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src/dbconnectionwatchdog.cpp 5.37 KB
fe12aa6a   Steven de Ridder   Initial commit. d...
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  /* ****************************************************************************
   * Copyright 2019 Open Systems Development BV                                 *
   *                                                                            *
   * Permission is hereby granted, free of charge, to any person obtaining a    *
   * copy of this software and associated documentation files (the "Software"), *
   * to deal in the Software without restriction, including without limitation  *
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,   *
   * and/or sell copies of the Software, and to permit persons to whom the      *
   * Software is furnished to do so, subject to the following conditions:       *
   *                                                                            *
   * The above copyright notice and this permission notice shall be included in *
   * all copies or substantial portions of the Software.                        *
   *                                                                            *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,   *
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL    *
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING    *
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER        *
   * DEALINGS IN THE SOFTWARE.                                                  *
   * ***************************************************************************/
  
  #include "dbconnectionwatchdog.h"
  #include "log.h"
  
  #include <QSqlDatabase>
  #include <QSqlError>
  
  using namespace osdev::components;
  
  DbConnectionWatchDog::DbConnectionWatchDog( int check_interval, QObject *_parent )
      : QObject( _parent )
      , m_pTimer( new QTimer( this ) )
      , m_check_interval( check_interval )
      , m_original_interval( check_interval )
      , m_dbc_valid( true )
  {
  
      #if( QT_VERSION >= QT_VERSION_CHECK( 5, 7, 0) )
      {
          QObject::connect( m_pTimer.data(), &QTimer::timeout, this, &DbConnectionWatchDog::slotStartConnectionCheck );
      }
      #else
      {
          QObject::connect( m_pTimer.data(), SIGNAL( timeout() ), this, SLOT( slotStartConnectionCheck() ) );
      }
      #endif
  
  }
  
  void DbConnectionWatchDog::slotStartConnectionCheck()
  {
      LogDebug( "[DbConnectionWatchDog::slotStartConnectionCheck]", QString( "Checking Database Connection...." ) );
      // Get all the connections from QSqlDatabase
      QStringList connection_names = QSqlDatabase::connectionNames();
      for( QString &conn_name : connection_names )
      {
          QSqlDatabase dbConn = QSqlDatabase::database( conn_name, false );
  
  
          // Check to see if we can execute a query. Not all databases drivers report a database as "open"
          // without actually accessing. It all depends on the Operating System and the connectiontype.
          if( 0 == dbConn.tables().count() )
          {
              // Check the error cause we didn't got any tablenames.
              switch( dbConn.lastError().type() )
              {
                  case QSqlError::NoError:
                      LogWarning( "[DbConnectionWatchDog::slotStartConnectionCheck]", QString( "No Error or database unavailable on connection %1" ).arg( conn_name ) );
                      dbConn.open();
                      // Set the check interval to 1 second until the connection is back on.
                      m_check_interval = 1;
                      break;
  
                  case QSqlError::ConnectionError:
                      LogWarning( "[DbConnectionWatchDog::slotStartConnectionCheck]", QString( "Connection Error on connection %1" ).arg( conn_name ) );
                      dbConn.open();
                      // Set the check interval to 1 second until the connection is back on.
                      m_check_interval = 1;
                      break;
                  case QSqlError::UnknownError:
                      LogWarning( "[DbConnectionWatchDog::slotStartConnectionCheck]", QString( "Unknown Error on connection %1" ).arg( conn_name ) );
                      // Set the check interval to 1 second until the connection is back on.
                      m_check_interval = 1;
                      break;
  
                  // The following Errors are not connection related but need to be here to satisfy the compiler.
                  case QSqlError::StatementError:
                  case QSqlError::TransactionError:
                      break;
                  default:
                      LogInfo( "[DbConnectionWatchDog::slotStartConnectionCheck]", QString( "Database connection Healthy...." ) )
              }
  
              if( m_dbc_valid )
              {
                  m_dbc_valid = false;
              }
  
              emit signalDbConnected( conn_name, false );
          }
          else
          {
              m_check_interval = m_original_interval;
              if( !m_dbc_valid )
              {
                  LogInfo( "[DbConnectionWatchDog::slotStartConnectionCheck]", "Database connection restored.." );
                  m_dbc_valid = true;
                  emit signalDbConnected( conn_name, m_dbc_valid );
              }
          }
      }
  
      // Restart the watchDog
      this->start();
  }
  
  void DbConnectionWatchDog::start()
  {
      m_pTimer->setInterval( m_check_interval * 1000 );
      m_pTimer->setSingleShot( true );
  
      m_pTimer->start();
  }