terragrunt-validator_skill

Overview

This skill is a comprehensive toolkit for validating, linting, testing, and automating Terragrunt configurations, HCL files, and Stacks. It bundles formatting, HCL and Terraform validation, linting, security scans, dependency graph checks, and dry-run planning into repeatable scripts and commands. Use it to enforce best practices, detect custom providers/modules, and produce run reports for CI/CD. It targets Terragrunt 0.93+ and supports multi-module and stack workflows.

How this skill works

The skill runs a combined validation pipeline or individual checks: HCL formatting, Terragrunt HCL input validation, terragrunt init/validate, tflint linting, Trivy/Checkov security scans, dependency DAG checks, and terragrunt plan dry-runs. It includes scripts to detect custom providers and modules, enumerate versions and sources, and emit human-readable or JSON reports for automation. Environment variables allow skipping costly steps (plan, lint, security) and enabling strict mode to fail on deprecated features. It also exposes Terragrunt stack operations (generate, run, clean, output) and new CLI commands like render and info print.

When to use it

• Validating .hcl, terragrunt.hcl, and terragrunt.stack.hcl files before commits or PRs
• Running full validation and security scans in CI pipelines for infrastructure-as-code
• Debugging Terragrunt configs, detecting custom providers/modules and researching required docs
• Performing dry-run testing with terragrunt plan across single or all modules
• Generating dependency graphs or run reports for audits and run summaries

Best practices

• Run terragrunt hcl fmt --check in pre-commit hooks and auto-fix with terragrunt hcl fmt
• Enable TG_STRICT_MODE=true in CI to catch deprecated commands and CLI changes early
• Always look up documentation for every detected custom provider/module and record version-specific auth/config requirements
• Skip expensive steps selectively in CI with SKIP_PLAN, SKIP_LINT, or SKIP_SECURITY when appropriate
• Use terragrunt run --all for multi-module operations and prefer new CLI aliases introduced in 0.93+

Example use cases

• Full validation before merging infrastructure changes: bash scripts/validate_terragrunt.sh ./infrastructure/prod
• CI job that runs format, lint, Trivy security scan, terragrunt init/validate, and terragrunt run --all plan
• Audit custom providers: run detect_custom_resources.py and fetch docs per provider/module version
• Generate and validate a Terragrunt Stack: terragrunt stack generate && terragrunt stack run plan
• Produce a dependency diagram for review: terragrunt dag graph | dot -Tpng > dependencies.png