Using lighthouse in combination with Puppeteer

Hello,

I’m would like to launch a chrome instance, connect puppeteer to it to login, and then start lighthouse, is that possible ? I couldn’t find a way to connect puppeteer to a chrome instance started with chrome-launcher.

I’ve tried something like this but with no success

function launchChromeAndRunLighthouse(url, opts, config = null) {
	return chromeLauncher.launch({chromeFlags: opts.chromeFlags}).then(async chrome => {
		opts.port = chrome.port;
		const url = 'ws://localhost:' + chrome.port + '/devtools/browser/';
		const browser = await puppeteer.connect({
			browserWSEndpoint: url
		});
                // this throws the following WS error: (node:9000)
                // UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: unexpected server response (404)

because I’m missing the browser id after browser/ and it doesn’t seem to be exposed by lighthouse

I’ve seen issues where it says to manually connect before running lighthouse on a website where login is mandatory. Is there any other fully automated way to do this ?

[ebidel]

This should work:

const chromeLauncher = require('chrome-launcher');
const puppeteer = require('puppeteer');
const lighthouse = require('lighthouse');
const request = require('request');
const util = require('util');

(async() => {

const URL = 'https://www.chromestatus.com/features';

const opts = {
  //chromeFlags: ['--headless'],
  logLevel: 'info',
  output: 'json'
};

// Launch chrome using chrome-launcher.
const chrome = await chromeLauncher.launch(opts);
opts.port = chrome.port;

// Connect to it using puppeteer.connect().
const resp = await util.promisify(request)(`http://localhost:${opts.port}/json/version`);
const {webSocketDebuggerUrl} = JSON.parse(resp.body);
const browser = await puppeteer.connect({browserWSEndpoint: webSocketDebuggerUrl});

// Run Lighthouse.
const lhr = await lighthouse(URL, opts, null);
console.log(`Lighthouse score: ${lhr.score}`);

await browser.disconnect();
await chrome.kill();

})();

[ebidel]

@Antonhansel what’s the use case for using chrome-launcher? Why not just launch chrome using puppeteer?