Simple Process Manager (SPaM)

 

SPAM is a module for simple node.js process management, and wraps the cluster module. It has nothing to do with email spam.

Use

Yarn is recommended as a package manager, but npm can be used as an alternative.

To install:

``sh


install yarn if required


npm install -g yarn
yarn add 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

`javascript
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
`javascript
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.

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

To stop all the processes:
`javascript
// 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();

`javascript
// using the signal module
var signal = require('spam').signal;
signal.ready();

// using the process.send method
process.send({ cmd: 'ready'});
`

$3

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

`sh


clone repo and install dependencies

git clone git@github.com:iandotkelly/spam.git
cd spam
yarn

run tests

yarn test
`

Coverage can be measured after running the tests, and an html coverage report is written in the coverage/lcov-report directory:
`sh
open coverage/lcov-report/index.html
``

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