robinbortlik/rails_event_store_library

Library app

Setup

git clone git@github.com:robinbortlik/rails_event_store_library.git

bundle install
bundle exec rake db:setup

About project

This is experimental project built just for education purposes.

Application implements basic "Library" functions to keep evidence of borrowed and returned books.

Demo app

App is available on https://rails-event-store-library.herokuapp.com/

Screenshots

Architecture

All object state changes are handled as events with help of Rails Event Store library

Files structure

- app
 |
  - lib
   |
    - Domain (Books, Users)
      |
        - Purpose (Models, Events, Commands, Aggregates)
          |
          - Class/Module name (book.rb, borrow.rb, on_return.rb)

Flow

  HTTP -> controller#action
          -> command_bus(command)
            -> aggregate.action
              -> event triggered
                -> event store updated
                -> read_model updated

Unknowns

• How to correctly design and update the read model, so I do not need to duplicate business logic between aggregate root and read model

• How read model handles updates on linked objects:

  Example: Book read model stores User full name. User updates his name, shall I subscribe book to User name changed event and update the user name stored on the book record?