feat: lighthouse report on frontend PRs

.github/lighthouserc.js

@@ -0,0 +1,44 @@
+let previewBaseUrl = '';
+try {
+  const previewUrlBase64 = process.env.LHCI_PREVIEW_URL_BASE64;
+  console.log("environemtnt variable LHCI_PREVIEW_URL:", previewUrlBase64);
+  if (previewUrlBase64) {
+    const decodedUrl = Buffer.from(previewUrlBase64, 'base64').toString('utf-8');
+    console.log("Decoded preview URL:", decodedUrl);
+    previewBaseUrl = decodedUrl;
+  } else {
+    console.error("LHCI_PREVIEW_URL_BASE64 environment variable is not set.");
+  }
+} catch (error) {
+  console.error("Error decoding LHCI_PREVIEW_URL_BASE64:", error);
+}
+
+module.exports = {
+  ci: {
+    collect: {
+      url: [
+        `${previewBaseUrl}/`,
+        `${previewBaseUrl}/feeds`,
+        `${previewBaseUrl}/feeds/gtfs/mdb-2126`,
+        `${previewBaseUrl}/feeds/gtfs_rt/mdb-2585`,
+        `${previewBaseUrl}/gbfs/gbfs-flamingo_porirua`
+      ],
+      numberOfRuns: 1, // 1 to speed up the CI process but can be increased for more reliable results
+      settings: {
+        formFactor: 'desktop',
+        throttlingMethod: 'provided',
+        skipAudits: ['robots-txt', 'is-crawlable'],
+        screenEmulation: {
+          mobile: false,
+          width: 1350,
+          height: 940,
+          deviceScaleRatio: 1,
+          disabled: false
+        }
+      }
+    },
+    upload: {
+      target: 'temporary-public-storage'
+    }
+  }
+};

.github/workflows/web-app-deployer.yml

@@ -321,4 +321,59 @@ jobs:
           HOSTING_EXPIRATION_DATE=$(npx firebase hosting:channel:list | grep ${{ inputs.PREVIEW_HOST_NAME }} | awk '{printf "%s %s\n",$9,$10;}')
           echo "hosting_url=$HOSTING_URL" >> "$GITHUB_OUTPUT"
           echo "hosting_expiration_date=$HOSTING_EXPIRATION_DATE" >> "$GITHUB_OUTPUT"
+
+      - name: Lighthouse Check
+        id: lighthouse-check
+        if: ${{ inputs.PREVIEW_DEPLOYMENT }}
+        uses: treosh/lighthouse-ci-action@v12
+        # Runs on: Homepage, Search page, GTFS page, GTFS-RT page, and GBFS page
+        with:
+          configPath: ./.github/lighthouserc.js
+          temporaryPublicStorage: true
+        env:
+          LHCI_PREVIEW_URL_BASE64: ${{ steps.deploy-preview.outputs.hosting_url }}
+
+
+      - name: Format lighthouse score
+        id: format_lighthouse_score
+        if: ${{ inputs.PREVIEW_DEPLOYMENT }}
+        uses: actions/github-script@v3
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          script: |
+            const results = ${{ steps.lighthouse-check.outputs.manifest }}
+            const links = ${{ steps.lighthouse-check.outputs.links }}
+            let comment = []
+            results.forEach((resultData, index) => {
+                const result = resultData.summary;
+
+                const formatResult = (res) => Math.round((res * 100))
+                Object.keys(result).forEach(key => result[key] = formatResult(result[key]))
+
+                const score = res => res >= 90 ? '🟢' : res >= 50 ? '🟠' : '🔴'
+                const link = Object.keys(links)[index] ?? 'Unknown URL';
+                const linkUrl = links[link] ?? '#';
+                comment = comment.concat(...[
+                    `*Lighthouse ran on ${link} * (Desktop)`,
+                    `⚡️ HTML Report [Lighthouse report](${linkUrl}) for the changes in this PR:`,
+                    '| Performance | Accessibility | Best Practices | SEO |',
+                    '| --- | --- | --- | --- |',
+                    `| ${score(result.performance)} ${result.performance} | ${score(result.accessibility)} ${result.accessibility} | ${score(result['best-practices'])} ${result['best-practices']} | ${score(result.seo)} ${result.seo} |`,
+                    ' ',
+                    ' ',
+                ])
+            })
+            const finalComment = comment.join('\n')
+            core.setOutput("comment", finalComment); 
+
+      - name: Add lighthouse comment to PR
+        id: comment_to_pr
+        if: ${{ inputs.PREVIEW_DEPLOYMENT }}
+        uses: marocchino/sticky-pull-request-comment@v1
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          number: ${{ github.event.issue.number }}
+          header: lighthouse
+          message: |
+            ${{ steps.format_lighthouse_score.outputs.comment }}