Rust envconfig example

Cargo.toml

[package]
name = "rust-envconfig-sample"
version = "0.1.0"
authors = ["Yutaka Yawata"]
edition = "2018"

[dependencies]
envconfig = "0.5.0"
envconfig_derive = "0.5.0"

main.rs

use envconfig_derive::Envconfig;
use envconfig::Envconfig;
use std::process;

#[derive(Envconfig, Debug)]
struct Config {
    #[envconfig(from = "HOST")]
    host: String,
    #[envconfig(from = "PORT", default = "8080")]
    port: u16,
}

fn main() {
    // HOST=myserver
    // PORT=8080

    let config = match Config::init() {
        Ok(val) => val,
        Err(err) => {
            println!("{}",err);
            process::exit(1);
        }
    };

    println!("{:#?}", config);

    assert_eq!(config.host, "myserver");
    assert_eq!(config.port, 8080);
}