index.js

// For more information on building apps:
// https://probot.github.io/docs/

// To get your app running against GitHub, see:
// https://probot.github.io/docs/development/

/**
 * This is the main entrypoint to your Probot app
 * @param {import('probot').Application} app
 */
module.exports = app => {
  // app.on('issues.opened', async context => {
  //     app.log(context)
  //     const issueComment = context.issue({ body: 'Thanks for opening this issue!' })
  //     return context.github.issues.createComment(issueComment)
  // })

  app.on("check_run.completed", async context => {
    const repo = context.payload.repository;
    const owner = repo.owner.login;
    const check_suite = context.payload.check_run.check_suite
    
    if (check_suite.app.slug != "github-actions") {
      return
    }

    const workflow_runs = (await context.github.actions.listRepoWorkflowRuns({
      owner: owner,
      repo: repo.name,
      author: context.payload.sender.login
    })).data.workflow_runs;

    // TODO: There may be a race condition in retrieving the
    // artifacts; sometimes the result is an empty list, but will
    // succeed when run after a short break.
    const artifacts = (await context.github.actions.listWorkflowRunArtifacts({
      owner: owner,
      repo: repo.name,
      run_id: workflow_runs[0].id
    })).data.artifacts;
    
    app.log(check_suite.pull_requests)

    // TODO: The check_suite event is not guaranteed to have associated pull requests
    for (const pull of check_suite.pull_requests) {
      app.log(pull)
      const message = `Draft PDF in [${artifacts[0].name}.zip](https://github.com/${owner}/${repo.name}/suites/${check_suite.id}/artifacts/${artifacts[0].id})`
      app.log(message)
      return context.github.issues.createComment({
        owner: owner,
        repo: repo.name,
        issue_number: pull.number,
        body: message
      });
    }
  });
};