Boost 日志 - 使用 severity_channel_logger 格式化

Question

我看过几个带有格式化程序的示例，但那些使用的是自定义属性。

如何指定 severity_channel_logger 的格式？我现在得到的是：

[2015-07-20 11:53:09.879305] [0x00007f047b525740] [trace]   Bla, bla bla, bla bla bla.
[2015-07-20 11:53:09.879370] [0x00007f047b525740] [trace]   Bla, bla bla, bla bla bla.
[2015-07-20 11:53:09.879376] [0x00007f047b525740] [fatal]   Bla, bla bla, bla bla bla.

logger.h

#ifndef LOGGER_H_
#define LOGGER_H_

#include <boost/log/trivial.hpp>
#include <boost/log/core.hpp>
#include <boost/log/sources/global_logger_storage.hpp>
#include <boost/log/sources/record_ostream.hpp>
#include <boost/log/sources/channel_feature.hpp>
#include <boost/log/sources/severity_channel_logger.hpp>

#include <string>

namespace Logging {

typedef boost::log::sources::severity_channel_logger<boost::log::trivial::severity_level,std::string> LoggerType;

BOOST_LOG_GLOBAL_LOGGER(clogger,LoggerType)

} // namespace Logging

#endif

logger.cpp

#include "logger.h"
#include <memory>

#include <boost/log/core/core.hpp>
#include <boost/log/expressions/formatters/date_time.hpp>
#include <boost/log/expressions.hpp>
#include <boost/log/sinks/sync_frontend.hpp>
#include <boost/log/sinks/text_ostream_backend.hpp>
#include <boost/log/sources/severity_logger.hpp>
#include <boost/log/support/date_time.hpp>
#include <boost/core/null_deleter.hpp>
#include <boost/log/utility/setup/common_attributes.hpp>
#include <boost/make_shared.hpp>
#include <boost/shared_ptr.hpp>

using namespace Logging;

BOOST_LOG_GLOBAL_LOGGER_INIT(clogger, LoggerType)
{
    boost::log::sources::severity_channel_logger< boost::log::trivial::severity_level, std::string > lg;
    return lg;
}

main.cpp

#include "logger.h"
#include <boost/log/attributes/named_scope.hpp>
using namespace Logging;

int main()
{
    BOOST_LOG_FUNCTION();
    BOOST_LOG(clogger::get()) << "Bla, bla bla, bla bla bla.";
    BOOST_LOG_CHANNEL(clogger::get(),"standard") << "Bla, bla bla, bla bla bla.";
    BOOST_LOG_CHANNEL_SEV(clogger::get(),"standard",boost::log::trivial::fatal) << "Bla, bla bla, bla bla bla.";
}

Answer 1

其实boost.org里面有很多介绍。现在我会给我我的代码：

#include <fstream>
#include <boost/smart_ptr/shared_ptr.hpp>
#include <boost/smart_ptr/make_shared_object.hpp>
#include <boost/log/core.hpp>
#include <boost/log/trivial.hpp>
#include <boost/log/expressions.hpp>
#include <boost/log/sinks/sync_frontend.hpp>
#include <boost/log/sinks/text_ostream_backend.hpp>
#include <boost/log/sources/severity_logger.hpp>
#include <boost/log/sources/record_ostream.hpp>
#include <boost/log/utility/setup/common_attributes.hpp>
#include <boost/log/support/date_time.hpp>

namespace logging = boost::log;
namespace src = boost::log::sources;
namespace expr = boost::log::expressions;
namespace sinks = boost::log::sinks;
namespace keywords = boost::log::keywords;

void init()
{
    typedef sinks::synchronous_sink< sinks::text_ostream_backend > text_sink;
    boost::shared_ptr< text_sink > sink = boost::make_shared< text_sink >();

    sink->locked_backend()->add_stream(
        boost::make_shared< std::ofstream >("sample.log"));

    sink->set_formatter
    (
        expr::stream
           // line id will be written in hex, 8-digits, zero-filled
        << expr::format_date_time< boost::posix_time::ptime >("TimeStamp", "%Y-%m-%d, %H:%M:%S")
        << std::hex << std::setw(8) << std::setfill('0') << expr::attr< unsigned int >("LineID")
        << ": <" << logging::trivial::severity
        << "> " << expr::smessage
);

logging::core::get()->add_sink(sink);
}

int main()
{
init();
logging::add_common_attributes();

using namespace logging::trivial;
src::severity_logger< severity_level > lg;

BOOST_LOG_SEV(lg, trace) << "A trace severity message";
BOOST_LOG_SEV(lg, debug) << "A debug severity message";
BOOST_LOG_SEV(lg, info) << "An informational severity message";
BOOST_LOG_SEV(lg, warning) << "A warning severity message";
BOOST_LOG_SEV(lg, error) << "An error severity message";
BOOST_LOG_SEV(lg, fatal) << "A fatal severity message";

return 0;

}

根据我的代码，你会得到一个sample.log的格式输出。它将显示为timestamp和log level。有关详细信息，您应该访问站点[http://www.boost.org/doc/libs/1_58_0/libs/log/example/doc/tutorial_fmt_format.cpp]。我希望这可以帮助你。顺便说一句，输出是：

2015-07-20, 23:19:0200000001: <trace> A trace severity message
2015-07-20, 23:19:0200000002: <debug> A debug severity message
2015-07-20, 23:19:0200000003: <info> An informational severity message
2015-07-20, 23:19:0200000004: <warning> A warning severity message
2015-07-20, 23:19:0200000005: <error> An error severity message
2015-07-20, 23:19:0200000006: <fatal> A fatal severity message

Answer 2

您需要为接收器设置格式器。格式化程序可以在 multiple ways 中定义，但底线是它从日志记录中提取属性值并将它们放入字符串中。属性是由用户还是库定义的并不重要 - 您只需要属性名称及其值的类型。

severity_channel_logger 是一个复合记录器，它将 severity level and a channel 插入通过该记录器创建的日志记录中。因此，您将从文档中得知属性名称分别为 "Severity" 和 "Channel"，并且属性值类型是您指定为记录器模板参数的类型 - boost::log::trivial::severity_level std::string 你的情况。

现在您可以将您想要的格式化程序设置到接收器。例如：

namespace expr = boost::log::expressions;

sink->set_formatter(
    expr::stream
        << expr::attr< boost::log::trivial::severity_level >("Severity")
        << " [" << expr::attr< std::string >("Channel") << "]: "
        << expr::smessage;
);

Boost 日志 - 使用 severity_channel_logger 格式化

Boost log - formatting with severity_channel_logger

c++

boost

boost-log