Deploying Node.js apps to Heroku

This post covers the main notes from setting up the Heroku CLI tool to CI/CD pipeline with Github actions.

Prerequisites

• Run the following command to install the CLI tool

curl https://cli-assets.heroku.com/install.sh | sh

• Create an account or log in if you already have an account

heroku login

Node server

• Run the following commands for packages setup

npm init -y
npm i express

• Write basic server

// server.js
const express = require('express');
const app = express();
const PORT = process.env.PORT || 8080;
app.get('/', (_, res) => res.send('Hello world'));
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

• Configure start script

// package.json
{
  "scripts": {
    "start": "node server.js"
  }
}

Project setup

The following command will create a project with the provided name. Project URL will be <PROJECT_NAME>.herokuapp.com

heroku create -a <PROJECT_NAME>
git init
heroku git:remote -a <PROJECT_NAME>

Create a Procfile with a command for starting the server.

# Procfile
web: npm start

Environment variables

The following commands can be used to set the provided environment variable and restart the server, show the list of already set variables, remove the provided variable and restart the server, and append the set variables to a local file (.env in this case). Heroku will set up the server port's environment variable (PORT).

heroku config:set VARIABLE_NAME=value
heroku config
heroku config:remove VARIABLE_NAME
heroku config -s >> .env

Addons

The following commands add and remove specified add-ons.

heroku addons:create <ADDON_NAME>
heroku addons:remove <ADDON_NAME>

Databases

Redis

Run the following commands to provision the Redis database. Heroku will set the environment variables for the database connection.

heroku addons:create upstash-redis:free

Postgres

Run the following command to bootstrap a Postgres database.

heroku addons:create heroku-postgresql

The previous command will set the database connection string in DATABASE_URL environment variable.

Check the database info with the following command.

heroku pg:info

Release command in Procfile can run migrations.

# Procfile
release: npm run migrate

The following commands create the database backups, check the progress of the last backup, and show the list of the previous backups.

heroku pg:backups:capture
heroku pg:backups:info
heroku pg:backups

Debugging

• Get the real-time logs

heroku logs --tail

• Get the specific number of lines of logs

heroku logs -n 20

• Get the info about the app

heroku info

• Get the state of the project to check if there are any issues

heroku status

• Run bash on the app dyno

heroku run bash

• Restart the app dynos

heroku restart

Deployment

Manual deployment

Deploy and open the deployed version with the following commands.

git add .
git commit -m "Initial commit"
git push origin master
heroku open

If the command for opening the project in the browser doesn't work in Windows Subsystem for Linux, set BROWSER environment in the corresponding shell configuration file (e.g., ~/.zshrc)

export BROWSER=wslview

CI/CD pipeline

Connect the app with Github on Deploy → Deployment method page and enable CI and automatic deploys.

Add .github/workflows/config.yml file with the following configuration for the CI pipeline.

name: CI pipeline
on:
  push:
    branches:
      - master
jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    container: node:20.9.0-alpine3.17
    steps:
      - name: Github checkout
        uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm ci
      - run: npm run lint
      - run: npm test
      - run: npm audit

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