Units

A unit is configured in a terragrunt.hcl file in the unit’s directory, e.g.:

terragrunt.hcl

include "root" {
  path = find_in_parent_folders("root.hcl")
}

dependencies {
  paths = ["../vpc", "../mysql", "../redis"]
}

Terragrunt also reads JSON-serialized HCL from terragrunt.hcl.json files. Wherever the docs mention terragrunt.hcl, a terragrunt.hcl.json file works too.

Terragrunt uses the first of these as a unit’s configuration file:

1. The file the --config flag names.
2. The file the TG_CONFIG environment variable names.
3. A terragrunt.hcl file in the current working directory.
4. A terragrunt.hcl.json file in the current working directory.

If none of them exists, Terragrunt exits with an error.

Blocks

Name	Description
catalog	Configures the module catalogs that the catalog and scaffold commands read.
expansion	Generates one instance of a dependency, unit, or stack block per element of a collection.
remote_state	Configures the OpenTofu/Terraform backend that stores a unit's state.
terraform	Configures where Terragrunt gets the OpenTofu/Terraform module and how it runs tofu or terraform.

The Blocks page documents the blocks not listed here.

Attributes

Name	Description
download_dir	Overrides the directory Terragrunt downloads OpenTofu/Terraform modules into.
iam_assume_role_duration	Sets the STS session duration, in seconds, for the IAM role Terragrunt assumes.
iam_assume_role_session_name	Sets the STS session name for the IAM role Terragrunt assumes.
iam_role	Sets the IAM role Terragrunt assumes before invoking OpenTofu/Terraform.
iam_web_identity_token	Sets the web identity token, or the path to it, for assuming iam_role with AssumeRoleWithWebIdentity.
inputs	Sets the input variables Terragrunt passes to OpenTofu/Terraform.
prevent_destroy	Stops the destroy and run --all destroy commands from destroying a unit's resources.
terraform_binary	Overrides the OpenTofu/Terraform binary Terragrunt calls.
terraform_version_constraint	Sets the OpenTofu/Terraform versions a unit accepts.
terragrunt_version_constraint	Specifies which versions of the Terragrunt CLI can be used with your configuration.

Functions

Name	Description
get_env	Returns the value of an environment variable.

The Functions page documents the functions not listed here.