Project: Config Management System

{
  "app": {
    "name": "MyApp",
    "version": "1.0.0",
    "debug": false,
    "env": "production"
  },
  "database": {
    "host": "localhost",
    "port": 5432,
    "name": "mydb",
    "username": "admin",
    "password": "secret"
  },
  "server": {
    "host": "0.0.0.0",
    "port": 8000,
    "ssl": true
  },
  "features": {
    "enableCache": true,
    "enableLogs": true,
    "maxConnections": 100
  }
}

import json
from pathlib import Path

class ConfigManager:
    def __init__(self, config_file='config.json'):
        self.config_file = Path(config_file)
        self.config = {}
        self.load()

    def load(self):
        """Load config from file"""
        if self.config_file.exists():
            with open(self.config_file, 'r') as f:
                self.config = json.load(f)
        else:
            self.create_default()

    def get(self, key, default=None):
        """Get config value, supports nested keys like 'database.host'"""
        keys = key.split('.')
        value = self.config
        for k in keys:
            if isinstance(value, dict):
                value = value.get(k)
            else:
                return default
        return value if value is not None else default

    def set(self, key, value):
        """Set config value"""
        keys = key.split('.')
        config = self.config
        for k in keys[:-1]:
            if k not in config:
                config[k] = {}
            config = config[k]
        config[keys[-1]] = value
        self.save()

    def save(self):
        """Save config to file"""
        with open(self.config_file, 'w') as f:
            json.dump(self.config, f, indent=2)

# Usage Example
config = ConfigManager()
print(config.get('database.host'))  # localhost
config.set('server.port', 9000)
config.save()