Molecule provides a recommended way to configure and test infrastructure configured by Ansible roles. This is all in support of immutable infrastructure.
This document should be referenced whenever creating new ansible roles.
- Ansible - https://www.ansible.com/ - configuration management tool.
- Git - https://git-scm.com/ - source code management.
- Molecule - https://molecule.readthedocs.io/ - testing convention tool for ansible roles.
- Python - https://www.python.org/ - scripting language used by Ansible and Molecule.
- Vagrant - https://www.vagrantup.com/ - VirtualBox provisioning layer.
- Virtualenv - https://virtualenv.pypa.io/ - user-managed python environment which simplifies development.
Whenever creating a role for the GIMP CI system or related projects, the following best practices must be followed to keep the quality of the code high.
Molecule provides convention around unit testing roles, using vagrant or docker, and setting up the scaffolding.
Create a starting point for the role. Start by installing all prereqs.
virtualenv --python=$(type -p python2.7) .venv
source .venv/bin/activate
pip install -U pip
pip install molecule
pip install python-vagrant
pip install -U ansible-lint
Create the initial scaffolding for the role. All role names must begin with
ansible-. This makes searching for them on GitHub much easier.
molecule init --role ansible-myrole
cd ansible-myrole
Freeze the python dependencies so that testing is repeatable.
pip freeze > test-reqs.txt
Start developing the role and use molecule converge to keep testing. When
ready, initialize the role as a git repository to be uploaded to the
gimp-ci organization.
cat > .gitignore <<EOF
/.molecule
/.vagrant
/.venv
__pycache__
/playbook.retry
/.cache
*.pyc
EOF
git init
git add .
git commit -m 'initial commit'Publish to gimp-ci when you're ready.
git remote add origin git@github.com:gimp-ci/ansible-<YOUR ROLE>.git
git push origin -u master
Remember, documentation is everything. Don't forget to add to the README.md
file of your Ansible role how to get started with furthering development and
testing. For example, a "Getting Started" section should contain the following.
git clone <repository>
cd ansible-myrole
virtualenv --python=$(type -p python2.7) .venv
source .venv/bin/activate
pip install -U pip
pip install -r test-reqs.txt
#now ready for development or running
molecule test