Crate yasec

Yasec is a Rust library that helps to initialize configuration structure from environment variables. It makes use of custom derive macros to reduce boilerplate.

Example

#[macro_use]
extern crate yasec_derive;
extern crate yasec;

use std::env;
use yasec::Yasec;

#[derive(Yasec)]
struct Config {
    #[yasec(from = "DB_HOST")]
    pub db_host: String,

    #[yasec(from = "DB_PORT")]
    pub db_port: Option<u16>,

    #[yasec(from = "HTTP_PORT", default = 8080)]
    pub http_port: u16,
}

fn main() {
    // We assume that those environment variables are set somewhere outside
    env::set_var("DB_HOST", "localhost");
    env::set_var("DB_PORT", "5432");

    // Initialize config from environment variables
    let config = Config::init().unwrap();

    assert_eq!(config.db_host, "localhost");
    assert_eq!(config.db_port, Some(5432));
    assert_eq!(config.http_port, 8080);
}

The library uses std::str::FromStr trait to convert environment variables into custom data type. So, if your data type does not implement std::str::FromStr the program will not compile.

Structs

Context

Error

ParseError

Traits

Yasec

Indicates that structure can be initialize from environment variables.