使用C++11标准，构建了一个方便使用的、轻量化的日志系统。封装线程安全的lockQueue，实现对每条日志添加信息、push到lockQueue中的LogTmp类，实现一个多线程异步的日志系统Logger。
lockqueue.h
#pragma once
#include <queue>
#include <string>
#include <thread>
#include <mutex> // pthread_mutex_t
#include <condition_variable> // pthread_condition_t
// 异步写日志的日志队列
class LockQueue
{
public:
// 多个worker线程都会写日志queue
void Push(const std::string &data)
{
std::lock_guard<std::mutex> lock(m_mutex);
m_queue.push(data);
m_condvariable.notify_one();
}
// 一个线程读日志queue，写日志文件
std::string Pop()
{
std::unique_lock<std::mutex> lock(m_mutex);
while (m_queue.empty())
{
// 日志队列为空，线程进入wait状态
m_condvariable.wait(lock);
}
std::string data = m_queue.front();
m_queue.pop();
return data;
}
private:
std::queue<std::string> m_queue;
std::mutex m_mutex;
std::condition_variable m_condvariable;
};logger.h
#pragma once
#include "lockqueue.h"
#include "timestamp.h"
#include <sstream>
#include <string>
#include <mutex>
#include <fstream>
#include <atomic>
// 定义日志级别 INFO ERROR FATAL DEBUG
enum LogLevel
{
DEBUG = 0, // 调试信息
INFO, // 普通信息
ERROR, // 错误信息
FATAL, // core信息
};
class LogTmp;
class Logger;
// 直接使用左移运算法<<进行输出，末尾不需要加换行
#define LOG_INFO \
if(Logger::getInstance()->isEnable() && LogLevel::INFO >= Logger::getInstance()->getLogLevel()) \
LogTmp::ptr(new LogTmp(Logger::getInstance(), INFO, __FILE__, __LINE__, __FUNCTION__))->getStringStream()
// 直接使用左移运算法<<进行输出，末尾不需要加换行
#define LOG_ERROR \
if(Logger::getInstance()->isEnable() && LogLevel::ERROR >= Logger::getInstance()->getLogLevel()) \
LogTmp::ptr(new LogTmp(Logger::getInstance(), ERROR, __FILE__, __LINE__, __FUNCTION__))->getStringStream()
// 直接使用左移运算法<<进行输出，末尾不需要加换行
#define LOG_FATAL \
if(Logger::getInstance()->isEnable() && LogLevel::FATAL >= Logger::getInstance()->getLogLevel()) \
LogTmp::ptr(new LogTmp(Logger::getInstance(), FATAL, __FILE__, __LINE__, __FUNCTION__))->getStringStream()
#define LOG_DEBUG \
if(Logger::getInstance()->isEnable() && LogLevel::DEBUG >= Logger::getInstance()->getLogLevel()) \
LogTmp::ptr(new LogTmp(Logger::getInstance(), DEBUG, __FILE__, __LINE__, __FUNCTION__))->getStringStream()
class LogTmp{
public:
using ptr = std::unique_ptr<LogTmp>; // 使用指针，防止对象提前被析构
LogTmp(Logger* logger, const int logLevel, const char *file, const int line, const char* func);
~LogTmp();
std::stringstream& getStringStream();
private:
Logger* logger_;
std::stringstream ss_; // 通过<<接收用户的多种数据的log信息
};
// 可以设置是否启用日志（默认为启用）和日志等级（默认为最低级）
class Logger
{
public:
// static std::stringstream& getStringStream(const int logLevel,
// const char* file = __FILE__,
// const int line = __LINE__,
// const char* func = __FUNCTION__);
static Logger* getInstance();
void setEnableLogger(bool flag);
void setLogLevel(LogLevel level);
int getLogLevel(){ return logLevel_; }
bool isEnable(){ return enableLogger_; }
void pushLog(const std::string& log);
private:
Logger();
~Logger();
std::atomic_bool enableLogger_; // 设置是否启用日志功能，默认为true
std::atomic_int logLevel_;
// 静态变量，全局只有一个，在多线程的多个实例化对象中也可保持线程安全
static std::mutex fileMutex_;
static std::mutex loggerMutex_;
static LockQueue lockQue_;
static std::unique_ptr<std::thread> writeLogThread_;
static Logger *logger_;
