litellm/litellm-rust/crates/cache-redis/src/cache.rs
Yujong Lee 93ba409adf fix(rust): address Redis cache review findings
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-09-16 23:19:28 +00:00

315 lines
9.9 KiB
Rust

use std::sync::{Arc, Mutex, MutexGuard};
use std::time::Duration;
use litellm_cache::{
BaseCache, CacheConnectionResult, CacheConnectionStatus, CacheEntry, CacheFuture, CacheKwargs,
Error,
};
use redis::Commands;
const DEFAULT_TTL: Duration = Duration::from_secs(600);
const KEY_PREFIX: &str = "litellm-cache:";
pub struct RedisCache<C = redis::Connection> {
connection: Arc<Mutex<C>>,
default_ttl: Duration,
}
impl RedisCache<redis::Connection> {
pub fn new(url: &str, default_ttl: Option<Duration>) -> Result<Self, Error> {
let client = redis::Client::open(url).map_err(|_| Error::Unavailable)?;
let connection = client.get_connection().map_err(|_| Error::Unavailable)?;
Ok(Self::with_connection(connection, default_ttl))
}
}
impl<C> RedisCache<C>
where
C: redis::ConnectionLike + Send + 'static,
{
fn with_connection(connection: C, default_ttl: Option<Duration>) -> Self {
Self {
connection: Arc::new(Mutex::new(connection)),
default_ttl: default_ttl.unwrap_or(DEFAULT_TTL),
}
}
fn connection(&self) -> Result<MutexGuard<'_, C>, Error> {
self.connection.lock().map_err(|_| Error::Unavailable)
}
fn namespaced_key(key: &str) -> String {
format!("{KEY_PREFIX}{key}")
}
fn namespaced_pattern() -> &'static str {
const PATTERN: &str = "litellm-cache:*";
PATTERN
}
fn encode(value: &CacheEntry) -> Result<Vec<u8>, Error> {
serde_json::to_vec(value).map_err(|_| Error::InvalidEntry)
}
fn decode(value: Vec<u8>) -> Result<CacheEntry, Error> {
serde_json::from_slice(&value).map_err(|_| Error::InvalidEntry)
}
fn ttl_seconds(ttl: Duration) -> u64 {
ttl.as_secs()
.saturating_add(u64::from(ttl.subsec_nanos() > 0))
.max(1)
}
fn run_blocking<T, F>(connection: Arc<Mutex<C>>, operation: F) -> CacheFuture<'static, T>
where
T: Send + 'static,
F: FnOnce(&mut C) -> Result<T, Error> + Send + 'static,
{
Box::pin(async move {
tokio::task::spawn_blocking(move || {
let mut connection = connection.lock().map_err(|_| Error::Unavailable)?;
operation(&mut connection)
})
.await
.map_err(|_| Error::Unavailable)?
})
}
}
impl<C> BaseCache for RedisCache<C>
where
C: redis::ConnectionLike + Send + 'static,
{
type Value = CacheEntry;
fn default_ttl(&self) -> Duration {
self.default_ttl
}
fn set_cache(&self, key: &str, value: Self::Value, kwargs: CacheKwargs) -> Result<(), Error> {
let payload = Self::encode(&value)?;
let ttl = Self::ttl_seconds(self.get_ttl(&kwargs));
self.connection()?
.set_ex::<_, _, ()>(Self::namespaced_key(key), payload, ttl)
.map_err(|_| Error::Unavailable)
}
fn get_cache(&self, key: &str, _: &CacheKwargs) -> Result<Option<Self::Value>, Error> {
self.connection()?
.get::<_, Option<Vec<u8>>>(Self::namespaced_key(key))
.map_err(|_| Error::Unavailable)?
.map(Self::decode)
.transpose()
}
fn delete_cache(&self, key: &str) -> Result<(), Error> {
self.connection()?
.del::<_, ()>(Self::namespaced_key(key))
.map_err(|_| Error::Unavailable)
}
fn flush_cache(&self) -> Result<(), Error> {
let mut connection = self.connection()?;
let keys = connection
.scan_match(Self::namespaced_pattern())
.map_err(|_| Error::Unavailable)?
.collect::<redis::RedisResult<Vec<String>>>()
.map_err(|_| Error::Unavailable)?;
if keys.is_empty() {
return Ok(());
}
connection
.del::<_, usize>(keys)
.map(|_| ())
.map_err(|_| Error::Unavailable)
}
fn async_set_cache<'a>(
&'a self,
key: &'a str,
value: Self::Value,
kwargs: CacheKwargs,
) -> CacheFuture<'a, ()> {
let payload = Self::encode(&value);
let key = Self::namespaced_key(key);
let ttl = Self::ttl_seconds(self.get_ttl(&kwargs));
Self::run_blocking(Arc::clone(&self.connection), move |connection| {
connection
.set_ex::<_, _, ()>(key, payload?, ttl)
.map_err(|_| Error::Unavailable)
})
}
fn async_get_cache<'a>(
&'a self,
key: &'a str,
_: &'a CacheKwargs,
) -> CacheFuture<'a, Option<Self::Value>> {
let key = Self::namespaced_key(key);
Box::pin(async move {
Self::run_blocking(Arc::clone(&self.connection), move |connection| {
connection
.get::<_, Option<Vec<u8>>>(key)
.map_err(|_| Error::Unavailable)
})
.await?
