text: #ifndef ESP_IOT_CONFIG
  #define ESP_IOT_CONFIG
  
  #include "spiffs.h"
  #include <Arduino.h>
  #include <ArduinoJson.h>
  
  #define CONFIG_FILE "/config_file.json"
  
  class EspConfig
  {
  private:
    static EspConfig esp_config_instance_;
    char* aws_url_;
    char* mqtt_pub_topic_;
    char* mqtt_sub_topic_;
    char* device_id_;
    char* wifi_ssid_;
    char* wifi_pswd_;
    char* device_position_;
    uint8_t logger_level_;
    uint8_t logger_output_;
    uint16_t aws_port_;
    EspSpiffs spiffs_;
  
  public:
    static EspConfig* getInstance()
    {
      return &esp_config_instance_;
    }
    void readConfig();
    char* getWifiSSID();
    char* getWifiPSWD();
    char* getMqttPubTopic();
    char* getMqttSubTopic();
    char* getDeviceID();
    char* getAwsUrl();
    char* getDevicePosition();
    uint8_t getLoggerLevel();
    uint8_t getLoggerOutput();
    uint16_t getAwsPort();
  };
  
  #endif