feat(cache): add semantic cache context and unsupported operation error

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm-rust/crates/cache/src/base_cache.rs

@@ -32,6 +32,28 @@ impl CacheContext for ExactCacheContext {
     }
 }
 
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct SemanticCacheContext {
+    pub input: Option<serde_json::Value>,
+    pub messages: Option<serde_json::Value>,
+    pub metadata: Option<serde_json::Value>,
+    pub scope: Option<String>,
+    pub ttl: Option<Duration>,
+}
+
+impl CacheContext for SemanticCacheContext {
+    fn ttl(&self) -> Option<Duration> {
+        self.ttl
+    }
+
+    fn with_ttl(&self, ttl: Option<Duration>) -> Self {
+        Self {
+            ttl,
+            ..self.clone()
+        }
+    }
+}
+
 #[derive(Clone, Copy, Debug, Deserialize, Serialize, PartialEq, Eq)]
 #[serde(rename_all = "lowercase")]
 pub enum CacheConnectionStatus {
@@ -105,3 +127,31 @@ pub trait BaseCache: Send + Sync {
 
     fn test_connection(&self) -> impl Future<Output = Result<CacheConnectionResult, Error>> + Send;
 }
+
+#[cfg(test)]
+mod tests {
+    use std::time::Duration;
+
+    use serde_json::json;
+
+    use super::{CacheContext, SemanticCacheContext};
+
+    #[test]
+    fn semantic_context_with_ttl_only_replaces_ttl() {
+        let context = SemanticCacheContext {
+            input: Some(json!({"input": "hello"})),
+            messages: Some(json!([{"role": "user", "content": "hello"}])),
+            metadata: Some(json!({"tenant": "team"})),
+            scope: Some("scope".into()),
+            ttl: Some(Duration::from_secs(10)),
+        };
+
+        let updated = context.with_ttl(Some(Duration::from_secs(20)));
+
+        assert_eq!(updated.ttl, Some(Duration::from_secs(20)));
+        assert_eq!(updated.input, context.input);
+        assert_eq!(updated.messages, context.messages);
+        assert_eq!(updated.metadata, context.metadata);
+        assert_eq!(updated.scope, context.scope);
+    }
+}

litellm-rust/crates/cache/src/error.rs

@@ -6,4 +6,6 @@ pub enum Error {
     InvalidEntry,
     #[error("flushing Redis requires an explicit namespace")]
     UnscopedFlush,
+    #[error("cache operation is not supported by this backend")]
+    UnsupportedOperation,
 }

litellm-rust/crates/cache/src/lib.rs

@@ -8,7 +8,7 @@ mod error;
 
 pub use base_cache::{
     BaseCache, BatchEntry, CacheConnectionResult, CacheConnectionStatus, CacheContext,
-    ExactCacheContext,
+    ExactCacheContext, SemanticCacheContext,
 };
 pub use cache_type::CacheType;
 pub use caching::{Cache, CacheBackend, get_cache, set_cache};