Re: [boost] .[asio] : Problem while clean shut down of multi threaded server

From: Gaurav.Jain_at_[hidden]
Date: 2007-05-22 11:00:01

> On Mon, 21 May 2007 16:37:28 +0530, Gaurav.Jain <at>
iflexsolutions.com said:
> > Hi,
> > 
> > I am using boost boost 1.33.1 with asio 0.3.8rc2. I have develop a
> > Multi-threaded server program using pool of io_service. In my design
i
> > have pool of io_service object and this pool is controlled by a pool
> > manager, which is running over a seprate io_service. I want to do
clean
> > shutdown of the server. In the clean shut down i want to close each
> > connection running over related io_service.
> 
> It's worth noting that this is not the only way to do clean shutdown.
> The new HTTP server examples ("server2" and "server3") also perform a
> clean shutdown. However, rather than explicitly closing the
connections,
> they simply rely on the fact that the io_service destructor will
destroy
> all handler objects associated with unfinished operations.
> 
> > What i am doing is, while
> > shutting down the server, pool manager is posting a request to each
> > io_service object to shut it down. Each io_service object in turn
> > posting a request to all the connection it is hosting to stop
> > themselves. The problem i am facing : connection stop method is not
> > getting executed at all for each running connection.
> > 
> > Here is a code snippet of what i am doing : 
> [...]
> > 	scheduler.stop();
> 
> What is scheduler? Is it an io_service? If so, by explicitly stopping
it
> some of your completion handlers will never be called. If you want to
> use this particular clean shutdown design, it is better to wait for
the
> io_service::run() call to finish  automatically once all the
outstanding
> operations have finished

Yes scheduler is an io_service. I am now not using scheduler.stop() in
my code & 
doing what have you suggested in your reply. But still server is not
getting cleanly 
shutdown as per my design. Here is what am I doing :

void tcp_server::handle_stop()
{
        acceptor_.close();
        if(io_object_pool_)
        {	
                delete io_object_pool_;
                io_object_pool_ = NULL;
        }
}

io_object_pool::~io_object_pool()
{
        shutdown_pool();
}

void io_object_pool::shutdown_pool()
{
        std::vector<io_object*>::const_iterator iter_output =
io_object_vec.begin();
        std::vector<io_object*>::const_iterator iter_end_output =
io_object_vec.end();

        for(; iter_output != iter_end_output; )
        {
                io_object* io_object_temp = *iter_output;
                iter_output++;
        
io_object_temp->get_ioservice().post(boost::bind(&io_object::stop_all,
io_object_temp));
        }
        io_object_vec.clear();
}

void io_object::stop_all()
{
        std::set<connection_ptr >::const_iterator iter_output =
connections_.begin();
        std::set<connection_ptr >::const_iterator iter_end_output =
connections_.end();

        for(; iter_output != iter_end_output;)
        {
                connection_ptr conn_temp = *iter_output;
                iter_output++;
        
conn_temp->socket().io_service().post(boost::bind(&tcp_connection::stop,
conn_temp));
        }
                
        //scheduler.stop();
        execution_thread->join();
}

In above code I have also tried with io_service().wrap() instead of
post(), but all in vein

void tcp_connection::stop()
{
        try
        {
                std::cout << "tcp_connection stop called" << std::endl;
                assigned_io_object_->stop(shared_from_this());
                socket_.close();
                assigned_io_object_->remove_request();
                assigned_io_object_ = NULL;
                is_connection_stop = true;
        }
        catch (std::exception&)
        {
        }
}

The above cout statement is not getting printed, not even for single
connection.

Can you pls suggest what else is getting wrong here

Regards,
Gaurav

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