This firebase cloud function takes screenshot of google home page and saves in firebase storage bucket under screenshots/google.png, every time it is run.

google-screenshot-firebase-cloud-function.ts

import * as functions from 'firebase-functions';
import * as admin from "firebase-admin";
import * as puppeteer from "puppeteer";

admin.initializeApp()

export const takeGoogleScreenshot = functions
.runWith({ memory: "1GB" })
.https.onRequest(async (request, response) => {
    const browser = await puppeteer.launch({
        args: ["--no-sandbox", "--disable-setuid-sandbox"]
    })
    const page = await browser.newPage()
    await page.goto("https://www.google.com", {waitUntil: 'networkidle2'})
    const bucket = admin.storage().bucket("screenshots")
    const file = bucket.file("google.png")
    const screenshotBuffer = await page.screenshot({ fullPage: true })
    await file.save(screenshotBuffer)
    await browser.close()
    response.send("done")
})

This is just what I needed for my app thank you. I have modified it to run on a firestore cloud function trigger but I am hitting an error in the logs when the cloud function executes:

"Exception from a finished function: Error: Could not find expected browser (chrome) locally. Run npm install to download the correct Chromium revision (1045629).

Adding chromuim in the dependencies doesn't fix it unfortunately