lino-arguments (Rust)

A unified configuration library combining environment variables and CLI arguments with a clear priority chain.

Overview

lino-arguments provides a unified configuration system that automatically loads configuration from multiple sources with a clear priority chain:

1. CLI arguments - Highest priority (manually entered options)
2. Environment variables - With case-insensitive lookup
3. Configuration file - Dynamic config file path via CLI
4. Default values - Fallback values

Installation

Add to your Cargo.toml:

[dependencies]
lino-arguments = "0.1"

Quick Start

use clap::Parser;
use lino_arguments::{getenv, getenv_int, getenv_bool};

#[derive(Parser)]
struct Args {
    #[arg(short, long, default_value_t = getenv_int("PORT", 3000) as u16)]
    port: u16,

    #[arg(short, long, default_value = getenv("API_KEY", ""))]
    api_key: String,

    #[arg(short, long, default_value_t = getenv_bool("VERBOSE", false))]
    verbose: bool,
}

fn main() {
    let args = Args::parse();
    println!("Server starting on port {}", args.port);
}

API Reference

Environment Variable Helpers

getenv(key, default)

Get environment variable as string with case-insensitive lookup.

let api_key = getenv("apiKey", "default-key");  // Tries API_KEY, apiKey, etc.

getenv_int(key, default)

Get environment variable as integer.

let port = getenv_int("PORT", 3000);

getenv_bool(key, default)

Get environment variable as boolean. Accepts: "true", "false", "1", "0", "yes", "no".

let debug = getenv_bool("DEBUG", false);

Case Conversion Utilities

• to_upper_case(s) - Convert to UPPER_CASE
• to_camel_case(s) - Convert to camelCase
• to_kebab_case(s) - Convert to kebab-case
• to_snake_case(s) - Convert to snake_case
• to_pascal_case(s) - Convert to PascalCase

use lino_arguments::{to_upper_case, to_camel_case, to_kebab_case};

assert_eq!(to_upper_case("apiKey"), "API_KEY");
assert_eq!(to_camel_case("api-key"), "apiKey");
assert_eq!(to_kebab_case("apiKey"), "api-key");

Testing

# Run all tests
cargo test

# Run tests with output
cargo test -- --nocapture

# Run specific test
cargo test case_conversion

Development

# Build
cargo build

# Build release
cargo build --release

# Run clippy
cargo clippy

# Format code
cargo fmt

License

This is free and unencumbered software released into the public domain. See the LICENSE file for details.