C++项目实战——基于多设计模式下的同步异步日志系统-⑪-日志器管理类与全局建造者类设计（单例模式）

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🌸作者简介：花想云 ，在读本科生一枚，C/C++领域新星创作者，新星计划导师，阿里云专家博主，CSDN内容合伙人…致力于 C/C++、Linux 学习。

🌸专栏简介：本文收录于 C++项目——基于多设计模式下的同步与异步日志系统

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日志器建造者类完善

实现了异步日志器设计之后，将异步日志器添加到日志器建造者类当中。

// 1.抽象一个日志器建造者类（完成日志器所需零部件的构建 & 日志器的构建）
//  1.设置日志器类型
//  2.将不同类型的日志器的创建放到同一个日志器建造者类中完成
enum class LoggerType
{LOGGER_SYNC,LOGGER_ASYNC
};
class LoggerBuilder
{
public:LoggerBuilder() : _logger_type(LoggerType::LOGGER_SYNC),_limit_level(LogLevel::value::DEBUG),_looper_type(AsyncType::ASYNC_SAFE){}void buildLoggerType(LoggerType type) { _logger_type = type; }void buildEnableUnSafeAsync() { _looper_type = AsyncType::ASYNC_UNSAFE; }void buildLoggerName(const std::string &name) { _logger_name = name; }void buildLoggerLevel(LogLevel::value level) { _limit_level = level; }void buildFormatter(const std::string &pattern){_formatter = std::make_shared<Formatter>(pattern);}template <typename SinkType, typename... Args>void buildSink(Args &&...args) // 由用户自己决定落地方式{LogSink::ptr psink = SinkFactory::create<SinkType>(std::forward<Args>(args)...);_sinks.push_back(psink);}virtual Logger::ptr build() = 0;
protected:AsyncType _looper_type;LoggerType _logger_type;std::string _logger_name;std::atomic<LogLevel::value> _limit_level;Formatter::ptr _formatter;std::vector<LogSink::ptr> _sinks;
};
/*2.派生出具体的建造者类---局部日志器的建造者 & 全局日志器的建造者*/
class LocalLoggerBuilder : public LoggerBuilder
{
public:Logger::ptr build() override{assert(_logger_name.empty() == false);if (_formatter.get() == nullptr){_formatter = std::make_shared<Formatter>();}if (_sinks.empty()){buildSink<StdOutSink>();}if (_logger_type == LoggerType::LOGGER_ASYNC){return std::make_shared<AsyncLogger>(_logger_name, _limit_level, _formatter, _sinks, _looper_type);}return std::make_shared<SyncLogger>(_logger_name, _limit_level, _formatter, _sinks);}
};

单例日志器管理类设计思想

通过局部日志器建造者创建的日志器受到作用域的限制。但是日志的输出，我们希望能够在任意位置。

因此为了突破日志器作用域的限制，我们创建一个日志器管理类，且该类是一个单例类，这样我们就可以在任意位置通过单例管理器单例获取到指定的日志器进行输出了。

基于单例日志器管理类的设计思想，我们对于日志器建造者类进行继承，继承出一个全局日志器建造者类，实现一个日志器在创建完毕后，直接将其添加到单例的日志器管理器当中，以便于能够在任意位置通过日志器名称能够获取到指定的日志器进行输出。

