Hydroconf is a configuration management library for Rust, based on [config-rs]
and heavily inspired by Python's [dynaconf].
# Features
* 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.
[config-rs]: https://github.com/mehcode/config-rs
[dynaconf]: https://github.com/rochacbruno/dynaconf
[12-factor]: https://12factor.net/config
[JSON]: https://github.com/serde-rs/json
[TOML]: https://github.com/toml-lang/toml
[YAML]: https://github.com/chyh1990/yaml-rust
[HJSON]: https://github.com/hjson/hjson-rust
[INI]: https://github.com/zonyitoo/rust-ini
# Quickstart
Suppose you have the following file structure:
```
├── config
│ ├── .secrets.toml
│ └── settings.toml
└── your-executable
```
`settings.toml`:
```toml
[default]
pg.port = 5432
pg.host = 'localhost'
[production]
pg.host = 'db-0'
```
`.secrets.toml`:
```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):
```rust
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:
```sh
$ ./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:
```sh
$ 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:
```bash
$ 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](https://docs.rs/hydroconf).
