Product model Can be updated by multiple users. However, at a time only one user should able to update. For that, I want to use optimistic locking for Product model using updated_at.

I have implemented the following code for the optimistic lock. There are other ways to implement optimistic locking like using lock_version. However, due to existing code restriction, I am not able to implement using lock_version.

  Product Model   MAX_RETRIES = 3   attr_writer :original_updated_at   def original_updated_at     @original_updated_at || updated_at   end    def stale_object?     if self.updated_at > original_updated_at       @original_updated_at = nil       return true     else       return false     end   end    def public_method     ##code      result = nil     begin       result = private_method       self.original_updated_at = self.updated_at     rescue ActiveRecord::StaleObjectError => e       errors.add(:base, ": Following records are changed while you were editing.")       changes.except("updated_at").each do |name, values|         errors.add(name, values)       end     rescue Exception => error       ##code     end     result   end    def private_method     tries = 0     begin       raise ActiveRecord::StaleObjectError.new(self, "Product is changed while you were editing") if stale_object?       attributes = #create hash using some code       #some code        attributes["updated_at"] = Time.now.utc       Product.where(:id => self.id).update_all(attributes)       self.original_updated_at = self.updated_at     rescue ActiveRecord::StaleObjectError => e       if tries < MAX_RETRIES         tries += 1         sleep(1 + tries)         self.reload         retry       else         raise ActiveRecord::StaleObjectError.new(self, "Product is changed while you were editing")       end     end     attributes   end