Convert load balancing policy to TypedExtensionConfig

Removes LoadBalancingPolicy.Policy type from v4alpha. Changes the type of an unimplemented field.

Signed-off-by: Eugene Chan <eugenechan@google.com>

api/envoy/config/cluster/v3/cluster.proto

@@ -1094,6 +1094,7 @@ message Cluster {
 message LoadBalancingPolicy {
   option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.LoadBalancingPolicy";
 
+  // Deprecated and replaced by TypedExtensionConfig.
   message Policy {
     option (udpa.annotations.versioning).previous_message_type =
         "envoy.api.v2.LoadBalancingPolicy.Policy";
@@ -1111,7 +1112,7 @@ message LoadBalancingPolicy {
   // Each client will iterate over the list in order and stop at the first policy that it
   // supports. This provides a mechanism for starting to use new LB policies that are not yet
   // supported by all clients.
-  repeated Policy policies = 1;
+  repeated core.v3.TypedExtensionConfig policies = 1;
 }
 
 // An extensible structure containing the address Envoy should bind to when

envoy/upstream/load_balancer.h

@@ -189,7 +189,7 @@ class TypedLoadBalancerFactory : public Config::UntypedFactory {
   virtual ThreadAwareLoadBalancerPtr
   create(const PrioritySet& priority_set, ClusterStats& stats, Stats::Scope& stats_scope,
          Runtime::Loader& runtime, Random::RandomGenerator& random,
-         const ::envoy::config::cluster::v3::LoadBalancingPolicy::Policy& lb_policy) PURE;
+         const ::envoy::config::core::v3::TypedExtensionConfig& lb_policy) PURE;
 
   std::string category() const override { return "envoy.load_balancers"; }
 };

envoy/upstream/upstream.h

@@ -787,11 +787,10 @@ class ClusterInfo {
   }
 
   /**
-   * @return const envoy::config::cluster::v3::LoadBalancingPolicy_Policy& the load balancing policy
-   * to use for this cluster.
+   * @return const envoy::config::core::v3::TypedExtensionConfig& the load balancing policy to use
+   * for this cluster.
    */
-  virtual const envoy::config::cluster::v3::LoadBalancingPolicy_Policy&
-  loadBalancingPolicy() const PURE;
+  virtual const envoy::config::core::v3::TypedExtensionConfig& loadBalancingPolicy() const PURE;
 
   /**
    * @return const envoy::config::cluster::v3::Cluster::CommonLbConfig& the common configuration for

source/common/upstream/upstream_impl.cc

@@ -821,7 +821,7 @@ ClusterInfoImpl::ClusterInfoImpl(
     const auto& lb_policy =
         std::find_if(config.load_balancing_policy().policies().begin(),
                      config.load_balancing_policy().policies().end(),
-                     [](envoy::config::cluster::v3::LoadBalancingPolicy_Policy policy) {
+                     [](const envoy::config::core::v3::TypedExtensionConfig& policy) {
                        return Registry::FactoryRegistry<TypedLoadBalancerFactory>::getFactory(
                                   policy.name()) != nullptr;
                      });

source/common/upstream/upstream_impl.h

@@ -568,8 +568,7 @@ class ClusterInfoImpl : public ClusterInfo,
 
   // Upstream::ClusterInfo
   bool addedViaApi() const override { return added_via_api_; }
-  const envoy::config::cluster::v3::LoadBalancingPolicy_Policy&
-  loadBalancingPolicy() const override {
+  const envoy::config::core::v3::TypedExtensionConfig& loadBalancingPolicy() const override {
     return load_balancing_policy_;
   }
   const envoy::config::cluster::v3::Cluster::CommonLbConfig& lbConfig() const override {
@@ -755,7 +754,7 @@ class ClusterInfoImpl : public ClusterInfo,
   LoadBalancerSubsetInfoImpl lb_subset_;
   const envoy::config::core::v3::Metadata metadata_;
   Envoy::Config::TypedMetadataImpl<ClusterTypedMetadataFactory> typed_metadata_;
-  envoy::config::cluster::v3::LoadBalancingPolicy_Policy load_balancing_policy_;
+  envoy::config::core::v3::TypedExtensionConfig load_balancing_policy_;
   const envoy::config::cluster::v3::Cluster::CommonLbConfig common_lb_config_;
   const Network::ConnectionSocket::OptionsSharedPtr cluster_socket_options_;
   const bool drain_connections_on_host_removal_;

test/common/upstream/cluster_manager_impl_test.cc

@@ -761,7 +761,7 @@ class CustomLbFactory : public TypedLoadBalancerFactoryBase {
   ThreadAwareLoadBalancerPtr
   create(const PrioritySet&, ClusterStats&, Stats::Scope&, Runtime::Loader&,
          Random::RandomGenerator&,
-         const ::envoy::config::cluster::v3::LoadBalancingPolicy::Policy&) override {
+         const ::envoy::config::core::v3::TypedExtensionConfig&) override {
     return std::make_unique<ThreadAwareLbImpl>();
   }
 

test/mocks/upstream/cluster_info.h

@@ -105,8 +105,8 @@ class MockClusterInfo : public ClusterInfo {
               (const));
   MOCK_METHOD(ProtocolOptionsConfigConstSharedPtr, extensionProtocolOptions, (const std::string&),
               (const));
-  MOCK_METHOD(const envoy::config::cluster::v3::LoadBalancingPolicy_Policy&, loadBalancingPolicy,
-              (), (const));
+  MOCK_METHOD(const envoy::config::core::v3::TypedExtensionConfig&, loadBalancingPolicy, (),
+              (const));
   MOCK_METHOD(const envoy::config::cluster::v3::Cluster::CommonLbConfig&, lbConfig, (), (const));
   MOCK_METHOD(LoadBalancerType, lbType, (), (const));
   MOCK_METHOD(envoy::config::cluster::v3::Cluster::DiscoveryType, type, (), (const));