大写的 Boost 日志严重性级别输出

Question

我尝试使用 Boost Log V2 设置记录器。输出应如下所示（文件 blubb.log）：

2019-08-24 23:24:08 - 错误：来自源代码的您好。

我目前正在与严重级别的大写字母作斗争。其余的工作到目前为止。

severity level 提供 ::to_string() 对话，但我没有让它在 severity_type 中工作。所以我试图把数据放到一个字符串流中。

logger.cpp（不包含）

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

BOOST_LOG_ATTRIBUTE_KEYWORD(att_channel, "Channel", std::string);

typedef src::severity_channel_logger<logging::trivial::severity_level, std::string> severity_channel_logger_t;
typedef sinks::synchronous_sink< sinks::text_ostream_backend > synchronous_sink_t;

static std::map<std::string, severity_channel_logger_t> map_logger;
static std::unordered_set<std::string> profiles = { "blubb",  "configreader", "connector", "downloader", "mlog", "output", "provider", "rest" };

static std::unordered_map<std::string, logging::trivial::severity_level> levels = {
    { "trace"   , logging::trivial::trace},
    { "debug"   , logging::trivial::debug},
    { "info"    , logging::trivial::info},
    { "warning" , logging::trivial::warning},
    { "error"   , logging::trivial::error},
    { "fatal"   , logging::trivial::fatal}
};

Logger::Logger()
{
    for (std::unordered_set<std::string>::iterator it = profiles.begin(); it != profiles.end(); it++)
    {
        map_logger[*it] = severity_channel_logger_t(keywords::channel = *it);
        create_channel_logger(*it);
    }
    logging::add_common_attributes();
}

std::stringstream Logger::sev_toupper(logging::trivial::severity_type severity)
{
    std::stringstream in;
    std::stringstream out;
    char c;
    in << severity;
    while (in >> c)
    {
        out << toupper(c);
    }
    return out;
}

void Logger::logmsg(std::string channel, const std::string level, const std::string message)
{
    // fallback channel, if not in list
    if (profiles.find(channel) == profiles.end())
        channel = "rest";
    BOOST_LOG_SEV(map_logger[channel], levels[level]) << message;
}

void Logger::create_channel_logger(std::string channel)
{
    logging::add_file_log
    (
        keywords::file_name = channel+".log",
        keywords::open_mode = std::ios_base::app,           
        keywords::filter = att_channel == channel,
        keywords::auto_flush = true,                        
        keywords::format =
        (
            expr::stream
                << expr::format_date_time<boost::posix_time::ptime>("TimeStamp", "%Y-%m-%d %H:%M:%S")
                << " - "
                << std::right << std::setw(7) << sev_toupper(logging::trivial::severity).str().c_str()
                << std::left << ": " << expr::smessage
        )
    );
}

main.cpp

int main(int, char*[])
{
    Logger * lg = new Logger();
    lg->logmsg("blubb", "error", "Hi, from Source Code!");
    delete lg;
}

我的函数 sev_toupper() 产生 gargabe。 expr::stream 似乎以不同于 std::stringstream 的方式处理 logging::trivial::severity。

Answer 1

我会避免将stringstreams 用于简单的单词。您可以使用std::transform 通过转换字符串的函数运行字符串的每个字符，如下所示：

#include <algorithm>
#include <cctype>

std::string Logger::sev_toupper(logging::trivial::severity_type severity)
{
    std::string text = logging::trivial::to_string(severity);
    std::transform(text.begin(), text.end(), text.begin(), toupper);
    return text;
}