Migrating a Rails 5 application to Rails 7 involves several steps, including updating dependencies, refactoring code, and ensuring compatibility with new features and changes introduced in Rails 6 and 7. Here’s a detailed guide to help you through the process:

 

1. Preparation

Backup Your Application

Before starting the migration, ensure you have a complete backup of your application, including the database.

Review Release Notes

Read through the Rails 6 and Rails 7 release notes to understand the changes, new features, and deprecations:

• Rails 6 Release Notes
• Rails 7 Release Notes

Update Ruby

Ensure you are using a compatible Ruby version. Rails 7 requires Ruby 2.7.0 or newer. Consider upgrading to the latest stable Ruby version.

 

2. Upgrade to Rails 6

Update Gemfile

Update your Gemfile to use Rails 6.0.x:

gem 'rails', '~> 6.0.0'

 

Update Dependencies

Update other gems to be compatible with Rails 6. Run:

bundle install

 

Run Update Task

Run the Rails update task to generate necessary configuration files:

rails app:update

Review and merge the changes carefully, paying attention to config files.

 

Fix Deprecations and Warnings

Run your test suite and fix any deprecations and warnings. This will make the upgrade smoother.

 

3. Migrate to Rails 6.1

Update Gemfile

Change your Gemfile to use Rails 6.1.x:

gem 'rails', '~> 6.1.0'

 

Update Dependencies

Update gems again:

bundle update

 

Run Update Task

Run the update task for Rails 6.1:

rails app:update

Review and merge changes.

 

Update Database Configuration

Rails 6.1 introduced support for multiple databases and improved database configurations. Update your config/database.yml accordingly.

 

Fix Deprecations and Warnings

Run your test suite again and address any new deprecations or warnings.

 

4. Upgrade to Rails 7

Update Gemfile

Change your Gemfile to use Rails 7.0.x:

gem 'rails', '~> 7.0.0'

 

Update Dependencies

Update your gems:

bundle update

 

Run Update Task

Run the update task for Rails 7:

rails app:update

Review and merge changes.

 

5. Key Changes and Refactoring

JavaScript and CSS

Rails 7 introduces new default front-end frameworks and tools like Hotwire and Tailwind CSS. You might want to consider adopting these, but it is optional.

• Hotwire: Combines Turbo and Stimulus for reactive applications without much JavaScript.
• Import Maps: Allow you to manage JavaScript dependencies without a bundler.

 

Active Storage Changes

Rails 7 includes several improvements to Active Storage. Ensure you review any deprecations or changes if you use Active Storage.

 

Zeitwerk Autoloader

Rails 7 uses Zeitwerk as the default autoloader. Ensure your application is compatible with Zeitwerk's conventions.

 

Configurations and Initializers

Review your config and initializers to align with the latest conventions. Remove deprecated settings and update to the latest configurations.

 

6. Testing

Run Tests

Run your full test suite to ensure everything works correctly: 

rails test

 

Fix Issues

Address any issues or failures that arise from the test suite.

 

7. Deployment

Staging Environment

Deploy your application to a staging environment first to catch any deployment-specific issues.

 

Production Deployment

Once everything is verified, deploy to production.

 

8. Post-Upgrade Tasks

Monitor Logs

Monitor your application logs for any unexpected errors or deprecations.

 

Performance Testing

Run performance tests to ensure your application performs well under the new Rails version.

 

9. Optional: Adopt New Features

Hotwire and Turbo

Consider adopting Hotwire and Turbo for a more interactive user experience without much custom JavaScript.

 

ViewComponent

Explore using ViewComponent for building reusable, testable view components.

 

Active Job and Action Mailbox

Leverage improvements in Active Job and Action Mailbox for background processing and handling inbound emails.

 

Conclusion

Migrating from Rails 5 to Rails 7 is a significant upgrade that involves several steps and careful consideration of changes introduced in intermediate versions. By following these detailed steps and thoroughly testing at each stage, you can ensure a smooth and successful migration of your application.

 

Certainly! Here's a comprehensive guide to migrating application to Rails 7, with each step explained in detail. For more detailed reference, you can refer to the official Rails upgrading guide.