Activerecord::Transactionable

Provides a method, transaction_wrapper at the class and instance levels that can be used instead of ActiveRecord#transaction.

Useful as an example of correct behavior for wrapping transactions.

NOTE: Rails' transactions are per-database connection, not per-model, nor per-instance, see: http://api.rubyonrails.org/classes/ActiveRecord/Transactions/ClassMethods.html

Installation

Add this line to your application's Gemfile:

gem 'activerecord-transactionable'

And then execute:

$ bundle

Or install it yourself as:

$ gem install activerecord-transactionable

Usage

class Car < ActiveRecord::Base
  include Activerecord::Transactionable # Note lowercase "r" in Activerecord (different namespace than rails' module)

  validates_presence_of :name
end

When creating, saving, deleting within the transaction make sure to use the bang methods (!) in order to ensure a rollback on failure.

When everything works:

car = Car.new(name: "Fiesta")
car.transaction_wrapper do
  car.save!
end
car.persisted? # => true

When something goes wrong:

car = Car.new(name: nil)
car.transaction_wrapper do
  car.save!
end
car.persisted? # => false
car.errors.full_messages # => ["Name can't be blank"]

These examples are too simple to be useful with transactions, but if you are working with multiple records then it will make sense.

Also see the specs.

If you need to lock the car as well as have a transaction (note: will reload the car):

car = Car.new(name: nil)
car.transaction_wrapper(lock: true) do # uses ActiveRecord's with_lock
  car.save!
end
car.persisted? # => false
car.errors.full_messages # => ["Name can't be blank"]

If you need to know if the transaction succeeded:

car = Car.new(name: nil)
result = car.transaction_wrapper(lock: true) do # uses ActiveRecord's with_lock
           car.save!
         end
result # => true, false or nil

Meanings of transaction_wrapper return values:

nil - ActiveRecord::Rollback was raised, and then caught by the transaction, and not re-raised; the transaction failed. false - An error was raised which was handled by the transaction_wrapper; the transaction failed. true - The transaction was a success.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec 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

Bug reports and pull requests are welcome on GitHub at https://github.com/pboling/activerecord-transactionable.