[router] Support history management using conversation (#11339)

sgl-router/src/server.rs

@@ -2,9 +2,10 @@ use crate::{
     config::{ConnectionMode, HistoryBackend, RouterConfig, RoutingMode},
     core::{LoadMonitor, WorkerManager, WorkerRegistry, WorkerType},
     data_connector::{
-        MemoryConversationStorage, MemoryResponseStorage, NoOpConversationStorage,
-        NoOpResponseStorage, OracleConversationStorage, OracleResponseStorage,
-        SharedConversationStorage, SharedResponseStorage,
+        MemoryConversationItemStorage, MemoryConversationStorage, MemoryResponseStorage,
+        NoOpConversationStorage, NoOpResponseStorage, OracleConversationItemStorage,
+        OracleConversationStorage, OracleResponseStorage, SharedConversationStorage,
+        SharedResponseStorage,
     },
     logging::{self, LoggingConfig},
     metrics::{self, PrometheusConfig},
@@ -56,6 +57,7 @@ pub struct AppContext {
     pub router_manager: Option<Arc<RouterManager>>,
     pub response_storage: SharedResponseStorage,
     pub conversation_storage: SharedConversationStorage,
+    pub conversation_item_storage: crate::data_connector::SharedConversationItemStorage,
     pub load_monitor: Option<Arc<LoadMonitor>>,
     pub configured_reasoning_parser: Option<String>,
     pub configured_tool_parser: Option<String>,
@@ -121,8 +123,8 @@ impl AppContext {
                         format!("failed to initialize Oracle response storage: {err}")
                     })?;
 
-                let conversation_storage =
-                    OracleConversationStorage::new(oracle_cfg).map_err(|err| {
+                let conversation_storage = OracleConversationStorage::new(oracle_cfg.clone())
+                    .map_err(|err| {
                         format!("failed to initialize Oracle conversation storage: {err}")
                     })?;
 
@@ -130,6 +132,20 @@ impl AppContext {
             }
         };
 
+        // Conversation items storage (memory-backed for now)
+        let conversation_item_storage: crate::data_connector::SharedConversationItemStorage =
+            match router_config.history_backend {
+                HistoryBackend::Oracle => {
+                    let oracle_cfg = router_config.oracle.clone().ok_or_else(|| {
+                        "oracle configuration is required when history_backend=oracle".to_string()
+                    })?;
+                    Arc::new(OracleConversationItemStorage::new(oracle_cfg).map_err(|e| {
+                        format!("failed to initialize Oracle conversation item storage: {e}")
+                    })?)
+                }
+                _ => Arc::new(MemoryConversationItemStorage::new()),
+            };
+
         let load_monitor = Some(Arc::new(LoadMonitor::new(
             worker_registry.clone(),
             policy_registry.clone(),
@@ -152,6 +168,7 @@ impl AppContext {
             router_manager,
             response_storage,
             conversation_storage,
+            conversation_item_storage,
             load_monitor,
             configured_reasoning_parser,
             configured_tool_parser,
@@ -400,6 +417,29 @@ async fn v1_conversations_delete(
         .await
 }
 
+#[derive(Deserialize, Default)]
+struct ListItemsQuery {
+    limit: Option<usize>,
+    order: Option<String>,
+    after: Option<String>,
+}
+
+async fn v1_conversations_list_items(
+    State(state): State<Arc<AppState>>,
+    Path(conversation_id): Path<String>,
+    Query(ListItemsQuery {
+        limit,
+        order,
+        after,
+    }): Query<ListItemsQuery>,
+    headers: http::HeaderMap,
+) -> Response {
+    state
+        .router
+        .list_conversation_items(Some(&headers), &conversation_id, limit, order, after)
+        .await
+}
+
 #[derive(Deserialize)]
 struct AddWorkerQuery {
     url: String,
@@ -674,6 +714,10 @@ pub fn build_app(
                 .post(v1_conversations_update)
                 .delete(v1_conversations_delete),
         )
+        .route(
+            "/v1/conversations/{conversation_id}/items",
+            get(v1_conversations_list_items),
+        )
         .route_layer(axum::middleware::from_fn_with_state(
             app_state.clone(),
             middleware::concurrency_limit_middleware,