A Rails directory tree that expresses DDD layers and bounded contexts.

ddd-rails-tree.txt

components/
  my_bounded_context/
    app/
      presentation/      # This is called the "UI" layer in DDD literature, but it is also 
                         # where things like JSON interfaces live -- any kind of presentation 
                         # or handshake to anything outside. So "presentation" rather than "ui".
        assets/
        helpers/
        mailers/
        views/
      operation/         # Would be named "application" if we weren't already in an "app" directory
        controllers/
        listeners/       # Wisper plumbing. These should traffic in Domain Events.
        services/        # Application services, as distinct from domain services. 
                         # http://gorodinski.com/blog/2012/04/14/services-in-domain-driven-design-ddd/
        workers/         # Thin Sidekiq shells that delegate to domain services.
      domain/
        my_bounded_context/
          my_first_aggregate/
            repository.rb
            my_first_aggregate_root_entity_name.rb
            another_entity_in_this_aggregate.rb
            an_event_about_this_stuff.rb
            value_object_only_in_this_aggregate.rb
            a_relevant_factory.rb
            a_relevant_service.rb
          another_aggregate/
            repository.rb
            another_aggregate_root_entity_name.rb
            second_entity_in_this_other_aggregate.rb
            another_event.rb
          a_domain_topic_that_is_not_an_aggregate/
            a_service_here.rb
            perhaps_an_event.rb
            and_a_value_object.rb
      infrastructure/
        persistence/     # ActiveRecords
                         # This will frequently get broken out as its own component 
                         # that depends on the domain.
          my_bounded_context/
            whatever_record.rb
            whatever_record_repository.rb     # gets registered as the provider for the domain repository
        # TODO what else in infrastructure? I'm not clear on how anything other than persistence is 
        # distinguished from application ("operations") logic. 
        # Perhaps simply promote persistence a level instead?