Golden Test Comment workflow (uber-go/nilaway)

name: Golden Test Comment
 
# See ".github/workflows/golden-test-build.yml" for more details.
on:
  workflow_run:
    workflows: [Golden Test]
    types:
      - completed
 
permissions:
  actions: read
  pull-requests: write
  statuses: write
 
jobs:
  comment:
    timeout-minutes: 30
    name: Comment
    runs-on: latchkey-small
    if: >
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.conclusion == 'success'
    steps:
      # Since our Golden Test Comment is always executed on main branch, such that its status does
      # not show up in the PR page. However, if this job fails we should still block the PR, since
      # the Golden Test result is stale and can not be trusted. Here, we leverage the GitHub commit
      # status API to report the status.
      - name: Set PR status to be running
        uses: actions/github-script@v9
        with:
          script: |
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: '${{ github.event.workflow_run.head_sha }}',
              target_url: '${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}',
              state: 'pending',
              context: "Golden Test / Comment",
            });
 
      # We do not have a good way to find the PR number from the workflow run event [1]. Therefore,
      # here we list all open PRs and find the one that has the same SHA as the workflow run.
      # This is a workaround until GitHub provides a better way to find the associated PR.
      #
      # [1]: https://github.com/orgs/community/discussions/25220
      - name: Find associated pull request
        id: pr
        uses: actions/github-script@v9
        with:
          script: |
            const { data: pulls } = await github.rest.pulls.list({
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: 'open',
            });
 
            const pr = pulls.find(pr => pr.head.sha === '${{ github.event.workflow_run.head_sha }}');
            if (pr === undefined || pr === null) {
              throw new Error(`Cannot find the associated pull request for the workflow run ${context.runId}`);
            }
            
            console.info("Pull request number is", pr.number);
            return pr.number;
 
      - name: Download Golden Test result artifact
        uses: actions/github-script@v9
        with:
          script: |
            const artifacts = await github.rest.actions.listWorkflowRunArtifacts({
              owner: context.repo.owner,
              repo: context.repo.repo,
              run_id: ${{ github.event.workflow_run.id }},
            });
            const matchArtifact = artifacts.data.artifacts.filter((artifact) => {
              return artifact.name == "golden-test-comment.md";
            })[0];
            const download = await github.rest.actions.downloadArtifact({
              owner: context.repo.owner,
              repo: context.repo.repo,
              artifact_id: matchArtifact.id,
              archive_format: 'zip',
            });
            const fsp = require('fs').promises;
            await fsp.writeFile('${{ github.workspace }}/golden-test-comment.md.zip', Buffer.from(download.data));
 
      - run: unzip golden-test-comment.md.zip
 
      - name: Upload the Golden Test result
        uses: actions/github-script@v9
        with:
          script: |
            const fsp = require('fs').promises;
 
            const issueNumber = ${{ steps.pr.outputs.result }};
            const owner = context.repo.owner;
            const repo = context.repo.repo;
            const rawData = await fsp.readFile('./golden-test-comment.md', 'utf8');
 
            // GitHub API has a limit of 65536 bytes for a comment body, so here we shrink the
            // diff part (anything between <details> and </details>) to 10,000 characters if it
            // is too long.
            const pattern = /(<details>)([\s\S]*?)(<\/details>)/;
 
            const body = rawData.replace(pattern, function(match, p1, p2, p3) {
              if (p2.length > 10000) {
                return p1 + p2.substring(0, 5000) + '\n\n ...(truncated)...\n\n' + p2.substring(p2.length - 5000) + p3;
              }
              // No need to change anything if it is not too long.
              return match;
            });
 
            // First find the comments made by the bot.
            const comments = await github.rest.issues.listComments({
              owner: owner,
              repo: repo,
              issue_number: issueNumber
            });
            const botComment = comments.data.find(comment => comment.user.login === 'github-actions[bot]' && comment.body.startsWith('## Golden Test'));
 
            // Update or create the PR comment.
            if (botComment) {
              await github.rest.issues.updateComment({
                owner: owner,
                repo: repo,
                comment_id: botComment.id,
                body: body
              });
            } else {
              await github.rest.issues.createComment({
                owner: owner,
                repo: repo,
                issue_number: issueNumber,
                body: body
              });
            }
 
      # `success()` can only be called in `if:` condition, so we convert it as a step output here
      # to be used in reporting the final status of this job.
      - name: Check if the job is successful
        id: success
        if: success()
        run: |
          echo "success=true" >> $GITHUB_OUTPUT
 
      - name: Set final PR status
        uses: actions/github-script@v9
        if: always()
        with:
          script: |
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: '${{ github.event.workflow_run.head_sha }}',
              target_url: '${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}',
              state: '${{ steps.success.outputs.success }}' === 'true' ? 'success' : 'failure',
              context: "Golden Test / Comment",
            });