config_lite

This lightweight and customizable Rust library provides a simple configuration file parser that can read JSON and YAML files as well as referencing environment variables defined in the config file.

It defines a Config struct that represents a configuration file and provides methods for initializing and retrieving values from it.

Inspired by node config

Installation

You can add this library to your project by adding the following to your Cargo.toml file:

[dependencies]
config_lite = "2.1.0-beta"

Usage

To use the Config struct, you can import it and call its methods as follows, given the configuration json file below in config/default.json at the root dir of your project:

{
  "foo": "bar",
  "test": {
   "user": {
      "id": 1,
      "name": "Foo Baz",
      "screen_name": "foo_baz",
      "isActive": true
    }
  },
  "database": {
    "password": "{{DATABASE_PASSWORD}}" // config will read this value from the env var $DATABASE_PASSWORD
  }
}

use config::Config;
use serde::Deserialize;

#[derive(Deserialize, Debug)]
struct User {
  id: u32,
  name: String,
  screen_name: String,
  #[serde(rename(deserialize = "isActive"))]
  is_active: bool,
}

let config = Config::init()?;

let value = config.get::<String>("foo")?;
let user = config.get::<User>("test.user")?;
let database_password = config.get::<String>("database.password")?;

The init() method initializes the Config object by searching for the configuration file in the file system and reading its contents.

The get() method retrieves a value from the configuration file given a string path, delimited with a period ..

Customization

Some attributes of the library can be customized by the user:

1. The config environment which will determine which config file to read from can be set via the CONFIG_LITE_ENV env var. The default environment is default. Which expects at the very least a default.json or default.yaml config file to exist in the config directory
2. The config directory name can be customized by changing the CONFIG_LITE_DIRECTORY_NAME env var. The default directory name is config and is expected to be defined at the root dir of your crate.

Caveats

The values from the config type must be mapped to owned types and not shared types.

License

This library is released under the MIT License. See the LICENSE file for more information.

Contributing

I am still open to build upon this library, currently what is out is a proof of concept. If you would like to contribute to this project, feel free to open a pull request or issue on the GitHub repository.