Envconfig

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:

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

You can achieve this with the following code without boilerplate:

```rust

[macro_use]

extern crate envconfig_derive; extern crate envconfig;

use envconfig::Envconfig;

[derive(Envconfig)]

pub struct Config { #[envconfig(from = "DBHOST")] pub dbhost: String,

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

}

fn main() { // Assuming the following environment variables are set std::env::setvar("DBHOST", "127.0.0.1"); std::env::setvar("DBPORT", "5432");

// 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

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

License

MIT © Sergey Potapov

Contributors

• greyblake Potapov Sergey - creator, maintainer.