dbconnectionwatchdog.cpp
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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();
}