Hydroconf is a configuration management library for Rust, based on config-rs and heavily inspired by Python's dynaconf.
- Inspired by the 12-factor configuration principles
- Effective separation of sensitive information (secrets)
- Layered system for multi environments (e.g. development, staging, production, etc.)
- Sane defaults, with a 1-line configuration loading
- Read from JSON, TOML, YAML, HJSON, INI files
The config-rs library is a great building block, but it does not provide a default mechanism to load configuration and merge secrets, while keeping the different environments separated. Hydroconf fills this gap.
Suppose you have the following file structure:
├── config │ ├── .secrets.toml │ └── settings.toml └── your-executable settings.toml:
[default] pg.port = 5432 pg.host = 'localhost' [production] pg.host = 'db-0'.secrets.toml:
[default] pg.password = 'a password' [production] pg.password = 'a strong password'Then, in your executable source (make sure to add serde = { version = "1.0", features = ["derive"] } to your dependencies):
use serde::Deserialize; use hydroconf::Hydroconf; #[derive(Debug, Deserialize)] struct Config { pg: PostgresConfig, } #[derive(Debug, Deserialize)] struct PostgresConfig { host: String, port: u16, password: String, } fn main() { let conf: Config = match Hydroconf::default().hydrate() { Ok(c) => c, Err(e) => { println!("could not read configuration: {:#?}", e); std::process::exit(1); } }; println!("{:#?}", conf); }If you compile and execute the program (making sure the executable is in the same directory where the config directory is), you will see the following:
$ ./your-executable Config { pg: PostgresConfig { host: "localhost", port: 5432, password: "a password" } }Hydroconf will select the settings in the [default] table by default. If you set ENV_FOR_HYDRO to production, Hydroconf will overwrite them with the production ones:
$ ENV_FOR_HYDRO=production ./your-executable Config { pg: PostgresConfig { host: "db-0", port: 5432, password: "a strong password" } }Settings can always be overridden with environment variables:
$ HYDRO_PG__PASSWORD="an even stronger password" ./your-executable Config { pg: PostgresConfig { host: "localhost", port: 5432, password: "an even stronger password" } }The description of all Hydroconf configuration options and how the program configuration is loaded can be found in the documentation.