# Activerecord::Transactionable
Provides a method, `transaction_wrapper` at the class and instance levels that can be used instead of `ActiveRecord#transaction`. Enables you to do transactions properly, including with or without locking.
| Project | Activerecord::Transactionable |
|------------------------ | ----------------- |
| gem name | activerecord-transactionable |
| license | [](https://opensource.org/licenses/MIT) |
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| download rank | [](https://rubygems.org/gems/activerecord-transactionable) |
| version | [](http://badge.fury.io/rb/activerecord-transactionable) |
| dependencies | [](https://gemnasium.com/pboling/activerecord-transactionable) |
| code quality | [](https://codeclimate.com/github/pboling/activerecord-transactionable) |
| inline documenation | [](http://inch-ci.org/github/pboling/activerecord-transactionable) |
| continuous integration | [](https://travis-ci.org/pboling/activerecord-transactionable) |
| test coverage | [](https://coveralls.io/github/pboling/activerecord-transactionable?branch=master) |
| homepage | [https://github.com/pboling/activerecord-transactionable][homepage] |
| documentation | [http://rdoc.info/github/pboling/activerecord-transactionable/frames][documentation] |
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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
## Upgrading to Version 2
In version 1 the `transaction_wrapper` returned `true` or `false`. In version 2 it returns an instance of `Activerecord::Transactionable::Result`, which has a `value`, and two methods:
```ruby
result = transaction_wrapper(...) do
something
end
result.fail?
result.success?
```
Where you used to have:
```ruby
if result
# ...
end
```
You must update to:
```ruby
if result.success?
# ...
end
```
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'activerecord-transactionable'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install activerecord-transactionable
## Usage
```ruby
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:
```ruby
car = Car.new(name: "Fiesta")
car.transaction_wrapper do
car.save!
end
car.persisted? # => true
```
When something goes wrong:
```ruby
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`):
```ruby
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:
```ruby
car = Car.new(name: nil)
result = car.transaction_wrapper(lock: true) do # uses ActiveRecord's with_lock
car.save!
end
result # => an instance of Activerecord::Transactionable::Result
result.success? # => true or false
```
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.
## Update Example
```ruby
@client = Client.find(params[:id])
transaction_result = @client.transaction_wrapper(lock: true) do
@client.assign_attributes(client_params)
@client.save!
end
if transaction_result.success?
render :show, locals: { client: @client }, status: :ok
else
# Something prevented update
render json: @client.errors, status: :unprocessable_entity
end
```
## Find or create
NOTE: The `is_retry` is passed to the block by the gem, and indicates whether the block is running for the first time or the second time.
The block will never be retried more than once.
```ruby
Car.transaction_wrapper(outside_retriable_errors: ActivRecord::RecordNotFound) do |is_retry|
if is_retry
Car.create!(vin: vin)
else
Car.find_by!(vin: vin)
end
end
```
## Create or find
NOTE: The `is_retry` is passed to the block by the gem, and indicates whether the block is running for the first time or the second time.
The block will never be retried more than once.
```ruby
Car.transaction_wrapper(outside_retriable_errors: ActivRecord::RecordNotUnique) do |is_retry|
if is_retry
Car.find_by!(vin: vin)
else
Car.create!(vin: vin)
end
end
```
## Reporting to SAAS Error Tools (like Raygun, etc)
Hopefully there will be a better integration at some point, but for now, somewhere in your code do:
```ruby
module SendToRaygun
def transaction_error_logger(**args)
super
if args[:error]
begin
Raygun.track_exception(args[:error])
Rails.logger.debug("Sent Error to Raygun: #{args[:error].class}: #{args[:error].message}")
rescue => e
Rails.logger.debug("Sending Error #{args[:error].class}: #{args[:error].message} to Raygun Failed with: #{e.class}: #{e.message}")
end
end
end
end
Activerecord::Transactionable::ClassMethods.class_eval do
prepend SendToRaygun
end
```
## 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](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/pboling/activerecord-transactionable.
[semver]: http://semver.org/
[pvc]: http://docs.rubygems.org/read/chapter/16#page74
[railsbling]: http://www.railsbling.com
[peterboling]: http://www.peterboling.com
[documentation]: http://rdoc.info/github/pboling/activerecord-transactionable/frames
[homepage]: https://github.com/pboling/activerecord-transactionable