#config #env #macro #configuration #environment

envconfig

Build a config structure from environment variables without boilerplate

9 releases (breaking)

new 0.8.0 Mar 31, 2020
0.6.0 Dec 22, 2019
0.5.1 Apr 16, 2019
0.5.0 Sep 25, 2018

#17 in Configuration

Download history 269/week @ 2019-12-14 37/week @ 2019-12-21 28/week @ 2019-12-28 54/week @ 2020-01-04 136/week @ 2020-01-11 99/week @ 2020-01-18 62/week @ 2020-01-25 94/week @ 2020-02-01 206/week @ 2020-02-08 114/week @ 2020-02-15 392/week @ 2020-02-22 227/week @ 2020-02-29 419/week @ 2020-03-07 303/week @ 2020-03-14 325/week @ 2020-03-21 197/week @ 2020-03-28

845 downloads per month

MIT license

7KB
56 lines

Envconfig

Build Status License Documentation

Build a config structure from environment variables in Rust without boilerplate.

Usage

Let's say you application relies on the following environment variables:

  • DB_HOST
  • DB_PORT

And you want to initialize Config structure like this one:

struct Config {
    host: String,
    port: u16,
}

You can achieve this with the following code without boilerplate:

#[macro_use]
extern crate envconfig_derive;
extern crate envconfig;

use envconfig::Envconfig;

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

    #[envconfig(from = "DB_PORT", default = "5432")]
    pub db_port: u16,
}

fn main() {
    // Assuming the following environment variables are set
    std::env::set_var("DB_HOST", "127.0.0.1");

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

    assert_eq!(config.db_host, "127.0.0.1");
    assert_eq!(config.db_port, 5432);
}

Running tests

Tests do some manipulation with environment variables, so to prevent flaky tests they have to be executed in a single thread:

cargo test -- --test-threads=1

Roadmap

  • - migrate to the latest versions of syn and quote
  • - support Option<T> (issue)
  • - support default attribute (issue)
  • - support nested structures?

License

MIT © Sergey Potapov

Contributors

  • greyblake Potapov Sergey - creator, maintainer.
  • allevo Tommaso Allevi - support nested structures
  • hobofan Maximilian Goisser - update dependencies

Dependencies

~460–770KB
~18K SLoC