stacks/my-stack/terragrunt.stack.hcl (in your catalog repository)

cas — Stack integration via update_source_with_cas

The cas experiment now integrates with stacks. Units and terraform blocks can set update_source_with_cas = true to use relative source paths in catalog repositories, removing the need to plumb remote Git URLs through values expressions.

# stacks/my-stack/terragrunt.stack.hcl (in your catalog repository)

unit "service" {
  source = "../..//units/my-service"

  update_source_with_cas = true

  path = "service"
}

During stack generation, Terragrunt rewrites these relative sources to cas:: references that resolve against content stored in the CAS. The repository is cloned once, and subsequent stack generations resolve content from the local store without network access. Generated .terragrunt-stack files contain deterministic CAS references, so regeneration does not produce spurious diffs.

CAS also supports SHA-256 repositories now, detected automatically via git rev-parse --show-object-format. The on-disk store layout was reorganized into blobs/ and trees/ namespaces under ~/.cache/terragrunt/cas/store/.

To learn more, see the CAS documentation and Explicit Stacks: CAS Integration.