From 535de53dccd91393a0c076c4ae4970fbe1c8a018 Mon Sep 17 00:00:00 2001
From: Henry Yang <hyang@lyft.com>
Date: Thu, 22 Aug 2019 15:45:12 -0700
Subject: [PATCH] Fix onHostHealthUpdate got called before the cluster is
 resolved.

Signed-off-by: Henry Yang <hyang@lyft.com>
---
 source/extensions/clusters/redis/redis_cluster_lb.cc    | 5 +++++
 test/extensions/clusters/redis/redis_cluster_lb_test.cc | 1 +
 2 files changed, 6 insertions(+)

diff --git a/source/extensions/clusters/redis/redis_cluster_lb.cc b/source/extensions/clusters/redis/redis_cluster_lb.cc
index fefd17fff2fc..b4f3b1d06a2c 100644
--- a/source/extensions/clusters/redis/redis_cluster_lb.cc
+++ b/source/extensions/clusters/redis/redis_cluster_lb.cc
@@ -75,6 +75,11 @@ void RedisClusterLoadBalancerFactory::onHostHealthUpdate() {
     current_shard_vector = shard_vector_;
   }
 
+  // This can get called by cluster initialization before the Redis Cluster topology is resolved.
+  if (!current_shard_vector) {
+    return;
+  }
+
   auto shard_vector = std::make_shared<std::vector<RedisShardSharedPtr>>();
 
   for (auto const& shard : *current_shard_vector) {
diff --git a/test/extensions/clusters/redis/redis_cluster_lb_test.cc b/test/extensions/clusters/redis/redis_cluster_lb_test.cc
index dedcf8e51ec8..5e0ae78de9b2 100644
--- a/test/extensions/clusters/redis/redis_cluster_lb_test.cc
+++ b/test/extensions/clusters/redis/redis_cluster_lb_test.cc
@@ -44,6 +44,7 @@ class RedisClusterLoadBalancerTest : public testing::Test {
     factory_ = std::make_shared<RedisClusterLoadBalancerFactory>(random_);
     lb_ = std::make_unique<RedisClusterThreadAwareLoadBalancer>(factory_);
     lb_->initialize();
+    factory_->onHostHealthUpdate();
   }
 
   void validateAssignment(Upstream::HostVector& hosts,