fix(parser) add HTTPRoute combined services routes

Add support for combined service routes when parsing gw api HTTPRoutes

internal/dataplane/parser/translate_httproute.go

@@ -59,28 +59,65 @@ func (p *Parser) ingressRulesFromHTTPRoute(result *ingressRules, httproute *gate
 		return fmt.Errorf("no rules provided")
 	}
 
-	// each rule may represent a different set of backend services that will be accepting
-	// traffic, so we make separate routes and Kong services for every present rule.
-	for ruleNumber, rule := range spec.Rules {
+	for _, rule := range spec.Rules {
 		// TODO: add this to a generic HTTPRoute validation, and then we should probably
 		//       simply be calling validation on each httproute object at the begininning
 		//       of the topmost list.
 		if len(rule.BackendRefs) == 0 {
 			return fmt.Errorf("missing backendRef in rule")
 		}
+	}
+
+	if p.featureEnabledCombinedServiceRoutes {
+		return p.ingressRulesFromHTTPRouteWithCombinedServiceRoutes(httproute, result)
+	}
+
+	return p.ingressRulesFromHTTPRouteLegacyFallback(httproute, result)
+}
+
+func (p *Parser) ingressRulesFromHTTPRouteWithCombinedServiceRoutes(httproute *gatewayv1beta1.HTTPRoute, result *ingressRules) error {
+	for i, translationMeta := range translators.TranslateHTTPRoute(httproute) {
+		// HTTPRoute uses a wrapper HTTPBackendRef to add optional filters to its BackendRefs
+		backendRefs := httpBackendRefsToBackendRefs(translationMeta.BackendRefs)
+
+		// create a service and attach the routes to it
+		service, err := generateKongServiceFromBackendRef(p.logger, p.storer, result, httproute, i, "http", backendRefs...)
+		if err != nil {
+			return err
+		}
+
+		// generate the routes for the service and attach them to the service
+		for ruleNumber, rule := range translationMeta.Rules {
+			routes, err := generateKongRoutesFromHTTPRouteRule(httproute, ruleNumber, rule, p.flagEnabledRegexPathPrefix)
+			if err != nil {
+				return err
+			}
+			service.Routes = append(service.Routes, routes...)
+		}
+
+		// cache the service to avoid duplicates in further loop iterations
+		result.ServiceNameToServices[*service.Service.Name] = service
+	}
+
+	return nil
+}
+
+// ingressRulesFromHTTPRouteLegacyFallback is to be depracated in favor of the combined service routes.
+func (p *Parser) ingressRulesFromHTTPRouteLegacyFallback(httproute *gatewayv1beta1.HTTPRoute, result *ingressRules) error {
+	// each rule may represent a different set of backend services that will be accepting
+	// traffic, so we make separate routes and Kong services for every present rule.
+	for ruleNumber, rule := range httproute.Spec.Rules {
 
 		// determine the routes needed to route traffic to services for this rule
 		routes, err := generateKongRoutesFromHTTPRouteRule(httproute, ruleNumber, rule, p.flagEnabledRegexPathPrefix)
 		if err != nil {
 			return err
 		}
 
-		// create a service and attach the routes to it
-		var backendRefs []gatewayv1beta1.BackendRef
 		// HTTPRoute uses a wrapper HTTPBackendRef to add optional filters to its BackendRefs
-		for _, hRef := range rule.BackendRefs {
-			backendRefs = append(backendRefs, hRef.BackendRef)
-		}
+		backendRefs := httpBackendRefsToBackendRefs(rule.BackendRefs)
+
+		// create a service and attach the routes to it
 		service, err := generateKongServiceFromBackendRef(p.logger, p.storer, result, httproute, ruleNumber, "http", backendRefs...)
 		if err != nil {
 			return err
@@ -90,7 +127,6 @@ func (p *Parser) ingressRulesFromHTTPRoute(result *ingressRules, httproute *gate
 		// cache the service to avoid duplicates in further loop iterations
 		result.ServiceNameToServices[*service.Service.Name] = service
 	}
-
 	return nil
 }
 
