configbuilder_pattern_substitution/
prefix_whitelist_policy.rs

1use crate::{SubstitutionError, SubstitutionPolicy};
2
3/// Allows only environment variables whose names start with one of the given prefixes.
4#[derive(Debug)]
5pub struct PrefixWhitelistPolicy {
6    prefixes: Vec<String>,
7}
8
9impl PrefixWhitelistPolicy {
10    /// Create a prefix-based whitelist policy.
11    pub fn new(prefixes: Vec<String>) -> Self {
12        Self { prefixes }
13    }
14
15    /// Return the configured allowed prefixes.
16    pub fn prefixes(&self) -> &[String] {
17        &self.prefixes
18    }
19}
20
21impl SubstitutionPolicy for PrefixWhitelistPolicy {
22    fn validate(&self, var_name: &str) -> Result<(), SubstitutionError> {
23        if self
24            .prefixes()
25            .iter()
26            .any(|p| var_name.starts_with(p.as_str()))
27        {
28            Ok(())
29        } else {
30            Err(SubstitutionError::VariableRejected {
31                var_name: var_name.to_string(),
32                reason: format!(
33                    "does not match any allowed prefix: {}",
34                    self.prefixes().join(", ")
35                ),
36                policy: self.description(),
37            })
38        }
39    }
40
41    fn description(&self) -> String {
42        format!("PrefixWhitelist({})", self.prefixes().join(", "))
43    }
44}

configbuilder_pattern_substitution/prefix_whitelist_policy.rs

configbuilder_pattern_substitution/
prefix_whitelist_policy.rs