Dummy database (#258)

It does nothing. It is to avoid writing large amounts of data to
QCDB during benchmarks.

Author: knopers8

Framework/CMakeLists.txt

@@ -56,7 +56,8 @@ add_library(QualityControl
             src/PostProcessingRunner.cxx
             src/PostProcessingFactory.cxx
             src/PostProcessingConfig.cxx
-            src/PostProcessingInterface.cxx)
+            src/PostProcessingInterface.cxx
+            src/DummyDatabase.cxx)
 
 if(ENABLE_MYSQL)
   target_sources(QualityControl PRIVATE src/MySqlDatabase.cxx)

Framework/include/QualityControl/DummyDatabase.h

@@ -0,0 +1,46 @@
+// Copyright CERN and copyright holders of ALICE O2. This software is
+// distributed under the terms of the GNU General Public License v3 (GPL
+// Version 3), copied verbatim in the file "COPYING".
+//
+// See http://alice-o2.web.cern.ch/license for full licensing information.
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+///
+/// \file   DummyDatabase.h
+/// \author Piotr Konopka
+///
+
+#ifndef QC_REPOSITORY_DUMMYDATABASE_H
+#define QC_REPOSITORY_DUMMYDATABASE_H
+
+#include "QualityControl/DatabaseInterface.h"
+
+namespace o2::quality_control::repository
+{
+
+/// \brief Dummy database which does nothing. Use it to avoid writing to QC repository.
+class DummyDatabase : public DatabaseInterface
+{
+ public:
+  DummyDatabase() = default;
+  virtual ~DummyDatabase() = default;
+
+  void connect(std::string host, std::string database, std::string username, std::string password) override;
+  void connect(const std::unordered_map<std::string, std::string>& config) override;
+  void store(std::shared_ptr<o2::quality_control::core::MonitorObject> mo) override;
+  core::MonitorObject* retrieve(std::string path, std::string objectName, long timestamp = 0) override;
+  std::string retrieveJson(std::string path, std::string objectName) override;
+  void disconnect() override;
+  void prepareTaskDataContainer(std::string taskName) override;
+  std::vector<std::string> getPublishedObjectNames(std::string taskName) override;
+  void truncate(std::string taskName, std::string objectName) override;
+
+ private:
+};
+
+} // namespace o2::quality_control::repository
+
+#endif // QC_REPOSITORY_DUMMYDATABASE_H

Framework/src/DatabaseFactory.cxx

@@ -18,6 +18,7 @@
 // O2
 #include <Common/Exceptions.h>
 // QC
+#include "QualityControl/DummyDatabase.h"
 #include "QualityControl/DatabaseFactory.h"
 #include "QualityControl/QcInfoLogger.h"
 #ifdef _WITH_MYSQL
@@ -45,6 +46,9 @@ std::unique_ptr<DatabaseInterface> DatabaseFactory::create(std::string name)
     // TODO check if CCDB installed
     QcInfoLogger::GetInstance() << "CCDB backend selected" << QcInfoLogger::endm;
     return std::make_unique<CcdbDatabase>();
+  } else if (name == "Dummy") {
+    QcInfoLogger::GetInstance() << "Dummy backend selected, MonitorObjects will not be stored nor retrieved" << QcInfoLogger::endm;
+    return std::make_unique<DummyDatabase>();
   } else {
     BOOST_THROW_EXCEPTION(FatalException() << errinfo_details("No database named " + name));
   }

Framework/src/DummyDatabase.cxx

@@ -0,0 +1,60 @@
+// Copyright CERN and copyright holders of ALICE O2. This software is
+// distributed under the terms of the GNU General Public License v3 (GPL
+// Version 3), copied verbatim in the file "COPYING".
+//
+// See http://alice-o2.web.cern.ch/license for full licensing information.
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+///
+/// \file   DummyDatabase.cxx
+/// \author Piotr Konopka
+///
+
+#include "QualityControl/DummyDatabase.h"
+
+namespace o2::quality_control::repository
+{
+
+void DummyDatabase::connect(std::string, std::string, std::string, std::string)
+{
+}
+
+void DummyDatabase::connect(const std::unordered_map<std::string, std::string>&)
+{
+}
+
+void DummyDatabase::store(std::shared_ptr<o2::quality_control::core::MonitorObject>)
+{
+}
+
+core::MonitorObject* DummyDatabase::retrieve(std::string, std::string, long)
+{
+  return nullptr;
+}
+
+std::string DummyDatabase::retrieveJson(std::string, std::string)
+{
+  return std::string();
+}
+
+void DummyDatabase::disconnect()
+{
+}
+
+void DummyDatabase::prepareTaskDataContainer(std::string)
+{
+}
+
+std::vector<std::string> DummyDatabase::getPublishedObjectNames(std::string)
+{
+  return std::vector<std::string>();
+}
+
+void DummyDatabase::truncate(std::string, std::string)
+{
+}
+
+} // namespace o2::quality_control::repository

Framework/test/testDbFactory.cxx

@@ -28,6 +28,7 @@
 //#include <cassert>
 //#include <iostream>
 
+#include <QualityControl/DummyDatabase.h>
 #include <QualityControl/CcdbDatabase.h>
 #include <QualityControl/MonitorObject.h>
 #include <TH1F.h>
@@ -58,6 +59,10 @@ BOOST_AUTO_TEST_CASE(db_factory_test)
   std::unique_ptr<DatabaseInterface> database3 = DatabaseFactory::create("CCDB");
   BOOST_CHECK(database3);
   BOOST_CHECK(dynamic_cast<CcdbDatabase*>(database3.get()));
+
+  std::unique_ptr<DatabaseInterface> database4 = DatabaseFactory::create("Dummy");
+  BOOST_CHECK(database4);
+  BOOST_CHECK(dynamic_cast<DummyDatabase*>(database4.get()));
 }
 
 BOOST_AUTO_TEST_CASE(db_ccdb_listing)

doc/DevelopersTips.md

@@ -40,6 +40,10 @@ When we don't see the monitoring data in grafana, here is what to do to pinpoint
     5. `select count(*) from cpuUsedPercentage` <-- use the correct metrics name
     6. Repeat the last command and see if the number increases. If it increases it denotes that the metrics is stored correctly in the database. If it is the case, the problem lies in your grafana.
 
+### Avoid writing QC objects to a repository
+
+In case of a need to avoid writing QC objects to a repository, one can choose the "Dummy" database implementation in the config file. This is might be useful when one expects very large amounts of data that would be stored, but not actually needed (e.g. benchmarks).
+
 ### QCG 
 
 #### Generalities