1 files changed, 318 insertions, 0 deletions
diff --git a/lib/base/workqueue.cpp b/lib/base/workqueue.cpp
new file mode 100644
index 0000000..0b1214b
--- /dev/null
+++ b/lib/base/workqueue.cpp
@@ -0,0 +1,318 @@
+/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
+
+#include "base/workqueue.hpp"
+#include "base/utility.hpp"
+#include "base/logger.hpp"
+#include "base/convert.hpp"
+#include "base/application.hpp"
+#include "base/exception.hpp"
+#include <boost/thread/tss.hpp>
+#include <math.h>
+
+using namespace icinga;
+
+std::atomic<int> WorkQueue::m_NextID(1);
+boost::thread_specific_ptr<WorkQueue *> l_ThreadWorkQueue;
+
+WorkQueue::WorkQueue(size_t maxItems, int threadCount, LogSeverity statsLogLevel)
+	: m_ID(m_NextID++), m_ThreadCount(threadCount), m_MaxItems(maxItems),
+	m_TaskStats(15 * 60), m_StatsLogLevel(statsLogLevel)
+{
+	/* Initialize logger. */
+	m_StatusTimerTimeout = Utility::GetTime();
+
+	m_StatusTimer = Timer::Create();
+	m_StatusTimer->SetInterval(10);
+	m_StatusTimer->OnTimerExpired.connect([this](const Timer * const&) { StatusTimerHandler(); });
+	m_StatusTimer->Start();
+}
+
+WorkQueue::~WorkQueue()
+{
+	m_StatusTimer->Stop(true);
+
+	Join(true);
+}
+
+void WorkQueue::SetName(const String& name)
+{
+	m_Name = name;
+}
+
+String WorkQueue::GetName() const
+{
+	return m_Name;
+}
+
+std::unique_lock<std::mutex> WorkQueue::AcquireLock()
+{
+	return std::unique_lock<std::mutex>(m_Mutex);
+}
+
+/**
+ * Enqueues a task. Tasks are guaranteed to be executed in the order
+ * they were enqueued in except if there is more than one worker thread.
+ */
+void WorkQueue::EnqueueUnlocked(std::unique_lock<std::mutex>& lock, std::function<void ()>&& function, WorkQueuePriority priority)
+{
+	if (!m_Spawned) {
+		Log(LogNotice, "WorkQueue")
+			<< "Spawning WorkQueue threads for '" << m_Name << "'";
+
+		for (int i = 0; i < m_ThreadCount; i++) {
+			m_Threads.create_thread([this]() { WorkerThreadProc(); });
+		}
+
+		m_Spawned = true;
+	}
+
+	bool wq_thread = IsWorkerThread();
+
+	if (!wq_thread) {
+		while (m_Tasks.size() >= m_MaxItems && m_MaxItems != 0)
+			m_CVFull.wait(lock);
+	}
+
+	m_Tasks.emplace(std::move(function), priority, ++m_NextTaskID);
+
+	m_CVEmpty.notify_one();
+}
+
+/**
+ * Enqueues a task. Tasks are guaranteed to be executed in the order
+ * they were enqueued in except if there is more than one worker thread or when
+ * allowInterleaved is true in which case the new task might be run
+ * immediately if it's being enqueued from within the WorkQueue thread.
+ */
+void WorkQueue::Enqueue(std::function<void ()>&& function, WorkQueuePriority priority,
+	bool allowInterleaved)
+{
+	bool wq_thread = IsWorkerThread();
+
+	if (wq_thread && allowInterleaved) {
+		function();
+
+		return;
+	}
+
+	auto lock = AcquireLock();
+	EnqueueUnlocked(lock, std::move(function), priority);
+}
+
+/**
+ * Waits until all currently enqueued tasks have completed. This only works reliably
+ * when no other thread is enqueuing new tasks when this method is called.
+ *
+ * @param stop Whether to stop the worker threads
+ */
+void WorkQueue::Join(bool stop)
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	while (m_Processing || !m_Tasks.empty())
+		m_CVStarved.wait(lock);
+
+	if (stop) {
+		m_Stopped = true;
+		m_CVEmpty.notify_all();
+		lock.unlock();
+
+		m_Threads.join_all();
+		m_Spawned = false;
+
+		Log(LogNotice, "WorkQueue")
+			<< "Stopped WorkQueue threads for '" << m_Name << "'";
+	}
+}
+
+/**
+ * Checks whether the calling thread is one of the worker threads
+ * for this work queue.
+ *
+ * @returns true if called from one of the worker threads, false otherwise
+ */
+bool WorkQueue::IsWorkerThread() const
+{
+	WorkQueue **pwq = l_ThreadWorkQueue.get();
+
+	if (!pwq)
+		return false;
+
+	return *pwq == this;
+}
+
+void WorkQueue::SetExceptionCallback(const ExceptionCallback& callback)
+{
+	m_ExceptionCallback = callback;
+}
+
+/**
+ * Checks whether any exceptions have occurred while executing tasks for this
+ * work queue. When a custom exception callback is set this method will always
+ * return false.
