Scheduling Node.js script on GCP using Cloud Functions - node.js

Question

I've created a script that scrapes information from a webpage and writes it to a Google Sheet. This is working great on my local machine, but I'd like to schedule this on GCP.
It sounds like Cloud Functions are the way to go, but when I deploy my function I'm getting this error:
Function failed on loading user code. Error message: Node.js module defined by file working.js is expected to export function named run
I'm not sure what I should be using as the "Function to execute". Here's the function I've uploaded:
const puppeteer = require('puppeteer');
const jsonexport = require('jsonexport');
const GoogleSpreadsheet = require('google-spreadsheet');
const creds = require('./google-generated-creds.json');
const fs = require('fs');
var doc = new GoogleSpreadsheet('1qaFi0xnhaCZEduylUvGXWpyMJv00Rz6Y9qqyFR1E9oI');
function run() {
return new Promise(async (resolve, reject) => {
try {
const browser = await puppeteer.launch({args: ['--no-sandbox', '--disable-setuid-sandbox']});
const page = await browser.newPage();
const urls = [
"https://www.marksandspencer.com/pure-cotton-long-sleeve-jumpsuit/p/p60258655?image=SD_01_T42_6701_XB_X_EC_90&color=INDIGO&prevPage=plp",
"https://www.marksandspencer.com/cotton-rich-striped-3-4-sleeve-t-shirt/p/p60210598?prevPage=plp",
"https://www.marksandspencer.com/high-neck-long-sleeve-blouse/p/p60260040?image=SD_01_T43_5168_HD_X_EC_90&color=LIGHTDENIM&prevPage=plp",
"https://www.marksandspencer.com/pure-cotton-printed-short-sleeve-t-shirt/p/p60263529?image=SD_01_T41_8030Z_Z4_X_EC_90&color=WHITEMIX&prevPage=plp",
"https://www.marksandspencer.com/pure-cotton-button-detailed-denim-mini-skirt/p/p60260145?image=SD_01_T57_4004_QP_X_EC_90&color=DARKINDIGO&prevPage=plp",
"https://www.marksandspencer.com/pure-cotton-long-sleeve-shirt-midi-dress/p/p60258654?image=SD_01_T42_6703_HP_X_EC_90&color=DENIM&prevPage=plp",
"https://www.marksandspencer.com/mid-rise-skinny-leg-ankle-grazer-jeans/p/p60220155?prevPage=plp",
"https://www.marksandspencer.com/pure-cotton-long-sleeve-shirt/p/p60260208?image=SD_01_T43_5181_HP_X_EC_90&color=DENIM&prevPage=plp",
"https://www.marksandspencer.com/long-sleeve-shirt-mini-dress/p/p60258652?image=SD_01_T42_6704_HP_X_EC_90&color=DENIM&prevPage=plp",
"https://www.marksandspencer.com/wide-fit-suede-lace-up-trainers/p/p60216277?prevPage=plp",
"https://www.marksandspencer.com/suede-ankle-boots/p/p60226911?prevPage=plp",
"https://www.marksandspencer.com/leather-buckle-hip-belt/p/p60186701?prevPage=plp",
"https://www.marksandspencer.com/cross-body-bag/p/p60215352?prevPage=plp"
];
const productsList = [];
for (let i = 0; i < urls.length; i++) {
const url = urls[i];
await page.goto(url);
let products = await page.evaluate(() => {
let product = document.querySelector('h1[itemprop=name]').innerText;
let results = [];
let items = document.querySelectorAll('[data-ttip-id=sizeGridTooltip] tbody tr td label');
items.forEach((element) => {
let size = element.getAttribute('for');
let stockLevel = "";
let nearest_td = element.closest('td');
if (nearest_td.classList.contains('low-stock')) {
stockLevel = "Low stock"
} else if (nearest_td.classList.contains('out-of-stock')) {
stockLevel = "Out of stock"
} else {
stockLevel = "In stock"
}
results.push({
product: product,
size: size,
stock: stockLevel
})
});
return results
})
productsList.push(products)
}
browser.close();
function flatten(arr) {
return arr.reduce(function(flat, toFlatten) {
return flat.concat(Array.isArray(toFlatten) ? flatten(toFlatten) : toFlatten);
}, []);
}
var flatProducts = flatten(productsList)
flatProducts.forEach(function(row) {
// Authenticate with the Google Spreadsheets API.
doc.useServiceAccountAuth(creds, function(err) {
// Get all of the rows from the spreadsheet.
doc.addRow(1, row, function(err, rows) {
console.log(row);
});
});
});
} catch (e) {
return reject(e);
}
})
}
run().then(console.log).catch(console.error);
I've never used Cloud Functions before so unsure how much I'd need to modify my script.

Answer 1

You can't just upload any script to run. You have to define a function using either the Cloud tools (via gcloud) or the Firebase tools and SDK. You will also have to figure out how you want to trigger it. When the function is triggered, then you can arrange to have your code executed.
I would say that it's mostly non-trivial to just port an existing script to Cloud Functions. You will have to take time to learn about how the system works in order to make effective use of it.

Answer 2

What that errors is referring to is that Cloud Functions can't find a function to run in that file (working.js) because you haven't exported one. For example, if you create a Cloud Function named run, then you must export a function in the script by assigning it to exports.run in your module:
exports.run = (event, callback) => {
callback(null, `Hello ${event.data.name || 'World'}!`);
};
There's more examples in the documentation, but it's likely that other changes will be necessary in your script for authentication, etc, to work from GCP.