Atlantis

Command Requirements

Intro

Atlantis requires certain conditions be satisfied before atlantis apply and atlantis import commands can be run:

  • Approved – requires pull requests to be approved by at least one user other than the author
  • Mergeable – requires pull requests to be able to be merged
  • UnDiverged - requires pull requests to be ahead of the base branch

What Happens If The Requirement Is Not Met?

If the requirement is not met, users will see an error if they try to run atlantis apply: Mergeable Apply Requirement

Supported Requirements

Approved

The approved requirement will prevent applies unless the pull request is approved by at least one person other than the author.

Usage

The approved requirement by:

  1. Passing the --require-approval flag to atlantis server or

  2. Creating a repos.yaml file with the apply_requirements key:

    repos:
- id: /.*/
  apply_requirements: [approved]

  3. Or by allowing an atlantis.yaml file to specify the apply_requirements key in the repos.yaml config:

    repos.yaml

    repos:
- id: /.*/
  allowed_overrides: [apply_requirements]

    atlantis.yaml

    version: 3
projects:
- dir: .
  apply_requirements: [approved]

Meaning

Each VCS provider has different rules around who can approve:

  • GitHub – Any user with read permissions to the repo can approve a pull request
  • GitLab – The user who can approve can be set in the repo settingsopen in new window
  • Bitbucket Cloud (bitbucket.org) – A user can approve their own pull request but Atlantis does not count that as an approval and requires an approval from at least one user that is not the author of the pull request
  • Azure DevOps – All builtin groups include the "Contribute to pull requests" permission and can approve a pull request

Tip

To require certain people to approve the pull request, look at the mergeable requirement.

Mergeable

The mergeable requirement will prevent applies unless a pull request is able to be merged.

Usage

Set the mergeable requirement by:

  1. Passing the --require-mergeable flag to atlantis server or

  2. Creating a repos.yaml file with the apply_requirements key:

    repos:
- id: /.*/
  apply_requirements: [mergeable]

  3. Or by allowing an atlantis.yaml file to specify plan_requirements, apply_requirements and import_requirements keys in the repos.yaml config:

    repos.yaml

    repos:
- id: /.*/
  allowed_overrides: [plan_requirements, apply_requirements, import_requirements]

    atlantis.yaml

    version: 3
projects:
- dir: .
  plan_requirements: [mergeable]
  apply_requirements: [mergeable]
  import_requirements: [mergeable]

Meaning

Each VCS provider has a different concept of "mergeability":

WARNING

Some VCS providers have a feature for branch protection to control "mergeability". To use it, limit the base branch so to not bypass the branch protection. See also the branch keyword in Server Side Repo Config for more details.

GitHub

In GitHub, if you're not using Protected Branchesopen in new window then all pull requests are mergeable unless there is a conflict.

If you set up Protected Branches then you can enforce:

  • Requiring certain status checks to be passing
  • Requiring certain people to have reviewed and approved the pull request
  • Requiring CODEOWNERS to have reviewed and approved the pull request
  • Requiring that the branch is up to date with main

See https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/about-protected-branchesopen in new window for more details.

WARNING

If you have the Restrict who can push to this branch requirement, then the Atlantis user needs to be part of that list in order for it to consider a pull request mergeable.

WARNING

If you set atlantis/apply to the mergeable requirement, use the --gh-allow-mergeable-bypass-apply flag or set the ATLANTIS_GH_ALLOW_MERGEABLE_BYPASS_APPLY=true environment variable. This flag and environment variable allow the mergeable check before executing atlantis apply to skip checking the status of atlantis/apply.

GitLab

For GitLab, a merge request will be merged if there are no conflicts, no unresolved discussions if it is a project requirement and if all necessary approvers have approved the pull request.

For pipelines, if the project requires that pipelines must succeed, all builds except the apply command status will be checked.

For Jobs with allow_failure setting set to true, will be ignored. If the pipeline has been skipped and the project allows merging, it will be marked as mergeable.

Bitbucket.org (Bitbucket Cloud) and Bitbucket Server (Stash)

For Bitbucket, we just check if there is a conflict that is preventing a merge. We don't check anything else because Bitbucket's API doesn't support it.

