Yaml parameter configuration based on singleton mode

use Meyers Single case , Simply write the file parameter configuration library , Support multiple sub modules yaml File parameter configuration
config_manager.h

#include <map>
#include <string>
#include <mutex>
#include <iostream>

#include <yaml-cpp/yaml.h>

#include "../log/log.h"

class ConfigManager
{
    
public:
  ~ConfigManager();

private:
  //  Privatize default constructor 、 Copy construction and copy assignment are prohibited 
  ConfigManager();
  ConfigManager(const ConfigManager &) = delete;
  ConfigManager &operator=(const ConfigManager &) = delete;

  // thread-safe interface.
  bool Init();

  // thread-safe interface.
  bool Reset();
  size_t NumModels() const {
     return model_config_map_.size(); }

private:
  bool InitInternal();

  // key: model_name
  std::map<std::string, std::string> model_config_map_;
  std::mutex mutex_; // multi-thread init safe.
  bool inited_ = false;

public:
  //  Local static variable singleton mode 
  bool GetModelConfig(const std::string &model_name, std::string &model_config);
  static ConfigManager *getinstance();
};

config_manager.cpp

#include "config_manager.h"

ConfigManager::ConfigManager() {
    }
ConfigManager::~ConfigManager() {
    }

bool ConfigManager::Init()
{
    
  std::lock_guard<std::mutex> lck(mutex_);
  return InitInternal();
}

bool ConfigManager::InitInternal()
{
    
  if (inited_)
  {
    
    return true;
  }
  model_config_map_.clear();

  std::string yaml_module_path = "config/config_manager.yaml";
  YAML::Node config;
  try
  {
    
    config = YAML::LoadFile(yaml_module_path);
  }
  catch (YAML::Exception &ex)
  {
    
    AERROR << "yaml_module_path : " << yaml_module_path << " get file list error.";
  }
  AINFO << "config_root_path: " << yaml_module_path;

  //  Store the function class name and configuration parameter file path of each module in the dictionary  model_config_map_  in 
  for (YAML::Node::iterator it = config.begin(); it != config.end(); it++)
  {
    
    model_config_map_[it->first.as<std::string>()] = it->second.as<std::string>();
  }

  AINFO << "finish to load ModelConfigs. NumModels: " << model_config_map_.size();
  inited_ = false;

  return true;
}

bool ConfigManager::GetModelConfig(const std::string &model_name, std::string &model_config)
{
    
  if (!inited_ && !Init())
  {
    
    return false;
  }

  auto citer = model_config_map_.find(model_name);
  if (citer == model_config_map_.end())
  {
    
    return false;
  }
  model_config = citer->second;
  return true;
}

ConfigManager *ConfigManager::getinstance()
{
    
  static ConfigManager obj;
  return &obj;
}

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