@@ -317,3 +353,12 @@ func generateRequestHeaderModifierKongPlugin(modifier *gatewayv1beta1.HTTPReques
 func kongHeaderFormatter(header gatewayv1beta1.HTTPHeader) string {
 	return fmt.Sprintf("%s:%s", header.Name, header.Value)
 }
+
+func httpBackendRefsToBackendRefs(httpBackendRef []gatewayv1beta1.HTTPBackendRef) []gatewayv1beta1.BackendRef {
+	var backendRefs []gatewayv1beta1.BackendRef
+
+	for _, hRef := range httpBackendRef {
+		backendRefs = append(backendRefs, hRef.BackendRef)
+	}
+	return backendRefs
+}

internal/dataplane/parser/translate_httproute_test.go

@@ -38,7 +38,10 @@ var (
 func TestIngressRulesFromHTTPRoutes(t *testing.T) {
 	fakestore, err := store.NewFakeStore(store.FakeObjects{})
 	require.NoError(t, err)
-	p := NewParser(logrus.New(), fakestore)
+	parser := NewParser(logrus.New(), fakestore)
+	parserWithCombinedServiceRoutes := NewParser(logrus.New(), fakestore)
+	parserWithCombinedServiceRoutes.EnableCombinedServiceRoutes()
+
 	httpPort := gatewayv1beta1.PortNumber(80)
 
 	for _, tt := range []struct {
@@ -640,27 +643,32 @@ func TestIngressRulesFromHTTPRoutes(t *testing.T) {
 			},
 		},
 	} {
-		t.Run(tt.msg, func(t *testing.T) {
-			ingressRules := newIngressRules()
+		withParser := func(p *Parser) func(t *testing.T) {
+			return func(t *testing.T) {
+				ingressRules := newIngressRules()
 
-			var errs []error
-			for _, httproute := range tt.routes {
-				// initialize the HTTPRoute object
-				httproute.SetGroupVersionKind(httprouteGVK)
+				var errs []error
+				for _, httproute := range tt.routes {
+					// initialize the HTTPRoute object
+					httproute.SetGroupVersionKind(httprouteGVK)
 
-				// generate the ingress rules
-				err := p.ingressRulesFromHTTPRoute(&ingressRules, httproute)
-				if err != nil {
-					errs = append(errs, err)
+					// generate the ingress rules
+					err := p.ingressRulesFromHTTPRoute(&ingressRules, httproute)
+					if err != nil {
+						errs = append(errs, err)
+					}
 				}
-			}
 
-			// verify that we receive the expected values
-			assert.Equal(t, tt.expected, ingressRules)
+				// verify that we receive the expected values
+				assert.Equal(t, tt.expected, ingressRules)
 
-			// verify that we receive any and all expected errors
-			assert.Equal(t, tt.errs, errs)
-		})
+				// verify that we receive any and all expected errors
+				assert.Equal(t, tt.errs, errs)
+			}
+		}
+
+		t.Run(tt.msg+" using lagacy parser", withParser(parser))
+		t.Run(tt.msg+" using combined service routes parser", withParser(parserWithCombinedServiceRoutes))
 	}
 }
 
@@ -715,8 +723,11 @@ func TestGetHTTPRouteHostnamesAsSliceOfStringPointers(t *testing.T) {
 func TestIngressRulesFromHTTPRoutes_RegexPrefix(t *testing.T) {
 	fakestore, err := store.NewFakeStore(store.FakeObjects{})
 	require.NoError(t, err)
-	p := NewParser(logrus.New(), fakestore)
-	p.EnableRegexPathPrefix()
+	parser := NewParser(logrus.New(), fakestore)
+	parser.EnableRegexPathPrefix()
+	parserWithCombinedServiceRoutes := NewParser(logrus.New(), fakestore)
+	parserWithCombinedServiceRoutes.EnableRegexPathPrefix()
+	parserWithCombinedServiceRoutes.EnableCombinedServiceRoutes()
 	httpPort := gatewayv1beta1.PortNumber(80)
 
