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Terragrunt comes packed with a variety of built-in utilities beyond the core functions you’ve already learned. These helpers can streamline your configurations, reduce repetition, and integrate seamlessly with AWS and other environments.

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Official Documentation

Always keep an eye on the latest features and advanced utilities in the Terragrunt docs:

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Common Built-In Functions

FunctionDescriptionExample
getenv("VAR_NAME")Retrieve the value of an environment variable.locals { region = getenv("AWS_REGION") }
get_aws_account_id()Fetch the AWS account ID for the current credentials.locals { account_id = get_aws_account_id() }
get_aws_caller_identity()Return AWS caller identity details (user/role ARN, account ID).locals { caller = get_aws_caller_identity() }

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Creating Custom Functions

If your scenario demands logic beyond built-ins, Terragrunt’s plugin system lets you author custom helpers in Go.
When writing custom plugins:
  • Follow Go module conventions.
  • Respect Terragrunt’s plugin API.
  • Version and distribute via your internal registry.
Custom plugins can introduce breaking changes if not versioned properly.
Always pin plugin versions in your terragrunt.hcl and test in a sandbox environment.

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Best Practices & Tips

  • Organize functions into logical groups (e.g., AWS, GCP, environment variables).
  • Keep locals blocks concise and well-documented.
  • Reuse common logic through shared modules or parent configurations.

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