+ */
+bool WorkQueue::HasExceptions() const
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	return !m_Exceptions.empty();
+}
+
+/**
+ * Returns all exceptions which have occurred for tasks in this work queue. When a
+ * custom exception callback is set this method will always return an empty list.
+ */
+std::vector<boost::exception_ptr> WorkQueue::GetExceptions() const
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	return m_Exceptions;
+}
+
+void WorkQueue::ReportExceptions(const String& facility, bool verbose) const
+{
+	std::vector<boost::exception_ptr> exceptions = GetExceptions();
+
+	for (const auto& eptr : exceptions) {
+		Log(LogCritical, facility)
+			<< DiagnosticInformation(eptr, verbose);
+	}
+
+	Log(LogCritical, facility)
+		<< exceptions.size() << " error" << (exceptions.size() != 1 ? "s" : "");
+}
+
+size_t WorkQueue::GetLength() const
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	return m_Tasks.size();
+}
+
+void WorkQueue::StatusTimerHandler()
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	ASSERT(!m_Name.IsEmpty());
+
+	size_t pending = m_Tasks.size();
+
+	double now = Utility::GetTime();
+	double gradient = (pending - m_PendingTasks) / (now - m_PendingTasksTimestamp);
+	double timeToZero = pending / gradient;
+
+	String timeInfo;
+
+	if (pending > GetTaskCount(5)) {
+		timeInfo = " empty in ";
+		if (timeToZero < 0 || std::isinf(timeToZero))
+			timeInfo += "infinite time, your task handler isn't able to keep up";
+		else
+			timeInfo += Utility::FormatDuration(timeToZero);
+	}
+
+	m_PendingTasks = pending;
+	m_PendingTasksTimestamp = now;
+
+	/* Log if there are pending items, or 5 minute timeout is reached. */
+	if (pending > 0 || m_StatusTimerTimeout < now) {
+		Log(m_StatsLogLevel, "WorkQueue")
+			<< "#" << m_ID << " (" << m_Name << ") "
+			<< "items: " << pending << ", "
+			<< "rate: " << std::setw(2) << GetTaskCount(60) / 60.0 << "/s "
+			<< "(" << GetTaskCount(60) << "/min " << GetTaskCount(60 * 5) << "/5min " << GetTaskCount(60 * 15) << "/15min);"
+			<< timeInfo;
+	}
+
+	/* Reschedule next log entry in 5 minutes. */
+	if (m_StatusTimerTimeout < now) {
+		m_StatusTimerTimeout = now + 60 * 5;
+	}
+}
+
+void WorkQueue::RunTaskFunction(const TaskFunction& func)
+{
+	try {
+		func();
+	} catch (const std::exception&) {
+		boost::exception_ptr eptr = boost::current_exception();
+
+		{
+			std::unique_lock<std::mutex> mutex(m_Mutex);
+
+			if (!m_ExceptionCallback)
+				m_Exceptions.push_back(eptr);
+		}
+
+		if (m_ExceptionCallback)
+			m_ExceptionCallback(eptr);
+	}
+}
+
+void WorkQueue::WorkerThreadProc()
+{
+	std::ostringstream idbuf;
+	idbuf << "WQ #" << m_ID;
+	Utility::SetThreadName(idbuf.str());
+
+	l_ThreadWorkQueue.reset(new WorkQueue *(this));
+
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	for (;;) {
+		while (m_Tasks.empty() && !m_Stopped)
+			m_CVEmpty.wait(lock);
+
+		if (m_Stopped)
+			break;
+
+		if (m_Tasks.size() >= m_MaxItems && m_MaxItems != 0)
+			m_CVFull.notify_all();
+
+		Task task = m_Tasks.top();
+		m_Tasks.pop();
+
+		m_Processing++;
+
+		lock.unlock();
+
+		RunTaskFunction(task.Function);
+
+		/* clear the task so whatever other resources it holds are released _before_ we re-acquire the mutex */
+		task = Task();
+
+		IncreaseTaskCount();
+
+		lock.lock();
+
+		m_Processing--;
+
+		if (m_Tasks.empty())
+			m_CVStarved.notify_all();
+	}
+}
+
+void WorkQueue::IncreaseTaskCount()
+{
+	m_TaskStats.InsertValue(Utility::GetTime(), 1);
+}
+
+size_t WorkQueue::GetTaskCount(RingBuffer::SizeType span)
+{
+	return m_TaskStats.UpdateAndGetValues(Utility::GetTime(), span);
+}
+
+bool icinga::operator<(const Task& a, const Task& b)
+{
+	if (a.Priority < b.Priority)
+		return true;
+
+	if (a.Priority == b.Priority) {
+		if (a.ID > b.ID)
+			return true;
+		else
+			return false;
+	}
+
+	return false;
+}