Implement basic I/O engine

diff --git a/lib/base/CMakeLists.txt b/lib/base/CMakeLists.txt
index 9e04de723f7e9c32fea608ad24662f2130f158ea..9260b31ed6adf3a919ef4b2e2407721a4b5938a7 100644 (file)
--- a/lib/base/CMakeLists.txt
+++ b/lib/base/CMakeLists.txt
@@ -34,6 +34,7 @@ set(base_SOURCES
   filelogger.cpp filelogger.hpp filelogger-ti.hpp
   function.cpp function.hpp function-ti.hpp function-script.cpp functionwrapper.hpp
   initialize.cpp initialize.hpp
+  io-engine.cpp io-engine.hpp
   json.cpp json.hpp json-script.cpp
   lazy-init.hpp
   library.cpp library.hpp

diff --git a/lib/base/io-engine.cpp b/lib/base/io-engine.cpp
new file mode 100644 (file)
index 0000000..e1aeeb0
--- /dev/null
+++ b/lib/base/io-engine.cpp
@@ -0,0 +1,96 @@
+/******************************************************************************
+ * Icinga 2                                                                   *
+ * Copyright (C) 2012-2018 Icinga Development Team (https://icinga.com/)      *
+ *                                                                            *
+ * This program is free software; you can redistribute it and/or              *
+ * modify it under the terms of the GNU General Public License                *
+ * as published by the Free Software Foundation; either version 2             *
+ * of the License, or (at your option) any later version.                     *
+ *                                                                            *
+ * This program is distributed in the hope that it will be useful,            *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
+ * GNU General Public License for more details.                               *
+ *                                                                            *
+ * You should have received a copy of the GNU General Public License          *
+ * along with this program; if not, write to the Free Software Foundation     *
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
+ ******************************************************************************/
+
+#include "base/exception.hpp"
+#include "base/io-engine.hpp"
+#include "base/lazy-init.hpp"
+#include "base/logger.hpp"
+#include <exception>
+#include <memory>
+#include <thread>
+#include <boost/asio/io_service.hpp>
+#include <boost/asio/spawn.hpp>
+#include <boost/date_time/posix_time/ptime.hpp>
+
+using namespace icinga;
+
+CpuBoundWork::CpuBoundWork(boost::asio::yield_context yc)
+{
+       auto& ioEngine (IoEngine::Get());
+
+       for (;;) {
+               auto availableSlots (ioEngine.m_CpuBoundSemaphore.fetch_sub(1));
+
+               if (availableSlots < 1) {
+                       ioEngine.m_CpuBoundSemaphore.fetch_add(1);
+                       ioEngine.m_AlreadyExpiredTimer.async_wait(yc);
+                       continue;
+               }
+
+               break;
+       }
+}
+
+CpuBoundWork::~CpuBoundWork()
+{
+       IoEngine::Get().m_CpuBoundSemaphore.fetch_add(1);
+}
+
+LazyInit<std::unique_ptr<IoEngine>> IoEngine::m_Instance ([]() { return std::unique_ptr<IoEngine>(new IoEngine()); });
+
+IoEngine& IoEngine::Get()
+{
+       return *m_Instance.Get();
+}
+
+boost::asio::io_service& IoEngine::GetIoService()
+{
+       return m_IoService;
+}
+
+IoEngine::IoEngine() : m_IoService(), m_KeepAlive(m_IoService), m_AlreadyExpiredTimer(m_IoService)
+{
+       m_AlreadyExpiredTimer.expires_at(boost::posix_time::neg_infin);
+
+       auto concurrency (std::thread::hardware_concurrency());
+
+       if (concurrency < 2) {
+               m_CpuBoundSemaphore.store(1);
+       } else {
+               m_CpuBoundSemaphore.store(concurrency - 1u);
+       }
+
+       for (auto i (std::thread::hardware_concurrency()); i; --i) {
+               std::thread(&IoEngine::RunEventLoop, this).detach();
+       }
+}
+
+void IoEngine::RunEventLoop()
+{
+       for (;;) {
+               try {
+                       m_IoService.run();
+
+                       break;
+               } catch (const std::exception& e) {
+                       Log(LogCritical, "IoEngine", "Exception during I/O operation!");
+                       Log(LogDebug, "IoEngine") << "Exception during I/O operation: " << DiagnosticInformation(e);
+               }
+       }
+}

diff --git a/lib/base/io-engine.hpp b/lib/base/io-engine.hpp
new file mode 100644 (file)
index 0000000..df84df9
--- /dev/null
+++ b/lib/base/io-engine.hpp
@@ -0,0 +1,85 @@
+/******************************************************************************
+ * Icinga 2                                                                   *
+ * Copyright (C) 2012-2018 Icinga Development Team (https://icinga.com/)      *
+ *                                                                            *
+ * This program is free software; you can redistribute it and/or              *
+ * modify it under the terms of the GNU General Public License                *
+ * as published by the Free Software Foundation; either version 2             *
+ * of the License, or (at your option) any later version.                     *
+ *                                                                            *
+ * This program is distributed in the hope that it will be useful,            *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
+ * GNU General Public License for more details.                               *
+ *                                                                            *
+ * You should have received a copy of the GNU General Public License          *
+ * along with this program; if not, write to the Free Software Foundation     *
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
+ ******************************************************************************/
+
+#ifndef IO_ENGINE_H
+#define IO_ENGINE_H
+
+/**
+ * Boost.Coroutine2 (the successor of Boost.Coroutine)
+ * (1) doesn't even exist in old Boost versions and
+ * (2) isn't supported by ASIO, yet.
+ */
+#define BOOST_COROUTINES_NO_DEPRECATION_WARNING 1
+
+#include "base/lazy-init.hpp"
+#include <atomic>
+#include <memory>
+#include <boost/asio/deadline_timer.hpp>
+#include <boost/asio/io_service.hpp>
+#include <boost/asio/spawn.hpp>
+
+/**
+ * Scope lock for CPU-bound work done in an I/O thread
+ *
+ * @ingroup base
+ */
+class CpuBoundWork
+{
+public:
+       CpuBoundWork(boost::asio::yield_context yc);
+       CpuBoundWork(const CpuBoundWork&) = delete;
+       CpuBoundWork(CpuBoundWork&&) = delete;
+       CpuBoundWork& operator=(const CpuBoundWork&) = delete;
+       CpuBoundWork& operator=(CpuBoundWork&&) = delete;
+       ~CpuBoundWork();
+};
+
+/**
+ * Async I/O engine
+ *
+ * @ingroup base
+ */
+class IoEngine
+{
+       friend CpuBoundWork;
+
+public:
+       IoEngine(const IoEngine&) = delete;
+       IoEngine(IoEngine&&) = delete;
+       IoEngine& operator=(const IoEngine&) = delete;
+       IoEngine& operator=(IoEngine&&) = delete;
+
+       static IoEngine& Get();
+
+       boost::asio::io_service& GetIoService();
+
+private:
+       IoEngine();
+
+       void RunEventLoop();
+
+       static LazyInit<std::unique_ptr<IoEngine>> m_Instance;
+
+       boost::asio::io_service m_IoService;
+       boost::asio::io_service::work m_KeepAlive;
+       boost::asio::deadline_timer m_AlreadyExpiredTimer;
+       std::atomic_uint_fast32_t m_CpuBoundSemaphore;
+};
+
+#endif /* IO_ENGINE_H */