github-action-required-labels

This action allows you to fail the build if/unless a certain combination of labels are applied to a pull request.

Usage

This action has three required inputs; labels, mode and count

Name	Description	Required	Default
labels	New line separated list of labels to match	true
mode	The mode of comparison to use. One of: exactly, minimum, maximum	true
count	The required number of labels to match	true
token	The GitHub token to use when calling the API	false	${{ github.token }}
message	The message to log and to add to the PR (if add_comment is true). See the README for available placeholders	false
add_comment	Add a comment to the PR if required labels are missing. If a comment already exists, it will be updated. When the action passes, the comment will be deleted	false	false
exit_type	The exit type of the action. One of: failure, success	false
use_regex	Evaluate the values in labels as regular expressions	false

This action calls the GitHub API to fetch labels for a PR rather than reading event.json. This allows the action to run as intended when an earlier step adds a label. It will use github.token by default, and you can set the token input to provide alternative authentication.

If successful, any matching labels will be output in outputs.labels as a comma separated string.

Examples

Complete example

name: Pull Request Labels
on:
  pull_request:
    types: [opened, labeled, unlabeled, synchronize]
jobs:
  label:
    runs-on: ubuntu-latest
    permissions:
      issues: write
      pull-requests: write
    steps:
      - uses: mheap/github-action-required-labels@v5
        with:
          mode: exactly
          count: 1
          labels: "semver:patch, semver:minor, semver:major"

Prevent merging if a label exists

- uses: mheap/github-action-required-labels@v5
  with:
    mode: exactly
    count: 0
    labels: "do not merge"

Post a comment when the check fails

You can choose to add a comment to the PR when the action fails. The default format is:

Label error. Requires {{ errorString }} {{ count }} of: {{ provided }}. Found: {{ applied }}

- uses: mheap/github-action-required-labels@v5
  with:
    mode: exactly
    count: 1
    labels: "semver:patch, semver:minor, semver:major"
    add_comment: true

If a comment already exists, it will be updated. When the action passes, the comment will be deleted.

Customising the failure message / comment

You can also customise the message used by providing the message input:

- uses: mheap/github-action-required-labels@v5
  with:
    mode: exactly
    count: 1
    labels: "semver:patch, semver:minor, semver:major"
    add_comment: true
    message: "This PR is being prevented from merging because you have added one of our blocking labels: {{ provided }}. You'll need to remove it before this PR can be merged."

The following tokens are available for use in custom messages:

Token	Value
mode	One of: exactly, minimum, maximum
count	The value of the count input
errorString	One of: exactly, at least, at most
provided	The value of the labels input
applied	The labels that are applied to the PR

Require multiple labels

- uses: mheap/github-action-required-labels@v5
  with:
    mode: minimum
    count: 2
    labels: "community-reviewed, team-reviewed, codeowner-reviewed"

Use regular expressions

- uses: mheap/github-action-required-labels@v5
  with:
    mode: exactly
    count: 1
    labels: "semver:.*"
    use_regex: true

Preventing comment collisions

This action uses a combination of the workflow name/path, job ID, and step ID to add an invisible "match token" to the beginning of any comments it creates. That way, it can later know which comments it owns when modifying them, while supporting multiple "instances" of this action to be run at the same time within a repo.

However, note that if any of those three identifiers change, any "in flight" comments on open PRs may be orphaned (since the final match token will have changed between runs). If you rename any of those identifiers, you will have to delete any orphaned comments manually.

Controlling failure

You can set exit_type to success then inspect outputs.status to see if the action passed or failed. This is useful when you want to perform additional actions if a label is not present, but not fail the entire build.

- uses: mheap/github-action-required-labels@v5
  with:
    mode: minimum
    count: 2
    labels: "community-reviewed, team-reviewed, codeowner-reviewed"
    exit_type: success # Can be: success or failure (default: failure)

If the action passed, outputs.status will be success. If it failed, outputs.status will be failure.

Here is a complete workflow example for this use case:

name: Pull Request Labels
on:
  pull_request:
    types: [opened, labeled, unlabeled, synchronize]
jobs:
  label:
    runs-on: ubuntu-latest
    permissions:
      issues: write
      pull-requests: write
    outputs:
      status: ${{ steps.check-labels.outputs.status }}
    steps:
      - id: check-labels
        uses: mheap/github-action-required-labels@v5
        with:
          mode: exactly
          count: 1
          labels: "semver:patch, semver:minor, semver:major"
          exit_type: success
  do-other:
    runs-on: ubuntu-latest
    needs: label
    steps:
      - run: echo SUCCESS
        if: needs.label.outputs.status == 'success'
      - run: echo FAILURE && exit 1
        if: needs.label.outputs.status == 'failure'

Using Output Labels

If the action was successful you can access the matching labels via outputs.labels. This is useful if you want to use the labels in a later step.

name: Pull Request Labels
on:
  pull_request:
    types: [opened, labeled, unlabeled, synchronize]
jobs:
  label:
    runs-on: ubuntu-latest
    steps:
      - id: check-labels
        uses: mheap/github-action-required-labels@v5
        with:
          mode: minimum
          count: 1
          labels: "feature-1, feature-2, feature-3"
      - run: |
          echo "Enabled Features:"
          for f in $(echo "{{steps.check-labels.outputs.labels}}" | sed "s/,/ /g")
          do
            echo "$f"
          done