Refactor Puppeteer launch options for improved configurability

This update introduces a new module, `puppeteerLaunchOptions.js`, which centralizes the Puppeteer launch configuration. The `getPuppeteerLaunchOptions` function is added to provide customizable launch arguments, enhancing the flexibility of browser instantiation in both `mailworker.js` and `pdffactory.js`. This refactor improves code maintainability and allows for easier adjustments to Puppeteer settings in the future.

src/mailworker.js

@@ -7,6 +7,7 @@ import puppeteer from 'puppeteer';
 import nodemailer from 'nodemailer';
 import log4js from 'log4js';
 import config from './config.js';
+import { getPuppeteerLaunchOptions } from './puppeteerLaunchOptions.js';
 
 const baseUrl = (urlClient) => (urlClient || 'http://localhost:3000').replace(/\/$/, '');
 
@@ -77,14 +78,9 @@ async function sendEmail(payload) {
   let html = '';
   let browser;
   try {
-    browser = await puppeteer.launch({
-      headless: 'new',
-      args: [
-        '--no-sandbox',
-        '--disable-setuid-sandbox',
-        '--disable-features=SameSiteByDefaultCookies',
-      ],
-    });
+    browser = await puppeteer.launch(
+      getPuppeteerLaunchOptions(['--disable-features=SameSiteByDefaultCookies'])
+    );
     const page = await browser.newPage();
     page.on('console', (msg) => {
       const text = msg.text();

src/puppeteerLaunchOptions.js

@@ -0,0 +1,16 @@
+import puppeteer from 'puppeteer';
+
+const BASE_ARGS = ['--no-sandbox', '--disable-setuid-sandbox'];
+
+/**
+ * Puppeteer launch options using the Chrome downloaded to the Puppeteer cache
+ * (e.g. /home/farmcontrol/.cache/puppeteer on Linux), not a system-installed browser.
+ */
+export function getPuppeteerLaunchOptions(extraArgs = []) {
+  return {
+    executablePath:
+      process.env.PUPPETEER_EXECUTABLE_PATH || puppeteer.executablePath(),
+    headless: true,
+    args: [...BASE_ARGS, ...extraArgs],
+  };
+}

src/templates/__tests__/pdffactory.test.js

@@ -16,6 +16,7 @@ const browserInstance = {
 
 const puppeteer = {
   launch: jest.fn().mockResolvedValue(browserInstance),
+  executablePath: jest.fn().mockReturnValue('/fake/puppeteer/chrome'),
 };
 
 jest.unstable_mockModule('puppeteer', () => ({

src/templates/pdffactory.js

@@ -1,15 +1,11 @@
 import log4js from 'log4js';
 import puppeteer from 'puppeteer';
 import config from '../config.js';
+import { getPuppeteerLaunchOptions } from '../puppeteerLaunchOptions.js';
 
 const logger = log4js.getLogger('PDF Factory');
 logger.level = config.server.logLevel;
 
-const LAUNCH_OPTIONS = {
-  headless: true,
-  args: ['--no-sandbox', '--disable-setuid-sandbox'],
-};
-
 let browser = null;
 let launchPromise = null;
 let shutdownRegistered = false;
@@ -20,7 +16,7 @@ function isBrowserConnected() {
 
 async function launchBrowser() {
   logger.info('Launching persistent Puppeteer browser...');
-  const instance = await puppeteer.launch(LAUNCH_OPTIONS);
+  const instance = await puppeteer.launch(getPuppeteerLaunchOptions());
   instance.on('disconnected', () => {
     if (browser === instance) {
       logger.warn('Puppeteer browser disconnected');