Mongoid::Locking

It adds Optimistic Locking to Mongoid::Document objects.

This gem is inspired in the ActiveRecord::Locking module.

Install the gem and add to the application's Gemfile by executing:

$ bundle add mongoid-locking

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install mongoid-locking

• Include Mongoid::Locking module

  class Order
    include Mongoid::Document
    include Mongoid::Locking
  end

• Handle Mongoid::StaleObjectError when performing updates

  # ...
  def update_order
    Order.update(attributes)
  rescue Mongoid::StaleObjectError => e
    add_error("This order has been changed ...")
  end
end

• Use with_locking to automatically handle Mongoid::StaleObjectError

By default, with_locking will retry the update 3 times in case of a Mongoid::StaleObjectError.

  def process_with_locking
    Order.with_locking do
      # Ensure the block is idempotent
      # Reload object(s) within the block to get the latest changes
      order.reload
      # Your code here
      # ...
    end
  end

Adjust the max_retries parameter to control the number of retry attempts in case of a Mongoid::StaleObjectError.

  # ...
  def update_order
    order.with_locking(max_retries: 2) do
      order.update(attributes)
    end
  end
end

• Use with_locking at the instance level to automatically reload the instance on each retry

def process_with_locking
  order.with_locking do
    # The instance is automatically reloaded for each retry
    # Your code here
    # ...
  end
end

The with_locking method at the instance level combines class-level locking with automatic reloading on each retry. This ensures that the instance reflects the latest changes, providing seamless control over optimistic locking.

NOTE: The with_locking method will add a delay between retries to avoid contention. More info.

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 the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/fullhealthmedical/fhweb/mongoid-locking. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

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

Everyone interacting in the Mongoid::Locking project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.