[NET-5457] Golden Files for Multiple Virtual Hosts (#19131)

* Add new golden file tests

* Update with latest deterministic code

agent/xds/routes.go

@@ -15,6 +15,7 @@ import (
 	envoy_route_v3 "github.com/envoyproxy/go-control-plane/envoy/config/route/v3"
 	envoy_matcher_v3 "github.com/envoyproxy/go-control-plane/envoy/type/matcher/v3"
 	"golang.org/x/exp/maps"
+	"golang.org/x/exp/slices"
 
 	"google.golang.org/protobuf/proto"
 	"google.golang.org/protobuf/types/known/durationpb"
@@ -435,9 +436,15 @@ func (s *ResourceGenerator) routesForIngressGateway(cfgSnap *proxycfg.ConfigSnap
 func (s *ResourceGenerator) routesForAPIGateway(cfgSnap *proxycfg.ConfigSnapshot) ([]proto.Message, error) {
 	var result []proto.Message
 
+	// Build up the routes in a deterministic way
 	readyListeners := getReadyListeners(cfgSnap)
-
+	listenerNames := maps.Keys(readyListeners)
-	for _, readyListener := range readyListeners {
+	sort.Strings(listenerNames)
+	for _, listenerName := range listenerNames {
+		readyListener, ok := readyListeners[listenerName]
+		if !ok {
+			continue
+		}
 		// Do not create any route configuration for TCP listeners
 		if readyListener.listenerCfg.Protocol != structs.ListenerProtocolHTTP {
 			continue
@@ -466,6 +473,7 @@ func (s *ResourceGenerator) routesForAPIGateway(cfgSnap *proxycfg.ConfigSnapshot
 		// Gateway + HTTPRoutes, then the virtual host will be "*".
 		for _, consolidatedRoute := range consolidatedRoutes {
 			upstream := buildHTTPRouteUpstream(consolidatedRoute, readyListener.listenerCfg)
+			// Consolidate all routes for this listener into the minimum possible set based on hostname matching.
 			uid := proxycfg.NewUpstreamID(&upstream)
 			chain := cfgSnap.APIGateway.DiscoveryChain[uid]
 			if chain == nil {
@@ -485,6 +493,13 @@ func (s *ResourceGenerator) routesForAPIGateway(cfgSnap *proxycfg.ConfigSnapshot
 		}
 
 		if len(listenerRoute.VirtualHosts) > 0 {
+			// Build up the virtual hosts in a deterministic way
+			slices.SortStableFunc(listenerRoute.VirtualHosts, func(a, b *envoy_route_v3.VirtualHost) int {
+				if a.Name < b.Name {
+					return -1
+				}
+				return 1
+			})
 			result = append(result, listenerRoute)
 		}
 	}

