cta/CTA#46: Adding garbage collection for object store structures:

Created a garbage collector subprocess for the drive daemon.
Created a AgentHeartbeat thread and added it to frontend, drive subprocess and GC subprocess.
Fixed logs and drive subprocess.
Renamed common/threading/Threading.[hc]pp to Thread.[hc]pp as there is only one class left in this file.

common/CMakeLists.txt

@@ -117,7 +117,7 @@ set (COMMON_LIB_SRC_FILES
   threading/Mutex.cpp
   threading/SocketPair.cpp
   threading/System.cpp
-  threading/Threading.cpp
+  threading/Thread.cpp
   threading/Semaphores.cpp
   threading/SubProcess.cpp
   utils/GetOptThreadSafe.cpp

common/threading/AtomicCounter.hpp

@@ -20,7 +20,7 @@
 #pragma once
 
 #include "common/threading/MutexLocker.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 
 namespace cta {
 namespace threading {

common/threading/AtomicCounterTest.cpp

@@ -21,7 +21,7 @@
  * @author Castor Dev team, castor-dev@cern.ch
  *****************************************************************************/
 #include <gtest/gtest.h>
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/threading/AtomicCounter.hpp"
 namespace unitTests {
   struct ThreadPlus : public cta::threading::Thread{

common/threading/AtomicFlag.hpp

@@ -20,7 +20,7 @@
 #pragma once
 
 #include "common/threading/MutexLocker.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 
 namespace cta {
 namespace threading {

common/threading/BlockingQueue.hpp

@@ -22,7 +22,7 @@
 #include <exception>
 
 #include "common/threading/MutexLocker.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/threading/Semaphores.hpp"
 
 namespace cta {

common/threading/Semaphores.cpp

@@ -18,7 +18,7 @@
 
 #include "common/threading/MutexLocker.hpp"
 #include "common/threading/Semaphores.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/exception/Errnum.hpp"
 #include "common/exception/Exception.hpp"
 #include <errno.h>

common/threading/Threading.cpp → common/threading/Thread.cpp

@@ -16,7 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "Threading.hpp"
+#include "Thread.hpp"
 #include <errno.h>
 #include <typeinfo>
 #include <stdlib.h>

common/threading/ThreadingMPTests.cpp

@@ -17,7 +17,7 @@
  */
 
 #include <gtest/gtest.h>
-#include "Threading.hpp"
+#include "Thread.hpp"
 #include "ChildProcess.hpp"
 
 /* This is a collection of multi process unit tests, which can (and should)

common/threading/ThreadingMTTests.cpp

@@ -17,7 +17,7 @@
  */
 
 #include "common/threading/MutexLocker.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/threading/Semaphores.hpp"
 
 #include <gtest/gtest.h>

common/threading/ThreadingTests.cpp

@@ -17,7 +17,7 @@
  */
 
 #include "common/threading/MutexLocker.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/threading/ChildProcess.hpp"
 #include "common/threading/Semaphores.hpp"
 

objectstore/AgentHeartbeatThread.cpp

+/*
+ * The CERN Tape Archive (CTA) project
+ * Copyright (C) 2015  CERN
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "AgentHeartbeatThread.hpp"
+
+namespace cta { namespace objectstore {
+
+//------------------------------------------------------------------------------
+// AgentHeartbeatThread::stopAndWaitThread
+//------------------------------------------------------------------------------
+void AgentHeartbeatThread::stopAndWaitThread() {
+  m_exit.set_value();
+  wait();
+}
+
+//------------------------------------------------------------------------------
+// AgentHeartbeatThread::stopAndWaitThread
+//------------------------------------------------------------------------------
+void AgentHeartbeatThread::run() {
+  while (std::future_status::ready != m_exit.get_future().wait_for(m_heartRate)) {
+    m_agentReference.bumpHeatbeat(m_backend);
+  }
+}
+
+
+
+}} // namespace cta::objectstore

