Deploying a Rails 4.0.0 Application on Heroku

When deploying a new Rails application using version 4.0.0.RC1 to Heroku, you may encounter issues with asset loading. This guide provides troubleshooting steps to resolve these issues.

Initial Setup

You should have your application set up with the following technologies:

  • Ruby 2.0
  • Rails 4.0.0.RC1
  • Bootstrap with Sass
  • Devise for authentication
  • Custom Sass stylesheets

Common Asset Loading Issues

After deploying your application, you might notice that styles and images are not being displayed correctly. The Heroku logs may indicate that assets are being precompiled, but they fail to load when the application starts. You might see errors similar to:

heroku[router]: at=info method=GET path=/assets/logo.png host=your-app.herokuapp.com status=404

This indicates that the assets are not found, leading to a 404 error.

Troubleshooting Steps

  1. Precompile Assets Locally: Before deploying, ensure that your assets are precompiled. Run the following command locally:

    RAILS_ENV=production bundle exec rake assets:precompile

    After precompiling, commit the changes to your repository.

  2. Gemfile Configuration: Ensure your Gemfile includes the necessary gems for asset management. Here’s a sample configuration:

    source 'https://rubygems.org'
ruby '2.0.0'
gem 'rails', '4.0.0.rc1'
gem 'sass-rails', '~> 4.0.0.rc1'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.0.0'
gem 'jquery-rails'
gem 'turbolinks'
gem 'devise', '~> 3.0.0.rc'
gem 'bootstrap-sass', '~> 2.3.1.2'
gem 'rails_log_stdout', github: 'heroku/rails_log_stdout'
gem 'rails3_serve_static_assets', github: 'heroku/rails3_serve_static_assets'

  3. Heroku Configuration: Ensure that your Heroku environment is set up correctly. You can check your Heroku logs for any errors during deployment:

    heroku logs --tail

    Look for any messages related to asset compilation or loading.

  4. Static Assets Serving: If you are using Rails 4.0.0, make sure to include the following in your production.rb file:

    config.serve_static_assets = true

    This setting allows Rails to serve static files from the /public directory.

Conclusion

By following these steps, you should be able to resolve asset loading issues when deploying your Rails application to Heroku. If problems persist, consider checking the Heroku documentation for additional troubleshooting tips or community forums for similar issues.

Additional Resources