Logger for C++是一个为C++开发的日志项目, 可以将log输出到控制台或指定的文件

• 支持Linux/Windows
• 线程安全

• 支持C++17及以上的C++编译器
• CMake 3.11及以上版本
• Boost >= 1.75

如果CMake没有自动找到Boost路径, 可参考修改CMakeLists.txt

if (CMAKE_HOST_WIN32)
    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
        set(BOOST_ROOT "D:/OpenCode/boost/gcc")
    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
        set(BOOST_ROOT "D:/OpenCode/boost/msvc")
    endif ()
else ()
    set(BOOST_ROOT "/usr/local/boost")
endif ()

$ cmake -S . -B build -DENABLE_DEMO=ON
$ cd build
$ make
$ sudo make install

#include "log4cpp.hpp"

CMakeLists.txt示例:

add_executable(${TARGET_NAME} main.cpp)

include(FetchContent)
FetchContent_Declare(log4cpp GIT_REPOSITORY https://github.com/SandroDickens/log4cpp.git GIT_TAG v2.0.0)

FetchContent_MakeAvailable(log4cpp)

target_link_libraries(${TARGET_NAME} log4cpp)

1. 加载配置文件

如果当前路径下存在`log4cpp.json`, 会自动加载此配置文件. 如果配置文件不在当前路径或文件名不是`log4cpp.json`, 需要手动加载配置文件

log4cpp::logger_manager::load_config("./log4cpp.json");

2. 获取logger实例

通过`name`获取配置的`“name”: “consoleLogger”`logger, 如果不存在指定的logger, 则返回默认的`rootLogger`

std::shared_ptr<log4cpp::logger> logger = log4cpp::logger_manager::get_logger("recordLogger");

3. 输出log

void log(log_level level, const char *fmt, ...);

下面几个API是上面的特化

void trace(const char *__restrict fmt, ...);
void info(const char *__restrict fmt, ...);
void debug(const char *__restrict fmt, ...);
void warn(const char *__restrict fmt, ...);
void error(const char *__restrict fmt, ...);
void fatal(const char *__restrict fmt, ...);

#include <pthread.h>

#include "log4cpp.hpp"

void *child_thread_routine(void *) {
	pthread_setname_np(pthread_self(), "child");
	std::shared_ptr<log4cpp::logger> logger = log4cpp::logger_manager::get_logger("recordLogger");
	logger->trace("Child: this is a trace 0x%x", pthread_self());
	logger->info("Child: this is a info 0x%x", pthread_self());
	logger->debug("Child: this is a debug 0x%x", pthread_self());
	logger->error("Child: this is an error 0x%x", pthread_self());
	logger->fatal("Child: this is a fatal 0x%x", pthread_self());
	return nullptr;
}

int main() {
	pthread_t child_tid;
	pthread_create(&child_tid, nullptr, child_thread_routine, nullptr);
	pthread_setname_np(pthread_self(), "main");
	std::shared_ptr<log4cpp::logger> logger = log4cpp::logger_manager::get_logger("consoleLogger");
	logger->trace("Main: this is a trace 0x%x", pthread_self());
	logger->info("Main: this is a info 0x%x", pthread_self());
	logger->debug("Main: this is a debug 0x%x", pthread_self());
	logger->error("Main: this is an error 0x%x", pthread_self());
	logger->fatal("Main: this is a fatal 0x%x", pthread_self());

	pthread_join(child_tid, nullptr);

	return 0;
}

# 年-月-日 时:分:秒 [线程名或ID]: [log级别] -- log正文
year-mon-day hh:mm:ss [thread name@T${thread id}]: [log level] -- log message

其中:

1. 秒精确到小数点后三位(毫秒) 2. ${thread id}为线程ID, 某些系统无法设置线程名, 只能通过线程ID区分多线程 3. log级别的定义如下:

namespace log4cpp {
	enum class log_level {
		FATAL = 0, ERROR = 1, WARN = 2, INFO = 3, DEBUG = 4, TRACE = 5
	};
}

示例:

2024-03-09 18:33:24 [    main] [INFO ] - Main: this is a info 0x9b4b0b80
2024-03-09 18:33:24 [   child] [ERROR] - Child: this is an error 0x9adff640
2024-03-09 18:33:24 [    main] [WARN ] - Main: this is an warning 0x9b4b0b80
2024-03-09 18:33:24 [    main] [ERROR] - Main: this is an error 0x9b4b0b80
2024-03-09 18:33:24 [   child] [FATAL] - Child: this is a fatal 0x9adff640
2024-03-09 18:33:24 [    main] [FATAL] - Main: this is a fatal 0x9b4b0b80

参考配置文件示例

{
  // 输出格式, 暂未实现
  "pattern": "${yyyy}-${mm}-${dd} %{hh}:${mm}:${ss} [${t}]: [${l}] -- ${M}",
  // 输出器
  "logOutPut": {
    // 控制台输出器
    "consoleOutPut": {
      // 输出流，可以是stdout或stderr
      "outStream": "stdout"
    },
    // 文件输出器
    "fileOutPut": {
      // 输出文件
      "filePath": "log/log4cpp.log",
      // 追加还是覆盖, 默认覆盖
      "append": false
    },
    // TCP输出器, 暂未实现
    "tcpOutPut": {
      // 监听地址
      "localAddr": "172.0.0.1",
      // 监听端口
      "port": "9443"
    },
    // UDP输出器
    "udpOutPut": {
      "localAddr": "172.0.0.1",
      "port": "9443"
    }
  },
  "loggers": [
    {
      // logger名称
      "name": "consoleLogger",
      // log级别
      "logLevel": "info",
      // 使能的输出器
      "logOutPuts": [
        "consoleOutPut"
      ]
    },
    {
      "name": "recordLogger",
      "logLevel": "error",
      "logOutPuts": [
        "fileOutPut",
        "tcpOutPut",
        "udpOutPut"
      ]
    }
  ],
  // 默认logger
  "rootLogger": {
    "logLevel": "info",
    "logOutPuts": [
      "fileOutPut",
      "tcpOutPut",
      "udpOutPut"
    ]
  }
}

本项目使用GPLv3许可