Rust JSON Config Manager

Implement type-safe JSON configuration file management in Rust projects using the `cnctd_config` library.

What This Skill Does

This skill helps you integrate and use the `cnctd_config` library to manage application configurations stored as JSON files. The library provides automatic serialization/deserialization for any type implementing `Serialize` and `DeserializeOwned` traits.

Instructions

1. Add Dependency

First, verify or add the dependency to `Cargo.toml`:

```toml

[dependencies]

cnctd_config = "0.1.2"

serde = { version = "1.0", features = ["derive"] }

```

2. Define Configuration Structure

Create a struct representing your configuration data:

```rust

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]

struct AppSettings {

theme: String,

port: u16,

debug_mode: bool,

// Add any fields needed for your application

}

```

**Requirements:**

3. Create New Configuration

Initialize a new configuration with default values:

```rust

use cnctd_config::Config;

let settings = AppSettings {

theme: "dark".to_string(),

port: 8080,

debug_mode: false,

};

let config = Config::new(settings, "config/settings.json");

config.save()?; // Persists to disk

```

4. Load Existing Configuration

Load configuration from a JSON file:

```rust

let config = Config::<AppSettings>::load("config/settings.json")?;

let current_theme = &config.get().theme;

```

5. Update Configuration

Modify and save updated configuration:

```rust

let mut config = Config::<AppSettings>::load("config/settings.json")?;

let new_settings = AppSettings {

theme: "light".to_string(),

port: config.get().port, // Keep existing value

debug_mode: true,

};

config.update(new_settings)?; // Automatically saves to disk

```

6. Access Configuration Data

Read configuration values without modification:

```rust

let config = Config::<AppSettings>::load("config/settings.json")?;

let settings = config.get();

println!("Theme: {}", settings.theme);

println!("Port: {}", settings.port);

```

Common Patterns

Configuration with Nested Structures

```rust

#[derive(Serialize, Deserialize)]

struct DatabaseConfig {

host: String,

port: u16,

}

#[derive(Serialize, Deserialize)]

struct AppConfig {

app_name: String,

database: DatabaseConfig,

}

```

Optional Configuration Fields

```rust

#[derive(Serialize, Deserialize)]

struct AppSettings {

#[serde(default)]

optional_feature: Option<String>,

}

```

Multiple Configuration Files

```rust

let app_config = Config::<AppSettings>::load("config/app.json")?;

let db_config = Config::<DatabaseConfig>::load("config/database.json")?;

```

Error Handling

All operations that interact with the filesystem return `Result<T>`:

```rust

match Config::<AppSettings>::load("settings.json") {

Ok(config) => {

// Use config

},

Err(e) => {

eprintln!("Failed to load config: {}", e);

// Handle error or use defaults

}

}

```

Important Notes

Constraints