Sandthorn Event Sourcing

A ruby framework for saving an object's state as a series of events, and tracking non state changing events.

What is Event Sourcing

"Capture all changes to an application state as a sequence of events." Event Sourcing

The short story

Think of it as an object database where you not only what the new value of the attribute is but when and why it changed. Example:

# Setup the Aggregate

# The one available right now
require 'sandthorn'
require 'sandthorn_driver_sequel'
require 'sandthorn/aggregate_root_dirty_hashy'

class Ship
  include Sandthorn::AggregateRoot::DirtyHashy
  attr_reader :name

  def initialize name: nil, shipping_company: nil
    @name = name
  end

  # State-changing command
  def rename! new_name: ""
    unless new_name.empty? or new_name == name
      @name = new_name
      ship_was_renamed
    end
  end

  private

  # Commit the event and state-change is automatically recorded.
  def ship_was_renamed
    commit
  end
end

# Setup the framework with the sequel driver for persistance
url = "sqlite://spec/db/sequel_driver.sqlite3"
catch_all_config = [ { driver: SandthornDriverSequel.driver_from_url(url: url) } ]
Sandthorn.configuration = catch_all_config

# Migrate db schema for the sequel driver
migrator = SandthornDriverSequel::Migration.new url: url
SandthornDriverSequel.migrate_db url: url

# Usage
ship = Ship.new name: "Titanic"
ship.rename! new_name: "Vasa"

ship.save

new_ship = Ship.find ship.id
puts ship.name

# For more info look at the specs.

Installation

Add this line to your application's Gemfile:

gem 'sandthorn'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sandthorn

Usage

TODO: Write usage instructions here

Development

run: rake console

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request