Crate envy [−] [src]

envy is a library for deserializing env vars into typesafe structs

Examples

A typical use case for envy is deserializing configuration stored into an env into a struct whose fields map to the names of env vars.

Serde makes it easy to provide a deserializable struct with the serde_derive crate. Simply ask for an instance of that struct from envy's from_env function.

#[macro_use]
extern crate serde_derive;

extern crate envy;

#[derive(Deserialize, Debug)]
struct Config {
  foo: u16,
  bar: bool,
  baz: String,
  boom: Option<u64>
}

fn main() {
   match envy::from_env::<Config>() {
      Ok(config) => println!("{:#?}", config)
      Err(error) => panic!("{:#?}", error)
   }
}

Special treatment is given to collections. For config fields that store a Vec of values, use and env var that uses a comma separated value

All serde modifier should work as is

If you wish to use enum types use the following

#[macro_use]
extern crate serde_derive;

extern crate envy;

#[derive(Deserialize, Debug, PartialEq)]
#[serde(untagged)]
#[serde(field_identifier, rename_all = "lowercase")]
pub enum Size {
   Small,
   Medium,
   Large
}

#[derive(Deserialize, Debug)]
struct Config {
 size: Size,
}

fn main() {
   // set env var for size as `SIZE=medium`
   match envy::from_env::<Config>() {
      Ok(config) => println!("{:#?}", config)
      Err(error) => panic!("{:#?}", error)
   }
}

Structs

Prefixed

A type which filters env vars with a prefixed for use as serde field inputs

Enums

Error

Types of errors that may result from failed attempts to deserialize a type from env vars

Functions

from_env	Deserializes a type based on information based on env variables
from_iter	Deserializes a type based on an iterable of `(String, String)` representing keys and values
prefixed	produces a instance of `Prefixed` for prefixing env variable names

Type Definitions

Result

A type result type specific to envy::Errors