Vix.cpp

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Configuration ​

The vix::config::Config class loads a JSON file and provides safe, typed accessors. It is designed for:

  • JSON config files
  • Dot-path access (server.port, database.default.host, etc.)
  • Defaults on missing or invalid values
  • One-time load at startup
  • Optional environment override (example: DB_PASSWORD)

Include:

cpp
#include <vix/config/Config.hpp>

Namespace:

cpp
using vix::config::Config;

1. Config file format ​

Vix config is JSON. Nested objects are accessed via dot paths.

Example config/config.json:

json
{
  "server": {
    "port": 8080,
    "request_timeout": 2000,
    "io_threads": 0,
    "session_timeout_sec": 300
  },
  "logging": {
    "async": true,
    "queue_max": 20000,
    "drop_on_overflow": true
  },
  "waf": {
    "mode": "basic",
    "max_target_len": 4096,
    "max_body_bytes": 1048576
  },
  "database": {
    "default": {
      "host": "localhost",
      "port": 3306,
      "name": "mydb",
      "user": "myuser",
      "password": ""
    }
  }
}

2. Loading config ​

You can build a Config directly. The constructor searches common locations and loads if found.

cpp
Config cfg{"config/config.json"};

If no file is found, defaults are used.

Singleton access ​

The class also exposes a lazy singleton:

cpp
auto& cfg = Config::getInstance("config/config.json");

This is useful when you want a global config with a single load point.

3. Typed getters with defaults ​

The safe accessors always take a default value. If the key is missing or cannot be parsed, the default is returned.

cpp
Config cfg{"config/config.json"};

int port = cfg.getInt("server.port", 8080);
int timeout_ms = cfg.getInt("server.request_timeout", 2000);

bool log_async = cfg.getBool("logging.async", true);
std::string waf_mode = cfg.getString("waf.mode", "basic");

Supported getters:

  • getInt(dottedKey, defaultValue)
  • getBool(dottedKey, defaultValue)
  • getString(dottedKey, defaultValue)
  • has(dottedKey)

4. Dot-path lookup ​

Dot paths traverse nested JSON objects.

Examples:

  • server.port
  • logging.queue_max
  • database.default.host
  • waf.max_body_bytes
cpp
if (cfg.has("database.default.host"))
{
  auto host = cfg.getString("database.default.host", "localhost");
}

5. Convenience getters (server, logging, waf) ​

Config also stores parsed values and exposes dedicated getters. This avoids repeating dot paths in your runtime code.

Server:

  • getServerPort()
  • getRequestTimeout()
  • getIOThreads()
  • getSessionTimeoutSec()
  • setServerPort(port)

Logging:

  • getLogAsync()
  • getLogQueueMax()
  • getLogDropOnOverflow()

WAF:

  • getWafMode()
  • getWafMaxTargetLen()
  • getWafMaxBodyBytes()

Minimal usage:

cpp
auto& cfg = Config::getInstance("config/config.json");

int port = cfg.getServerPort();
int io_threads = cfg.getIOThreads();

if (cfg.getLogAsync())
{
  // configure async logger
}

6. Environment override (DB password) ​

Database password can be provided via environment variable:

  • DB_PASSWORD

getDbPasswordFromEnv() returns:

  • DB_PASSWORD if set
  • otherwise the config value

Example pattern:

cpp
auto& cfg = Config::getInstance("config/config.json");

std::string db_pass = cfg.getDbPasswordFromEnv();

This keeps secrets out of files.

7. Defaults and validation behavior ​

Important behavior from the implementation:

  • Missing file: uses defaults (no crash)
  • Missing key: returns your default
  • Wrong type: best-effort parse (example: string to int via stoi), otherwise default
  • setServerPort(port) validates range (0 or 1024..65535)

Best practices ​

  • Load config once at startup.
  • Always pass defaults to getInt/getBool/getString.
  • Keep secrets in environment variables (example: DB_PASSWORD).
  • Validate critical settings at boot (ports, timeouts, limits).
  • Avoid reading config per request.

Configuration should be stable and deterministic after startup.