# Apply Requirements

# Intro

Atlantis allows you to require certain conditions be satisfied before an atlantis apply command 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:

# 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

You can set 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 your 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 – You can set who is allowed to approve
• 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

# Mergeable

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

# Usage

You can 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 the apply_requirements key in your repos.yaml config:

   # repos.yaml

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

   # atlantis.yaml

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

# Meaning

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

# GitHub

In GitHub, if you're not using Protected Branches 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-branches for more details.

# 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 issue.

# 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 requests.

Branch policies 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.)

# 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 the apply_requirements key:

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

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

   # repos.yaml

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

   # atlantis.yaml

   version: 3
   projects:
   - dir: .
     apply_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 Apply Requirements

As mentioned above, you can set apply 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: /.*/
     apply_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
     apply_requirements: []
   - id: github.com/runatlantis/atlantis
     apply_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 apply_requirements to be set in 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: [apply_requirements]
     # Allow any repo to specify apply_requirements in atlantis.yaml
   

   # atlantis.yaml

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

• For more information on GitHub pull request reviews and approvals see: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/about-pull-request-reviews
• For more information on GitLab merge request reviews and approvals (only supported on GitLab Enterprise) see: https://docs.gitlab.com/ee/user/project/merge_requests/merge_request_approvals.html.
• For more information on Bitbucket pull request reviews and approvals see: https://confluence.atlassian.com/bitbucket/pull-requests-and-code-review-223220593.html
• For more information on Azure DevOps pull request reviews and approvals see: https://docs.microsoft.com/en-us/azure/devops/repos/git/pull-requests?view=azure-devops&tabs=browser