heroku

Heroku Best Practices

Developing on Heroku requires adherence to specific patterns to leverage its Platform-as-a-Service (PaaS) strengths. This guide focuses on the Twelve-Factor App methodology and Heroku's runtime principles to ensure your applications are scalable, resilient, and maintainable.

1. Code Organization and Structure

Maintain a clean, version-controlled codebase and clearly define your application's processes.

1.1. Procfile for Process Types

Explicitly declare your application's process types using a Procfile. This allows Heroku to run different types of dynos (web, worker, etc.) and scale them independently.

❌ BAD: Relying on default web process or running multiple concerns in one dyno.

# No Procfile, or a single 'web' process doing everything
web: npm start

✅ GOOD: Separate web and worker processes.

web: node src/server.js
worker: node src/worker.js
release: node src/db-migrate.js

• Context: Use web for HTTP traffic, worker for background jobs, and release for one-off tasks like database migrations before the app starts.

1.2. app.json for Declarative Setup

Use app.json for Heroku Button deployments, Review Apps, and to declare add-ons and environment variables.

❌ BAD: Manual setup of add-ons and config vars for each environment.

# No app.json, requiring manual configuration

✅ GOOD: Declarative app.json for consistent deployments.

// app.json
{
  "name": "My Awesome App",
  "description": "A description of my awesome app.",
  "repository": "https://github.com/myorg/my-awesome-app",
  "keywords": ["node", "express", "heroku"],
  "addons": [
    "heroku-postgresql",
    "heroku-redis"
  ],
  "env": {
    "NODE_ENV": {
      "description": "The environment the app is running in.",
      "value": "production"
    },
    "LOG_LEVEL": {
      "description": "Logging verbosity.",
      "value": "info"
    }
  },
  "scripts": {
    "postdeploy": "npm run db:seed"
  },
  "formation": {
    "web": {
      "quantity": 1,
      "size": "standard-1x"
    },
    "worker": {
      "quantity": 1,
      "size": "standard-1x"
    }
  }
}

• Context: app.json ensures consistency across environments and simplifies onboarding for new developers.