agent/xds/routes_test.go

@@ -262,6 +262,65 @@ func TestRoutesFromSnapshot(t *testing.T) {
 			// TODO(proxystate): terminating gateway will come at a later time
 			alsoRunTestForV2: false,
 		},
+		{
+			name: "api-gateway-with-multiple-hostnames",
+			create: func(t testinf.T) *proxycfg.ConfigSnapshot {
+				return proxycfg.TestConfigSnapshotAPIGateway(t, "default", nil, func(entry *structs.APIGatewayConfigEntry, bound *structs.BoundAPIGatewayConfigEntry) {
+					entry.Listeners = []structs.APIGatewayListener{
+						{
+							Name:     "http",
+							Protocol: structs.ListenerProtocolHTTP,
+							Port:     8080,
+							Hostname: "*.example.com",
+						},
+					}
+					bound.Listeners = []structs.BoundAPIGatewayListener{
+						{
+							Name: "http",
+							Routes: []structs.ResourceReference{
+								{Kind: structs.HTTPRoute, Name: "backend-route"},
+								{Kind: structs.HTTPRoute, Name: "frontend-route"},
+								{Kind: structs.HTTPRoute, Name: "generic-route"},
+							}},
+					}
+				},
+					[]structs.BoundRoute{
+						&structs.HTTPRouteConfigEntry{
+							Kind:      structs.HTTPRoute,
+							Name:      "backend-route",
+							Hostnames: []string{"backend.example.com"},
+							Parents:   []structs.ResourceReference{{Kind: structs.APIGateway, Name: "api-gateway"}},
+							Rules: []structs.HTTPRouteRule{
+								{Services: []structs.HTTPService{{Name: "backend"}}},
+							},
+						},
+						&structs.HTTPRouteConfigEntry{
+							Kind:      structs.HTTPRoute,
+							Name:      "frontend-route",
+							Hostnames: []string{"frontend.example.com"},
+							Parents:   []structs.ResourceReference{{Kind: structs.APIGateway, Name: "api-gateway"}},
+							Rules: []structs.HTTPRouteRule{
+								{Services: []structs.HTTPService{{Name: "frontend"}}},
+							},
+						},
+						&structs.HTTPRouteConfigEntry{
+							Kind:    structs.HTTPRoute,
+							Name:    "generic-route",
+							Parents: []structs.ResourceReference{{Kind: structs.APIGateway, Name: "api-gateway"}},
+							Rules: []structs.HTTPRouteRule{
+								{
+									Matches:  []structs.HTTPMatch{{Path: structs.HTTPPathMatch{Match: structs.HTTPPathMatchPrefix, Value: "/frontend"}}},
+									Services: []structs.HTTPService{{Name: "frontend"}},
+								},
+								{
+									Matches:  []structs.HTTPMatch{{Path: structs.HTTPPathMatch{Match: structs.HTTPPathMatchPrefix, Value: "/backend"}}},
+									Services: []structs.HTTPService{{Name: "backend"}},
+								},
+							},
+						},
+					}, nil, nil)
+			},
+		},
 	}
 
 	tests = append(tests, makeRouteDiscoChainTests(false)...)

agent/xds/testdata/routes/api-gateway-with-multiple-hostnames.latest.golden

@@ -0,0 +1,87 @@
+{
+  "nonce": "00000001",
+  "resources": [
+    {
+      "@type": "type.googleapis.com/envoy.config.route.v3.RouteConfiguration",
+      "name": "8080",
+      "validateClusters": true,
+      "virtualHosts": [
+        {
+          "domains": [
+            "backend.example.com",
+            "backend.example.com:8080"
+          ],
+          "name": "api-gateway-http-5a84e719",
+          "routes": [
+            {
+              "match": {
+                "prefix": "/"
+              },
+              "route": {
+                "cluster": "backend.default.dc1.internal.11111111-2222-3333-4444-555555555555.consul"
+              }
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "@type": "type.googleapis.com/envoy.config.route.v3.RouteConfiguration",
+      "name": "8080",
+      "validateClusters": true,
+      "virtualHosts": [
+        {
+          "domains": [
+            "frontend.example.com",
+            "frontend.example.com:8080"
+          ],
+          "name": "api-gateway-http-54620b06",
+          "routes": [
+            {
+              "match": {
+                "prefix": "/"
+              },
+              "route": {
+                "cluster": "frontend.default.dc1.internal.11111111-2222-3333-4444-555555555555.consul"
+              }
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "@type": "type.googleapis.com/envoy.config.route.v3.RouteConfiguration",
+      "name": "8080",
+      "validateClusters": true,
+      "virtualHosts": [
+        {
+          "domains": [
+            "*.example.com",
+            "*.example.com:8080"
+          ],
+          "name": "api-gateway-http-aa289ce2",
+          "routes": [
+            {
+              "match": {
+                "prefix": "/frontend"
+              },
+              "route": {
+                "cluster": "frontend.default.dc1.internal.11111111-2222-3333-4444-555555555555.consul"
+              }
+            },
+            {
+              "match": {
+                "prefix": "/backend"
+              },
+              "route": {
+                "cluster": "backend.default.dc1.internal.11111111-2222-3333-4444-555555555555.consul"
+              }
+            }
+          ]
+        }
+      ]
+    }
+  ],
+  "typeUrl": "type.googleapis.com/envoy.config.route.v3.RouteConfiguration",
+  "versionInfo": "00000001"
+}