CloudMonkey

Small infrastructure testing framework -- EXPERIMENTAL

The idea is to fill the gap between unit testing of infrastructure scripts (Terraform, CloudFormation, etc.) on the one hand, and live integration testing of the real infrastructure on the other hand. CloudMonkey pulls meta information of cloud infrastructure elements and provides them through a unified abstract interface for testing. Write assertions against your cloud infrastructure using your preferred test runner and assertion library. Services and resource types are extendable and pluggable.

Install

npm install cloudmonkey

Usage

A quick example (assuming mocha and chai):

const { CloudMonkey, EC2 } = require('cloudmonkey');
 
const monkey = new CloudMonkey();
monkey.register(new EC2({ region: 'eu-central-1' }));
 
describe('my subnets', () => {
  it('should be tagged "zone c" if public', async () => {
    const igw = await monkey.select.one.ec2.internetGateway({ vpc: 'vpc-12345678' });
    const rtb = await igw.travel.to.all.routeTables();
    const sn = await rtb.travel.to.all.subnets();
    expect(sn).to.containAll(subnet =>
      subnet.Tags.filter(tag =>
        tag.Key === 'security-zone' &&
        tag.Value === 'c').length);
  });
});

Prerequisites

Configure the AWS access keys.

Features

Register services and resource types

The interface model knows services and resource types. Services must be registered with CloudMonkey. Each service defines its resource types. Services are registered like this:

const { CloudMonkey, EC2 } = require('cloudmonkey');
 
const monkey = new CloudMonkey();
monkey.register(new EC2({ region: 'eu-central-1' }));
monkey.help();

Use help() to printout information such as the registered services, their resource types, filter and travel options:

CloudMonkey 1.0.0
 
service "ec2"
* resource type "instance"
  filter by "id", "vpc"
  travel to "subnet", "securityGroup"
* resource type "internetGateway"
  filter by "id", "vpc"
  travel to "routeTable"
* resource type "routeTable"
  filter by "id", "vpc"
  travel to "subnet"
* resource type "securityGroup"
  filter by "id", "name", "vpc"
* resource type "subnet"
  filter by "id", "vpc"
  travel to "instance"

Selecting resources

The selection interface provides a means to select resources in your infrastructure. For example:

const monkey = new CloudMonkey();
monkey.register(new EC2({ region: 'eu-central-1' }));
const igw = await monkey.select.one.ec2.internetGateway({ vpc: 'vpc-12345678' });

The select interface of CloudMonkey has the following format:

select.<quantifier>.<service>.<resourceType>(<filter>)

<qualifier> is one, some or all. one returns one single object while all and some return an array. one will throw an error if there is none or if there are more than one objects available. <service> must be one of the services registered. <resourceType> must be one of the resource types provided by the service (plural, i.e., adding an s for nicer reading, is supported).

The returned data (whether it is an array or a single object) provides the meta data of the selected infrastructure element(s). This can be used to further assertions, e.g., using mocha or jasmine or chai or any other assertion library of your choice.

In addition, it is decorated with dump() to simply print out the meta data.

const igw = await monkey.select.one.ec2.internetGateway({ vpc: 'vpc-12345678' });
igw.dump();
const rtb = await monkey.select.all.ec2.routeTables();
rtb.dump();

And it also provides the travel interface for traveling to related resources within the same service.

Travel to other resources

The travel interface allows to travel from resources (of one resource type) to related resources (of another resource type within the same service). It also accepts filters, just like the select interface. Use help() (see above) to learn which travel and filter options are available for a particular resource type.

const igw = await monkey.select.one.ec2.internetGateway();
const rtb = await igw.travel.to.all.routeTables();
const sn = await rtb.travel.to.all.subnets();
sn.dump();
// do some assertions here

The travel interface has the following format:

travel.to.<quantifier>.<resourceType>(<filter>)

Extending CloudMonkey with new services

CloudMonkey per se is cloud-agnostic. It only knows services (which strictly speaking don't even have to be cloud services) and their resource types. To add new services to CloudMonkey, simply derive from Service. A quick example:

const { CloudMonkey, Service } = require('cloudmonkey');
 
class FooService extends Service {
  constructor({ alias } = {}) {
    super({ name: 'foo', alias });
    // register resource type 'bar'
    this.register({
      name: 'bar',
      list: async () => Promise.resolve([]), // array of `bar` resources
      filters: {
        id: (bar, value) => bar.id === value,
      },
      identity: bar => bar.id,
      travel: {
        baz: async (bars) => Promise.resolve([]), // array of `baz` resources
      }
    });
    // register resource type 'baz'
    // ...
  }
}
 
const monkey = new CloudMonkey();
monkey.register(new FooService());
 
const bar = await monkey.select.one.foo.bar({ id: '1234' });
const bazs = await bar.travel.to.all.bazs();

CloudMonkey doesn't do any caching, i.e., if caching makes sense, the service has to take care itself.