How to make GitHub cancel all associated actions when a PR is closed?

Question

Our workflow is configured to run when the following conditions are met:

name: '[apps] deploy'
on:
  pull_request:
    types:
      - opened
      - synchronize
      - reopened
      - ready_for_review

The problem I am seeing is that if the PR gets closed, the actions that have already started are allowed to continue.

As an example:

In this picture we can see that the PR was closed 19 minutes ago, but then 13 minutes ago (6 minutes later) one of the workers reported an error.

How do I ensure that the moment the PR is closed, all actions are cancelled?

Answer 1

I thought this is going to be a question with an obvious answer that I just overlooked, but turns out it isn't.

The most basic way to do this is using actions/github-script, e.g.

jobs:
  comment:
    permissions:
      actions: write
      contents: read
    runs-on: ubuntu-latest
    if: ${{ github.event.pull_request.merged != true }}
    steps:
      - uses: actions/github-script@v7
        with:
          script: |
            const workflowIds = [
              '.github/workflows/deploy_review.yaml',
              '.github/workflows/packages.yaml',
            ];

            for (const workflowId of workflowIds) {
              const workflowRuns = await github.rest.actions.listWorkflowRuns({
                owner: context.repo.owner,
                repo: context.repo.repo,
                workflow_id: workflowId,
                per_page: 100,
                event: 'pull_request',
                branch: context.payload.pull_request.head.ref,
              });
            
              const activeRuns = workflowRuns.data.workflow_runs.filter((workflowRun) => {
                return workflowRun.status === 'queued' || workflowRun.status === 'in_progress';
              });
            
              for (const activeRun of activeRuns) {
                await github.rest.actions.cancelWorkflowRun({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  run_id: activeRun.id,
                });
              }
            }
name: Cancel workflows on PR close
on:
  pull_request:
    types:
      - closed

This workflow will be triggered when a PR is closed, and it will cancel workflows associated with the head branch.

This works, but it has a gotcha – this workflow will be queued just like any other workflow, so there are no guarantees that it will execute immediately.

Therefore, what we ended up doing is setting up a webhook that informs us of action = closed and triggers the same logic as above from the webhook handler.

I also want to mention that if you are using if: always() in your workflow, it cannot be cancelled. Consider replacing it with if: success() || failure().