ProjectRecoveryThread.cpp

#include "ProjectRecoveryThread.h"

#include "ApplicationWindow.h"
#include "Folder.h"
#include "ProjectSerialiser.h"
#include "globals.h"

#include "MantidAPI/FileProperty.h"
#include "MantidKernel/ConfigService.h"
#include "MantidKernel/Logger.h"

#include "boost/optional.hpp"

#include "Poco/DirectoryIterator.h"
#include "Poco/NObserver.h"

#include "Poco/Path.h"
#include "qmetaobject.h"

#include <chrono>
#include <condition_variable>
#include <ctime>
#include <iomanip>
#include <iostream>
#include <mutex>
#include <string>
#include <thread>

namespace {
// Config helper methods

template <typename T>
boost::optional<T> getConfigValue(const std::string &key) {
  T returnedValue;

  int valueIsGood =
      Mantid::Kernel::ConfigService::Instance().getValue<T>(key, returnedValue);

  if (valueIsGood != 1) {
    return boost::optional<T>{};
  }

  return boost::optional<T>{returnedValue};
}

boost::optional<bool> getConfigBool(const std::string &key) {
  auto returnedValue = getConfigValue<std::string>(key);
  if (!returnedValue.is_initialized()) {
    return boost::optional<bool>{};
  }

  return returnedValue->find("true") != std::string::npos;
}

/// Returns a string to the current top level recovery folder
std::string getRecoveryFolder() {
  static std::string recoverFolder =
      Mantid::Kernel::ConfigService::Instance().getAppDataDir() + "/recovery/";
  return recoverFolder;
}

/// Gets a formatted timestamp
std::string getTimeStamp() {
  const char *formatSpecifier = "%Y-%m-%d %H-%M-%S";
  auto time = std::time(nullptr);
  auto localTime = std::localtime(&time);

#if __GNUG__ < 5
  // Have to workaround GCC 4 not having std::put_time on RHEL7
  // this ifdef can be removed when RHEL7 uses a newer compiler
  char timestamp[20];
  if (strftime(timestamp, sizeof(timestamp), formatSpecifier, localTime) > 0) {
    return {formatSpecifier};
  }

  return {};
#else
  std::ostringstream timestamp;
  timestamp << std::put_time(localTime, formatSpecifier);
  return timestamp.str();
#endif
}

/// Returns a string to the current timestamped recovery folder
std::string getOutputPath() {

  auto timestamp = getTimeStamp();
  auto timestampedPath = getRecoveryFolder().append(timestamp);

  return timestampedPath;
}

const std::string OUTPUT_PROJ_NAME = "recovery.mantid";

// Config keys
const std::string SAVING_ENABLED_CONFIG_KEY = "projectRecovery.enabled";
const std::string SAVING_TIME_KEY = "projectRecovery.secondsBetween";
const std::string NO_OF_CHECKPOINTS_KEY = "projectRecovery.numberOfCheckpoints";

// Config values
const bool SAVING_ENABLED =
    getConfigBool(SAVING_ENABLED_CONFIG_KEY).get_value_or(false);
const int SAVING_TIME =
    getConfigValue<int>(SAVING_TIME_KEY).get_value_or(60); // Seconds
const int NO_OF_CHECKPOINTS =
    getConfigValue<int>(NO_OF_CHECKPOINTS_KEY).get_value_or(5);

// Implementation variables
Mantid::Kernel::Logger g_log("Project Recovery Thread");
const std::chrono::seconds TIME_BETWEEN_SAVING(SAVING_TIME);

} // namespace

namespace MantidQt {
namespace API {

/**
 * Constructs a new ProjectRecoveryThread, a class which encapsulates
 * a background thread to save periodically. This does not start the
 * background thread though
 *
 * @param windowHandle :: Pointer to the main application window
 */
ProjectRecoveryThread::ProjectRecoveryThread(ApplicationWindow *windowHandle)
    : m_backgroundSavingThread(), m_stopBackgroundThread(true),
      m_configKeyObserver(*this, &ProjectRecoveryThread::configKeyChanged),
      m_windowPtr(windowHandle) {}

/// Destructor which also stops any background threads currently in progress
ProjectRecoveryThread::~ProjectRecoveryThread() { stopProjectSaving(); }

/// Returns a background thread with the current object captured inside it
std::thread ProjectRecoveryThread::createBackgroundThread() {
  // Using a lambda helps the compiler deduce the this pointer
  // otherwise the resolution is ambiguous
  return std::thread([this] { projectSavingThreadWrapper(); });
}

/// Callback for POCO when a config change had fired for the enabled key
void ProjectRecoveryThread::configKeyChanged(
    Mantid::Kernel::ConfigValChangeNotification_ptr notif) {
  if (notif->key() != (SAVING_ENABLED_CONFIG_KEY)) {
    return;
  }

  if (notif->curValue() == "True") {
    startProjectSaving();
  } else {
    stopProjectSaving();
  }
}

/**
 * Deletes existing checkpoints, oldest first, in the recovery
 * folder. This is based on the configuration key which
 * indicates how many points to keep
 */
void ProjectRecoveryThread::deleteExistingCheckpoints(
    size_t checkpointsToKeep) {
  static auto workingFolder = getRecoveryFolder();
  Poco::Path recoveryPath;
  if (!recoveryPath.tryParse(workingFolder)) {
    // Folder may not exist yet
    g_log.debug("Project Saving: Failed to get working folder whilst deleting "
                "checkpoints");
    return;
  }

  std::vector<Poco::Path> folderPaths;

