xds/cds: add env var for aggregated and DNS cluster (#4440)

internal/xds/env/env.go

@@ -37,11 +37,13 @@ const (
 	// and kept in variable BootstrapFileName.
 	//
 	// When both bootstrap FileName and FileContent are set, FileName is used.
-	BootstrapFileContentEnv      = "GRPC_XDS_BOOTSTRAP_CONFIG"
+	BootstrapFileContentEnv = "GRPC_XDS_BOOTSTRAP_CONFIG"
+
 	circuitBreakingSupportEnv    = "GRPC_XDS_EXPERIMENTAL_CIRCUIT_BREAKING"
 	timeoutSupportEnv            = "GRPC_XDS_EXPERIMENTAL_ENABLE_TIMEOUT"
 	faultInjectionSupportEnv     = "GRPC_XDS_EXPERIMENTAL_FAULT_INJECTION"
 	clientSideSecuritySupportEnv = "GRPC_XDS_EXPERIMENTAL_SECURITY_SUPPORT"
+	aggregateAndDNSSupportEnv    = "GRPC_XDS_EXPERIMENTAL_ENABLE_AGGREGATE_AND_LOGICAL_DNS_CLUSTER"
 
 	c2pResolverSupportEnv                    = "GRPC_EXPERIMENTAL_GOOGLE_C2P_RESOLVER"
 	c2pResolverTestOnlyTrafficDirectorURIEnv = "GRPC_TEST_ONLY_GOOGLE_C2P_RESOLVER_TRAFFIC_DIRECTOR_URI"
@@ -60,6 +62,7 @@ var (
 	//
 	// When both bootstrap FileName and FileContent are set, FileName is used.
 	BootstrapFileContent = os.Getenv(BootstrapFileContentEnv)
+
 	// CircuitBreakingSupport indicates whether circuit breaking support is
 	// enabled, which can be disabled by setting the environment variable
 	// "GRPC_XDS_EXPERIMENTAL_CIRCUIT_BREAKING" to "false".
@@ -71,17 +74,24 @@ var (
 	// FaultInjectionSupport is used to control both fault injection and HTTP
 	// filter support.
 	FaultInjectionSupport = !strings.EqualFold(os.Getenv(faultInjectionSupportEnv), "false")
-	// C2PResolverSupport indicates whether support for C2P resolver is enabled.
-	// This can be enabled by setting the environment variable
-	// "GRPC_EXPERIMENTAL_GOOGLE_C2P_RESOLVER" to "true".
-	C2PResolverSupport = strings.EqualFold(os.Getenv(c2pResolverSupportEnv), "true")
 	// ClientSideSecuritySupport is used to control processing of security
 	// configuration on the client-side.
 	//
 	// Note that there is no env var protection for the server-side because we
 	// have a brand new API on the server-side and users explicitly need to use
 	// the new API to get security integration on the server.
 	ClientSideSecuritySupport = strings.EqualFold(os.Getenv(clientSideSecuritySupportEnv), "true")
+	// AggregateAndDNSSupportEnv indicates whether processing of aggregated
+	// cluster and DNS cluster is enabled, which can be enabled by setting the
+	// environment variable
+	// "GRPC_XDS_EXPERIMENTAL_ENABLE_AGGREGATE_AND_LOGICAL_DNS_CLUSTER" to
+	// "true".
+	AggregateAndDNSSupportEnv = strings.EqualFold(os.Getenv(aggregateAndDNSSupportEnv), "true")
+
+	// C2PResolverSupport indicates whether support for C2P resolver is enabled.
+	// This can be enabled by setting the environment variable
+	// "GRPC_EXPERIMENTAL_GOOGLE_C2P_RESOLVER" to "true".
+	C2PResolverSupport = strings.EqualFold(os.Getenv(c2pResolverSupportEnv), "true")
 	// C2PResolverTestOnlyTrafficDirectorURI is the TD URI for testing.
 	C2PResolverTestOnlyTrafficDirectorURI = os.Getenv(c2pResolverTestOnlyTrafficDirectorURIEnv)
 )

xds/internal/client/cds_test.go

@@ -124,6 +124,9 @@ func (s) TestValidateCluster_Failure(t *testing.T) {
 		},
 	}
 
+	oldAggregateAndDNSSupportEnv := env.AggregateAndDNSSupportEnv
+	env.AggregateAndDNSSupportEnv = true
+	defer func() { env.CircuitBreakingSupport = oldAggregateAndDNSSupportEnv }()
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			if update, err := validateClusterAndConstructClusterUpdate(test.cluster); err == nil {
@@ -261,6 +264,9 @@ func (s) TestValidateCluster_Success(t *testing.T) {
 	origCircuitBreakingSupport := env.CircuitBreakingSupport
 	env.CircuitBreakingSupport = true
 	defer func() { env.CircuitBreakingSupport = origCircuitBreakingSupport }()
+	oldAggregateAndDNSSupportEnv := env.AggregateAndDNSSupportEnv
+	env.AggregateAndDNSSupportEnv = true
+	defer func() { env.CircuitBreakingSupport = oldAggregateAndDNSSupportEnv }()
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			update, err := validateClusterAndConstructClusterUpdate(test.cluster)

xds/internal/client/xds.go

@@ -615,9 +615,15 @@ func validateClusterAndConstructClusterUpdate(cluster *v3clusterpb.Cluster) (Clu
 		ret.EDSServiceName = cluster.GetEdsClusterConfig().GetServiceName()
 		return ret, nil
 	case cluster.GetType() == v3clusterpb.Cluster_LOGICAL_DNS:
+		if !env.AggregateAndDNSSupportEnv {
+			return ClusterUpdate{}, fmt.Errorf("unsupported cluster type (%v, %v) in response: %+v", cluster.GetType(), cluster.GetClusterType(), cluster)
+		}
 		ret.ClusterType = ClusterTypeLogicalDNS
 		return ret, nil
 	case cluster.GetClusterType() != nil && cluster.GetClusterType().Name == "envoy.clusters.aggregate":
+		if !env.AggregateAndDNSSupportEnv {
+			return ClusterUpdate{}, fmt.Errorf("unsupported cluster type (%v, %v) in response: %+v", cluster.GetType(), cluster.GetClusterType(), cluster)
+		}
 		clusters := &v3aggregateclusterpb.ClusterConfig{}
 		if err := proto.Unmarshal(cluster.GetClusterType().GetTypedConfig().GetValue(), clusters); err != nil {
 			return ClusterUpdate{}, fmt.Errorf("failed to unmarshal resource: %v", err)
@@ -626,7 +632,7 @@ func validateClusterAndConstructClusterUpdate(cluster *v3clusterpb.Cluster) (Clu
 		ret.PrioritizedClusterNames = clusters.Clusters
 		return ret, nil
 	default:
-		return ClusterUpdate{}, fmt.Errorf("unexpected cluster type (%v, %v) in response: %+v", cluster.GetType(), cluster.GetClusterType(), cluster)
+		return ClusterUpdate{}, fmt.Errorf("unsupported cluster type (%v, %v) in response: %+v", cluster.GetType(), cluster.GetClusterType(), cluster)
 	}
 }