Enforcing Tagging Governance with Git Pre-commit Hooks and CloudFormation Guard

Amazon CloudFormation Guard (cfn-guard) is an open-source policy-as-code tool that validates infrastructure-as-code templates against rules written in its own domain-specific language, helping teams enforce standards before resources are ever deployed.

Git pre-commit hooks run automatically before a commit is finalized and can reject it outright if a check fails, giving teams a way to catch issues at the earliest point in the development workflow. The open-source pre-commit framework makes these checks easy to share and maintain across a team's repositories.

In this lab, you will configure a pre-commit hook that pulls centrally maintained tagging rules from Amazon S3, write a cfn-guard rule enforcing required tags, and apply that enforcement to both a CloudFormation template and a Terraform configuration, catching missing or invalid tags before either ever reaches a deploy.

Learning objectives

Upon completion of this beginner-level lab, you will be able to:

• Explain how commit-time tagging enforcement fits alongside org-level governance tools such as AWS Tag Policies and CloudFormation Hooks
• Write cfn-guard rules that enforce required tags and allowed tag values, and wire it into a Git pre-commit hook
• Apply the tagging enforcement pattern to a AWS CloudFormation template and a Terraform plan

Intended audience

• Cloud Engineers
• DevOps Engineers
• FinOps Engineers

Prerequisites

Familiarity with the following will be beneficial but is not required:

• Git and the pre-commit framework
• AWS CloudFormation
• Terraform

The following content can be used to fulfill the prerequisites:

• Introduction to Git
• AWS CloudFormation: Introduction to Infrastructure as Code