renovatebot_renovate/lib/modules/manager/terragrunt/readme.md

Currently by default, Terragrunt support is limited to Terraform registry sources and GitHub sources that include SemVer refs, e.g. like github.com/hashicorp/example?ref=v1.0.0.

You can create a custom versioning config to support non-SemVer references. For example, if you want to reference a tag like module-v1.2.5, a block like this would work:

{
  "terragrunt": {
    "versioning": "regex:^((?<compatibility>.*)-v|v*)(?<major>\\d+)\\.(?<minor>\\d+)\\.(?<patch>\\d+)$"
  }
}

Pinned Terragrunt dependencies like the following will get a PR whenever there is a newer version available:

terraform {
  source = "github.com/hashicorp/example?ref=v1.0.0"
}

Terraform lockfiles

The Terragrunt manager supports lock file maintenance for .terraform.lock.hcl artifacts. These artifacts will be updated if and only if the update type is lockFileMaintenance.