Re: [Dbus-cxx-devel] problem: multithreaded dbus-cxx apps

[Rick L. V. Jr. <rvi...@cs...>]

Hello,

Oliver Kowalke wrote:
> Hi,
>
> I've several apps using DBus and acting as server as well as client.
> Common
> pattern: app A registers on DBus signal Sig1 of app B. signal handler
> (callback) of Sig1 does some work including invoking method x() of app C
> (via
> DBus -> dbus_send_with_reply_blocking() or so).
> The problem is that the apps must be multithreaded too (for
> responsiveness).
> I wrote a small test app (echo_server, echo_client) where the client calls
> echo_serve::request() in 5 threads at the same time. I get sometimes
> exceptions thrown ("Not enought memory"). It seams to me this error is
> raised
> inside dbus (not dbus-cxx).
> My question is: is dbus-cxx prepared to be used in a multithreaded env
> where
> the app actrs a cleint as well server?

The intent is that it will work as a client as well as a server.

Have you applied any of the patches that Patrick Allison recently posted?
They related to the multi-threaded code and it's likely you're running up
against the bugs he tracked down.

Hopefully I'll have a chance later today or tomorrow to take a fuller look
at the patches and push out an update.



>
> regards,
> Oliver
>
> #### echo ###
>
> #ifndef TEST_ECHO_H
> #define TEST_ECHO_H
>
> #include <string>
>
> #include <sigc++/sigc++.h>
>
> namespace test {
>
> class echo
> {
> private:
>     sigc::signal< void, std::string > sig_;
>
> public:
>     std::string reply( std::string msg)
>     { return msg; }
>
>     sigc::signal< void, std::string > signal_event()
>     { return sig_; }
>
>     void do_emit_event( std::string const& msg)
>     { sig_.emit( msg); }
> };
>
> }
>
> #endif // TEST_ECHO_H
>
>
>
> ### server ####
>
> #include "echo_adapter.h"
> #include "echo.h"
>
> int main()
> {
>   DBus::init();
>
>   int ret;
>
>   DBus::Dispatcher dispatcher;
>
>   DBus::Connection::pointer conn =
> dispatcher.create_connection(DBus::BUS_SYSTEM);
>
>   // request a name on the bus
>   ret = conn->request_name( "test.echo.server",
> DBUS_NAME_FLAG_REPLACE_EXISTING);
>   if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) return 1;
>
>   test::echo handler;
>
>   test::echoAdapter::pointer adapter =
> test::echoAdapter::create(&handler);
>
>   conn->register_object( adapter);
>
>   std::cout << "Running" << std::flush;
>
>   for(;;)
>   {
>     std::cout << "." << std::flush;
>     sleep(1);
>   }
>
>   std::cout << std::endl;
>
>   return 0;
>
> }
>
>
> #### client #####
>
> include <iostream>
> #include <stdexcept>
> #include <sstream>
> #include <string>
>
> #include <boost/bind.hpp>
> #include <boost/ref.hpp>
> #include <boost/thread.hpp>
>
> #include "echo_proxy.h"
>
> #include <cstdlib>
>
> void request(
>         boost::barrier & b,
>         test::echoProxy::pointer echo,
>         std::string const& msg)
> {
>     std::stringstream ss;
>     ss << boost::this_thread::get_id();
>
>     try
>     {
>         b.wait();
>         fprintf( stderr, "thread %s: request == %s, reply == %s\n",
> ss.str().c_str(),  msg.c_str(), echo->reply( msg).c_str() );
>     }
>     catch ( std::exception const& e)
>     {
>         fprintf( stderr, "thread %s: exception catched == %s\n",
> ss.str().c_str(), e.what() );
>         ::abort();
>     }
>     catch (...)
>     { fprintf( stderr, "thread %s: unhandled exception catched\n",
> ss.str().c_str() ); }
> }
>
> int main(int argc, const char** argv)
> {
>     try
>     {
>         DBus::init();
>         DBus::Dispatcher dispatcher;
>         DBus::Connection::pointer connection =
> dispatcher.create_connection(
> DBus::BUS_SYSTEM);
>         test::echoProxy::pointer echo = test::echoProxy::create(
> connection);
>
>         boost::thread_group tg;
>         boost::barrier b( 5);
>
>         tg.create_thread(
>                 boost::bind(
>                     & request,
>                     boost::ref( b),
>                     echo,
>                     "abc") );
>         tg.create_thread(
>                 boost::bind(
>                     & request,
>                     boost::ref( b),
>                     echo,
> 		    "def") );
>         tg.create_thread(
>                 boost::bind(
>                     & request,
>                     boost::ref( b),
>                     echo,
>                     "ghi") );
>         tg.create_thread(
>                 boost::bind(
>                     & request,
>                     boost::ref( b),
>                     echo,
>                     "jkl") );
>         tg.create_thread(
>                 boost::bind(
>                     & request,
>                     boost::ref( b),
>                     echo,
>                     "mno") );
>
>         tg.join_all();
>
>         return 0;
>     }
>     catch ( std::exception const& e)
>     { std::cerr << "exception catched: " << e.what() << std::endl; }
>     catch (...)
>     { std::cerr << "unhandled exception catched" << std::endl; }
>
>     return -1;
> }
>
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