qtwebapp::FileLogger Class Reference

#include <filelogger.h>

Inheritance diagram for qtwebapp::FileLogger:

Collaboration diagram for qtwebapp::FileLogger:

Public Member Functions
	FileLogger (QSettings *settings, const int refreshInterval=10000, QObject *parent=0)
	FileLogger (const FileLoggerSettings &settings, const int refreshInterval=10000, QObject *parent=0)
virtual	~FileLogger ()
FileLoggerSettings	getFileLoggerSettings () const
void	setFileLoggerSettings (const FileLoggerSettings &settings)
virtual void	write (const LogMessage *logMessage)
Public Member Functions inherited from qtwebapp::Logger
	Logger (QObject *parent)
	Logger (const QString msgFormat="{timestamp} {type} {msg}", const QString timestampFormat="yyyy-MM-dd HH:mm:ss.zzz", const QtMsgType minLevel=QtDebugMsg, const int bufferSize=0, QObject *parent=0)
virtual	~Logger ()
virtual void	log (const QtMsgType type, const QString &message, const QString &file="", const QString &function="", const int line=0)
void	installMsgHandler ()
void	setMinMessageLevel (const QtMsgType &minMsgLevel)
QtMsgType	getMinMessageLevel () const
virtual void	clear (const bool buffer=true, const bool variables=true)

Protected Member Functions
void	timerEvent (QTimerEvent *event)

Private Member Functions
void	open ()
void	close ()
void	rotate ()
void	refreshSettings ()
void	refreshQtSettings ()
void	refreshFileLogSettings ()

Private Attributes
QString	fileName
long	maxSize
int	maxBackups
QSettings *	settings
FileLoggerSettings	fileLoggerSettings
QFile *	file
QBasicTimer	refreshTimer
QBasicTimer	flushTimer
bool	useQtSettings

Additional Inherited Members
Static Public Member Functions inherited from qtwebapp::Logger
static void	set (const QString &name, const QString &value)
Protected Attributes inherited from qtwebapp::Logger
QString	msgFormat
QString	timestampFormat
QtMsgType	minLevel
int	bufferSize
Static Protected Attributes inherited from qtwebapp::Logger
static QMutex	mutex

Detailed Description

Logger that uses a text file for output. Settings are read from a config file using a QSettings object. Config settings can be changed at runtime.

Example for the configuration settings:

fileName=logs/QtWebApp.log
maxSize=1000000
maxBackups=2
minLevel=0
msgformat={timestamp} {typeNr} {type} thread={thread}: {msg}
timestampFormat=yyyy-MM-dd HH:mm:ss.zzz
bufferSize=0

• fileName is the name of the log file, relative to the directory of the settings file. In case of windows, if the settings are in the registry, the path is relative to the current working directory.
• maxSize is the maximum size of that file in bytes. The file will be backed up and replaced by a new file if it becomes larger than this limit. Please note that the actual file size may become a little bit larger than this limit. Default is 0=unlimited.
• maxBackups defines the number of backup files to keep. Default is 0=unlimited.
• minLevel defines the minimum type of messages that are written (together with buffered messages) into the file. Defaults is 0=debug.
• msgFormat defines the decoration of log messages, see LogMessage class. Default is "{timestamp} {type} {msg}".
• timestampFormat defines the format of timestamps, see QDateTime::toString(). Default is "yyyy-MM-dd HH:mm:ss.zzz".
• bufferSize defines the size of the buffer. Default is 0=disabled.

See also

set() describes how to set logger variables

LogMessage for a description of the message decoration.

Logger for a descrition of the buffer.

Definition at line 54 of file filelogger.h.

Constructor & Destructor Documentation

FileLogger() [1/2]

FileLogger::FileLogger	(	QSettings *	settings,
		const int	refreshInterval = 10000,
		QObject *	parent = 0
	)

Constructor.

Parameters

settings	Configuration settings, usually stored in an INI file. Must not be 0. Settings are read from the current group, so the caller must have called settings->beginGroup(). Because the group must not change during runtime, it is recommended to provide a separate QSettings instance to the logger that is not used by other parts of the program.
refreshInterval	Interval of checking for changed config settings in msec, or 0=disabled
parent	Parent object

Definition at line 97 of file filelogger.cpp.

