Crate env_init

EnvInit

This is a small crate to help initializing environment variable structs, accepting any environment provider and by default automatically parsing the strings into their corresponding types in the struct.

Example Usage with dotenvy

.env

SOME_INT=42
SOME_STR=Hello
SOME_OTHER_STR=World

main.rs

use env_init::{Env, EnvGetter, EnvOnce};

#[derive(Debug)]
pub struct MyEnv {
    some_int: i32,
    some_other_int: i32,
    opt_int: Option<i32>,
    some_str: &'static str,
    owned_str: String
}

impl Env for MyEnv {
    fn new() -> Self {
        // Defining a getter that calls dotenvy::var
        let g = EnvGetter::new(|x| dotenvy::var(x));

        Self {
            some_int: g.owned_var("SOME_INT"),
            some_other_int: g.owned_var_or("SOME_OTHER_INT", 100),
            opt_int: g.owned_var_try("SOME_OPTIONAL_INT").ok(),
            some_str: g.var::<String>("SOME_STR").as_str(),
            owned_str: g.owned_var("SOME_OTHER_STR"),
        }
    }
}

// Our global environment object
pub static ENV: EnvOnce<MyEnv> = EnvOnce::new();

fn main() {
    dotenvy::dotenv().unwrap();
    ENV.init();

    assert_eq!(ENV.some_int, 42);
    assert_eq!(ENV.some_other_int, 100);
    assert_eq!(ENV.opt_int, None);
    assert_eq!(ENV.some_str, "Hello");
    assert_eq!(ENV.owned_str, "World");
}

Structs

EnvGetter

Struct that holds a closure to get environment variables.

EnvLazy

Wrapper over a LazyLock<T> where T implements Env

EnvOnce

Wrapper over a OnceLock<T> where T implements Env

Enums

EnvError

Custom error type, which can be a GetterError (error returned by closure) or ParseError (error returned by FromStr).

Traits

Env

This trait is used to create a new environment struct.