Improve gateway transport and usage runtime

apps/aether-gateway/src/scheduler/candidate/affinity.rs

@@ -17,9 +17,6 @@ pub(super) fn build_scheduler_affinity_cache_key(
     global_model_name: &str,
     client_session_affinity: Option<&ClientSessionAffinity>,
 ) -> Option<String> {
-    if !has_explicit_session_affinity(client_session_affinity) {
-        return None;
-    }
     let api_key_id = auth_snapshot
         .map(|snapshot| snapshot.api_key_id.trim())
         .filter(|value| !value.is_empty())?;

apps/aether-gateway/src/scheduler/candidate/selection.rs

@@ -225,6 +225,7 @@ pub(super) async fn collect_selectable_enumerated_candidates_with_skip_reasons(
     );
     let cached_affinity_target = if ordering_config.scheduling_mode
         == SchedulerSchedulingMode::CacheAffinity
+        && has_explicit_session_affinity(client_session_affinity)
     {
         affinity_cache_key.as_deref().and_then(|cache_key| {
             runtime_state.read_cached_scheduler_affinity_target(cache_key, SCHEDULER_AFFINITY_TTL)

apps/aether-gateway/src/scheduler/candidate/tests/affinity.rs

@@ -36,6 +36,7 @@ async fn select_candidate(
     global_model_name: &str,
     require_streaming: bool,
     auth_snapshot: Option<&GatewayAuthApiKeySnapshot>,
+    client_session_affinity: Option<&ClientSessionAffinity>,
     now_unix_secs: u64,
 ) -> Result<Option<SchedulerMinimalCandidateSelectionCandidate>, GatewayError> {
     select_candidate_impl(
@@ -46,7 +47,7 @@ async fn select_candidate(
         require_streaming,
         None,
         auth_snapshot,
-        None,
+        client_session_affinity,
         now_unix_secs,
         false,
     )
@@ -207,9 +208,14 @@ async fn reuses_cached_scheduler_affinity_candidate_before_sorted_fallback() {
         );
 
     let auth_snapshot = sample_auth_snapshot("affinity-key-1");
-    let cache_key =
-        build_scheduler_affinity_cache_key(Some(&auth_snapshot), "openai:chat", "gpt-4.1", None)
-            .expect("cache key should build");
+    let client_session_affinity = ClientSessionAffinity::from_session_key("session-1");
+    let cache_key = build_scheduler_affinity_cache_key(
+        Some(&auth_snapshot),
+        "openai:chat",
+        "gpt-4.1",
+        Some(&client_session_affinity),
+    )
+    .expect("cache key should build");
     state.remember_scheduler_affinity_target(
         &cache_key,
         SchedulerAffinityTarget {
@@ -228,6 +234,7 @@ async fn reuses_cached_scheduler_affinity_candidate_before_sorted_fallback() {
         "gpt-4.1",
         false,
         Some(&auth_snapshot),
+        Some(&client_session_affinity),
         100,
     )
     .await
@@ -312,9 +319,14 @@ async fn cached_affinity_candidate_cannot_use_reserved_provider_key_rpm_capacity
         );
 
     let auth_snapshot = sample_auth_snapshot("api-key-cached-user");
-    let cache_key =
-        build_scheduler_affinity_cache_key(Some(&auth_snapshot), "openai:chat", "gpt-4.1", None)
-            .expect("cache key should build");
+    let client_session_affinity = ClientSessionAffinity::from_session_key("session-1");
+    let cache_key = build_scheduler_affinity_cache_key(
+        Some(&auth_snapshot),
+        "openai:chat",
+        "gpt-4.1",
+        Some(&client_session_affinity),
+    )
+    .expect("cache key should build");
     state.remember_scheduler_affinity_target(
         &cache_key,
         SchedulerAffinityTarget {
@@ -333,6 +345,7 @@ async fn cached_affinity_candidate_cannot_use_reserved_provider_key_rpm_capacity
         "gpt-4.1",
         false,
         Some(&auth_snapshot),
+        Some(&client_session_affinity),
         100,
     )
     .await