References file, flushTimer, refreshSettings(), refreshTimer, and settings.

                                                                                      :
        Logger(parent), fileName(""), useQtSettings(true)
{
    Q_ASSERT(settings != 0);
    Q_ASSERT(refreshInterval >= 0);

    this->settings = settings;
    file = 0;

    if (refreshInterval > 0) {
        refreshTimer.start(refreshInterval, this);
    }

    flushTimer.start(1000, this);

    refreshSettings();
}

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FileLogger() [2/2]

FileLogger::FileLogger	(	const FileLoggerSettings &	settings,
		const int	refreshInterval = 10000,
		QObject *	parent = 0
	)

Constructor.

Parameters

settings	Configuration settings as a simple structure (see: FileLoggerSettings).
refreshInterval	Interval of checking for changed config settings in msec, or 0=disabled
parent	Parent object

Definition at line 115 of file filelogger.cpp.

References file, fileLoggerSettings, flushTimer, refreshSettings(), refreshTimer, and settings.

                                                                                                     :
        Logger(parent), fileName(""), useQtSettings(false)
{
    Q_ASSERT(refreshInterval >= 0);

    fileLoggerSettings = settings;
    file = 0;

    if (refreshInterval > 0) {
        refreshTimer.start(refreshInterval, this);
    }

    flushTimer.start(1000, this);

    refreshSettings();
}

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~FileLogger()

FileLogger::~FileLogger ( )

virtual

Destructor. Closes the file.

Definition at line 132 of file filelogger.cpp.

References close().

{
    close();
}

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Member Function Documentation

close()

void FileLogger::close ( )

private

Close the output file

Definition at line 188 of file filelogger.cpp.

References file.

Referenced by refreshFileLogSettings(), refreshQtSettings(), timerEvent(), write(), and ~FileLogger().

{
    if (file)
    {
        file->close();
        delete file;
        file = 0;
    }
}

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getFileLoggerSettings()

FileLoggerSettings qtwebapp::FileLogger::getFileLoggerSettings ( ) const

inline

Get a file logger settings copy

Returns

The current file logger settings

Definition at line 87 of file filelogger.h.

Referenced by qtwebapp::LoggerWithFile::getLogFileName().

{ return fileLoggerSettings; }

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open()

void FileLogger::open ( )

private

Open the output file

Definition at line 166 of file filelogger.cpp.

References file, and fileName.

Referenced by refreshFileLogSettings(), refreshQtSettings(), and timerEvent().

{
    if (fileName.isEmpty())
    {
        fprintf(stderr, "FileLogger::open: Name of logFile is empty\n");
    }
    else
    {
        file = new QFile(fileName);

        if (!file->open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text))
        {
            fprintf(stderr, "FileLogger::open: Cannot open log file %s: %s\n", qPrintable(fileName), qPrintable(file->errorString()));
            file = 0;
        }
        else
        {
            fprintf(stderr, "FileLogger::open: Opened log file %s\n", qPrintable(fileName));
        }
    }
}

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refreshFileLogSettings()

void FileLogger::refreshFileLogSettings ( )

private

Refreshes the configuration settings with file log settings structure.

Definition at line 68 of file filelogger.cpp.

References qtwebapp::FileLoggerSettings::bufferSize, qtwebapp::Logger::bufferSize, close(), fileLoggerSettings, qtwebapp::FileLoggerSettings::fileName, fileName, qtwebapp::FileLoggerSettings::maxBackups, maxBackups, qtwebapp::FileLoggerSettings::maxSize, maxSize, qtwebapp::FileLoggerSettings::minLevel, qtwebapp::Logger::minLevel, qtwebapp::FileLoggerSettings::msgFormat, qtwebapp::Logger::msgFormat, open(), qtwebapp::FileLoggerSettings::timestampFormat, and qtwebapp::Logger::timestampFormat.

Referenced by refreshSettings().

