Firebase Cloud Functions - debug with VSC

Question

I have a node project created with Vue using Firebase Hosting, Cloud Functions and Firestore.

I can deploy locally with npm run build | firebase serve. In the Vue app I'm calling a Cloud Function with firebase.functions().httpsCallable('placeOrder').then((result) => {...})

A
Is it possible to make it so that the Function call calls the Functions emulator (running on port 5001) and I can step through the code with breakpoints?

B
If it's not possible to call the emulator from the locally hosted site, how can I do Cloud Functions development locally? I've read a bunch of articles, but they seem to be outdated. I can emulate a function with the Functions Framework and get the logs when I call it, but I'm not sure how to attach a debugger to it. Also, what happens if that Function reads / writes Firestore? Will it read / write the emulated one?

Cheers

Answer 1

I'll tell you what had worked for me. I love firebase but, using the local emulators has been kind of like a pain for me. I know it will get better with time but is not there yet. Maybe someone else can give us a better approach

Use express and serve your function in the port 5001. You can attach the debugger to use breakpoints. Check here.

Folder structure

| functions/
----| index.js
----| app.js
----| tests/
--------| app.spec.js
| serve.js

index.js

const functions = require('firebase-functions');
const app = require('./app');

module.exports.app  = functions.https.onRequest(app);

app.js

const express = require('express');

const app = express();

app.use('/', (req, res) => {
    // do stuff
});

module.exports = app;

serve.js

const bodyParser = require('body-parser');

const port = 5001;

const app = require('./functions/app.js');

app.use(bodyParser.json());

const message = `app is listening on port ${port}!`;

app.listen(port, () => console.log(message));

Unit testing will make your life easier when dealing with cloud functions. They will make you save time and they will make you a better programmer at the same time.

Note: in this case, you are actually using the firestore database, so make sure you have a development environment. If you ever use the emulator for firestore it's in your local machine so it doesn't write to the real database. Hope that helps