Fabricate

A Python Fabric based set of conventions for AWS CloudFormation.

Install

1. Set up a virtualenv (I recommend pyenv-virtualenv, highly):

• pyenv virtualenv fabricate
• pyenv activate fabricate

2. Install dependencies:

• pip install -U -r requirements.txt

3. From this point forward, the fab command will be available to run the tasks from fabfile.py.

Create a Project

Files in projects represent unique instantiations of templates for a particular purpose.

Create a projects/${PROJECTNAME}.yaml file and ensure it refers to a template and has parameters outlined:

# projects/my-project.yaml

template: standard_vpc                  # Required: an existing template in 'templates/'

az_count: 3                             # Any overridden variables for the Jinja render.

parameters:                             # Parameter injection for the template
  ResourcePrefix: dliggat-vpc
  VpcCidr: "10.0.0.0/16"
  PublicSubnetAZ0Cidr: "10.0.0.0/24"
  PublicSubnetAZ1Cidr: "10.0.1.0/24"
  PrivateSubnetAZ0Cidr: "10.0.3.0/24"
  PrivateSubnetAZ1Cidr: "10.0.4.0/24"

Note that project files must not contain spaces, underscores, or special characters, as the filename is eventually used as a CloudFormation stack name. Alphanumeric with hyphens is best.

Render & Validate

There are fab tasks to render a CloudFormation file, and validate it against the API.

fab --set project=my-project render validate

This creates a new directory in _output of the following form:

_output/my-project
├── parameters.json   # Parameters file
└── template.yaml     # Rendered template file

These outputs can be used directly with the CloudFormation CLI (aws cloudformation).

Provisioning

To provision a stack:

fab --set project=my-project provision

Or all at once:

fab --set project=my-project render validate provision

Stack Updates

The project name is used directly as the CloudFormation stack name. If a stack by that name already exists, the provision command will issue a CloudFormation update instead of create.

Describing Stacks

To get a list of stack properties, use the describe task:

fab --set project=my-project describe