notifying_action.rb

class Chef
  class SubResourceCollection < ResourceCollection
    def initialize(parent)
      @parent = parent
      super()
    end

    def lookup(resource)
      super
    rescue Chef::Exceptions::ResourceNotFound
      @parent.lookup(resource)
    end
  end

  class Provider
    class << self
      def notifying_action(key, &block)
        action key do
          # So that we can refer to these within the sub-run-context
          # block.
          cached_new_resource = new_resource
          cached_current_resource = current_resource

          # Setup a sub-run-context.
          sub_run_context = @run_context.dup
          sub_run_context.resource_collection =
             Chef::SubResourceCollection.new(@run_context.resource_collection)

          # Declare sub-resources within the sub-run-context. Since they
          # are declared here, they do not pollute the parent run-context.
          begin
            original_run_context, @run_context =
                @run_context, sub_run_context
            instance_eval(&block)
          ensure
            @run_context = original_run_context
          end

          # Converge the sub-run-context inside the provider action.
          # Make sure to mark the resource as updated-by-last-action if
          # any sub-run-context resources were updated (any actual
          # actions taken against the system) during the
          # sub-run-context convergence.
          begin
            Chef::Runner.new(sub_run_context).converge
          ensure
            if sub_run_context.resource_collection.any?(&:updated?)
              new_resource.updated_by_last_action(true)
            end
          end
        end
      end
    end
  end
end