AngularJS Chaos Monkey Service

This is a simple service you can inject anywhere inside an AngularJS application. It allows you to test random oddities in data throughout your application to ensure robust architecture.

Example Use Case An application that asynchronously retrieves and uses data from a server. That data may be lost in transit under certain circumstances, which leads to nondeterministic application behavior if not handled correctly. You can use Chaos Monkey to simulate that random data loss at any point your application.

Set Up

Include Source

You can include the minified version chaosMonkey-v0.1.min.js with your application or compile/minify on your own by including chaosMonkey-v0.1.coffee with your application assets.

Expose to Angular

Once Chaos Monkey is included with your app assets, include as an application dependency:

// Add Chaos Monkey as a dependency to your app
angular.module('your-angular-app', ['chaosmonkey']);

Then you can use Chaos Monkey anywhere in your application by injecting it as a dependency:

// Use Chaos Monkey in your Foo Controller
angular.module('your-angular-app').controller('FooCtrl', function($scope, ChaosMonkey) {
	// ...
});

Using Chaos Monkey

Chaos Monkey accepts any data and returns either the data untouched (i.e. what normal application flow should look like) or messed up in some way (simulating some application breakdown, network failure, etc.). The Monkey will accept a configuration object where you can specify any non-default behavior. See below for more details on configuration options. An example:

// Your normal data
var data = [1,2,3,4,5];

// Custom Chaos
var chaos_config = {'chaos_probability': 0.5};

// Overwrite data with output of Chaos monkey
data = ChaosMonkey.messItUp(data, chaos_config);

// Proceed to your normal next step
console.log('My data! ' + data);

The example above will, about half the time, return null instead of your normal value of data. You can also define a custom transform function to manipulate your data in some predetermined way, e.g. a function that doubles every array value whenever chaos strikes:

// Transform function
var chaos_fn = function (orig_arr) {
	var new_arr = [];
	for (var i = 0; i<orig_arr.length; i++) {
		new_arr.push(orig_arr[i]*2);
	};
	return new_arr;
};

// Tell chaos monkey about it
var chaos_config = {'chaos_function': chaos_fn};

// Use our newly configured monkey
data = ChaosMonkey.messItUp(data, chaos_config);

Configuration Options

Chaos Monkey's main method is messItUp, which expects to see at least some data and optionally some user_monkey_settings

data can be anything.

user_monkey_settings is in the form of a dictionary with the following possible options:

chaos_probability	- Chaos Probability (defaults to 0.1)
chaos_return_value	- Return value in event of chaos (defaults to null)
logging				- Logging (defaults to false)
chaos_function		- Chaos Transform Function (optional)

Chaos Monkey will return one of the following based on Chaos Probability: