DB Locker

gistfile1.ruby

module Synchronizable
  DEFAULT_WAIT_TIME = 10.seconds

  extend self

  def synchronize(*args, &block)
    Transaction.run { with_advisory_lock(*args, &block) }
  end

  private

  def with_advisory_lock(object = self, wait_time: DEFAULT_WAIT_TIME, **params)
    lock_name = lock_name_for(object, params)
    ActiveRecord::Base.logger.debug "Locking with #{lock_name}"

    wait_time = nil if Rails.env.in?(%w[development test])

    wrapped_block = proc do
      ActiveRecord::Base.uncached do
        ActiveRecord::Base._with_advisory_lock(lock_name) do
          object.reload if object.is_a?(ActiveRecord::Base)
          yield
        end
      end
    end

    if WithAdvisoryLock::Base.lock_stack.empty?
      # We have to pass Timeout::Error explicitly so that transactions properly work
      Timeout.timeout(wait_time, Timeout::Error, &wrapped_block)
    else
      wrapped_block.call
    end
  end

  def lock_name_for(object, params)
    name_parts =
      case object
      when String, Symbol
        [object]
      when Class
        [object.name.underscore.dasherize]
      else
        [object.class.name.underscore.dasherize, object.try(:id)]
      end

    [name_parts, *params].flatten.compact.join("-")
  end
end