Introduction to

Cookiecutter Overview

• Project templating tool
• Language agnostic
• Uses Jinja templating
• Installs with Python
• FOSS: https://github.com/cookiecutter/cookiecutter

A Hypothetical Situation

• Starting a new client
• Need to deploy some projects
• Modules to do the hard work already exist
• Still need some implementation repositories

How do I do this? Copy & paste some previous project? ¯\_(ツ)_/¯

What This Results In

• No clear process for deploying modules
• Quite often end up reinventing the wheel
• Copying over baggage from previous clients
• Changes may not be simple search & replace
• No way to easily share fixes/enhancements

A Solution

• boilerplate | scaffolding
• clone template -> generate project

Some implementaitons:

• Yeoman: https://yeoman.io/
• JHipster: https://www.jhipster.tech/
• Maven archetypes: https://maven.apache.org/archetypes/
• Create React App: https://github.com/facebook/create-react-app
• Cookiecutter: https://github.com/cookiecutter/cookiecutter

Why Cookiecutter?

• Language agnostic, unopinionated
• Interactive prompts for values
• Simple Jinja templating
• Doesn’t require Nodejs

Installation

pip3 install --user cookiecutter

Usage

$ cookiecutter git@gitlab-ssh.runcmd.cmdsolutions.com.au:cmd-terraform/cookiecutter-tf-aws-eks.git --checkout init

… then fill out the prompts

Demo

<demo goes here>

Cookiecutter relies on adoption to be useful

Creating Your Own Cookiecutter

Cookiecutter Example

cookiecutter-tf-aws-eks $ tree
.
├── CODEOWNERS
├── README.md
├── cookiecutter.json
└── {{ cookiecutter.project_slug }}
    ├── backend.tf
    ├── docker-compose.yml
    ├── envvars.yml
    ├── locals.tf
    ├── main.tf
    ├── Makefile
    ├── provider.tf
    └── README.md

backend.tf:

terraform {
  backend "s3" {
    bucket  = "{{ cookiecutter.client_name }}-terraform-backend"
    key     = "{{ cookiecutter.client_name }}-tf-aws-eks"
    region  = "ap-southeast-2"
    profile = "{{ cookiecutter.client_name }}-tfbackend"
    # https://github.com/terraform-providers/terraform-provider-aws/issues/5018#issuecomment-465332353
    skip_metadata_api_check = true
  }
}

cookiecutter.json:

{
  "client_name_pretty": "Name of the client the implementation is being created for, prettified e.g. 'Mantel Group'",
  "client_name": "{{ cookiecutter.client_name_pretty.lower().replace(' ', '-') }}",
  "project_name": "{{ cookiecutter.client_name_pretty }} TF AWS EKS",
  "project_slug": "{{ cookiecutter.project_name.lower().replace(' ', '-') }}",
  "project_short_description": "{{ cookiecutter.client_name_pretty }} Terraform AWS EKS Implementation",
  "aws_account_id_sandpit": "AWS Account ID of your sandpit account for assume role",
  "aws_account_id_nonprod": "AWS Account ID of your nonprod account for assume role",
  "aws_account_id_prod": "AWS Account ID of your prod account for assume role",
  "aws_account_id_tfbackend": "AWS Account ID of your tfbackend account for backend assume role"
}

Advanced Usage

Retroactive Updates

First commit should be the cookie without any edits to allow future updates

5. Both application changes and     <---- merge branch --+   4. Updated cookie
   and features from cookiecutter
                                                                     ^
       ^                                                             |
       |                                                             |
       |                                                             |
       |                                                             |
       +                                                             |
                                                             Rerun cookiecutter
2. application development, custom changes                           |
                                                                     |
       ^                                                             |
       |                                                             |
       |                                                             |
       +                                                             +

1. root commit   +--------- branch ---------------------->   3. detached commit

CI/CD on Cookiecutters

Makefile:

clone:
	docker-compose run --rm cookiecutter --no-input --overwrite-if-exists . project_name='Python Test Project'
	$(MAKE) -C python-test-project .env

recursive:
	$(MAKE) -C python-test-project deps build styleTest run #deploy smokeTest remove

Source: https://github.com/aarongorka/serverless-python-boilerplate/blob/master/Makefile

Fim