Add workflow to check for new files so CODEOWNERS can be updated (#5110)

* Add workflow to check for new files

* update codeowners link

* Add newlines

* Move var into env var

* Update workflow to pull codeowners from current branch

* Only run check if there are new files

* Split out inline github scripts into its own JS file

* Fix typos

* Don't filter out documentation-team owners

* Console log new files found before adding a comment to the PR

* Don't hardcode fetch url

* Specify version for ignore package

* Update workflow based on feedback

* Return the entire github.paginate call in order to return the file count

Author: timngyn

.github/workflows/check_for_new_files.yml

@@ -0,0 +1,37 @@
+name: Validate CODEOWNERS
+on:
+  pull_request:
+    branches: [main]
+jobs:
+  checkIfCodeownersUpdateNeeded:
+    permissions:
+      pull-requests: write # Used to add comment to PR
+    name: Check if CODEOWNERS needs to be updated
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+      - name: Get count of added files
+        uses: actions/[email protected]
+        id: set-added-files-count
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          result-encoding: string
+          script: |
+            const { getAddedFiles } = require('./.github/workflows/scripts/check_for_new_files.js');
+            return getAddedFiles({github, context, core});
+      - name: Install npm package ignore
+        if: ${{ steps.set-added-files-count.outputs.result > 0 }}
+        run: yarn add [email protected] -W # help verify CODEOWNERS
+      - name: Check file against CODEOWNERS
+        if: ${{ steps.set-added-files-count.outputs.result > 0 }}
+        uses: actions/[email protected]
+        env:
+          CURRENT_BRANCH: ${{ github.head_ref }}
+          CURRENT_REPO: ${{ github.repository }}
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const ignore = require('ignore');
+            const { validateCodeowners } = require('./.github/workflows/scripts/check_for_new_files.js');
+            validateCodeowners({github, context, fetch, ignore});

.github/workflows/scripts/check_for_new_files.js

@@ -0,0 +1,82 @@
+module.exports = {
+  getAddedFiles: ({ github, context, core }) => {
+    const {
+      issue: { number: issue_number },
+      repo: { owner, repo }
+    } = context;
+
+    // Use the Github API to query for the list of files from the PR
+    return github
+      .paginate(
+        'GET /repos/{owner}/{repo}/pulls/{pull_number}/files',
+        { owner, repo, pull_number: issue_number },
+        (response) => response.data.filter((file) => file.status === 'added')
+      )
+      .then((files) => {
+        // Save these values to the Github env
+        core.exportVariable('NEW_FILES', files);
+
+        console.log('New files: ', files);
+
+        // Return the new files count to be used in the github workflow
+        return files.length;
+      });
+  },
+  validateCodeowners: async ({ github, context, fetch, ignore }) => {
+    const { NEW_FILES, CURRENT_BRANCH, CURRENT_REPO } = process.env;
+
+    const codeownersFile = `https://github.com/raw/${CURRENT_REPO}/${CURRENT_BRANCH}/.github/CODEOWNERS`;
+
+    console.log('Fetching CODEOWNERS from: ', codeownersFile);
+
+    const response = await fetch(codeownersFile);
+    const body = await response.text();
+
+    // Filter out comments from CODEOWNERS file
+    const codeownersFilePatterns = body
+      .split('\n')
+      .filter((e) => !e.startsWith('#'))
+      .filter((e) => e.length > 1)
+      .map((e) => e.split(/\s+/)[0]);
+
+    console.log(
+      'CODEOWNERS patterns to match new files against: ',
+      codeownersFilePatterns
+    );
+
+    // Add the patterns to the ignore package
+    const ig = ignore().add(codeownersFilePatterns);
+
+    const filesNotInCodeowners = [];
+
+    JSON.parse(NEW_FILES).forEach((newFile) => {
+      // Check if the file isn't covered by our list of patterns
+      if (!ig.ignores(newFile.filename)) {
+        console.log(`${newFile.filename} is not covered by CODEOWNERS`);
+        filesNotInCodeowners.push(newFile.filename);
+      }
+    });
+
+    const {
+      issue: { number: issue_number },
+      repo: { owner, repo }
+    } = context;
+
+    console.log('New files: ', filesNotInCodeowners);
+
+    // If we found files not covered by CODEOWNERS, then add a comment to the PR
+    if (filesNotInCodeowners.length > 0) {
+      const files = filesNotInCodeowners.map((e) => `- ${e}\n`).join('');
+
+      const needCodeownersUpdateComment = `CODEOWNERS need to be updated because these new files are not covered:\n ${files}`;
+      github.rest.issues.createComment({
+        owner,
+        repo,
+        issue_number,
+        body: needCodeownersUpdateComment
+      });
+      const labels = ['update-codeowners'];
+      github.rest.issues.addLabels({ owner, repo, issue_number, labels });
+    }
+  }
+};