日志器管理器的作用

• 对所有创建的日志器进行管理；
• 可以在程序的任意位置进，获取相同的单例对象，获取其中的日志器进行日志输出；

单例日志器管理类设计

管理的成员：

• 默认日志器；
• 所管理的日志器数组（使用哈希表，日志器名称为key，日志器对象为value）；
• 互斥锁；

提供的操作：

• 添加日志器管理；
• 判断是否管理了指定名称的日志器；
• 获取指定名称的日志器；
• 获取默认日志器；

class LoggerManager
{
public:static LoggerManager& getInstance(){// c++11之后，静态局部变量，编译器在编译的层面实现了线程安全// 当静态局部变量在没有构造完成之前，其他线程进入就会阻塞static LoggerManager eton;return eton;}void addLogger(Logger::ptr &logger){if(hasLogger(logger->name())) return;std::unique_lock<std::mutex> lock(_mutex);_loggers.insert(std::make_pair(logger->name(), logger));}bool hasLogger(const std::string name){std::unique_lock<std::mutex> lock(_mutex);auto it = _loggers.find(name);if(it == _loggers.end()){return false;}return true;}Logger::ptr getLogger(const std::string name){std::unique_lock<std::mutex> lock(_mutex);auto it = _loggers.find(name);if(it == _loggers.end()){return Logger::ptr();}return it->second;}Logger::ptr rootLogger(){return _root_logger;}
private:// 构造函数私有化LoggerManager(){std::unique_ptr<LOG::LoggerBuilder> builder(new LOG::LocalLoggerBuilder());builder->buildLoggerName("root");_root_logger = builder->build();_loggers.insert(std::make_pair("root", _root_logger));}
private:std::mutex _mutex;Logger::ptr _root_logger; // 默认日志器std::unordered_map<std::string, Logger::ptr> _loggers // 日志器数组;
};

全局建造者类设计

为了降低用户的使用复杂度，我们提供一个全局日志器建造者类。全局建造者类的设计思想非常简单，即在局部的基础上增加了一个功能：

• 将日志器添加到单例对象中。

class GlobalLoggerBuilder : public LoggerBuilder
{
public:Logger::ptr build() override{assert(_logger_name.empty() == false);if (_formatter.get() == nullptr){_formatter = std::make_shared<Formatter>();}if (_sinks.empty()){buildSink<StdOutSink>();}Logger::ptr logger;if (_logger_type == LoggerType::LOGGER_ASYNC){logger = std::make_shared<AsyncLogger>(_logger_name, _limit_level, _formatter, _sinks, _looper_type);}else{logger = std::make_shared<SyncLogger>(_logger_name, _limit_level, _formatter, _sinks);}LoggerManager::getInstance().addLogger(logger);return logger;}
};

