spdlog/example/example.cpp

//
// Copyright(c) 2015 Gabi Melman.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
//
//
// spdlog usage example
//
//

#define SPDLOG_TRACE_ON
#define SPDLOG_DEBUG_ON

#include "spdlog/sinks/file_sinks.h"
#include "spdlog/sinks/stdout_color_sinks.h"

#include <iostream>
#include <memory>

void async_example();
void user_defined_example();
void err_handler_example();

namespace spd = spdlog;
int main(int, char *[])
{

    try
    {
        auto console = spdlog::stdout_color_st("console");
        console->info("Welcome to spdlog!");

        console->info("Welcome to spdlog!");
        console->error("Some error message with arg: {}", 1);
        err_handler_example();
        // Formatting examples
        console->warn("Easy padding in numbers like {:08d}", 12);
        console->critical("Support for int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
        console->info("Support for floats {:03.2f}", 1.23456);
        console->info("Positional args are {1} {0}..", "too", "supported");
        console->info("{:<30}", "left aligned");

        spd::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name) function");

        // Create basic file logger (not rotated)
        auto my_logger = spd::basic_logger_mt("basic_logger", "logs/basic-log.txt");
        my_logger->info("Some log message");

        // Create a file rotating logger with 5mb size max and 3 rotated files
        auto rotating_logger = spd::rotating_logger_mt("some_logger_name", "logs/rotating.txt", 1048576 * 5, 3);
        for (int i = 0; i < 10; ++i)
        {
            rotating_logger->info("{} * {} equals {:>10}", i, i, i * i);
        }

        // Create a daily logger - a new file is created every day on 2:30am
        auto daily_logger = spd::daily_logger_mt("daily_logger", "logs/daily.txt", 2, 30);
        // trigger flush if the log severity is error or higher
        daily_logger->flush_on(spd::level::err);
        daily_logger->info(123.44);

        // Customize msg format for all messages
        spd::set_pattern("[%^+++%$] [%H:%M:%S %z] [thread %t] %v"); 

        console->info("This an info message with custom format");
        console->error("This an error message with custom format");

        // Runtime log levels
        spd::set_level(spd::level::info); // Set global log level to info
        console->debug("This message should not be displayed!");
        console->set_level(spd::level::debug); // Set specific logger's log level
        console->debug("This message should be displayed..");

        // Compile time log levels
        // define SPDLOG_DEBUG_ON or SPDLOG_TRACE_ON
        SPDLOG_TRACE(console, "Enabled only #ifdef SPDLOG_TRACE_ON..{} ,{}", 1, 3.23);
        SPDLOG_DEBUG(console, "Enabled only #ifdef SPDLOG_DEBUG_ON.. {} ,{}", 1, 3.23);

        // Asynchronous logging is very fast..
        // Just call spdlog::set_async_mode(q_size) and all created loggers from now on will be asynchronous..
        async_example();

        // Log user-defined types example
        user_defined_example();

        // Change default log error handler
        err_handler_example();

        // Apply a function on all registered loggers
        spd::apply_all([&](std::shared_ptr<spdlog::logger> l) { l->info("End of example."); });

        // Release and close all loggers
        spdlog::drop_all();
    }
    // Exceptions will only be thrown upon failed logger or sink construction (not during logging)
    catch (const spd::spdlog_ex &ex)
    {
        std::cout << "Log init failed: " << ex.what() << std::endl;
        return 1;
    }
}
// must be included to use async logger
#include "spdlog/async.h"
void async_example()
{
    auto async_file = spd::basic_logger_mt<spdlog::create_async>("async_file_logger", "logs/async_log.txt");
    for (int i = 0; i < 100; ++i)
    {
        async_file->info("Async message #{}", i);
    }

    // you can also modify thread pool settings *before* creating the logger:
    // spdlog::init_thread_pool(32768, 4); // queue with 32k of pre allocated items and 4 backing threads.
    // if not called a defaults are: preallocated 8192 queue items and 1 worker thread.
}

// syslog example (linux/osx/freebsd)
#ifndef _WIN32
#include "spdlog/sinks/syslog_sink.h"
void syslog_example()
{
    std::string ident = "spdlog-example";
    auto syslog_logger = spd::syslog_logger("syslog", ident, LOG_PID);
    syslog_logger->warn("This is warning that will end up in syslog.");
}
#endif

// Android example
#if defined(__ANDROID__)
#incude "spdlog/sinks/android_sink.h"
void android_example()
{
    std::string tag = "spdlog-android";
    auto android_logger = spd::android_logger("android", tag);
    android_logger->critical("Use \"adb shell logcat\" to view this message.");
}

#endif

// user defined types logging by implementing operator<<
struct my_type
{
    int i;
    template<typename OStream>
    friend OStream &operator<<(OStream &os, const my_type &c)
    {
        return os << "[my_type i=" << c.i << "]";
    }
};

#include "spdlog/fmt/ostr.h" // must be included
void user_defined_example()
{
    spd::get("console")->info("user defined type: {}", my_type{14});
}

//
// custom error handler
//
void err_handler_example()
{
    // can be set globaly or per logger(logger->set_error_handler(..))
    spdlog::set_error_handler([](const std::string &msg) { spd::get("console")->error("*******my err handler: {}", msg); });
    spd::get("console")->info("some invalid message to trigger an error {}{}{}{}", 3);
    // spd::get("console")->info("some invalid message to trigger an error {}{}{}{}", 3);
}