Struct ConfigLoader 

pub struct ConfigLoader { /* private fields */ }

Configuration loader with precedence-based resolution

Implements the 5-layer configuration precedence system:

1. Environment variables (highest priority)
2. Project-specific config ({workspace}/config/{module}.{env}.toml)
3. User config (~/.config/iron/{module}.toml)
4. Workspace defaults ({workspace}/config/{module}.default.toml)
5. Crate defaults (lowest priority)

Examples

use iron_config_loader::ConfigLoader;
use serde::Deserialize;

#[derive(Deserialize)]
struct DatabaseConfig {
  url: String,
  max_connections: u32,
}

let loader = ConfigLoader::new("iron_token_manager")?;
let db_config: DatabaseConfig = loader.get("database")?;

Implementations

impl ConfigLoader

pub fn new(module: impl Into<String>) -> Result<Self>

Create new configuration loader for module

Arguments

• module - Module name (e.g., “iron_token_manager”)

Errors

Returns error if workspace cannot be detected.

Examples

let loader = ConfigLoader::new("iron_token_manager")?;

pub fn with_env( module: impl Into<String>, env: impl Into<String>, ) -> Result<Self>

Create new configuration loader with custom environment

Arguments

• module - Module name
• env - Environment (e.g., “development”, “test”, “production”)

Examples

let loader = ConfigLoader::with_env("iron_token_manager", "production")?;

pub fn with_defaults(module: impl Into<String>, defaults: &str) -> Result<Self>

Create configuration loader with custom default values

Arguments

• module - Module name
• defaults - Default configuration as TOML string

Examples

let defaults = r#"
[database]
url = "sqlite:///:memory:"
max_connections = 5
"#;

let loader = ConfigLoader::with_defaults("iron_token_manager", defaults)?;

pub fn get<T: DeserializeOwned>(&self, key: &str) -> Result<T>

Get configuration value by key path

Arguments

• key - Configuration key path (e.g., “database.url”)

Errors

Returns error if key not found or value cannot be deserialized.

Examples

let url: String = loader.get("database.url")?;
let max_conn: u32 = loader.get("database.max_connections")?;

pub fn get_opt<T: DeserializeOwned>(&self, key: &str) -> Result<Option<T>>

Get optional configuration value

Returns None if key not found, otherwise same as get().

Examples

if let Some(url) = loader.get_opt::<String>("database.url")? {
  println!("Database URL: {}", url);
}

pub fn get_section<T: DeserializeOwned>(&self, prefix: &str) -> Result<T>

Get configuration subtree as struct

Arguments

• prefix - Key prefix (e.g., “database”)

Errors

Returns error if subtree cannot be deserialized.

Examples

#[derive(Deserialize)]
struct DatabaseConfig {
  url: String,
  max_connections: u32,
}

let db_config: DatabaseConfig = loader.get_section("database")?;

pub fn keys(&self) -> Vec<String>

Get all configuration keys

pub fn get_with_source<T: DeserializeOwned>( &self, key: &str, ) -> Result<(T, String)>

Get configuration value with source information

Returns the value along with information about which layer provided it.

Examples

let (url, source) = loader.get_with_source::<String>("database.url")?;
println!("Database URL: {} (from {})", url, source);

pub fn debug_summary(&self) -> String

Print configuration summary for debugging

Shows all resolved configuration values with their sources.