{
    // Save old file name for later comparison with new settings
    QString oldFileName = fileName;

    // Load new config settings
    fileName = fileLoggerSettings.fileName;

    // Convert relative fileName to absolute, based on the current working directory
    if (QDir::isRelativePath(fileName)) {
        fileName = QFileInfo(QDir::currentPath(), fileName).absoluteFilePath();
    }

    maxSize = fileLoggerSettings.maxSize;
    maxBackups = fileLoggerSettings.maxBackups;
    msgFormat = fileLoggerSettings.msgFormat;
    timestampFormat = fileLoggerSettings.timestampFormat;
    minLevel = fileLoggerSettings.minLevel;
    bufferSize = fileLoggerSettings.bufferSize;

    // Create new file if the filename has been changed
    if (oldFileName != fileName)
    {
        fprintf(stderr, "FileLogger::refreshQtSettings: Logging to new file %s\n", qPrintable(fileName));
        close();
        open();
    }
}

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refreshQtSettings()

void FileLogger::refreshQtSettings ( )

private

Refreshes the configuration settings with Qt settings.

Definition at line 32 of file filelogger.cpp.

References qtwebapp::Logger::bufferSize, close(), fileName, maxBackups, maxSize, qtwebapp::Logger::minLevel, qtwebapp::Logger::msgFormat, open(), settings, and qtwebapp::Logger::timestampFormat.

Referenced by refreshSettings().

{
    // Save old file name for later comparison with new settings
    QString oldFileName = fileName;

    // Load new config settings
    settings->sync();
    fileName = settings->value("fileName").toString();

    // Convert relative fileName to absolute, based on the directory of the config file.
#ifdef Q_OS_WIN32
    if (QDir::isRelativePath(fileName) && settings->format()!=QSettings::NativeFormat)
#else
    if (QDir::isRelativePath(fileName))
#endif
    {
        QFileInfo configFile(settings->fileName());
        fileName = QFileInfo(configFile.absolutePath(), fileName).absoluteFilePath();
    }

    maxSize = settings->value("maxSize", 0).toLongLong();
    maxBackups = settings->value("maxBackups", 0).toInt();
    msgFormat = settings->value("msgFormat", "{timestamp} {type} {msg}").toString();
    timestampFormat = settings->value("timestampFormat", "yyyy-MM-dd HH:mm:ss.zzz").toString();
    minLevel = static_cast<QtMsgType>(settings->value("minLevel", 0).toInt());
    bufferSize = settings->value("bufferSize", 0).toInt();

    // Create new file if the filename has been changed
    if (oldFileName != fileName)
    {
        fprintf(stderr, "FileLogger::refreshQtSettings: Logging to %s\n", qPrintable(fileName));
        close();
        open();
    }
}

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refreshSettings()

void FileLogger::refreshSettings ( )

private

Refreshes the configuration settings. This method is thread-safe.

Definition at line 19 of file filelogger.cpp.

References qtwebapp::Logger::mutex, refreshFileLogSettings(), refreshQtSettings(), and useQtSettings.

Referenced by FileLogger(), and timerEvent().

{
    mutex.lock();

    if (useQtSettings) {
        refreshQtSettings();
    } else {
        refreshFileLogSettings();
    }

    mutex.unlock();
}

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rotate()

void FileLogger::rotate ( )

private

Rotate files and delete some backups if there are too many

Definition at line 198 of file filelogger.cpp.

References arg(), fileName, i, and maxBackups.

Referenced by timerEvent().

{
    fprintf(stderr, "FileLogger::rotate\n");
    // count current number of existing backup files
    int count = 0;

    forever
    {
        QFile bakFile(QString("%1.%2").arg(fileName).arg(count + 1));

        if (bakFile.exists()) {
            ++count;
        } else {
            break;
        }
    }

    // Remove all old backup files that exceed the maximum number
    while (maxBackups > 0 && count >= maxBackups)
    {
        QFile::remove(QString("%1.%2").arg(fileName).arg(count));
        --count;
    }

    // Rotate backup files
    for (int i = count; i > 0; --i)
    {
        QFile::rename(QString("%1.%2").arg(fileName).arg(i), QString("%1.%2").arg(fileName).arg(i + 1));
    }

    // Backup the current logfile
    QFile::rename(fileName, fileName + ".1");
}

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setFileLoggerSettings()

void qtwebapp::FileLogger::setFileLoggerSettings ( const FileLoggerSettings &  settings )

inline

Set new file logger settings data

Parameters

File	logger settings to replace current data

Definition at line 93 of file filelogger.h.

Referenced by qtwebapp::LoggerWithFile::createOrSetFileLogger().

