Dry::Facts

EventSourcing ruby toolkit, somewhat based on dry-rb primitives. Opinionated. Raw.

Rationale

People dont know or understand software projects, people navigate themselves through software projects. To effectively navigate through structure and mutable state of big systems - programmers need sub-systems to be isolated. Usable incapsulation - barriers have to be visible and hard to break. Readability matters - declarative readable code wins.

Goals

• General EventSourcing toolkit for Ruby
• Ability to generate GraphQL interface to Bounded Contexts
• Idiomatic human-friendly API/DSL
• Explore data-primitives-first approach minimize usage of Classes and inheritance

Basic concepts

Example module structure:

# Bounded Context - isolated autonomous module
# it governs own state
# and encapsulates interactions with outer world
module AccountManagementContext
  # State of the context is derived from persisted facts
  module Events
    Corrected
    SignedUp
    SignedIn
    SignedOut
    PasswordResetLinkRequested
    PasswordResetLinkSent
    PasswordUpdated
  end

  # Commands modify state by persisting events and
  # encapsulate behaviors
  module Commands
    Correct
    SignUp                    
    SignIn                    
    SignOut                   
    PasswordResetTokenRequest
    PasswordResetTokenSend    
    PasswordReset
  end

  # Queries allow read access of context's state
  # for inner and outer usage
  # multiple storages of various types may be used
  module Queries
    IsEmailAvialable
    AccountByUUID
    AccountByEmail
    AccountByPasswordResetToken
    AccountByEmailAndEncryptedPassword

    IsValidAuthTokenForAccount            
    IsValidPasswordResetTokenForAccount   
  end

  # Aggregates are optionally post-processed
  # collections of events, used for representation of data
  module Aggregates
    Account
  end

end

Installation

Add this line to your application's Gemfile:

gem 'dry-facts'

And then execute:

$ bundle

Or install it yourself as:

$ gem install dry-facts

Usage

See example usage in test/dummy_app

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Active development is visible in develop branch. Bug reports and pull requests are welcome on GitHub at https://github.com/andriytyurnikov/dry-facts.

License

The gem is available as open source under the terms of the MIT License.