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.

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"] }

Basic 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",
),

pool {
MAX_SIZE: usize => 15,
},
},

sentry {
DSN: Option<&'static str>,
},

feature {
static CORS: bool => false,

static GRAPHQL_PLAYGROUND: bool => false,
},
}

fn main () {
// dotenv().expect("dotenv setup to be successful");
// or
env::set_var("FEATURE_CORS", "true");

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::database::pool::MAX_SIZE(), 15);
assert_eq!(config::sentry::DSN(), None);
assert_eq!(config::feature::CORS(), true);
}

Macro is an optional feature, disabled by default. You can use this library without macro.

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

fn main() {
// dotenv().expect("dotenv setup to be successful");
// or
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);
}

Available features

• default - ["primitives"]
• macro - Activates config! macros for easy configure web application.
• 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
• json_array - Add EnvString impl for vector type (uses optional serde_json package). ⚠ DEPRECATED