Terraform Validate Command

Validate configuration files for syntax and internal consistency.

Usage

/tf-validate              # Basic validation
/tf-validate -json       # JSON output for CI/CD

What This Command Does

1. Checks HCL syntax
2. Validates resource configurations
3. Checks provider requirements
4. Validates variable types
5. Checks module configurations
6. Does NOT access remote state or APIs

Execution Steps

Step 1: Initialize (Required)

# Must init first
terraform init

Step 2: Validate

# Basic validation
terraform validate

# JSON output (CI/CD)
terraform validate -json

# No color (CI/CD)
terraform validate -no-color

Step 3: Fix Issues

Common validation errors:

• Missing required arguments
• Invalid argument names
• Type mismatches
• Circular references
• Missing providers

Output

Success

Success! The configuration is valid.

JSON Success

{
  "valid": true,
  "error_count": 0,
  "warning_count": 0,
  "diagnostics": []
}

Failure Example

Error: Missing required argument

  on main.tf line 5, in resource "aws_instance" "web":
   5: resource "aws_instance" "web" {

The argument "ami" is required, but no definition was found.

CI/CD Integration

GitHub Actions

- name: Terraform Validate
  id: validate
  run: terraform validate -no-color

With JSON Parsing

- name: Terraform Validate
  id: validate
  run: |
    terraform validate -json > validation.json
    if [ $(jq '.valid' validation.json) != "true" ]; then
      jq '.diagnostics' validation.json
      exit 1
    fi

Pre-Commit Hook

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

Common Errors

Missing Provider

Error: Missing required provider

This configuration requires provider "aws", but no such provider
is configured. Please add a provider block.

Fix: Add provider configuration or required_providers block.

Invalid Argument

Error: Unsupported argument

  on main.tf line 10, in resource "aws_instance" "web":
  10:   invalid_arg = "value"

An argument named "invalid_arg" is not expected here.

Fix: Check provider documentation for valid arguments.

Type Mismatch

Error: Invalid value for input variable

The given value is not valid for variable "count": a number is required.

Fix: Ensure variable values match declared types.

Best Practices

1. Run validate after every change
2. Include in CI/CD pipeline
3. Use as pre-commit hook
4. Check JSON output in automation
5. Always init before validate