installing jscoverage from github, just:

$ make test-cov