# config-rs
[](https://travis-ci.org/mehcode/config-rs)
> Layered configuration system for Rust applications (with strong support for [12-factor] applications).
[12-factor]: https://12factor.net/config
- Set defaults
- Set explicit values (to programmatically override)
- Read from [JSON] and [TOML] files
- Read from environment
- Loosely typed — Configuration values may be read in any supported type, as long as there exists a reasonable conversion
[JSON]: https://github.com/serde-rs/json
[TOML]: https://github.com/toml-lang/toml
## Install
```toml
[dependencies]
config = { git = "https://github.com/mehcode/config-rs.git" }
```
#### Features
- **json** - Adds support for reading JSON files
- **toml** - Adds support for reading TOML files (included by default)
## Usage
Configuration is gathered by building a `Source` and then merging that source into the
current state of the configuration.
```rust
// Add environment variables that begin with RUST_
config::merge(config::Environment::new("RUST"));
// Add 'Settings.json'
config::merge(config::File::new("Settings", config::FileFormat::Json));
// Add 'Settings.$(RUST_ENV).json`
let name = format!("Settings.{}", config::get_str("env").unwrap());
config::merge(config::File::new(&name, config::FileFormat::Json));
```
Note that in the above example the calls to `config::merge` could have
been re-ordered to influence the priority as each successive merge
is evaluated on top of the previous.
See the [examples](https://github.com/mehcode/config-rs/tree/master/examples) for
more usage information.
## Roadmap
- [ ] Read from remote source — [etcd](https://github.com/jimmycuadra/rust-etcd) and [consul](https://github.com/stusmall/consul-rust)
- [ ] Read from YAML files
- [ ] Read from Libconfig files
All suggestions are welcome. Please make an issue.
## License
config-rs is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT for details.