CODEWITHSUNDEEP
c++loggingspdlog
Turgut
Turgut

Reputation: 809

C++ spdlog write logs to a file

I made a logger using spdlog which I use all over my program. But I also want to flush everything to a log file when the program is completed. How can I achieve this? I'm new to spdlog and I couldn't find proper documentation suitable for my situation.

Here are my file's:

Log.h:

#pragma once

#include "spdlog/spdlog.h"
#include "spdlog/fmt/ostr.h"

namespace Engine{
    class Log{
    public:
        static void init();
        inline static std::shared_ptr<spdlog::logger>& GetCoreLoger() { return s_CoreLogger; }
        inline static std::shared_ptr<spdlog::logger>& GetClientLogger  () { return s_ClientLogger;}

        // I want something like this:
        void flush_to_file();

    private:
        static std::shared_ptr<spdlog::logger> s_CoreLogger;
        static std::shared_ptr<spdlog::logger> s_ClientLogger;
    };
}



//Client log macros
#define VI_TRACE(...)      ::Engine::Log::GetClientLogger()->trace(__VA_ARGS__)
#define VI_INFO(...)       ::Engine::Log::GetClientLogger()->info(__VA_ARGS__)
#define VI_WARN(...)       ::Engine::Log::GetClientLogger()->warn(__VA_ARGS__)
#define VI_ERROR(...)      ::Engine::Log::GetClientLogger()->error(__VA_ARGS__)

Log.cpp:

#include "spdlog/sinks/stdout_color_sinks.h"

namespace Engine {
    std::shared_ptr<spdlog::logger> Log::s_CoreLogger;
    std::shared_ptr<spdlog::logger> Log::s_ClientLogger;

    void Log::init() {
        spdlog::set_pattern("%^[%T] %n: %v%$");
        s_CoreLogger = spdlog::stdout_color_mt("VIO");
        s_CoreLogger->set_level(spdlog::level::trace);

        s_ClientLogger = spdlog::stdout_color_mt("APP");
        s_ClientLogger->set_level(spdlog::level::trace);
    }

    // This is what I want:
    void Log::flush_to_file(){
       spdlog::write_to_file(); // Something like this
    }
};

I want everything that spdlog have logged so far to be written into the file when I call that function. Is this possible? If so how can I do it?

Upvotes: 1

Views: 4159

Answers (1)

fcatho
fcatho

Reputation: 367

What you probably need it is a multisink logger, a sink for stdout as you already have and a new one to also log to a file.

auto console_sink = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
auto basic_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("mylog.log");
std::vector<spdlog::sink_ptr> sinks{console_sink, basic_sink};
auto logger = std::make_shared<spdlog::logger>("main", sinks.begin(), sinks.end());

spdlog::register_logger(logger); //if it would be used in some other place

Your function flush_to_file probably should call

logger->flush();

To see the file content before the logger shutdown or automatic flush, try to add:

logger->flush_on(spdlog::level::info);

Upvotes: 3

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