FileLogger.h

Go to the documentation of this file.

// Copyright Onix Solutions Limited [OnixS]. All rights reserved.
//
// This software owned by Onix Solutions Limited [OnixS] and is
// protected by copyright law and international copyright treaties.
//
// Access to and use of the software is governed by the terms of the applicable
// OnixS Software Services Agreement (the Agreement) and Customer end user license
// agreements granting a non-assignable, non-transferable and non-exclusive license
// to use the software for it's own data processing purposes under the terms defined
// in the Agreement.
//
// Except as otherwise granted within the terms of the Agreement, copying or
// reproduction of any part of this source code or associated reference material
// to any other location for further reproduction or redistribution, and any
// amendments to this copyright notice, are expressly prohibited.
//
// Any reproduction or redistribution for sale or hiring of the Software not in
// accordance with the terms of the Agreement is a violation of copyright law.
//

#pragma once

#include <OnixS/CME/MDH/String.h>
#include <OnixS/CME/MDH/Integral.h>

#include <OnixS/CME/MDH/Logger.h>
#include <OnixS/CME/MDH/Watch.h>

ONIXS_CMEMDH_NAMESPACE_BEGIN

/// Base parameters affecting synchronous logging services.
class ONIXS_CMEMDH_LTWT FileLoggerSettings
{
public:
    /// Initializes parameters with default values.
    FileLoggerSettings()
        : filename_()
        , fileSizeLimit_(2145386496)
        , severity_(LogSeverity::Regular)
        , watch_(&UtcWatch::service())
    {
    }

    /// Cleans everything up.
    ~FileLoggerSettings() {}

    /// Log file name.
    ///
    /// Ignored if logging is disabled.
    const std::string& filename() const
    {
        return filename_;
    }

    /// Updates log file name.
    ///
    /// Ignored if logging is disabled.
    void filename(const std::string& value)
    {
        filename_ = value;
    }

    /// Log file size limit (in bytes).
    ///
    /// Handler detaches logged data into separate
    /// file upon reaching given size limit.
    ///
    /// @note Default value is '2145386496'.
    UInt64 fileSizeLimit() const
    {
        return fileSizeLimit_;
    }

    /// Sets logFileSizeLimit. @see logFileSizeLimit.
    void fileSizeLimit(UInt64 value)
    {
        fileSizeLimit_ = value;
    }

    /// Specifies whether the logger should output events
    /// and which of events should be put into the log.
    ///
    /// @note The default value is LogEntrySeverity::Regular.
    LogSeverity::Enum severityLevel() const
    {
        return severity_;
    }

    /// Specifies whether logger should output its events
    /// and which of events should be put into the log.
    void severityLevel(LogSeverity::Enum value)
    {
        severity_ = value;
    }

    /// Watch service used by logger while
    /// assigning timestamps to log entries.
    WatchService& watch() const
    {
        return *watch_;
    }

    /// Watch service used by logger while
    /// assigning timestamps to log entries.
    void watch(WatchService& watch)
    {
        watch_ = &watch;
    }

private:
    std::string filename_;
    UInt64 fileSizeLimit_;

    LogSeverity::Enum severity_;

    WatchService* watch_;
};

/// Makes filename for log file for the given channel.
ONIXS_CMEMDH_EXPORTED
std::string makeLogFilename(UInt32);

ONIXS_CMEMDH_EXPORTED_CLASS_DECL(FileLogger);

/// Collection of events raised by FileLogger during its life time.
struct ONIXS_CMEMDH_EXPORTED FileLoggerListener
{
    /// Invoked by FileLogger in case of issue.
    ///
    /// FileLogger may experience issues like inability to
    /// add a new entry due to insufficient disk space. Once
    /// occurred, issue is reported through given callback.
    virtual void onFileLoggerIssue(const FileLogger&, const Char*) {}
};

/// Implements logging services to put logged data into a
/// regular file. Provides additional facilities like splitting
/// logged data into chunks not exceeding specified size limit.
class ONIXS_CMEMDH_EXPORTED FileLogger : public Logger
{
public:
    /// Initializes logger according to given settings.
    FileLogger(const FileLoggerSettings&, FileLoggerListener* = ONIXS_CMEMDH_NULLPTR);

    /// Disposes logging machinery.
    ~FileLogger() ONIXS_CMEMDH_OVERRIDE;

    /// Configuration of given logger instance.
    const FileLoggerSettings& settings() const;

    /// Basic information on the implementation
    /// of the logging services.
    void info(std::string&) ONIXS_CMEMDH_OVERRIDE;

    /// Adds a new entry into the log.
    ///
    /// Returns instance for further fulfill or ONIXS_CMEMDH_NULLPTR if
    /// given severity is lower than defined by settings
    /// at the moment of instance construction.
    LogEntry* addEntry(LogSeverity::Enum) ONIXS_CMEMDH_OVERRIDE;

    /// Rolls over current log and starts recording a new chunk.
    ///
    /// Detached data is stored into a file whose name is
    /// suffixed with a timestamp taken at the moment of detach.
    /// Timestamp is taken using watch service associated with
    /// the logger using its settings.
    ///
    /// @return Name of file containing detached data.
    std::string rollover();

private:
    // File logger machinery implementation.
    ONIXS_CMEMDH_LTWT_CLASS_DECL(Workhorse);

    Workhorse* workhorse_;
};

ONIXS_CMEMDH_NAMESPACE_END