Firebase functions: koa.js server how to deploy

Question

I already have an app written in MERN stack with koa server prepared build version. My main node file to run by node server.js command to start the whole app looks like this.

In every tutorial, I see that I need to add functions.https.request etc. in the beginning of coding (or at least to suppose doing it). How could I host my app on firebase the same as I could on heroku - with whole server side?

Answer 1

It is possible to host Koa app using firebase functions, I figure it out after some Googling and analyzing.

This is a piece of code from my project, it is now hosted with firebase functions:

const Koa = require('koa');
const app = new Koa();

// ... routes code here ...

// This is just for running Koa and testing on the local machine
const server = app.listen(config.port, () => {
  console.log(`HITMers-server is running on port ${config.port}`);
});
module.exports = server;

// This export is for Firebase functions
exports.api = functions.https.onRequest(app.callback());

You can see the docs and tutorial video for more information.

By the way, here is another example to deploy Koa to now.sh version 2.

Answer 2

You can actually skip the listen call entirely, and use app.callback(). This seems to make more sense than listening on a random port that never actually gets hit.

const functions = require('firebase-functions');
const app = new Koa();
... // set up your koa app however you normally would
app.use(router.routes());
module.exports.api = functions.https.onRequest(app.callback());