objectstore/AgentHeartbeatThread.hpp

+/*
+ * The CERN Tape Archive (CTA) project
+ * Copyright (C) 2015  CERN
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "AgentReference.hpp"
+#include "common/threading/Thread.hpp"
+
+#include <future>
+#include <chrono>
+
+namespace cta { namespace objectstore {
+
+/**
+ * Thread handler managing a heartbeat updated for the agent object representing
+ * the process. Just needs to be started and stopped.
+ */
+class AgentHeartbeatThread: private cta::threading::Thread {
+public:
+  /**
+   * Constructor
+   * @param agentReference reference to the agent object.
+   */
+  AgentHeartbeatThread(AgentReference & agentReference, Backend & backend):
+    m_backend(backend) , m_agentReference(agentReference) {}
+  
+  /**
+   * Start the thread
+   */
+  void startThread() { start(); }
+  
+  /**
+   * Stop and wait for the thread (graceful shutdown)
+   */
+  void stopAndWaitThread();
+  
+private:
+  /// Reference to the object store backend.
+  Backend & m_backend;
+  
+  /// Reference to the agent
+  AgentReference & m_agentReference;
+  
+  /// The thread's run function
+  void run() override;
+  
+  /// A promise used for graceful exit.
+  std::promise<void> m_exit;
+  
+  /// The heartbeat update rate.
+  std::chrono::seconds const m_heartRate = std::chrono::seconds(30);
+};
+
+}} // namespace cta::objectstore
\ No newline at end of file

objectstore/AgentReference.cpp

@@ -79,6 +79,12 @@ void AgentReference::removeFromOwnership(const std::string& objectAddress, objec
   queueAndExecuteAction(a, backend);
 }
 
+void AgentReference::bumpHeatbeat(objectstore::Backend& backend) {
+  Action a{AgentOperation::Heartbeat, "", std::promise<void>()};
+  queueAndExecuteAction(a, backend);
+}
+
+
 void AgentReference::queueAndExecuteAction(Action& action, objectstore::Backend& backend) {
   // First, we need to determine if a queue exists or not.
   // If so, we just use it, and if not, we create and serve it.
@@ -161,6 +167,8 @@ void AgentReference::appyAction(Action& action, objectstore::Agent& agent) {
   case AgentOperation::Remove:
     agent.removeFromOwnership(action.objectAddress);
     break;
+  case AgentOperation::Heartbeat:
+    agent.bumpHeartbeat();
   default:
     throw cta::exception::Exception("In AgentReference::appyAction(): unknown operation.");
   }

objectstore/AgentReference.hpp

@@ -72,6 +72,12 @@ public:
    * @param objectAddress
    */
   void removeFromOwnership(const std::string &objectAddress, objectstore::Backend& backend);
+  
+  /**
+   * Bumps up the heart beat of the agent. This action is queued in memory like the
+   * additions and removals from ownership.
+   */
+  void bumpHeatbeat(objectstore::Backend& backend);
 
   /**
    * Gets the address of the Agent object generated on construction.
@@ -87,7 +93,8 @@ private:
    */
   enum class AgentOperation: char {
     Add,
-    Remove
+    Remove,
+    Heartbeat
   };
   
   /**

objectstore/CMakeLists.txt

@@ -51,6 +51,7 @@ add_library (ctaobjectstore SHARED
   ${CTAProtoSources}
   RootEntry.cpp
   Agent.cpp
+  AgentHeartbeatThread.cpp
   AgentReference.cpp
   AgentRegister.cpp
   AgentWatchdog.cpp

tapeserver/castor/tape/tapeserver/daemon/DataTransferSessionTest.cpp

@@ -39,7 +39,7 @@
 #include "common/log/StringLogger.hpp"
 #include "common/make_unique.hpp"
 #include "common/processCap/ProcessCapDummy.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/utils/utils.hpp"
 #include "mediachanger/MediaChangerFacade.hpp"
 //#include "smc_struct.h"

tapeserver/castor/tape/tapeserver/daemon/DiskReadThreadPool.hpp

@@ -28,7 +28,7 @@
 #include "castor/tape/tapeserver/daemon/TaskWatchDog.hpp"
 #include "castor/tape/tapeserver/file/RadosStriperPool.hpp"
 #include "common/threading/BlockingQueue.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/threading/AtomicCounter.hpp"
 #include "common/log/LogContext.hpp"
 #include "common/Timer.hpp"

tapeserver/castor/tape/tapeserver/daemon/DiskWriteThreadPool.hpp

@@ -24,7 +24,7 @@
 #pragma once
 
 #include "common/threading/BlockingQueue.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/threading/AtomicCounter.hpp"
 #include "common/log/LogContext.hpp"
 #include "castor/tape/tapeserver/utils/suppressUnusedVariable.hpp"

tapeserver/castor/tape/tapeserver/daemon/MigrationMemoryManager.hpp

@@ -24,7 +24,7 @@
 #pragma once
 
 #include "common/threading/BlockingQueue.hpp"
-#include "common/threading/Threading.hpp"
+#include "common/threading/Thread.hpp"
 #include "common/log/LogContext.hpp"
 
 namespace castor {