config-rs

Layered configuration system for Rust applications (with strong support for 12-factor applications).

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

Install

[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.

// 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 for more usage information.

Roadmap

Read from remote source — etcd and consul
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).