itconfig

Easy build a configs from environment variables and use it in globally.

We recommend you start with the documentation.

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.

Installation

These macros require a Rust compiler version 1.31 or newer.

Add itconfig = { version = "1.0", features = ["macro"] } as a dependency in Cargo.toml.

Cargo.toml example:

[package]
name = "my-crate"
version = "0.1.0"
authors = ["Me <user@rust-lang.org>"]

[dependencies]
itconfig = { version = "1.0", features = ["macro"] }

Example usage

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

config! {
    DEBUG: bool => false,
    
    #[env_name = "APP_HOST"]
    HOST: String => "127.0.0.1",
    
    DATABASE_URL < (
        "postgres://",
        POSTGRES_USERNAME => "user",
        ":",
        POSTGRES_PASSWORD => "pass",
        "@",
        POSTGRES_HOST => "localhost:5432",
        "/",
        POSTGRES_DB => "test",
    ),
    
    APP {
        static BASE_URL => "/api", // &'static str by default
    
        ARTICLE {
            static PER_PAGE: u32 => 15,
        }
        
        #[cfg(feature = "companies")]
        COMPANY {
            #[env_name = "INSTITUTIONS_PER_PAGE"]
            static PER_PAGE: u32 => 15,
        }
    }
    
    FEATURE {
        NEW_MENU: bool => false,
    
        COMPANY {
            PROFILE: bool => false,
        }
    }
}

fn main () {
    // dotenv().ok();
    env::set_var("FEATURE_NEW_MENU", "t");
    
    config::init();
    assert_eq!(config::HOST(), String::from("127.0.0.1"));
    assert_eq!(config::DATABASE_URL(), String::from("postgres://user:pass@localhost:5432/test"));
    assert_eq!(config::APP:ARTICLE:PER_PAGE(), 15);
    assert_eq!(config::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);
}

Running tests

cargo test

Roadmap

• Add namespace for variables
• Custom env name
• Support feature config and other meta directives
• Add default value to env if env is not found
• Concat env variables to one variable
• Add nested namespaces
• Support meta for namespaces
• Support array type
• Rewrite to proc macro
• Support hashmap type
• Support custom env type
• Common configuration for namespace variables

Available features

• default - ["primitives"]
• macro - Activates config! macros for easy configure web application.
• array - Add EnvString impl for vector type (uses optional serde_json package).
• primitives - Group for features: numbers and bool.
• numbers - Group for features: int, uint and float.
• int - Group for features: i8, i16, i32, i64, i128 and isize.
• uint - Group for features: u8, u16, u32, u64, u128 and usize.
• float - Group for features: f32 and f64
• i8 - impl EnvString for i8 type
• i16 - impl EnvString for i16 type
• i32 - impl EnvString for i32 type
• i64 - impl EnvString for i64 type
• i128 - impl EnvString for i128 type
• isize - impl EnvString for isize type
• u8 - impl EnvString for u8 type
• u16 - impl EnvString for u16 type
• u32 - impl EnvString for u32 type
• u64 - impl EnvString for u64 type
• u128 - impl EnvString for u128 type
• usize - impl EnvString for usize type
• f32 - impl EnvString for f32 type
• f64 - impl EnvString for f64 type
• bool - impl EnvString for bool type

License

MIT © Ice Temple

Contributors

pleshevskiy (Dmitriy Pleshevskiy) – creator, maintainer.