  Poco::DirectoryIterator dirIterator(recoveryPath);
  Poco::DirectoryIterator end;
  // Find all the folders which exist in this folder
  while (dirIterator != end) {
    std::string iterPath = workingFolder + dirIterator.name() + '/';
    Poco::Path foundPath(iterPath);

    if (foundPath.isDirectory()) {
      folderPaths.push_back(std::move(foundPath));
    }
    ++dirIterator;
  }

  size_t numberOfDirsPresent = folderPaths.size();
  if (numberOfDirsPresent <= checkpointsToKeep) {
    // Nothing to do
    return;
  }

  // Ensure the oldest is first in the vector
  std::sort(folderPaths.begin(), folderPaths.end(),
            [](const Poco::Path &a, const Poco::Path &b) {
              return a.toString() < b.toString();
            });

  size_t checkpointsToRemove = numberOfDirsPresent - checkpointsToKeep;
  bool recurse = true;
  for (size_t i = 0; i < checkpointsToRemove; i++) {
    Poco::File(folderPaths[i]).remove(recurse);
  }
}

/// Starts a background thread which saves out the project periodically
void ProjectRecoveryThread::startProjectSaving() {
  // Close the existing thread first
  stopProjectSaving();

  if (!SAVING_ENABLED) {
    return;
  }

  // Spin up a new thread
  {
    std::lock_guard<std::mutex> lock(m_notifierMutex);
    m_stopBackgroundThread = false;
  }

  m_backgroundSavingThread = createBackgroundThread();
}

/// Stops any existing background threads which are running
void ProjectRecoveryThread::stopProjectSaving() {
  {
    std::lock_guard<std::mutex> lock(m_notifierMutex);
    m_stopBackgroundThread = true;
    m_threadNotifier.notify_all();
  }

  if (m_backgroundSavingThread.joinable()) {
    m_backgroundSavingThread.join();
  }
}

/// Top level thread wrapper which catches all exceptions to gracefully handle
/// them
void ProjectRecoveryThread::projectSavingThreadWrapper() {
  try {
    projectSavingThread();
  } catch (std::exception const &e) {
    std::string preamble("Project recovery has stopped. Please report"
                         " this to the development team.\nException:\n");
    g_log.warning(preamble + e.what());
  } catch (...) {
    g_log.warning("Project recovery has stopped. Please report"
                  " this to the development team.");
  }
}

/**
 * Main thread body which is run to save out projects. A member mutex is
 * locked and monitored on a timeout to indicate if the thread should
 * exit early. After the timeout elapses, if the thread has not been
 * requested to exit, it will save the project out
 */
void ProjectRecoveryThread::projectSavingThread() {
  while (!m_stopBackgroundThread) {
    std::unique_lock<std::mutex> lock(m_notifierMutex);
    // The condition variable releases the lock until the var changes
    if (m_threadNotifier.wait_for(lock, TIME_BETWEEN_SAVING, [this]() {
          return m_stopBackgroundThread;
        })) {
      // Exit thread
      g_log.information("Project Recovery: Stopping background saving thread");
      return;
    }

    g_log.information("Project Recovery: Saving started");
    // "Timeout" - Save out again
    // Generate output paths
    const auto basePath = getOutputPath();
    auto projectFile = Poco::Path(basePath).append(OUTPUT_PROJ_NAME);

    // Python's OS module cannot handle Poco's parsed paths
    // so use std::string instead and let OS parse the '/' char on Win
    saveWsHistories(basePath);
    saveOpenWindows(projectFile.toString());

    // Purge any excessive folders
    deleteExistingCheckpoints(NO_OF_CHECKPOINTS);
    g_log.information("Project Recovery: Saving finished");
  }
}

/**
 * Saves open all open windows using the main GUI thread
 *
 * @param projectDestFile :: The full path to write to
 * @throws If saving fails in the main GUI thread
 */
void ProjectRecoveryThread::saveOpenWindows(
    const std::string &projectDestFile) {
  bool saveCompleted = false;
  if (!QMetaObject::invokeMethod(m_windowPtr, "saveProjectRecovery",
                                 Qt::BlockingQueuedConnection,
                                 Q_RETURN_ARG(bool, saveCompleted),
                                 Q_ARG(const std::string, projectDestFile))) {
    throw std::runtime_error(
        "Project Recovery: Failed to save project windows - Qt binding failed");
  }

  if (!saveCompleted) {
    throw std::runtime_error(
        "Project Recovery: Failed to write out project file");
  }
}

/**
 * Saves all workspace histories by using an external python script
 *
 * @param historyDestFolder:: The folder to write all histories to
 * @throw If saving fails in the script
 */
void ProjectRecoveryThread::saveWsHistories(
    const std::string &historyDestFolder) {
  QString projectSavingCode =
      "from mantid.simpleapi import write_all_workspaces_histories\n"
      "write_all_workspaces_histories(\"" +
      QString::fromStdString(historyDestFolder) + "\")\n";

  if (!m_windowPtr->runPythonScript(projectSavingCode)) {
    throw std::runtime_error("Project Recovery: Python saving failed");
  }
}

} // namespace API
} // namespace MantidQt