If you need a specific check, please open an issueopen in new window.

Azure DevOps

In Azure DevOps, all pull requests are mergeable unless there is a conflict. You can set a pull request to "Complete" right away, or set "Auto-Complete", which will merge after all branch policies are met. See Review code with pull requestsopen in new window.

Branch policiesopen in new window can:

  • Require a minimum number of reviewers
  • Allow users to approve their own changes
  • Allow completion even if some reviewers vote "Waiting" or "Reject"
  • Reset code reviewer votes when there are new changes
  • Require a specific merge strategy (squash, rebase, etc.)

WARNING

At this time, the Azure DevOps client only supports merging using the default 'no fast-forward' strategy. Make sure your branch policies permit this type of merge.

UnDiverged

Prevent applies if there are any changes on the base branch since the most recent plan. Applies to merge checkout strategy only.

Usage

You can set the undiverged requirement by:

  1. Creating a repos.yaml file with plan_requirements, apply_requirements and import_requirements keys:

    repos:
- id: /.*/
  plan_requirements: [undiverged]
  apply_requirements: [undiverged]
  import_requirements: [undiverged]

  2. Or by allowing an atlantis.yaml file to specify the plan_requirements, apply_requirements and import_requirements keys in your repos.yaml config:

    repos.yaml

    repos:
- id: /.*/
  allowed_overrides: [plan_requirements, apply_requirements, import_requirements]

    atlantis.yaml

    version: 3
projects:
- dir: .
  plan_requirements: [undiverged]
  apply_requirements: [undiverged]
  import_requirements: [undiverged]

Meaning

The merge checkout strategy creates a temporary merge commit and runs the plan on the Atlantis local version of the PR source and destination branch. The local destination branch can become out of date since changes to the destination branch are not fetched if there are no changes to the source branch. undiverged enforces that Atlantis local version of main is up to date with remote so that the state of the source during the apply is identical to that if you were to merge the PR at that time.

Setting Command Requirements

As mentioned above, you can set command requirements via flags, in repos.yaml, or in atlantis.yaml if repos.yaml allows the override.

Flags Override

Flags override any repos.yaml or atlantis.yaml settings so they are equivalent to always having that apply requirement set.

Project-Specific Settings

If you only want some projects/repos to have apply requirements, then you must

  1. Not set the --require-approval or --require-mergeable flags, since those will override any repos.yaml or atlantis.yaml settings

  2. Specifying which repos have which requirements via the repos.yaml file.

    repos:
- id: /.*/
  plan_requirements: [approved]
  apply_requirements: [approved]
  import_requirements: [approved]
# Regex that defaults all repos to requiring approval
- id: /github.com/runatlantis/.*/
  # Regex to match any repo under the atlantis namespace, and not require approval
  # except for repos that might match later in the chain
  plan_requirements: []
  apply_requirements: []
  import_requirements: []
- id: github.com/runatlantis/atlantis
  plan_requirements: [approved]
  apply_requirements: [approved]
  import_requirements: [approved]
  # Exact string match of the github.com/runatlantis/atlantis repo
  # that sets apply_requirements to approved

  3. Specify which projects have which requirements via an atlantis.yaml file, and allowing plan_requirements, apply_requirements and import_requirements to be set in atlantis.yaml by the server side repos.yaml config.

    For example if I have two directories, staging and production, I might use:

    repos.yaml

    repos:
- id: /.*/
  allowed_overrides: [plan_requirements, apply_requirements, import_requirements]
  # Allow any repo to specify apply_requirements in atlantis.yaml

    atlantis.yaml

    version: 3
projects:
- dir: staging
  # By default, plan_requirements, apply_requirements and import_requirements are empty so this
  # isn't strictly necessary.
  plan_requirements: []
  apply_requirements: []
  import_requirements: []
- dir: production
  # This requirement will only apply to the
  # production directory.
  plan_requirements: [mergeable]
  apply_requirements: [mergeable]
  import_requirements: [mergeable]

Multiple Requirements

You can set any or all of approved, mergeable, and undiverged requirements.

Who Can Apply?

Once the apply requirement is satisfied, anyone that can comment on the pull request can run the actual atlantis apply command.

Next Steps