3 releases
0.1.2 | Jul 31, 2024 |
---|---|
0.1.1 | Jul 29, 2024 |
0.1.0 | Jul 29, 2024 |
#253 in Configuration
41 downloads per month
17KB
derive_from_env
Extract type safe structured data from environment variables with procedural derive macros. Currently based on the FromStr trait.
Usage
- Add
derive_from_env
to your project's dependencies:
[dependencies]
derive_from_env = "0.1.1"
- Usage example:
use std::net::{IpAddr, Ipv4Addr};
use std::str::FromStr;
use derive_from_env::FromEnv;
#[derive(Debug, PartialEq, FromEnv)]
struct ServiceConfig {
api_key: String,
#[from_env(var = "EXT_SERVICE_URL")]
base_url: String,
}
#[derive(Debug, PartialEq)]
enum AuthMethod {
Bearer,
XAPIKey,
}
impl FromStr for AuthMethod {
type Err = String;
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s {
"Bearer" => Ok(AuthMethod::Bearer),
"X-API-Key" => Ok(AuthMethod::XAPIKey),
_ => Err("Invalid auth method".into()),
}
}
}
#[derive(Debug, PartialEq)]
#[derive(FromEnv)]
struct AuthConfig {
#[from_env(from_str)]
auth_method: AuthMethod,
api_key: String,
}
#[derive(Debug, PartialEq, FromEnv)]
struct AppConfig {
#[from_env(default = "0.0.0.0")]
addr: IpAddr,
port: Option<u16>,
external_service: ServiceConfig,
#[from_env(no_prefix)]
auth: AuthConfig
}
fn main() {
std::env::set_var("EXTERNAL_SERVICE_API_KEY", "api-key");
std::env::set_var("EXT_SERVICE_URL", "http://external.service/api");
std::env::set_var("PORT","8080");
std::env::set_var("AUTH_METHOD","Bearer");
std::env::set_var("API_KEY","api-key");
let app_config = AppConfig::from_env().unwrap();
assert_eq!(app_config, AppConfig {
port: Some(8080),
addr: IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)),
external_service: ServiceConfig {
api_key: "api-key".into(),
base_url: "http://external.service/api".into()
},
auth: AuthConfig {
auth_method: AuthMethod::Bearer,
api_key: "api-key".into()
}
});
}
In the future...
Dependencies
~0.6–1.1MB
~25K SLoC