Terraform Format Command

Format Terraform configuration files to canonical style.

Usage

/tf-fmt                   # Format current directory
/tf-fmt -check           # Check without changing
/tf-fmt -recursive       # Format all subdirectories
/tf-fmt -diff            # Show what would change

What This Command Does

1. Reads .tf files
2. Applies canonical formatting
3. Rewrites files (unless -check)
4. Handles indentation, alignment, spacing
5. Processes subdirectories (with -recursive)

Execution Steps

Step 1: Check Format

# Check without changes
terraform fmt -check

# Check with diff output
terraform fmt -check -diff

Step 2: Format Files

# Format current directory
terraform fmt

# Format recursively
terraform fmt -recursive

# Format specific file
terraform fmt main.tf

Common Options

Option	Description
-check	Check only, don't modify
-diff	Show formatting changes
-recursive	Process subdirectories
-write=false	Don't write changes
-list=false	Don't list formatted files

CI/CD Integration

GitHub Actions

- name: Terraform Format Check
  id: fmt
  run: terraform fmt -check -recursive
  continue-on-error: true

- name: Format Status
  if: steps.fmt.outcome == 'failure'
  run: |
    echo "Terraform files are not formatted!"
    terraform fmt -recursive -diff
    exit 1

Pre-Commit Hook

# .pre-commit-config.yaml
repos:
  - repo: https://github.com/antonbabenko/pre-commit-terraform
    rev: v1.83.5
    hooks:
      - id: terraform_fmt

Git Pre-Commit (Manual)

#!/bin/sh
# .git/hooks/pre-commit

# Check Terraform formatting
if ! terraform fmt -check -recursive; then
    echo "Terraform files are not formatted. Run 'terraform fmt -recursive'"
    exit 1
fi

Exit Codes

Code	Meaning
0	All files formatted (or no changes needed)
1	Formatting errors found (with -check)
2	Command error

Examples

Check All Files

terraform fmt -check -recursive

Show What Would Change

terraform fmt -diff -recursive

Format and List Changed Files

terraform fmt -recursive
# Output: main.tf
#         modules/vpc/main.tf

Format Without Listing

terraform fmt -recursive -list=false

Formatting Rules Applied

• 2-space indentation
• Aligned = signs in blocks
• Consistent spacing
• Sorted block attributes
• Standardized quotes

Before

resource "aws_instance" "web" {
ami = "ami-12345678"
  instance_type="t3.micro"
tags={Name="web"}
}

After

resource "aws_instance" "web" {
  ami           = "ami-12345678"
  instance_type = "t3.micro"
  tags = {
    Name = "web"
  }
}

Best Practices

1. Always format before commit
2. Use pre-commit hooks
3. Check in CI/CD (fail on unformatted)
4. Format recursively for full projects
5. Team should use same Terraform version