render_exception

# File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 63
      def render_exception(env, exception)
        log_error(exception)
        exception = original_exception(exception)

        request = Request.new(env)
        if @consider_all_requests_local || request.local?
          rescue_action_locally(request, exception)
        else
          rescue_action_in_public(exception)
        end
      rescue Exception => failsafe_error
        $stderr.puts "Error during failsafe response: #{failsafe_error}\n  #{failsafe_error.backtrace * "\n  "}"
        FAILSAFE_RESPONSE
      end