Simple Firebase function to keep a Heroku dyno alive

Recently I decided to take some time off and create a very simple Discord bot. The bot would have the task of playing an audio file at random in whatever voice channel I am in. This was accomplished rather quickly with the discord.js library, and I started looking at how to host it.

After some research I decided on Heroku, as I had never used it before. Their free server offering captured my attention, and I figured I could get it running continuously. The problem was that Heroku would put my server to sleep after 30 minutes of inactivity, and I did not expect the bot to be used so often.

The solution to this was to create a very simple Firebase Function that would send a request to the server every 28 minutes, thus keeping it alive.

The function is as follows:

"use strict";

const functions = require("firebase-functions");
const https = require("https");

exports.wakeUpHeroku = functions
  .pubsub.schedule("every 28 minutes")
  .onRun(async (_) => {
    return null;

async function sendReq() {
  https.get(process.env.BOT_URL, (res) => {
    res.on("done", console.log);

The function above is created in the European region, in the London timezone, and is set to run every 28 minutes using Google Pub/Sub. When it runs, it sends a simple request to the bot URL, and finishes.