v0.26.7

src/balance/model.rs

@@ -47,7 +47,7 @@ pub enum StickyMode {
     Cookie,
     IpHash,
 }
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(default, deny_unknown_fields)]
 pub struct Keepalive {
     pub enabled: bool,

src/balance/pool_core.rs

@@ -61,10 +61,24 @@ impl Pool {
                         &previous.settings.passive_health,
                     ))
                     .ok();
-            if same_origin && same_health && (old.definition.enabled || !member.definition.enabled)
-            {
-                // This pool has not been published or cloned into routes yet.
-                if let Some(member) = Arc::get_mut(member) {
+            let same_clients = member.backend.client.reusable_with(&old.backend.client)
+                && member
+                    .backend
+                    .websocket_client
+                    .reusable_with(&old.backend.websocket_client);
+            // This pool has not been published or cloned into routes yet.
+            if let Some(member) = Arc::get_mut(member) {
+                if same_clients {
+                    // Preserve the live Hyper pools and, with them, generation
+                    // age/request/rotation state across unrelated snapshot
+                    // rebuilds. Changed origins, address policy, keepalive or
+                    // connect timeout still receive newly compiled clients.
+                    member.backend = old.backend.clone();
+                }
+                if same_origin
+                    && same_health
+                    && (old.definition.enabled || !member.definition.enabled)
+                {
                     member.state = old.state.clone();
                     member.token = old.token.clone();
                 }

src/balance/tests/part_01.rs

@@ -98,6 +98,23 @@ fn upstream_pool_recycle_limits_are_bounded_and_can_be_disabled() {
     assert!(settings.validate().is_ok());
 }
 
+#[test]
+fn compatible_pool_rebuild_reuses_upstream_clients() {
+    let previous = pool(Algorithm::LeastConnections, StickyMode::Off);
+    let mut rebuilt = pool(Algorithm::LeastConnections, StickyMode::Off);
+    let rebuilt_mut = Arc::get_mut(&mut rebuilt).expect("fresh pool must be uniquely owned");
+
+    assert!(!Arc::ptr_eq(
+        &rebuilt_mut.members[0].backend,
+        &previous.members[0].backend
+    ));
+    rebuilt_mut.reuse_observations(&previous);
+    assert!(Arc::ptr_eq(
+        &rebuilt_mut.members[0].backend,
+        &previous.members[0].backend
+    ));
+}
+
 #[test]
 fn retry_policy_rejects_unbounded_or_non_5xx_configuration() {
     let mut settings = Settings::default();