Struct smart_config::fallback::Env

pub struct Env(pub &'static str);

Gets a string value from the specified env variable.

Examples

use smart_config::{fallback, testing, DescribeConfig, DeserializeConfig};

#[derive(DescribeConfig, DeserializeConfig)]
struct TestConfig {
    /// Log directives. Always read from `RUST_LOG` env var in addition to
    /// the conventional sources.
    #[config(default_t = "info".into(), fallback = &fallback::Env("RUST_LOG"))]
    log_directives: String,
}

let mut tester = testing::Tester::default();
let config: TestConfig = tester.test(smart_config::config!())?;
// Without env var set or other sources, the param will assume the default value.
assert_eq!(config.log_directives, "info");

tester.set_env("RUST_LOG", "warn");
let config: TestConfig = tester.test(smart_config::config!())?;
assert_eq!(config.log_directives, "warn");

// Mock env vars are still set here, but fallbacks have lower priority
// than other sources.
let input = smart_config::config!("log_directives": "info,my_crate=debug");
let config = tester.test(input)?;
assert_eq!(config.log_directives, "info,my_crate=debug");

Tuple Fields

0: &'static str

Implementations

impl Env

pub fn get_raw(&self) -> Option<String>

Gets the raw string value of the env var, taking mock vars into account.

Trait Implementations

impl Clone for Env

fn clone(&self) -> Env

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Env

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Env

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FallbackSource for Env

fn provide_value(&self) -> Option<WithOrigin>

Potentially provides a value for the param.

impl Copy for Env