3 releases (stable)
1.1.0 | Oct 5, 2023 |
---|---|
1.0.0 | Sep 20, 2023 |
0.1.0 | Sep 19, 2023 |
#2373 in Rust patterns
18KB
138 lines
A Rust library for modifying structs via environment variables.
Unlike envy, this does not create a new object. It is used to reconfigure an existing structure (after having parsed it from a config file, for example).
Ignored fields
If a certain field should not be configurable via environment variables, mark it with #[env(ignore)]
.
Examples
Creating a config structure:
use derive_environment::FromEnv;
#[derive(Default, FromEnv)]
pub struct Config {
// ...
}
// Creates a base configuration struct to add on to.
// Normally this would be created using `serde` from a config file.
let mut config = Config::default();
// Names the struct "MY_CONFIG", which acts as a prefix.
config.with_env("MY_CONFIG").unwrap();
Nesting fields:
use derive_environment::FromEnv;
#[derive(FromEnv)]
struct ServerConfig {
port: u16,
}
#[derive(FromEnv)]
pub struct Config {
server: ServerConfig,
}
Generates:
- MY_CONFIG_SERVER_PORT
Vector of Nested fields:
use derive_environment::FromEnv;
// `Vec`'s `FromEnv` implementation requires `Default`.
#[derive(Default, FromEnv)]
struct ServerConfig {
port: u16,
}
#[derive(FromEnv)]
pub struct Config {
servers: Vec<ServerConfig>,
}
Generates:
- MY_CONFIG_SERVER_0_PORT
Dependencies
~1–2.3MB
~59K SLoC