process-manager

process-manager is a module for simple node.js and io.js process management, and wraps the cluster module.

Previously called SPaM (https://github.com/iandotkelly/spam)

Use

To install:

$ npm install process-manager

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 pm = require('process-manager');
 
// to create 4 processes using the myscript.js script - ready on listen(),
// created in parallel, with a timeout of 60 seconds
pm.setScript('./myscript.js');
pm.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
pm.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 process-manager

pm.on('log', function(message) {
    // do some logging
    console.log('PM: ' + 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
pm.restart({ strategy: 'series' }, function(err) {
    if (err) {
        console.log('oops');
    }
});

To stop all the processes:

// stop all
pm.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 process-manager 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('process-manager').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/process-manager
$ 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

License

The MIT License (MIT)

Copyright (c) 2013-2015 Ian Kelly

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.