日志器类、建造者类整理

#ifndef __M_LOGGER_H__
#define __M_LOGGER_H__
#include "util.hpp"
#include "level.hpp"
#include "format.hpp"
#include "sink.hpp"
#include "looper.hpp"
#include <cstdarg>
#include <atomic>
#include <thread>
#include <mutex>
#include <unordered_map>namespace LOG
{class Logger{public:using ptr = std::shared_ptr<Logger>;Logger(const std::string &logger_name,LogLevel::value level,Formatter::ptr &formatter,std::vector<LogSink::ptr> &sinks) : _logger_name(logger_name),_limit_level(level),_formatter(formatter),_sinks(sinks.begin(), sinks.end()){}const std::string& name(){ return _logger_name; }void debug(const std::string &file, size_t line, const std::string &fmt, ...){// 通过传入的参数构造出一个日志消息对象， 进行日志格式化，最终落地// 判断当前的日志是否达到了输出等级if (LogLevel::value::DEBUG < _limit_level){return;}// 对fmt格式化字符串和不定参数进行字符串组织， 得到的日志消息字符串va_list ap;va_start(ap, fmt);char *res;int ret = vasprintf(&res, fmt.c_str(), ap);if (ret == 1){std::cout << "vasprintf failed\n";return;}va_end(ap);serialize(LogLevel::value::DEBUG, file, line, res);free(res);}void info(const std::string &file, size_t line, const std::string &fmt, ...){// 通过传入的参数构造出一个日志消息对象， 进行日志格式化，最终落地if (LogLevel::value::INFO < _limit_level){return;}// 对fmt格式化字符串和不定参数进行字符串组织， 得到的日志消息字符串va_list ap;va_start(ap, fmt);char *res;int ret = vasprintf(&res, fmt.c_str(), ap);if (ret == 1){std::cout << "vasprintf failed\n";return;}va_end(ap);serialize(LogLevel::value::INFO, file, line, res);free(res);}void warn(const std::string &file, size_t line, const std::string &fmt, ...){// 通过传入的参数构造出一个日志消息对象， 进行日志格式化，最终落地if (LogLevel::value::WARN < _limit_level){return;}// 对fmt格式化字符串和不定参数进行字符串组织， 得到的日志消息字符串va_list ap;va_start(ap, fmt);char *res;int ret = vasprintf(&res, fmt.c_str(), ap);if (ret == 1){std::cout << "vasprintf failed\n";return;}va_end(ap);serialize(LogLevel::value::WARN, file, line, res);free(res);}void error(const std::string &file, size_t line, const std::string &fmt, ...){// 通过传入的参数构造出一个日志消息对象， 进行日志格式化，最终落地if (LogLevel::value::ERROR < _limit_level){return;}// 对fmt格式化字符串和不定参数进行字符串组织， 得到的日志消息字符串va_list ap;va_start(ap, fmt);char *res;int ret = vasprintf(&res, fmt.c_str(), ap);if (ret == 1){std::cout << "vasprintf failed\n";return;}va_end(ap);serialize(LogLevel::value::ERROR, file, line, res);free(res);}void fatal(const std::string &file, size_t line, const std::string &fmt, ...){// 通过传入的参数构造出一个日志消息对象， 进行日志格式化，最终落地if (LogLevel::value::FATAL < _limit_level){return;}// 对fmt格式化字符串和不定参数进行字符串组织， 得到的日志消息字符串va_list ap;va_start(ap, fmt);char *res;int ret = vasprintf(&res, fmt.c_str(), ap);if (ret == 1){std::cout << "vasprintf failed\n";return;}va_end(ap);serialize(LogLevel::value::FATAL, file, line, res);free(res);}protected:void serialize(LogLevel::value level, const std::string &file, size_t line, char *str){// 构造LogMsg对象LogMsg msg(level, line, file, _logger_name, str);// 通过格式化工具对LogMsg进行格式化， 得到格式化后的日志字符串std::stringstream ss;_formatter->format(ss, msg);// 对日志进行落地log(ss.str().c_str(), ss.str().size());}virtual void log(const char *data, size_t len) = 0;protected:std::mutex _mutex;std::string _logger_name;                  // 日志器名称std::atomic<LogLevel::value> _limit_level; // 限制输出等级Formatter::ptr _formatter;std::vector<LogSink::ptr> _sinks;};class SyncLogger : public Logger{public:SyncLogger(const std::string &logger_name,LogLevel::value level,LOG::Formatter::ptr &formatter,std::vector<LogSink::ptr> &sinks) : Logger(logger_name, level, formatter, sinks){}protected:void log(const char *data, size_t len){std::unique_lock<std::mutex> lock(_mutex);if (_sinks.empty())return;for (auto &sink : _sinks){sink->log(data, len);}}};class AsyncLogger : public Logger{public:AsyncLogger(const std::string &logger_name,LogLevel::value level,LOG::Formatter::ptr &formatter,std::vector<LogSink::ptr> &sinks,AsyncType looper_type): Logger(logger_name, level, formatter, sinks),_looper(std::make_shared<AsyncLooper>(std::bind(&AsyncLogger::realLog, this, std::placeholders::_1), looper_type)){}// 将数据写入缓冲区 void log(const char *data, size_t len){_looper->push(data, len);}// 设计一个实际落地函数void realLog(Buffer &buf){if (_sinks.empty())return;for (auto &sink : _sinks){sink->log(buf.begin(), buf.readAbleSize());}}private:AsyncLooper::ptr _looper; // 异步工作器};// 1.