Hydra C++ example

config.yaml

app: ${hydra:runtime.cwd}/main
db:
  driver: mysql
  user: omry
  password: secret

main.cpp

#include <iostream>
#include <iomanip>
#include <nlohmann/json.hpp>
#include <fstream>

using json = nlohmann::json;

int main()
{
    std::ifstream file("config.json");
    json j = json::parse(file);
    // pretty print with indent of 4 spaces
    
    std::cout << "Config printed in C++\n" << std::setw(4) << j << '\n';
}

main.py

from omegaconf import DictConfig, OmegaConf

import hydra
import json
import subprocess

@hydra.main(config_name="config")
def my_app(cfg: DictConfig) -> None:
    container = OmegaConf.to_container(cfg, resolve=True)
    with open('config.json', 'w') as f:
        json.dump(container, f)
        
    subprocess.check_call([cfg.app])

if __name__ == "__main__":
    my_app()