Genies Derive

A powerful derive macro for configuration management in Rust, providing a flexible and type-safe way to handle application configurations.

Features

• 🔧 Default values via attributes
• 🌍 Environment variable support
• ✅ Configuration validation
• 📁 YAML file configuration
• 🔄 Hot reloading support
• 🏗️ Builder pattern
• 🔄 Type conversion
• 📦 Array and Option type support

Installation

Add this to your Cargo.toml:

[dependencies]

genies_derive = "0.1.0"

Quick Start

use genies_derive::Config;
use serde::{Deserialize, Serialize};

#[derive(Config, Debug, Deserialize, Serialize)]
struct ServerConfig {
    #[config(default = "localhost")]
    host: String,
    
    #[config(default = 8080)]
    #[config(validate(range(min = 1, max = 65535)))]
    port: u16,
    
    #[config(default = "topic1,topic2,topic3")]
    topics: Vec<String>,
    
    // Optional fields
    username: Option<String>,
    
    #[config(default = "60")]
    timeout_seconds: Option<u64>,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Load from file and environment variables
    let config = ServerConfig::from_sources("config.yml")?;
    println!("Config: {:?}", config);

    Ok(())
}

Configuration Sources

Configurations are loaded in the following priority order (highest first):

1. Environment variables
2. Configuration file
3. Default values
4. None (for optional fields)

Environment Variables

Field names are automatically converted to SCREAMING_SNAKE_CASE:

export HOST="production.example.com"

export PORT="443"

export TOPICS="prod/events,prod/logs,prod/metrics"

export USERNAME="admin"

export TIMEOUT_SECONDS="120"

YAML Configuration

host: "example.com"
port: 8080
topics:
  - "topic1"
  - "topic2"
username: "user"
timeout_seconds: 60

Features

Default Values

#[config(default = "localhost")]
host: String

Validation

#[config(validate(range(min = 1, max = 65535)))]
port: u16

Arrays

#[config(default = "topic1,topic2,topic3")]
topics: Vec<String>

Optional Fields

username: Option<String>

Hot Reloading

let mut config = ServerConfig::from_sources("config.yml")?;
config.reload().await?;

Examples

Check out the examples directory for more detailed examples.

Contributing

We welcome contributions! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.