xds: Use acceptResolvedAddresses() for PriorityLb children

PriorityLb should propagate config problems up to the name resolver so
it can refresh.

Author: ejona86

xds/src/main/java/io/grpc/xds/PriorityLoadBalancer.java

@@ -91,6 +91,7 @@ public Status acceptResolvedAddresses(ResolvedAddresses resolvedAddresses) {
     checkNotNull(config, "missing priority lb config");
     priorityNames = config.priorities;
     priorityConfigs = config.childConfigs;
+    Status status = Status.OK;
     Set<String> prioritySet = new HashSet<>(config.priorities);
     ArrayList<String> childKeys = new ArrayList<>(children.keySet());
     for (String priority : childKeys) {
@@ -105,12 +106,18 @@ public Status acceptResolvedAddresses(ResolvedAddresses resolvedAddresses) {
     for (String priority : priorityNames) {
       ChildLbState childLbState = children.get(priority);
       if (childLbState != null) {
-        childLbState.updateResolvedAddresses();
+        Status newStatus = childLbState.updateResolvedAddresses();
+        if (!newStatus.isOk()) {
+          status = newStatus;
+        }
       }
     }
     handlingResolvedAddresses = false;
-    tryNextPriority();
-    return Status.OK;
+    Status newStatus = tryNextPriority();
+    if (!newStatus.isOk()) {
+      status = newStatus;
+    }
+    return status;
   }
 
   @Override
@@ -140,7 +147,7 @@ public void shutdown() {
     children.clear();
   }
 
-  private void tryNextPriority() {
+  private Status tryNextPriority() {
     for (int i = 0; i < priorityNames.size(); i++) {
       String priority = priorityNames.get(i);
       if (!children.containsKey(priority)) {
@@ -151,8 +158,7 @@ private void tryNextPriority() {
         // Calling the child's updateResolvedAddresses() can result in tryNextPriority() being
         // called recursively. We need to be sure to be done with processing here before it is
         // called.
-        child.updateResolvedAddresses();
-        return; // Give priority i time to connect.
+        return child.updateResolvedAddresses(); // Give priority i time to connect.
       }
       ChildLbState child = children.get(priority);
       child.reactivate();
@@ -165,23 +171,24 @@ private void tryNextPriority() {
             children.get(p).deactivate();
           }
         }
-        return;
+        return Status.OK;
       }
       if (child.failOverTimer != null && child.failOverTimer.isPending()) {
         updateOverallState(priority, child.connectivityState, child.picker);
-        return; // Give priority i time to connect.
+        return Status.OK; // Give priority i time to connect.
       }
       if (priority.equals(currentPriority) && child.connectivityState != TRANSIENT_FAILURE) {
         // If the current priority is not changed into TRANSIENT_FAILURE, keep using it.
         updateOverallState(priority, child.connectivityState, child.picker);
-        return;
+        return Status.OK;
       }
     }
     // TODO(zdapeng): Include error details of each priority.
     logger.log(XdsLogLevel.DEBUG, "All priority failed");
     String lastPriority = priorityNames.get(priorityNames.size() - 1);
     SubchannelPicker errorPicker = children.get(lastPriority).picker;
     updateOverallState(lastPriority, TRANSIENT_FAILURE, errorPicker);
+    return Status.OK;
   }
 
   private void updateOverallState(
@@ -228,7 +235,11 @@ public void run() {
             Status.UNAVAILABLE.withDescription("Connection timeout for priority " + priority)));
         logger.log(XdsLogLevel.DEBUG, "Priority {0} failed over to next", priority);
         currentPriority = null; // reset currentPriority to guarantee failover happen
-        tryNextPriority();
+        Status status = tryNextPriority();
+        if (!status.isOk()) {
+          // A child had a problem with the addresses/config. Request it to be refreshed
+          helper.refreshNameResolution();
+        }
       }
     }
 
@@ -279,10 +290,10 @@ void tearDown() {
      * resolvedAddresses}, or when priority lb receives a new resolved addresses while the child
      * already exists.
      */
-    void updateResolvedAddresses() {
+    Status updateResolvedAddresses() {
       PriorityLbConfig config =
           (PriorityLbConfig) resolvedAddresses.getLoadBalancingPolicyConfig();
-      lb.handleResolvedAddresses(
+      return lb.acceptResolvedAddresses(
           resolvedAddresses.toBuilder()
               .setAddresses(AddressFilter.filter(resolvedAddresses.getAddresses(), priority))
               .setLoadBalancingPolicyConfig(config.childConfigs.get(priority).childConfig)
@@ -331,7 +342,11 @@ public void updateBalancingState(final ConnectivityState newState,
         // If we are currently handling newly resolved addresses, let's not try to reconfigure as
         // the address handling process will take care of that to provide an atomic config update.
         if (!handlingResolvedAddresses) {
-          tryNextPriority();
+          Status status = tryNextPriority();
+          if (!status.isOk()) {
+            // A child had a problem with the addresses/config. Request it to be refreshed
+            helper.refreshNameResolution();
+          }
         }
       }