feat(Core/Common): add Asio network threading (#6063)

src/server/shared/Network/SocketMgr.h

@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2016+ AzerothCore <www.azerothcore.org>, released under GNU AGPL v3 license: https://github.com/azerothcore/azerothcore-wotlk/blob/master/LICENSE-AGPL3
+ * Copyright (C) 2021+ WarheadCore <https://github.com/WarheadCore>
+ */
+
+#ifndef SocketMgr_h__
+#define SocketMgr_h__
+
+#include "AsyncAcceptor.h"
+#include "Errors.h"
+#include "NetworkThread.h"
+#include <boost/asio/ip/tcp.hpp>
+#include <memory>
+
+using boost::asio::ip::tcp;
+
+template<class SocketType>
+class SocketMgr
+{
+public:
+    virtual ~SocketMgr()
+    {
+        ASSERT(!_threads && !_acceptor && !_threadCount, "StopNetwork must be called prior to SocketMgr destruction");
+    }
+
+    virtual bool StartNetwork(acore::Asio::IoContext& ioContext, std::string const& bindIp, uint16 port, int threadCount)
+    {
+        ASSERT(threadCount > 0);
+
+        AsyncAcceptor* acceptor = nullptr;
+        try
+        {
+            acceptor = new AsyncAcceptor(ioContext, bindIp, port);
+        }
+        catch (boost::system::system_error const& err)
+        {
+            LOG_ERROR("network", "Exception caught in SocketMgr.StartNetwork (%s:%u): %s", bindIp.c_str(), port, err.what());
+            return false;
+        }
+
+        if (!acceptor->Bind())
+        {
+            LOG_ERROR("network", "StartNetwork failed to bind socket acceptor");
+            delete acceptor;
+            return false;
+        }
+
+        _acceptor = acceptor;
+        _threadCount = threadCount;
+        _threads = CreateThreads();
+
+        ASSERT(_threads);
+
+        for (int32 i = 0; i < _threadCount; ++i)
+            _threads[i].Start();
+
+        _acceptor->SetSocketFactory([this]() { return GetSocketForAccept(); });
+
+        return true;
+    }
+
+    virtual void StopNetwork()
+    {
+        _acceptor->Close();
+
+        if (_threadCount != 0)
+            for (int32 i = 0; i < _threadCount; ++i)
+                _threads[i].Stop();
+
+        Wait();
+
+        delete _acceptor;
+        _acceptor = nullptr;
+        delete[] _threads;
+        _threads = nullptr;
+        _threadCount = 0;
+    }
+
+    void Wait()
+    {
+        if (_threadCount != 0)
+            for (int32 i = 0; i < _threadCount; ++i)
+                _threads[i].Wait();
+    }
+
+    virtual void OnSocketOpen(tcp::socket&& sock, uint32 threadIndex)
+    {
+        try
+        {
+            std::shared_ptr<SocketType> newSocket = std::make_shared<SocketType>(std::move(sock));
+            newSocket->Start();
+
+            _threads[threadIndex].AddSocket(newSocket);
+        }
+        catch (boost::system::system_error const& err)
+        {
+            LOG_WARN("network", "Failed to retrieve client's remote address %s", err.what());
+        }
+    }
+
+    int32 GetNetworkThreadCount() const { return _threadCount; }
+
+    uint32 SelectThreadWithMinConnections() const
+    {
+        uint32 min = 0;
+
+        for (int32 i = 1; i < _threadCount; ++i)
+            if (_threads[i].GetConnectionCount() < _threads[min].GetConnectionCount())
+                min = i;
+
+        return min;
+    }
+
+    std::pair<tcp::socket*, uint32> GetSocketForAccept()
+    {
+        uint32 threadIndex = SelectThreadWithMinConnections();
+        return std::make_pair(_threads[threadIndex].GetSocketForAccept(), threadIndex);
+    }
+
+protected:
+    SocketMgr() :
+        _acceptor(nullptr), _threads(nullptr), _threadCount(0) { }
+
+    virtual NetworkThread<SocketType>* CreateThreads() const = 0;
+
+    AsyncAcceptor* _acceptor;
+    NetworkThread<SocketType>* _threads;
+    int32 _threadCount;
+};
+
+#endif // SocketMgr_h__