cache: wire rest get response caching

crates/crank-runtime/src/request_context.rs

@@ -1,9 +1,16 @@
 use std::collections::BTreeMap;
 
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct ResponseCacheScope {
+    pub workspace_key: String,
+    pub agent_key: String,
+}
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct RuntimeRequestContext {
     pub request_id: String,
     pub correlation_id: String,
+    pub response_cache_scope: Option<ResponseCacheScope>,
 }
 
 impl RuntimeRequestContext {
@@ -11,6 +18,7 @@ impl RuntimeRequestContext {
         Self {
             request_id: request_id.into(),
             correlation_id: correlation_id.into(),
+            response_cache_scope: None,
         }
     }
 
@@ -25,6 +33,22 @@ impl RuntimeRequestContext {
             ("x-correlation-id".to_owned(), self.correlation_id.clone()),
         ])
     }
+
+    pub fn with_response_cache_scope(
+        mut self,
+        workspace_key: impl Into<String>,
+        agent_key: impl Into<String>,
+    ) -> Self {
+        self.response_cache_scope = Some(ResponseCacheScope {
+            workspace_key: workspace_key.into(),
+            agent_key: agent_key.into(),
+        });
+        self
+    }
+
+    pub fn response_cache_scope(&self) -> Option<&ResponseCacheScope> {
+        self.response_cache_scope.as_ref()
+    }
 }
 
 #[cfg(test)]
@@ -37,5 +61,16 @@ mod tests {
 
         assert_eq!(context.request_id, "req_123");
         assert_eq!(context.correlation_id, "req_123");
+        assert!(context.response_cache_scope.is_none());
+    }
+
+    #[test]
+    fn attaches_response_cache_scope() {
+        let context = RuntimeRequestContext::from_request_id("req_123")
+            .with_response_cache_scope("ws_01", "agent_01");
+
+        let scope = context.response_cache_scope().unwrap();
+        assert_eq!(scope.workspace_key, "ws_01");
+        assert_eq!(scope.agent_key, "agent_01");
     }
 }