{ fileLoggerSettings = settings; }

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timerEvent()

void FileLogger::timerEvent ( QTimerEvent *  event )

protected

Handler for timer events. Refreshes config settings or synchronizes I/O buffer, depending on the event. This method is thread-safe.

Parameters

event

used to distinguish between the two timers.

Definition at line 232 of file filelogger.cpp.

References close(), file, flushTimer, maxSize, qtwebapp::Logger::mutex, open(), refreshSettings(), refreshTimer, and rotate().

{
    if (!event) {
        return;
    } else if (event->timerId() == refreshTimer.timerId()) {
        refreshSettings();
    }
    else if (event->timerId() == flushTimer.timerId() && file)
    {
        mutex.lock();

        // Flush the I/O buffer
        file->flush();

        // Rotate the file if it is too large
        if (maxSize > 0 && file->size() >= maxSize)
        {
            close();
            rotate();
            open();
        }

        mutex.unlock();
    }
}

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write()

void FileLogger::write ( const LogMessage *  logMessage )

virtual

Write a message to the log file

Reimplemented from qtwebapp::Logger.

Definition at line 137 of file filelogger.cpp.

References close(), file, fileName, qtwebapp::LogMessage::getType(), qtwebapp::Logger::msgFormat, qtwebapp::Logger::timestampFormat, qtwebapp::LogMessage::toString(), useQtSettings, and qtwebapp::Logger::write().

{
    // Try to write to the file
    if (file)
    {
        // Write the message
        file->write(qPrintable(logMessage->toString(msgFormat, timestampFormat)));

        // Flush error messages immediately, to ensure that no important message
        // gets lost when the program terinates abnormally.
        if (logMessage->getType() >= QtCriticalMsg) {
            file->flush();
        }

        // Check for success
        if (file->error())
        {
            close();
            fprintf(stderr, "FileLogger::write: Cannot write to log file %s: %s\n", qPrintable(fileName), qPrintable(file->errorString()));
        }
    }

    // Fall-back to the super class method, if writing failed
    if (!file && useQtSettings) {
        Logger::write(logMessage);
    }

}

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Member Data Documentation

file

QFile* qtwebapp::FileLogger::file

private

Output file, or 0=disabled

Definition at line 126 of file filelogger.h.

Referenced by close(), FileLogger(), open(), timerEvent(), and write().

fileLoggerSettings

FileLoggerSettings qtwebapp::FileLogger::fileLoggerSettings

private

Pointer to the configuration settings

Definition at line 123 of file filelogger.h.

Referenced by FileLogger(), and refreshFileLogSettings().

fileName

QString qtwebapp::FileLogger::fileName

private

Configured name of the log file

Definition at line 111 of file filelogger.h.

Referenced by open(), refreshFileLogSettings(), refreshQtSettings(), rotate(), and write().

flushTimer

QBasicTimer qtwebapp::FileLogger::flushTimer

private

Timer for flushing the file I/O buffer

Definition at line 132 of file filelogger.h.

Referenced by FileLogger(), and timerEvent().

maxBackups

int qtwebapp::FileLogger::maxBackups

private

Configured maximum number of backup files, or 0=unlimited

Definition at line 117 of file filelogger.h.

Referenced by refreshFileLogSettings(), refreshQtSettings(), and rotate().

maxSize

long qtwebapp::FileLogger::maxSize

private

Configured maximum size of the file in bytes, or 0=unlimited

Definition at line 114 of file filelogger.h.

Referenced by refreshFileLogSettings(), refreshQtSettings(), and timerEvent().

refreshTimer

QBasicTimer qtwebapp::FileLogger::refreshTimer

private

Timer for refreshing configuration settings

Definition at line 129 of file filelogger.h.

Referenced by FileLogger(), and timerEvent().

settings

QSettings* qtwebapp::FileLogger::settings

private

Pointer to the configuration settings

Definition at line 120 of file filelogger.h.

Referenced by FileLogger(), and refreshQtSettings().

useQtSettings

bool qtwebapp::FileLogger::useQtSettings

private

Use of Qt settings or simple structure settings

Definition at line 135 of file filelogger.h.

Referenced by refreshSettings(), and write().

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The documentation for this class was generated from the following files:

• logging/filelogger.h
• logging/filelogger.cpp