Setup 🛠 Rails 8 App – Part 1: Setup All Necessary Configurations | Ruby | Rails setup | Kamal | Rails Generations

Ruby on Rails 8 introduces several improvements that make development easier, more secure, and more maintainable. In this guide, we’ll walk through setting up a new Rails 8 application while noting the significant configurations and features that come out of the box.

1. Check Your Ruby and Rails Versions

If not installed Ruby 3.4 and Rails 8.0 please check: https://railsdrop.com/2025/02/11/installing-and-setup-ruby-3-rails-8-vscode-ide-on-macos-in-2025/

Before starting, ensure that you have the correct versions of Ruby and Rails installed:

$ ruby -v
ruby 3.4.1

$ rails -v
Rails 8.0.1

If you don’t have these versions installed, update them using your package manager or version manager (like rbenv or RVM).

2. Create a New Rails 8 Application

Run the following command to create a new Rails app:

$ rails new design_studio

Noteworthy Files and Directories Created

Here are some interesting files and directories that are generated with a new Rails 8 app:

 create  .ruby-version
 create  bin/brakeman
 create  bin/rubocop
 create  bin/docker-entrypoint
 create  .rubocop.yml
 create  .github/workflows
 create  .github/workflows/ci.yml
 create  config/cable.yml
 create  config/storage.yml
 create  config/initializers/content_security_policy.rb
 create  config/initializers/filter_parameter_logging.rb
 create  config/initializers/new_framework_defaults_8_0.rb

Key Takeaways:

• Security & Code Quality Tools: Brakeman (security scanner) and RuboCop (code style linter) are included by default.
• Docker Support: The presence of bin/docker-entrypoint suggests better built-in support for containerized deployment.
• GitHub Actions Workflow: The .github/workflows/ci.yml file provides default CI configurations.
• Enhanced Security: The content_security_policy.rb initializer helps enforce a strict security policy.
• New Rails Defaults: The new_framework_defaults_8_0.rb initializer helps manage breaking changes in Rails 8.

Rails automatically creates the following during the creation of the rails new app.

a. Configuring Import Maps and Installing Turbo & Stimulus

Rails 8 still defaults to Import Maps for JavaScript package management, avoiding the need for Node.js and Webpack:

$ rails turbo:install stimulus:install

This creates the following files:

create    config/importmap.rb
create    app/javascript/controllers
create    app/javascript/controllers/index.js
create    app/javascript/controllers/hello_controller.js
append    config/importmap.rb

Key Takeaways:

• Import Maps: Defined in config/importmap.rb, allowing dependency management without npm.
• Hotwired Support: Turbo and Stimulus are automatically configured for modern front-end development.
• Generated Controllers: Stimulus controllers are pre-configured inside app/javascript/controllers/.

b. Deploying with Kamal

Kamal simplifies deployment with Docker and Kubernetes. Rails 8 includes built-in support:

$ bundle binstubs kamal
$ bundle exec kamal init

This results in:

Created .kamal/secrets file
Created sample hooks in .kamal/hooks

Key Takeaways:

• Automated Deployment Setup: Kamal provides easy-to-use deployment scripts.
• Secret Management: The .kamal/secrets file ensures secure handling of credentials.
• Deployment Hooks: Custom hooks allow pre- and post-deployment scripts for automation.

c. Setting Up Caching and Queues with Solid Cache, Queue, and Cable

NOTE: Rails automatically creates this for you while creating the rails app.

Rails 8 includes Solid Cache, Solid Queue, and Solid Cable for enhanced performance and scalability:

$ rails solid_cache:install solid_queue:install solid_cable:install

This creates:

create  config/cache.yml
create  db/cache_schema.rb
create  config/queue.yml

Key Takeaways:

• Caching Support: config/cache.yml manages application-wide caching.
• Database-Powered Queue System: Solid Queue simplifies background job management without requiring external dependencies like Sidekiq.
• Real-Time WebSockets: Solid Cable offers Action Cable improvements for real-time features.

3. Rails 8 Migration Enhancements

Rails 8 provides new shortcuts and syntax improvements for database migrations:

NOT NULL Constraints with ! Shortcut

You can impose NOT NULL constraints directly from the command line using !:

# Example for not null constraints: 
➜ rails generate model User name:string!

Type Modifiers in Migrations

Rails 8 allows passing commonly used type modifiers directly via the command line. These modifiers are enclosed in curly braces {} after the field type.

# Example for model generation: 
➜ rails generate model Product name:string description:text
# Example for passing modifiers: 
➜ rails generate migration AddDetailsToProducts 'price:decimal{5,2}' supplier:references{polymorphic}

Generating a Scaffold for the Product Model

Let’s generate a complete scaffold for our Product model:

✗ rails generate scaffold product title:string! description:text category:string color:string 'size:string{10}' 'mrp:decimal{7,2}' 'discount:decimal{7,2}' 'rating:decimal{1,1}'
➜  design_studio git:(main) ✗ rails -v
Rails 8.0.1
➜  design_studio git:(main) ✗ ruby -v
ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [arm64-darwin24]
➜  design_studio git:(main) ✗ rails generate scaffold product title:string! description:text category:string color:string 'size:string{10}' 'mrp:decimal{7,2}' 'discount:decimal{7,2}' 'rating:decimal{1,1}'

Using the Rails Resource Generator

The rails g resource command is a powerful way to generate models, controllers, migrations, and routes all in one go. This is particularly useful when setting up RESTful resources in a Rails application.

Basic Syntax

➜ rails g resource product

This command creates the necessary files for a new resource, including:

• A model (app/models/product.rb)
• A migration file (db/migrate/)
• A controller (app/controllers/product_controller.rb)
• Routes in config/routes.rb
• A test file (test/controllers/product_controller_test.rb or spec/)

Example Usage

To generate a Post resource with attributes:

➜ rails g resource Product title:string! description:text brand:references

This will:

1. Create a Product model with title and description attributes.
2. Add a brand_id foreign key as a reference.
3. Apply a NOT NULL constraint on title (! shortcut).
4. Generate a corresponding migration file.
5. Set up routes automatically (resources :products).

Running the Migration

After generating a resource, apply the migration to update the database:

➜ rails db:migrate

Difference Between resource and scaffold

Rails provides both rails g resource and rails g scaffold, but they serve different purposes:

• rails g resource is minimal—it generates only essential files without view templates. It’s useful when you want more control over how your views and controller actions are built.
• rails g scaffold is more opinionated and generates full CRUD functionality with prebuilt forms and views, making it ideal for rapid prototyping.

If you need full CRUD functionality quickly, use scaffold. If you prefer a leaner setup with manual control over implementation, use resource.

Conclusion

Rails 8 significantly enhances the development experience with built-in security tools, CI/CD workflows, streamlined deployment via Kamal, and modern front-end support with Turbo & Stimulus. It also improves caching, background jobs, and real-time features with Solid tools.

These improvements make Rails 8 a robust framework for modern web applications, reducing the need for additional dependencies while keeping development efficient and secure.

Enjoy Rails! 🚀

Author: Abhilash

Hi, I’m Abhilash! A seasoned web developer with 15 years of experience specializing in Ruby and Ruby on Rails. Since 2010, I’ve built scalable, robust web applications and worked with frameworks like Angular, Sinatra, Laravel, Node.js, Vue and React. Passionate about clean, maintainable code and continuous learning, I share insights, tutorials, and experiences here. Let’s explore the ever-evolving world of web development together! View all posts by Abhilash