Component based Rails architecture

In lib/app_running_mode.rb

We can set ENV['APP_RUNNING_MODE'] to public/api or empty when you deploy which you can split your app to public_app or api_app.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
class AppRunningMode
  class << self
    def value
      case downcased_app_running_mode_env
        when 'public'
          :public
        when 'api'
          :api
        else
          :development
      end
    end

    def bundler_groups
      case value
        when :public
          [:public_app]
        when :api
          [:api_app]
        else
          [:public_app, :api_app]
      end
    end

    private

    def downcased_app_running_mode_env
      if ENV['APP_RUNNING_MODE']
        return ENV['APP_RUNNING_MODE'].downcase
      end
    end
  end
end

In application.rb

Add more groups for Gemfile.

1
Bundler.require(*Rails.groups + AppRunningMode.bundler_groups)

In routes.rb

Include different routes.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
case AppRunningMode.value
    when :api
      mount ApiComponent::Engine, at: '/api'
      # mount activeadmin routes with api component
      # you can mount with public if necessary(depend on traffic)
      # or you can separate it to an admin component if you want
      ActiveAdmin.routes(self)
    when :public
      mount PublicComponent::Engine, at: '/'
    else
      mount ApiComponent::Engine, at: '/api'
      mount PublicComponent::Engine, at: '/'
      ActiveAdmin.routes(self)
  end

In Gemfile

Bundle diff gem(generated by Rails engin) by you ENV[‘APP_RUNNING_MODE’] you specify.

1
2
3
4
5
6
7
8
9
10
11
group :api_app do
  path 'components' do
    gem 'api_component'
  end
end

group :public_app do
  path 'components' do
    gem 'public_component'
  end
end