抽象一个日志器建造者类（完成日志器所需零部件的构建 & 日志器的构建）//  1.设置日志器类型//  2.将不同类型的日志器的创建放到同一个日志器建造者类中完成enum class LoggerType{LOGGER_SYNC,LOGGER_ASYNC};class LoggerBuilder{public:LoggerBuilder() : _logger_type(LoggerType::LOGGER_SYNC),_limit_level(LogLevel::value::DEBUG),_looper_type(AsyncType::ASYNC_SAFE){}void buildLoggerType(LoggerType type) { _logger_type = type; }void buildEnableUnSafeAsync() { _looper_type = AsyncType::ASYNC_UNSAFE; }void buildLoggerName(const std::string &name) { _logger_name = name; }void buildLoggerLevel(LogLevel::value level) { _limit_level = level; }void buildFormatter(const std::string &pattern){_formatter = std::make_shared<Formatter>(pattern);}template <typename SinkType, typename... Args>void buildSink(Args &&...args) // 由用户自己决定落地方式{LogSink::ptr psink = SinkFactory::create<SinkType>(std::forward<Args>(args)...);_sinks.push_back(psink);}virtual Logger::ptr build() = 0;protected:AsyncType _looper_type;LoggerType _logger_type;std::string _logger_name;std::atomic<LogLevel::value> _limit_level;Formatter::ptr _formatter;std::vector<LogSink::ptr> _sinks;};/*2.派生出具体的建造者类---局部日志器的建造者 & 全局日志器的建造者*/class LocalLoggerBuilder : public LoggerBuilder{public:Logger::ptr build() override{assert(_logger_name.empty() == false);if (_formatter.get() == nullptr){_formatter = std::make_shared<Formatter>();}if (_sinks.empty()){buildSink<StdOutSink>();}if (_logger_type == LoggerType::LOGGER_ASYNC){return std::make_shared<AsyncLogger>(_logger_name, _limit_level, _formatter, _sinks, _looper_type);}return std::make_shared<SyncLogger>(_logger_name, _limit_level, _formatter, _sinks);}};class LoggerManager{public:static LoggerManager& getInstance(){// c++11之后，静态局部变量，编译器在编译的层面实现了线程安全// 当静态局部变量在没有构造完成之前，其他线程进入就会阻塞static LoggerManager eton;return eton;}void addLogger(Logger::ptr &logger){if(hasLogger(logger->name())) return;std::unique_lock<std::mutex> lock(_mutex);_loggers.insert(std::make_pair(logger->name(), logger));}bool hasLogger(const std::string name){std::unique_lock<std::mutex> lock(_mutex);auto it = _loggers.find(name);if(it == _loggers.end()){return false;}return true;}Logger::ptr getLogger(const std::string name){std::unique_lock<std::mutex> lock(_mutex);auto it = _loggers.find(name);if(it == _loggers.end()){return Logger::ptr();}return it->second;}Logger::ptr rootLogger(){return _root_logger;}private:// 构造函数私有化LoggerManager(){std::unique_ptr<LOG::LoggerBuilder> builder(new LOG::LocalLoggerBuilder());builder->buildLoggerName("root");_root_logger = builder->build();_loggers.insert(std::make_pair("root", _root_logger));}private:std::mutex _mutex;Logger::ptr _root_logger; // 默认日志器std::unordered_map<std::string, Logger::ptr> _loggers // 日志器数组;};class GlobalLoggerBuilder : public LoggerBuilder{public:Logger::ptr build() override{assert(_logger_name.empty() == false);if (_formatter.get() == nullptr){_formatter = std::make_shared<Formatter>();}if (_sinks.empty()){buildSink<StdOutSink>();}Logger::ptr logger;if (_logger_type == LoggerType::LOGGER_ASYNC){logger = std::make_shared<AsyncLogger>(_logger_name, _limit_level, _formatter, _sinks, _looper_type);}else{logger = std::make_shared<SyncLogger>(_logger_name, _limit_level, _formatter, _sinks);}LoggerManager::getInstance().addLogger(logger);return logger;}};
}#endif

日志器管理类测试

#include "logger.hpp"void log_test()
{LOG::Logger::ptr logger = LOG::LoggerManager::getInstance().getLogger("async_logger");logger->debug(__FILE__, __LINE__, "%s", "测试日志");logger->info(__FILE__, __LINE__, "%s", "测试日志");logger->warn(__FILE__, __LINE__, "%s", "测试日志");logger->error(__FILE__, __LINE__, "%s", "测试日志");logger->fatal(__FILE__, __LINE__, "%s", "测试日志");size_t count = 0;while(count < 300000){   logger->fatal(__FILE__, __LINE__, "测试日志-%d", count++);}
}
int main()
{   std::unique_ptr<LOG::LoggerBuilder> builder(new LOG::GlobalLoggerBuilder());builder->buildLoggerName("async_logger");builder->buildLoggerLevel(LOG::LogLevel::value::WARN);builder->buildFormatter("[%c]%m%n");builder->buildLoggerType(LOG::LoggerType::LOGGER_ASYNC);builder->buildEnableUnSafeAsync();builder->buildSink<LOG::FileSink>("./logfile/async.log");builder->buildSink<LOG::StdOutSink>();builder->build();log_test();return 0;
}