};logger.cc
#include "logger.h"
#include <thread>
#include <iostream>
LockQueue Logger::lockQue_;
std::mutex Logger::fileMutex_;
std::mutex Logger::loggerMutex_;
std::unique_ptr<std::thread> Logger::writeLogThread_;
Logger* Logger::logger_ = nullptr;
LogTmp::LogTmp(Logger* logger, const int logLevel, const char *file, const int line, const char* func)
: logger_(logger)
{
std::string time = Timestamp::now().toString();
ss_ << time;
switch (logLevel)
{
case INFO:
ss_ << "[INFO] ";
break;
case ERROR:
ss_ << "[ERROR]";
break;
case FATAL:
ss_ << "[FATAL]";
break;
case DEBUG:
ss_ << "[DEBUG]";
break;
default:
break;
}
ss_ << " FILE:" << file << " LINE:" << line << " FUNC:" << func << "::";
// std::cout << ss_.str() << std::endl;
}
LogTmp::~LogTmp(){
ss_ << std::endl;
// std::cout << "LogTmp::~LogTmp()" << std::endl;
logger_->pushLog(ss_.str());
}
std::stringstream& LogTmp::getStringStream(){
// std::cout << "LogTmp::getStringStream()" << std::endl;
return this->ss_;
}
Logger::Logger()
: enableLogger_(true), logLevel_(LogLevel::DEBUG)
{
// 启动写文件的新线程，专门从lockQue中取日志写文件
if(writeLogThread_ == nullptr){
writeLogThread_ = std::make_unique<std::thread>([&](){
while(1){
// 取出一条日志
std::string loginfo = lockQue_.Pop();
// std::cout << "aaa" << loginfo;
// 获取当前日期
std::string time = Timestamp::now().toString();
std::string filePath = time.substr(0, 10) + "-log.txt";
// std::cout << "aaa" << filePath << std::endl;
std::unique_lock<std::mutex> ulock(fileMutex_);
// C++ 文件流
std::ofstream file(filePath, std::ios::app);
if (file.is_open())
{
file << loginfo;
file.close();
}
else
{
std::cout << "error : log file not open!" << std::endl;
return;
}
}
});
// 设置分离线程，守护线程
writeLogThread_->detach();
}
}
// 在此处将ss_中所有内容写入LockQue
Logger::~Logger()
{}
void Logger::pushLog(const std::string& log){
lockQue_.Push(log);
}
// std::stringstream& Logger::getStringStream(const int logLevel, const char *file, const int line, const char *func)
// {
// {
// std::unique_lock<std::mutex> ulock(loggerMutex_);
// if(logger_ == nullptr){
// logger_ = new Logger();
// }
// }
// LogTmp logTmp(logger_, logLevel, file, line, func);
// return logTmp.getStringStream();
// }
Logger *Logger::getInstance()
{
std::unique_lock<std::mutex> ulock(loggerMutex_);
if(logger_ == nullptr){
logger_ = new Logger();
}
ulock.unlock();
return logger_;
}
void Logger::setEnableLogger(bool flag)
{
enableLogger_ = flag;
}
void Logger::setLogLevel(LogLevel level)
{
logLevel_ = level;
}testlog.cc
#include "logger.h"
int main(){
Logger::getInstance()->setLogLevel(LogLevel::DEBUG);
{
LOG_DEBUG << "debug";
LOG_INFO << "info";
LOG_ERROR << "error";
LOG_FATAL << "fatal";
}
Logger::getInstance()->setLogLevel(LogLevel::INFO);
{
LOG_DEBUG << "debug";
LOG_INFO << "info";
LOG_ERROR << "error";
LOG_FATAL << "fatal";
}
Logger::getInstance()->setLogLevel(LogLevel::ERROR);
{
LOG_DEBUG << "debug";
LOG_INFO << "info";
LOG_ERROR << "error";
LOG_FATAL << "fatal";
}
Logger::getInstance()->setLogLevel(LogLevel::FATAL);
{
LOG_DEBUG << "debug";
LOG_INFO << "info";
LOG_ERROR << "error";
LOG_FATAL << "fatal";
}
getchar();
return 0;
}日志写入测试结果
上图中空行是测试完成后手打进去的，便于查看日志分级结果。 （第一行的hello是之前的日志）
