[THRIFT-2075] C++ async client project

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: C++ - Compiler, C++ - Library
• Assignee: Unassigned
• Reporter: Konrad Grochowski
• Created: 29/Jun/13 15:17
• Updated: 08/May/15 04:28

Description

What do you think about such iface for async c++ client?

service Serv
{
  X fun(1: Y y)
}

class ServAsyncClient
{
  boost::future<X> fun(const Y& y);
};

it could be implemented as a wrapper around "normal" client - just a blocking queue of boost::package_tasks and one thread executing it one by one.
This would work best with C++11 support (move semantics and lambdas could be used).

I've made wrapper for generated clients but such wrapper requires a lot of hand work

example:

class AsyncClient
{
 public:
   AsyncClient(SyncClient* cli)
     : cli(cli) {}

  boost::future<X> fun(const Y& y)
  {
    addTask([this, y]() { return cli->fun(y); });
  }

private:
   blocking_queue<boost::function<void()> queue;

   template<typename Functor>
   boost::future<typename boost::result_of<Functor()>::type>
   addTask(Functor&& functor)
   {
      typedef typename boost::result_of<Functor()>::type result_type;
      typedef typename boost::packaged_task<result_type> task_type;
      typedef typename boost::shared_ptr<task_type> ptr_type;

      ptr_type ptr(new boost::packaged_task<result_type>(std::move(functor)));
      auto f = ptr->get_future();
      queue.push_back([ptr]{ (*ptr)(); });
      return f;
    }
 // ....
};

originally I used boost::asio, which enables me to schedules some tasks to be executed periodically (like ping) etc.

I haven't tested it yet enough but I could look into possibilities of adding new option to thrift compiler if such contribution would be anticipated
I can also send my boost.asio based wrapper for anyone who would like to write own async wrapper

Issue Links

• is related to: THRIFT-579 Alternative ASIO based fully async client/server for C++
• relates to: THRIFT-2717 C++V2 generator/library