From f0280f9d3d2f3fbe45de1ab5873a19ec678c74c8 Mon Sep 17 00:00:00 2001
From: Doug Fawley <dfawley@google.com>
Date: Tue, 11 Jul 2023 08:52:37 -0700
Subject: [PATCH] xds: require EDS service name in new-style CDS clusters (gRFC
 A47) (#6438)

---
 .../xdsclient/xdsresource/unmarshal_cds.go      |  4 ++++
 .../xdsclient/xdsresource/unmarshal_cds_test.go | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/xds/internal/xdsclient/xdsresource/unmarshal_cds.go b/xds/internal/xdsclient/xdsresource/unmarshal_cds.go
index 9f8530111a7..cb1d0b2dfdc 100644
--- a/xds/internal/xdsclient/xdsresource/unmarshal_cds.go
+++ b/xds/internal/xdsclient/xdsresource/unmarshal_cds.go
@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"net"
 	"strconv"
+	"strings"
 	"time"
 
 	v3clusterpb "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
@@ -173,6 +174,9 @@ func validateClusterAndConstructClusterUpdate(cluster *v3clusterpb.Cluster) (Clu
 		}
 		ret.ClusterType = ClusterTypeEDS
 		ret.EDSServiceName = cluster.GetEdsClusterConfig().GetServiceName()
+		if strings.HasPrefix(ret.ClusterName, "xdstp:") && ret.EDSServiceName == "" {
+			return ClusterUpdate{}, fmt.Errorf("CDS's EDS service name is not set with a new-style cluster name: %+v", cluster)
+		}
 		return ret, nil
 	case cluster.GetType() == v3clusterpb.Cluster_LOGICAL_DNS:
 		if !envconfig.XDSAggregateAndDNS {
diff --git a/xds/internal/xdsclient/xdsresource/unmarshal_cds_test.go b/xds/internal/xdsclient/xdsresource/unmarshal_cds_test.go
index e057b951326..67f0f7896b2 100644
--- a/xds/internal/xdsclient/xdsresource/unmarshal_cds_test.go
+++ b/xds/internal/xdsclient/xdsresource/unmarshal_cds_test.go
@@ -1347,6 +1347,23 @@ func (s) TestUnmarshalCluster(t *testing.T) {
 				Raw: v3ClusterAnyWithEDSConfigSourceSelf,
 			},
 		},
+		{
+			name: "xdstp cluster resource with unset EDS service name",
+			resource: testutils.MarshalAny(&v3clusterpb.Cluster{
+				Name:                 "xdstp:foo",
+				ClusterDiscoveryType: &v3clusterpb.Cluster_Type{Type: v3clusterpb.Cluster_EDS},
+				EdsClusterConfig: &v3clusterpb.Cluster_EdsClusterConfig{
+					EdsConfig: &v3corepb.ConfigSource{
+						ConfigSourceSpecifier: &v3corepb.ConfigSource_Ads{
+							Ads: &v3corepb.AggregatedConfigSource{},
+						},
+					},
+					ServiceName: "",
+				},
+			}),
+			wantName: "xdstp:foo",
+			wantErr:  true,
+		},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {