Struct PrefixWhitelistPolicy 

pub struct PrefixWhitelistPolicy { /* private fields */ }

Allows only environment variables whose names start with one of the given prefixes.

Implementations

impl PrefixWhitelistPolicy

pub fn new(prefixes: Vec<String>) -> Self

Create a prefix-based whitelist policy.

Examples found in repository

examples/prefix_whitelist.rs (line 10)

fn main() {
    // SAFETY: single-threaded example, no concurrent env access.
    unsafe { std::env::set_var("APP_HOST", "example.internal") };

    let policy = PrefixWhitelistPolicy::new(vec!["APP_".to_string()]);
    let resolver = EnvValueResolver;
    let substituter = Substituter::new(&policy, &resolver, "example.toml".to_string());

    match substituter.substitute("host = {{APP_HOST}}") {
        Ok(value) => println!("{value}"),
        Err(e) => eprintln!("substitution failed: {e}"),
    }
}

pub fn prefixes(&self) -> &[String]

Return the configured allowed prefixes.

Trait Implementations

impl Debug for PrefixWhitelistPolicy

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

Formats the value using the given formatter.

impl SubstitutionPolicy for PrefixWhitelistPolicy

fn validate(&self, var_name: &str) -> Result<(), SubstitutionError>

Decide whether var_name may be substituted into a config value.

fn description(&self) -> String

Human-readable label included in rejection error messages.