Crate itconfig

itconfig

Simple configuration with macro for rust application.

Motivation

I began to use rust with web programming experience where environment variables are widely used and often there are more then 50 of them. First I looked at already created libraries. But there it's necessary to initialise structure that needs to be moved to each function where you need variable. It uses little bit memory, but configuration lifetime is as long as application lifetime. Because of it I decided to create my own library.

Example usage

#[macro_use] extern crate itconfig;
use std::env;
// use dotenv::dotenv;

config! {
    DEBUG: bool => true,
    HOST: String => "127.0.0.1",

    DATABASE_URL < (
        "postgres://",
        POSTGRES_USERNAME => "user",
        ":",
        POSTGRES_PASSWORD => "pass",
        "@",
        POSTGRES_HOST => "localhost:5432",
        "/",
        POSTGRES_DB => "test",
    ),

    APP {
        ARTICLE {
            PER_PAGE: u32 => 15,
        }

        #[cfg(feature = "companies")]
        COMPANY {
            #[env_name = "INSTITUTIONS_PER_PAGE"]
            PER_PAGE: u32 => 15,
        }
    }

    FEATURE {
        NEW_MENU: bool => false,

        COMPANY {
            PROFILE: bool => false,
        }
    }
}

fn main () {
    // dotenv().ok();
    env::set_var("FEATURE_NEW_MENU", "t");

    cfg::init();
    assert_eq!(cfg::HOST(), String::from("127.0.0.1"));
    assert_eq!(cfg::DATABASE_URL(), String::from("postgres://user:pass@localhost:5432/test"));
    assert_eq!(cfg::APP::ARTICLE::PER_PAGE(), 15);
    assert_eq!(cfg::FEATURE::NEW_MENU(), true);
}

Macro is an optional feature, enabled by default. You can install itconfig without default features and use this lib as shown below

use itconfig::*;
use std::env;
// use dotenv::dotenv;

fn main() {
    env::set_var("DATABASE_URL", "postgres://127.0.0.1:5432/test");

    let database_url = get_env::<String>("DATABASE_URL").unwrap();
    let new_profile: bool = get_env_or_default("FEATURE_NEW_PROFILE", false);
    let articles_per_page: u32 = get_env_or_set_default("ARTICLES_PER_PAGE", 10);
}

Modules

envstr
prelude

Macros

config

This API requires the following crate features to be activated: macro

Enums

EnvError

Functions

get_env	Try to read environment variable and parse to expected type. You may to put to argument any type with FromEnvString trait.
get_env_or	This function returns env variable as EnvString structure. You can pass callback for custom default expression. Callback should return EnvString value or EnvError
get_env_or_default	This function is similar as get_env_or_panic, but you can pass default value for environment variable with ToEnvString trait.
get_env_or_panic	This function is similar as get_env, but it unwraps result with panic on error.
get_env_or_set_default	This function is similar as get_env_or_default, but the default value will be set to environment variable, if env variable is missed.