rollback_example.rb

require "dry/transaction"

class CreateUser
  include Dry::Transaction

  # step without rollback should not fail the whole process
  # its optional  
  step :process
  step :track, rollback: :rollback_track
  step :persist

  def process(input)
    Right(name: input["name"], email: input["email"])
  end

  def track(input)
    if input[:tracked]
      DB << input[:email] 
    else
      Right(input)
    end
  end
  
  def rollback_track(input)
    DB.delete(input[:email])
    # simply pass it down for further rollbacks
    Left(input)
  end

  def persist(input)
    if DB << input
      Right(input)
    else
      # Here we might control the value being sent to rollback operation/method      
      Left(input)
    end
  end
end