.map(Self::decode)
.transpose()
})
}
fn async_set_cache_pipeline<'a>(
&'a self,
cache_list: Vec<(String, Self::Value)>,
kwargs: CacheKwargs,
) -> CacheFuture<'a, ()> {
let entries = cache_list
.into_iter()
.map(|(key, value)| {
Self::encode(&value).map(|payload| (Self::namespaced_key(&key), payload))
})
.collect::<Result<Vec<_>, _>>();
let ttl = Self::ttl_seconds(self.get_ttl(&kwargs));
Self::run_blocking(Arc::clone(&self.connection), move |connection| {
for (key, payload) in entries? {
connection
.set_ex::<_, _, ()>(key, payload, ttl)
.map_err(|_| Error::Unavailable)?;
}
Ok(())
})
}
fn async_delete_cache<'a>(&'a self, key: &'a str) -> CacheFuture<'a, ()> {
let key = Self::namespaced_key(key);
Self::run_blocking(Arc::clone(&self.connection), move |connection| {
connection.del::<_, ()>(key).map_err(|_| Error::Unavailable)
})
}
fn disconnect(&self) -> CacheFuture<'_, ()> {
Box::pin(async { Ok(()) })
}
fn test_connection(&self) -> CacheFuture<'_, CacheConnectionResult> {
Box::pin(async move {
Self::run_blocking(Arc::clone(&self.connection), |connection| {
redis::cmd("PING")
.query::<String>(connection)
.map_err(|_| Error::Unavailable)
})
.await?;
Ok(CacheConnectionResult {
status: CacheConnectionStatus::Success,
message: "Redis cache connection test successful".into(),
error: None,
})
})
}
}
#[cfg(test)]
mod tests {
use super::RedisCache;
use litellm_cache::{BaseCache, CacheEntry, CacheKwargs};
use redis_test::{MockCmd, MockRedisConnection};
use serde_json::json;
use std::time::Duration;
fn entry() -> CacheEntry {
CacheEntry {
timestamp: 123.0,
response: json!({"choices": [{"text": "cached"}]}),
}
}
#[test]
fn cache_entries_round_trip_through_json() {
let entry = entry();
let encoded = RedisCache::<redis::Connection>::encode(&entry).unwrap();
assert_eq!(
RedisCache::<redis::Connection>::decode(encoded).unwrap(),
entry
);
}
#[test]
fn invalid_json_is_rejected() {
assert!(RedisCache::<redis::Connection>::decode(b"not json".to_vec()).is_err());
}
#[test]
fn ttl_seconds_rounds_up_and_keeps_expiration_positive() {
assert_eq!(
RedisCache::<redis::Connection>::ttl_seconds(Duration::ZERO),
1
);
assert_eq!(
RedisCache::<redis::Connection>::ttl_seconds(Duration::from_millis(1500)),
2
);
assert_eq!(
RedisCache::<redis::Connection>::ttl_seconds(Duration::from_secs(15)),
15
);
}
#[test]
fn redis_commands_round_trip_entries_and_delete_only_namespaced_keys() {
let value = entry();
let payload = RedisCache::<redis::Connection>::encode(&value).unwrap();
let connection = MockRedisConnection::new([
MockCmd::new(
redis::cmd("SETEX")
.arg("litellm-cache:key")
.arg(600)
.arg(payload.clone()),
Ok("OK"),
),
MockCmd::new(redis::cmd("GET").arg("litellm-cache:key"), Ok(payload)),
MockCmd::new(redis::cmd("DEL").arg("litellm-cache:key"), Ok(1u32)),
])
.assert_all_commands_consumed();
let cache = RedisCache::with_connection(connection, None);
cache
.set_cache("key", value.clone(), CacheKwargs::default())
.unwrap();
assert_eq!(
cache.get_cache("key", &CacheKwargs::default()).unwrap(),
Some(value)
);
cache.delete_cache("key").unwrap();
}
#[test]
fn flush_scans_and_deletes_only_cache_keys() {
let connection = MockRedisConnection::new([
MockCmd::new(
redis::cmd("SCAN")
.cursor_arg(0)
.arg("MATCH")
.arg("litellm-cache:*"),
Ok(redis_test::redis_value!(["0", ["litellm-cache:key"]])),
),
MockCmd::new(redis::cmd("DEL").arg("litellm-cache:key"), Ok(1u32)),
])
.assert_all_commands_consumed();
let cache = RedisCache::with_connection(connection, None);
cache.flush_cache().unwrap();
}
#[tokio::test]
async fn test_connection_runs_ping_off_executor() {
let connection = MockRedisConnection::new([MockCmd::new(redis::cmd("PING"), Ok("PONG"))])
.assert_all_commands_consumed();
let cache = RedisCache::with_connection(connection, None);
assert_eq!(
cache.test_connection().await.unwrap().status,
litellm_cache::CacheConnectionStatus::Success
);
}
}