Channeling my inner @thbishop, what are your thought on re-writing this w/ select:

      def parse_cf_stack_resources(cf_stack_resources)
        asgs = cf_stack_resources.select {|r| r['ResourceType'] == 'AWS::AutoScaling::AutoScalingGroup'}
        asgs.any? ? asgs.first['PhysicalResourceId'] : false
      end