Sagas

A dependency-free library to manage transactions in Ruby

Based on the sagas design pattern (http://www.cs.cornell.edu/andru/cs711/2002fa/reading/sagas.pdf)

Contents

• Installation
• Using Sagas
• License

Installation

Add this line to your application's Gemfile:

gem 'sagas'

And then execute:

$ bundle

Or Install locally:

$ gem install sagas

Using Sagas

require 'sagas'

num = 0

transaction = Sagas.transaction

exceptions_to_catch = [StandardError]
transaction.run_command(name: 'Add', catch_exceptions: exceptions_to_catch) do
  perform do
    num += 10
  end

  undo do
    num -= 10
  end
end

transaction.run_command(name: 'Multiply', catch_exceptions: exceptions_to_catch) do
  perform do
    num *= 2
    raise StandardError.new('Error while trying to perform')
  end

  undo do
    num /= 2
  end
end

transaction.run_command(name: 'Subtract', catch_exceptions: exceptions_to_catch) do
  perform do
    num -= 7
  end

  undo do
    num += 7
  end
end

  puts num #outputs 0 (will perform all undo effects up to the exception abort transaction)

License

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