vld-config

Validate configuration files (TOML, YAML, JSON, ENV) at load time using vld schemas. Supports both config-rs and figment.

Installation

[dependencies]
vld = "0.1"
vld-config = "0.1"                    # config-rs backend (default)
# vld-config = { version = "0.1", features = ["figment"] }  # figment backend
# vld-config = { version = "0.1", features = ["config-rs", "figment"] }  # both

Features

Feature	Default	Description
`config-rs`	yes	config backend — `from_config()`, `from_builder()`
`figment`	no	figment backend — `from_figment()`

Quick Start (config-rs)

use vld_config::prelude::*;

vld::schema! {
    #[derive(Debug)]
    pub struct AppSettings {
        pub host: String => vld::string().min(1),
        pub port: i64    => vld::number().int().min(1).max(65535),
        pub debug: bool  => vld::boolean(),
    }
}

let config = config::Config::builder()
    .add_source(config::File::with_name("config"))
    .add_source(config::Environment::with_prefix("APP"))
    .build()
    .unwrap();

let settings: AppSettings = from_config(&config).unwrap();
println!("{}:{}", settings.host, settings.port);

Quick Start (figment)

use vld_config::from_figment;

vld::schema! {
    #[derive(Debug)]
    pub struct AppSettings {
        pub host: String => vld::string().min(1),
        pub port: i64    => vld::number().int().min(1).max(65535),
        pub debug: bool  => vld::boolean(),
    }
}

let figment = figment::Figment::new()
    .merge(figment::providers::Serialized::defaults(
        serde_json::json!({"host": "0.0.0.0", "port": 3000, "debug": false}),
    ))
    .merge(figment::providers::Env::prefixed("APP_"));

let settings: AppSettings = from_figment(&figment).unwrap();

API

Function	Backend	Description
`from_config(&Config)`	config-rs	Validate a built `Config`
`from_builder(ConfigBuilder)`	config-rs	Build and validate in one step
`from_figment(&Figment)`	figment	Validate a `Figment`
`from_value(&Value)`	—	Validate raw `serde_json::Value`

All functions return Result<T, VldConfigError> where T: VldParse (implemented by vld::schema!).

Error Handling

match from_config::<AppSettings>(&config) {
    Ok(settings) => println!("{settings:?}"),
    Err(VldConfigError::Source(msg)) => {
        eprintln!("Failed to load config: {msg}");
    }
    Err(VldConfigError::Validation(err)) => {
        eprintln!("Invalid config:");
        for issue in &err.issues {
            eprintln!("  {}: {}", issue.path_string(), issue.message);
        }
    }
}

Running Examples

# config-rs
cargo run -p vld-config --example config_basic --features config-rs

# figment
cargo run -p vld-config --example figment_basic --features figment

License

MIT

vld-config 0.2.0