bubble down callbacks to embedded associations with mongoid

embedded_callbacks.rb

# encoding: utf-8
module Mongoid #:nodoc:
  module Associations #:nodoc:
    module EmbeddedCallbacks

      # bubble callbacks to embedded associations
      def run_callbacks(kind, *args, &block)
        # now bubble callbacks down
        self.associations.each_pair do |name, meta|
          if meta.association == Mongoid::Associations::EmbedsMany
            self.send(name).each { |doc| doc.send(:run_callbacks, kind, *args, &block) }
          elsif meta.association == Mongoid::Associations::EmbedsOne
            self.send(name).send(:run_callbacks, kind, *args, &block)
          end
        end
        super(kind, *args, &block) # defer to parent
      end

    end
  end
end

photo.rb

class Photo
  include Mongoid::Document
  include Mongoid::Timestamps

  mount_uploader :image, ImageFileUploader
  embedded_in :some_model, :inverse_of => :photos
  validates_presence_of :image
end

some_model.rb

class SomeModel
  include Mongoid::Document
  include Mongoid::Associations::EmbeddedCallbacks
  include Mongoid::Timestamps
  embeds_many :photos
end

You're getting multiple inserts on a sporadic basis because each run_callbacks call will trigger the block, which contains a persistence operation. (If you call it in a loop, watch out!) I ran into the same issue.

I submitted a pull request that resolves this problem. If it is still a blocker for you, please try out my patch and provide feedback!

https://github.com/mongoid/mongoid/pull/845

For the record I'm now using @paulrosania's patch with success, thanks Paul! Here's hoping it's merged soon.