Heroku Deployment Guide

Prep - Setup Heroku Account + CLI

In order to deploy Node JS apps to Heroku, we need two things:

• an Heroku account: https://signup.heroku.com/dc
• the Heroku CLI: https://devcenter.heroku.com/articles/heroku-cli

Afterwards we are able to deploy NodeJS apps.

Please visit the given two links to setup both.

Find here the general guideline for the creation & deployment of NodeJS APIs:

https://devcenter.heroku.com/articles/deploying-nodejs

Deployment preparation in code

Oursource confidential information

• Create a file .env (in top level of your project)
• Outsource all confidential info like secrets + DB connection strings + allowed Frontend URL into .env file
• Add .env to gitignore to prevent secrets being pushed to our codebase
• Adapt PORT too (process.env.PORT) => because we cannot dictate the port on provider

A typical sample .env file:

MONGO_URI=mongodb+srv://youruser:youruser@your-cluster.mongodb.net/your_db?retryWrites=true&w=majority
JWT_SECRET=silencio_i_am_secret
FRONTEND_ORIGIN=http://localhost:3000

Load environment into app

• Install dotenv package npm i dotenv

• Load environment variables in server.js with require("dotenv").config()

• Load environment variables in the seed script too

• Test your app locally, if it still connects to MongoDB (npm start + npm run seed)

• Add & Commit all code changes

Setup Heroku app & deployment

• Login to Heroku: heroku login

• Create Heroku app: heroku apps:create YOUR_APP_NAME

• Create environment variables on Heroku (either in app settings online: https://dashboard.heroku.com/apps or in terminal)

  • in terminal: heroku config:set KEY=VALUE

• Check if environment variables were placed successfully on Heroku server: heroku config

• Perform Deploy: git push heroku <yourLocalBranchName>:main

• Optional: Perform seed against Heroku database (in case you use a different one locally & centrally): heroku run "npm run seed"

• Open Webpage: heroku open

Troubleshooting

In case you receive "Application error" on any route of the deployed webpage

• View the central errors in the error log heroku logs or just output last error heroku logs --tail

Common issues:

• forgot to use process.env.PORT as port to listen too?
• forgot start script in package.json? Should be start: "node server.js"
• env variables spelling issues? compare heroku config with your keys in .env file - mismatch?

DONE!