From 153824a21c2f9cc2f9d16d86af5e539cc49fae84 Mon Sep 17 00:00:00 2001
From: Yousuk Seung <ysseung@google.com>
Date: Wed, 27 Sep 2023 10:22:28 -0700
Subject: [PATCH] [grpclb] set resolution note for empty list from balancer
 (#34487)

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---
 src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
index c256d2c87f6..22352903b6e 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
@@ -1767,6 +1767,9 @@ void GrpcLb::CreateOrUpdateChildPolicyLocked() {
     update_args.addresses = serverlist_->GetServerAddressList(
         lb_calld_ == nullptr ? nullptr : lb_calld_->client_stats());
     is_backend_from_grpclb_load_balancer = true;
+    if (update_args.addresses.ok() && update_args.addresses->empty()) {
+      update_args.resolution_note = "empty serverlist from grpclb balancer";
+    }
   }
   update_args.args =
       CreateChildPolicyArgsLocked(is_backend_from_grpclb_load_balancer);