Enforce Terraform Format (terraform fmt)

A GitHub Action that enforces Terraform formatting standards by running terraform fmt on all committed files. The workflow will fail if any files require reformatting.

Features

• Automatically checks Terraform file formatting on each pull request.
• Posts detailed comments on pull requests highlighting formatting issues when the GITHUB_TOKEN is provided.
• Ensures consistency across Terraform codebases.

Permissions Scopes

The following permissions scopes are needed:

Permission	Level	Description
contents	read	Work with the contents of the repository and list commits
pull-requests	write	Add comments to the Pull Request

Pull Request Comments

When the GITHUB_TOKEN is passed, the action posts a comment to the pull request. The comment includes:

• A list of files that require formatting.
• The specific differences introduced by running terraform fmt.

Example comment:

Determining Changed Files

To accurately determine changed files, set the fetch-depth in the checkout step:

• Recommended: Use fetch-depth: 0 to fetch the full commit history.
• Minimum Requirement: Set fetch-depth to at least 3.

If changed files cannot be identified (e.g., shallow fetch), the action will default to checking all Terraform files, including unchanged files.

Inputs

Name	Description	Required	Default
terraform_version	The version of Terraform to use	Yes	None

Example usage

name: Enforce Terraform Format
on:
  pull_request:
    paths:
      - '**/*.tf'
      - '**/*.tfvars'

jobs:
  terraform-fmt:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
    steps:
      - name: Checkout the contents
        uses: actions/checkout@v4
        with:
          fetch-depth: '0' # Fetch full history for accurate file change detection

      - name: Enforce Terraform formatting
        uses: pvicol/enforce-terraform-fmt@v1.2.0
        with:
          terraform_version: '1.9.8'
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}