It is built on top of seastar rpc infrastructure. I've sorted out all
the message VERBs which Origin use. All of them can be implemented using
this messaging_service.
Each Verb contains a handler. There are two types of handlers, one
will return a message back to sender, the other will not. The former
can be registered using ms.register_handler(), the latter can be
registered using ms.register_handler_oneway().
Usage example:
To use messaging_service to send a message. All you need is:
messaging_service& ms = get_local_messaging_service();
1) To register a message hander:
ms.register_handler(messaging_verb::ECHO, [] (int x, long y) {
print("Server got echo msg = (%d, %ld) \n", x, y);
std::tuple<int, long> ret(x*x, y*y);
return make_ready_future<decltype(ret)>(std::move(ret));
});
ms.register_handler_oneway(messaging_verb::GOSSIP_SHUTDOWN, [] (empty_msg msg) {
print("Server got shutdown msg = %s\n", msg);
return messaging_service::no_wait();
});
2) To send a message:
using RetMsg = std::tuple<int, long>;
return ms.send_message<RetMsg>(messaging_verb::ECHO, id, msg1, msg2).then([] (RetMsg msg) {
print("Client sent echo got reply = (%d , %ld)\n", std::get<0>(msg), std::get<1>(msg));
return sleep(100ms).then([]{
return make_ready_future<>();
});
});
return ms.send_message_oneway<void>(messaging_verb::GOSSIP_SHUTDOWN, std::move(id), std::move(msg)).then([] () {
print("Client sent gossip_shutdown got reply = void\n");
return make_ready_future<>();
});
Tests:
send to cpu 0
$ ./message --server 127.0.0.1 --cpuid 0 --smp 2
send to cpu 1
$ ./message --server 127.0.0.1 --cpuid 1 --smp 2
2f56a360e7