add clusters without endpoint (TODO)

agent/xds/clusters.go

@@ -266,6 +266,69 @@ func makePassthroughClusters(cfgSnap *proxycfg.ConfigSnapshot) ([]proto.Message,
 		}
 	}
 
+	for uid, entry := range cfgSnap.ConnectProxy.DestinationsUpstream {
+		_, ok := entry.(*structs.ServiceConfigEntry)
+		if !ok {
+			continue
+		}
+		sni := connect.ServiceSNI(
+			uid.Name, "", uid.NamespaceOrDefault(), uid.PartitionOrDefault(), cfgSnap.Datacenter, cfgSnap.Roots.TrustDomain)
+
+		// Prefixed with passthrough to distinguish from non-passthrough clusters for the same upstream.
+		name := "passthrough~" + sni
+
+		c := envoy_cluster_v3.Cluster{
+			Name: name,
+			ClusterDiscoveryType: &envoy_cluster_v3.Cluster_Type{
+				Type: envoy_cluster_v3.Cluster_STATIC,
+			},
+			LbPolicy: envoy_cluster_v3.Cluster_CLUSTER_PROVIDED,
+
+			ConnectTimeout: durationpb.New(5 * time.Second),
+		}
+		endpoints := []*envoy_endpoint_v3.LbEndpoint{
+			// TODO(egress-gtwy): use terminating gateway IPs
+			//makeEndpoint(opts.addressEndpoint.Address, opts.addressEndpoint.Port),
+		}
+
+		c.LoadAssignment = &envoy_endpoint_v3.ClusterLoadAssignment{
+			ClusterName: c.Name,
+			Endpoints: []*envoy_endpoint_v3.LocalityLbEndpoints{
+				{
+					LbEndpoints: endpoints,
+				},
+			},
+		}
+
+		spiffeID := connect.SpiffeIDService{
+			Host:       cfgSnap.Roots.TrustDomain,
+			Partition:  uid.PartitionOrDefault(),
+			Namespace:  uid.NamespaceOrDefault(),
+			Datacenter: cfgSnap.Datacenter,
+			Service:    uid.Name,
+		}
+
+		commonTLSContext := makeCommonTLSContext(
+			cfgSnap.Leaf(),
+			cfgSnap.RootPEMs(),
+			makeTLSParametersFromProxyTLSConfig(cfgSnap.MeshConfigTLSOutgoing()),
+		)
+		err := injectSANMatcher(commonTLSContext, spiffeID.URI().String())
+		if err != nil {
+			return nil, fmt.Errorf("failed to inject SAN matcher rules for cluster %q: %v", sni, err)
+		}
+		tlsContext := envoy_tls_v3.UpstreamTlsContext{
+			CommonTlsContext: commonTLSContext,
+			Sni:              sni,
+		}
+		transportSocket, err := makeUpstreamTLSTransportSocket(&tlsContext)
+		if err != nil {
+			return nil, err
+		}
+		c.TransportSocket = transportSocket
+		clusters = append(clusters, &c)
+	}
+
 	return clusters, nil
 }