rws_server/feature/
mod.rs

1//! Runtime feature toggles.
2//!
3//! `FeatureStore` is a global, mutable map of named boolean flags. Handlers
4//! check flags at request time; an MCP agent (or admin API) flips them without
5//! restarting the server.
6//!
7//! # Example
8//!
9//! ```rust,no_run
10//! # extern crate rws_server as rust_web_server;
11//! use rust_web_server::feature;
12//!
13//! // Register a flag with a default value at startup.
14//! feature::global().set("dark_launch_v2", false);
15//!
16//! // In a handler:
17//! if feature::global().is_enabled("dark_launch_v2") {
18//!     // serve new code path
19//! }
20//! ```
21
22#[cfg(test)]
23mod tests;
24
25use std::collections::HashMap;
26use std::sync::{Mutex, OnceLock};
27
28/// A thread-safe map of named boolean feature flags.
29pub struct FeatureStore {
30    flags: Mutex<HashMap<String, bool>>,
31}
32
33impl FeatureStore {
34    fn new() -> Self {
35        FeatureStore { flags: Mutex::new(HashMap::new()) }
36    }
37
38    /// Set (or create) a flag. `false` disables, `true` enables.
39    pub fn set(&self, name: &str, enabled: bool) {
40        self.flags.lock().unwrap().insert(name.to_string(), enabled);
41    }
42
43    /// Returns `true` if the flag exists and is set to `true`.
44    pub fn is_enabled(&self, name: &str) -> bool {
45        *self.flags.lock().unwrap().get(name).unwrap_or(&false)
46    }
47
48    /// Snapshot of all flags sorted by name.
49    pub fn list(&self) -> Vec<(String, bool)> {
50        let mut pairs: Vec<(String, bool)> = self.flags.lock().unwrap()
51            .iter()
52            .map(|(k, v)| (k.clone(), *v))
53            .collect();
54        pairs.sort_by(|a, b| a.0.cmp(&b.0));
55        pairs
56    }
57}
58
59static INSTANCE: OnceLock<FeatureStore> = OnceLock::new();
60
61/// Return the process-wide `FeatureStore` singleton.
62pub fn global() -> &'static FeatureStore {
63    INSTANCE.get_or_init(FeatureStore::new)
64}
rws_server/feature/mod.rs

rws_server/feature/
mod.rs
