If a labels exists on a pull_request, do something.

After fiddling through workflow expression syntax for the past few hours, I found it easier just to make an action that specifically checked if a pull_request had a certain label or not. I plan to expand this to issues as well.

● Using the action ● Install ● Configuration ● Events ● Real world

In this barebones example, we look to see if a pull_request pointing towards the main branch has a label 'preview'.

name: Has label

on:
 pull_request:
  types:
    - opened
    - synchronize
    - labeled
    - unlabeled
  branches:
    - main

jobs:
 haslabel:
  runs-on: ubuntu-latest
  steps:
    - uses: actions/checkout@v2
    - name: Labeled to preview
      id: haslabel
      uses: DanielTamkin/HasLabel@v1
      with:
        contains: 'preview'
    - name: Test action
      if: steps.haslabel.outputs.labeled-preview
      run: echo 'This pull_request has this label.'
    - name: Test action "no match"
      if: steps.haslabel.outputs.labeled-preview != 'true'
      run: echo 'This pull_request does not have this label.'
    - name: Test action "unlabeled"
      if: steps.haslabel.outputs.unlabeled
      run: echo 'This pull_request had this label removed.'

Click the button 'Use this workflow', or if you're on the marketplace 'Use latest version.'

Failure to supply either a contains or exact label will result in job failure.

You can either loosely check for a label, or strictly check, but not both. If you need to check for more than one label try and narrow down your usecases for your labels first. If you still need more than one label for a job to trigger, stack HasLabel! The Action outputs unique variables through the step.output context.

with:
  contains: 'label' # a label contains this string
  exact: 'label'    # a label contains exactly this string.

If a label contains the string provided, HasLabel will proceed by outputting labeled-$labelname. Useful for statically worded labels such as docs or feat where you have flexibility in the naming scheme.

If a label contains the string provided, HasLabel will proceed by outputting labeled-$labelname. Useful for statically worded labels such as docs or feat where you have flexability in the naming scheme.

HasLabel handles labeled, synchronize & unlabeled events by outputting unique variables accessable through steps.<stepid>.outputs.<event>-<label>. I'd suggest learning more about the steps context so to best utilize this Action.

Replace $labelname with the label name you specified. If the supplied label is found, HasLabel will signify this by outputting a unique variable in the form of labeled-$labelname, perfect for custom logic. This also goes for the unique synchronize event, allowing pull_request's dependent on push events on pull_requests

Example: A Step triggered when a pull_request has label preview.

  - name: Test action "no match"
    if: steps.haslabel.outputs.labeled-preview
    run: echo 'Handle a unlabeled event'

Replace $labelname with the label name you specified. If the supplied label is either not found or was just removed, HasLabel will signify this by outputting a unique variable in the form of unlabeled-$labelname. Especially useful if you want to trigger steps based on a loss of a label. Such as review checks, stagging builds or approvals.

Example: A Step triggered when a label is no-longer present.

  - name: Test action "no match"
    if: steps.haslabel.outputs.unlabeled-preview
    run: echo 'Handle a unlabeled event'

This is a good real-world example where you trigger @nwtgck's Netlify deploy action once the label preview is added.

You could just as easily have this action work in a single job too! Accessing the outputs of a step are easy to access through: steps.<jobid>.outputs.<labeled/unlabeled>-<label>

name: Preview

on:
 pull_request:
  types:
    - opened
    - synchronize
    - labeled
    - unlabeled
  branches:
    - master

jobs:
  haslabel:
    name: analyse labels
    runs-on: ubuntu-latest
    outputs:
      preview: ${{ steps.haslabel.outputs.labeled-preview }}
    steps:
      - name: Cancel Previous Runs
        uses: styfle/cancel-workflow-action@0.4.1
        with:
          access_token: ${{ github.token }}
      - uses: actions/checkout@v2
      - name: Labeled to preview
        id: haslabel
        uses: DanielTamkin/HasLabel@v1
        with:
          contains: 'preview'
  deploy:
    name: deploy
    needs: haslabel
    if: needs.haslabel.outputs.preview
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Deploy to Netlify
        uses: nwtgck/actions-netlify@v1.1
        with:
          NETLIFY_AUTH_TOKEN: ${{ secrets.NETLIFY_AUTH_TOKEN }}
          NETLIFY_SITE_ID: ${{ secrets.NETLIFY_SITE_ID }}
        timeout-minutes: 1

This is my first GitHub action, i'd love feedback! Create an issue or Tweet me.

This project uses the MIT license.