add test for current access of RateLimiter

Cargo.toml

@@ -22,6 +22,7 @@ thiserror = "1.0.60"
 [dev-dependencies]
 chrono = "0.4.38"
 tokio = { version = "1.37.0", features = ["full"] }
+futures = "0.3.30"
 
 [[example]]
 name = "rate_limiter"

README.md

@@ -34,17 +34,18 @@ fn check_rate_limit() {
 ### With `rate-limiter`
 
 ```rust
+use std::sync::Arc;
 use gcra::{GcraError, RateLimit, RateLimiter};
 
 #[tokio::main]
 async fn main() -> Result<(), GcraError> {
     let rate_limit = RateLimit::per_sec(2);
-    let rl = RateLimiter::new(4);
+    let rate_limiter = Arc::new(RateLimiter::new(4));
 
-    rl.check("key", rate_limit.clone(), 1).await?;
-    rl.check("key", rate_limit.clone(), 1).await?;
+    rate_limiter.check("key", &rate_limit, 1).await?;
+    rate_limiter.check("key", &rate_limit, 1).await?;
 
-    match rl.check("key", rate_limit.clone(), 1).await {
+    match rate_limiter.check("key", rate_limit.clone(), 1).await {
         Err(GcraError::DeniedUntil { next_allowed_at }) => {
             print!("Denied: Request next at {:?}", next_allowed_at);
             Ok(())

examples/rate_limiter.rs

@@ -1,3 +1,5 @@
+use std::sync::Arc;
+
 use gcra::{GcraError, RateLimit, RateLimiter};
 
 const CACHE_CAPACITY: usize = 4;
@@ -6,12 +8,12 @@ const WORKER_SHARD_COUNT: usize = 2;
 #[tokio::main]
 async fn main() -> Result<(), GcraError> {
     let rate_limit = RateLimit::per_sec(2);
-    let rl = RateLimiter::with_shards(CACHE_CAPACITY, WORKER_SHARD_COUNT);
+    let rate_limiter = Arc::new(RateLimiter::with_shards(CACHE_CAPACITY, WORKER_SHARD_COUNT));
 
-    rl.check("key", &rate_limit, 1).await?;
-    rl.check("key", &rate_limit, 1).await?;
+    rate_limiter.check("key", &rate_limit, 1).await?;
+    rate_limiter.check("key", &rate_limit, 1).await?;
 
-    match rl.check("key", &rate_limit, 1).await {
+    match rate_limiter.check("key", &rate_limit, 1).await {
         Err(GcraError::DeniedUntil { next_allowed_at }) => {
             print!("Denied: Request next at {:?}", next_allowed_at);
             Ok(())

src/lib.rs

@@ -29,17 +29,18 @@
 //! ## With `rate-limiter`
 //!
 //! ```rust
+//! use std::sync::Arc;
 //! use gcra::{GcraError, RateLimit, RateLimiter};
 //!
 //! #[tokio::main]
 //! async fn main() -> Result<(), GcraError> {
 //!     let rate_limit = RateLimit::per_sec(2);
-//!     let rl = RateLimiter::new(4);
+//!     let rate_limiter = Arc::new(RateLimiter::new(4));
 //!
-//!     rl.check("key", &rate_limit, 1).await?;
-//!     rl.check("key", &rate_limit, 1).await?;
+//!     rate_limiter.check("key", &rate_limit, 1).await?;
+//!     rate_limiter.check("key", &rate_limit, 1).await?;
 //!
-//!     match rl.check("key", &rate_limit, 1).await {
+//!     match rate_limiter.check("key", &rate_limit, 1).await {
 //!         Err(GcraError::DeniedUntil { next_allowed_at }) => {
 //!             print!("Denied: Request next at {:?}", next_allowed_at);
 //!             Ok(())

src/rate_limiter/rate_limiter.rs

@@ -134,9 +134,14 @@ where
 
 #[cfg(test)]
 mod tests {
+    use futures::stream::{self, StreamExt};
+
     use crate::clock::tests::FakeClock;
     use core::panic;
-    use std::time::{Duration, Instant};
+    use std::{
+        sync::Arc,
+        time::{Duration, Instant},
+    };
 
     use super::*;
 
@@ -161,6 +166,33 @@ mod tests {
         }
     }
 
+    #[tokio::test]
+    async fn rate_limiter_run_until_denied_concurrent_access() {
+        let rate_limit = RateLimit::new(3, Duration::from_secs(3));
+        let rate_limiter = Arc::new(RateLimiter::with_shards(4, 2));
+
+        let all_checked = stream::iter(0..rate_limit.resource_limit)
+            .then(|_| async {
+                let rate_limiter = rate_limiter.clone();
+                rate_limiter.check("key", &rate_limit, 1).await
+            })
+            .all(|result| async move { result.is_ok() })
+            .await;
+
+        assert!(
+            all_checked,
+            "All checks should have passed and not rate limited"
+        );
+
+        match rate_limiter.check("key", &rate_limit, 1).await {
+            Ok(_) => panic!("We should be rate limited"),
+            Err(GcraError::DeniedUntil { next_allowed_at }) => {
+                assert!(next_allowed_at > Instant::now())
+            }
+            Err(_) => panic!("Unexpected error"),
+        }
+    }
+
     #[tokio::test]
     async fn rate_limiter_indefinitly_denied() {
         let rate_limit = RateLimit::new(3, Duration::from_secs(3));