Refactor image rendering to use a browser pool and update dependencies

browserPool.js

@@ -0,0 +1,108 @@
+const puppeteer = require('puppeteer');
+
+const POOL_SIZE = parseInt(process.env.BROWSER_POOL_SIZE) || 5;
+const VIEWPORT_WIDTH = 3240;
+const VIEWPORT_HEIGHT = 3240;
+
+let browsers = [];
+let availablePages = [];
+let initPromise = null;
+
+
+async function initPool() {
+    if (initPromise) return initPromise;
+
+    initPromise = (async () => {
+        console.log(`Initializing browser pool with ${POOL_SIZE} instances...`);
+
+        for (let i = 0; i < POOL_SIZE; i++) {
+            const browser = await puppeteer.launch({
+                headless: true,
+                args: ['--no-sandbox', '--disable-setuid-sandbox']
+            });
+
+            browsers.push(browser);
+
+            const page = await browser.newPage();
+            await page.setViewport({
+                width: VIEWPORT_WIDTH,
+                height: VIEWPORT_HEIGHT
+            });
+
+            availablePages.push(page);
+        }
+
+        console.log(`Browser pool ready with ${POOL_SIZE} pages`);
+    })();
+
+    return initPromise;
+}
+
+async function acquirePage() {
+    await initPool();
+
+    // wait for available page
+    while (availablePages.length === 0) {
+        await new Promise(resolve => setTimeout(resolve, 50));
+    }
+
+    return availablePages.pop();
+}
+
+function releasePage(page) {
+    availablePages.push(page);
+}
+
+// renders html and returns screenshot as buffer
+async function renderHtml(html, waitTime = 1000) {
+    const page = await acquirePage();
+
+    try {
+        await page.setContent(html, { waitUntil: 'networkidle0' });
+
+        // wait for any animations or laoding
+        await new Promise(resolve => setTimeout(resolve, waitTime));
+
+        const screenshot = await page.screenshot({
+            type: 'png',
+            fullPage: false
+        });
+
+        return screenshot;
+    } finally {
+        releasePage(page);
+    }
+}
+
+
+async function shutdownPool() {
+    console.log('Shutting down browser pool...');
+
+    for (const browser of browsers) {
+        await browser.close();
+    }
+
+    browsers = [];
+    availablePages = [];
+    initPromise = null;
+
+    console.log('Browser pool shut down');
+}
+
+// Graceful shutdown handlers
+process.on('SIGINT', async () => {
+    await shutdownPool();
+    process.exit(0);
+});
+
+process.on('SIGTERM', async () => {
+    await shutdownPool();
+    process.exit(0);
+});
+
+module.exports = {
+    initPool,
+    renderHtml,
+    shutdownPool,
+    POOL_SIZE
+};