Atlantis with Terragrunt

Question

I use terragrunt to keep my code DRY, I have two repo structures one for modules and the other where my terragrunt files reside and inside the terragrunt.hcl I refer the source module via git .

Just checking out if anyone has successfully implemented Atlantis for terragrunt, not much documentation is available for the same.

If you have implemented pls share the repo for reference as most atlantis.yaml are meant for terraform not terragrunt

Answer 1

I've implemented it. The Atlantis docs have a section on Terragrunt now.

I will repost the Atlantis docs below in case the link breaks, but I would encourage you to look at the docs as that is the most up-to-date reference.

One thing to note is that the docs use $COMMENT_ARGS, but I don't recommend that as it may give the opportunity for command injection. I removed it.

---

You can either use your repo's atlantis.yaml file or the Atlantis server's repos.yaml file.

Given a directory structure:

.
└── live
    ├── prod
    │   └── terragrunt.hcl
    └── staging
        └── terragrunt.hcl

If using the server repos.yaml file, you would use the following config:

# repos.yaml
# Specify TERRAGRUNT_TFPATH environment variable to accommodate setting --default-tf-version
# Generate json plan via terragrunt for policy checks
repos:
- id: "/.*/"
  workflow: terragrunt
workflows:
  terragrunt:
    plan:
      steps:
      - env:
          name: TERRAGRUNT_TFPATH
          command: 'echo "terraform${ATLANTIS_TERRAFORM_VERSION}"'
      - env:
          # Reduce Terraform suggestion output
          name: TF_IN_AUTOMATION
          value: 'true'
      - run:
          # Allow for targetted plans/applies as not supported for Terraform wrappers by default
          command: terragrunt plan -input=false $(printf '%s' $COMMENT_ARGS | sed 's/,/ /g' | tr -d '\\') -no-color -out $PLANFILE
          output: hide
      - run: |
          terragrunt show $PLANFILE
    apply:
      steps:
      - env:
          name: TERRAGRUNT_TFPATH
          command: 'echo "terraform${ATLANTIS_TERRAFORM_VERSION}"'
      - env:
          # Reduce Terraform suggestion output
          name: TF_IN_AUTOMATION
          value: 'true'
      - run: terragrunt apply -input=false $PLANFILE
    import:
      steps:
      - env:
          name: TERRAGRUNT_TFPATH
          command: 'echo "terraform${DEFAULT_TERRAFORM_VERSION}"'
      - env:
          name: TF_VAR_author
          command: 'git show -s --format="%ae" $HEAD_COMMIT'
      # Allow for imports as not supported for Terraform wrappers by default
      - run: terragrunt import -input=false $(printf '%s' $COMMENT_ARGS | sed 's/,/ /' | tr -d '\\')
    state_rm:
      steps:
      - env:
          name: TERRAGRUNT_TFPATH
          command: 'echo "terraform${DEFAULT_TERRAFORM_VERSION}"'
      # Allow for state removals as not supported for Terraform wrappers by default
      - run: terragrunt state rm $(printf '%s' $COMMENT_ARGS | sed 's/,/ /' | tr -d '\\')

If using the repo's atlantis.yaml file you would use the following config:

version: 3
projects:
- dir: live/staging
  workflow: terragrunt
- dir: live/prod
  workflow: terragrunt
workflows:
  terragrunt:
    plan:
      steps:
      - env:
          name: TERRAGRUNT_TFPATH
          command: 'echo "terraform${ATLANTIS_TERRAFORM_VERSION}"'
      - env:
          # Reduce Terraform suggestion output
          name: TF_IN_AUTOMATION
          value: 'true'
      - run:
          command: terragrunt plan -input=false -out=$PLANFILE
          output: strip_refreshing
    apply:
      steps:
      - env:
          name: TERRAGRUNT_TFPATH
          command: 'echo "terraform${ATLANTIS_TERRAFORM_VERSION}"'
      - env:
          # Reduce Terraform suggestion output
          name: TF_IN_AUTOMATION
          value: 'true'
      - run: terragrunt apply $PLANFILE

NOTE: If using the repo's atlantis.yaml file, you will need to specify each directory that is a Terragrunt project.

⚠️ WARNING

Atlantis will need to have the terragrunt binary in its PATH. If you're using Docker you can build your own image

If you don't want to create/manage the repo's atlantis.yaml file yourself, you can use the tool terragrunt-atlantis-config to generate it.

The terragrunt-atlantis-config tool is a community project and not maintained by the Atlantis team.