Crate configure_me[−][src]
This library aims to help with reading configuration of application from files, environment variables and command line arguments, merging it together and validating. It auto-generates most of the code for you based on configuration (heh) file. It creates a struct for you, which contains all the parsed and validated fields, so you can access the information quickly easily and idiomatically.
Important note: since this is generating code, it's intended to be used from build script.
Example
Let's say, your application needs these parametrs to run:
- Port - this is mandatory
- IP address to bind to - defaults to 0.0.0.0
- Path to TLS certificate - optional, the server will be unsecure if not given
First you create Toml configuration file specifying all the parameters:
[[param]]
name = "port"
type = "u16"
optional = false
[[param]]
name = "bind_addr"
# Yes, this works and you can use your own T: Deserialize + FromStr as well!
type = "::std::net::Ipv4Addr"
default = "::std::net::Ipv4Addr::new(0, 0, 0, 0)" # Rust expression that creates the value
[[param]]
name = "tls_cert"
type = "String"
# optional = true is the default, no need to add it here
# If the type is optional, it will be represented as Option<T>
# e.g. Option<String> in this case.
Then, you create a build script like this:
extern crate configure_me; fn main() { let mut out: std::path::PathBuf = std::env::var_os("OUT_DIR").unwrap().into(); out.push("config.rs"); let config_spec = std::fs::File::open("config.toml").unwrap(); let config_code = std::fs::File::create(&out).unwrap(); configure_me::generate_source(config_spec, config_code).unwrap(); println!("rerun-if-changed=config.toml"); }
Add dependencies to Cargo.toml
:
[packge]
# ...
build = "build.rs"
[dependencies]
serde = "1"
serde_derive = "1"
toml = "0.4"
[build-dependencies]
configure_me = "0.1"
Create a module src/config.rs
for configuration:
include!(concat!(env!("OUT_DIR"), "/config.rs"));
And finally add appropriate incantiations into src/main.rs
:
extern crate serde; #[macro_use] extern crate serde_derive; extern crate toml; mod config; fn main() { // This will read configuration from "/etc/my_awesome_server/server.conf" file and // the command-line arguments. let server_config = config::Config::gather("/etc/my_awesome_server/server.conf").unwrap(); // Your code here // E.g.: let listener = std::net::TcpListener::bind((server_config.bind_addr, server_config.port)).expect("Failed to bind socket"); }
Structs
Error |
Error that occured during code generation |
Functions
generate_source |
Generates the source code for you from provided |