terragrunt.stack.hcl - Terragrunt

import FileTree from "@components/vendored/starlight/FileTree.astro"; import { Aside } from "@astrojs/starlight/components";

Generating a stack

hcl

# terragrunt.stack.hcl

unit "mother" {
	source = "units/chicken"
	path   = "mother"
}

unit "father" {
	source = "./units/chicken"
	path   = "father"
}

unit "chick_1" {
	source = "./units/chick"
	path   = "chicks/chick-1"
}

unit "chick_2" {
	source = "units/chick"
	path   = "chicks/chick-2"
}

Running the following:

bash

terragrunt stack generate

Generates the following stack:

terragrunt.stack.hcl
.terragrunt-stack
- mother
  - terragrunt.hcl
- father
  - terragrunt.hcl
- chicks
  - chick-1
    - terragrunt.hcl
  - chick-2
    - terragrunt.hcl

</FileTree> <Aside type="note"> Parallel Execution: Stack generation runs concurrently to improve performance. The number of parallel tasks is determined by the `GOMAXPROCS` environment variable and can be explicitly controlled using the `--parallelism` flag:

bash

terragrunt stack generate --parallelism 4

Automatic Discovery: The command automatically discovers all terragrunt.stack.hcl files within the directory structure and generates them in parallel.

Validation of Units and Stacks: During the stack generation, the system will validate that each unit and stack's target directory contains the appropriate configuration file (terragrunt.hcl for units and terragrunt.stack.hcl for stacks). This ensures the directories are correctly structured before proceeding with the stack generation. To skip this validation, you can use the --no-stack-validate flag:

bash

terragrunt stack generate --no-stack-validate

</Aside> <Aside type="caution"> Path Restrictions: If an absolute path is provided as an argument, `generate` will throw an error. Only relative paths within the working directory are supported. </Aside> <Aside type="caution"> Recreating the stack directory and cleaning stale files: By default, `terragrunt stack generate` does not delete files in `.terragrunt-stack` that are no longer produced by the current `terragrunt.stack.hcl`. If you removed or changed `values` or units and still see old files (e.g., a lingering `terragrunt.values.hcl`), regenerate from a clean state by either refreshing sources or cleaning the directory first:

bash

# Refresh sources and regenerate from a clean copy
terragrunt stack generate --source-update

# Or explicitly remove the generated directory first
terragrunt stack clean && terragrunt stack generate

You can also pass --source-update when running commands via stack run:

bash

terragrunt stack run plan --source-update

</Aside>