 	for _, tt := range []struct {
@@ -849,26 +860,31 @@ func TestIngressRulesFromHTTPRoutes_RegexPrefix(t *testing.T) {
 			},
 		},
 	} {
-		t.Run(tt.msg, func(t *testing.T) {
-			ingressRules := newIngressRules()
+		withParser := func(p *Parser) func(t *testing.T) {
+			return func(t *testing.T) {
+				ingressRules := newIngressRules()
 
-			var errs []error
-			for _, httproute := range tt.routes {
-				// initialize the HTTPRoute object
-				httproute.SetGroupVersionKind(httprouteGVK)
+				var errs []error
+				for _, httproute := range tt.routes {
+					// initialize the HTTPRoute object
+					httproute.SetGroupVersionKind(httprouteGVK)
 
-				// generate the ingress rules
-				err := p.ingressRulesFromHTTPRoute(&ingressRules, httproute)
-				if err != nil {
-					errs = append(errs, err)
+					// generate the ingress rules
+					err := p.ingressRulesFromHTTPRoute(&ingressRules, httproute)
+					if err != nil {
+						errs = append(errs, err)
+					}
 				}
-			}
 
-			// verify that we receive the expected values
-			assert.Equal(t, tt.expected, ingressRules)
+				// verify that we receive the expected values
+				assert.Equal(t, tt.expected, ingressRules)
 
-			// verify that we receive any and all expected errors
-			assert.Equal(t, tt.errs, errs)
-		})
+				// verify that we receive any and all expected errors
+				assert.Equal(t, tt.errs, errs)
+			}
+		}
+
+		t.Run(tt.msg+" using lagacy parser", withParser(parser))
+		t.Run(tt.msg+" using combined service routes parser", withParser(parserWithCombinedServiceRoutes))
 	}
 }

internal/dataplane/parser/translators/httproute.go

@@ -0,0 +1,124 @@
+package translators
+
+import (
+	"sort"
+	"strconv"
+	"strings"
+
+	gatewayv1beta1 "sigs.k8s.io/gateway-api/apis/v1beta1"
+)
+
+// HTTPRouteTranslationMeta is a translation of a single HTTPRoute into metadata
+// that can be used to instantiate Kong routes and services.
+// Rules from this object should route traffic to the BAckendRefs from this object.
+type HTTPRouteTranslationMeta struct {
+	BackendRefs []gatewayv1beta1.HTTPBackendRef
+	Rules       []gatewayv1beta1.HTTPRouteRule
+}
+
+// TranslateHTTPRoutes translates a list of HTTPRoutes into a list of HTTPRouteTranslationMeta
+// objects that can be used to instantiate Kong routes and services.
+// The translation is done by grouping the HTTPRoutes by their backendRefs.
+// This means that all the rules of a single HTTPRoute will be grouped together
+// if they share the same backendRefs.
+func TranslateHTTPRoute(route *gatewayv1beta1.HTTPRoute) []*HTTPRouteTranslationMeta {
+	index := newHTTPRouteTranslationIndex()
+	index.addRoute(route)
+	return index.translate()
+}
+
+// -----------------------------------------------------------------------------
+// HTTPRoute Translation - Private - Index
+// -----------------------------------------------------------------------------
+
+// httpRouteTranslationIndex aggregates all rules routing to the same backends group.
+type httpRouteTranslationIndex struct {
+	backendsRules map[httpBackendRefsKey][]gatewayv1beta1.HTTPRouteRule
+}
+
+// newHTTPRouteTranslationIndex creates a new httpRouteTranslationIndex.
+func newHTTPRouteTranslationIndex() *httpRouteTranslationIndex {
+	return &httpRouteTranslationIndex{
+		backendsRules: make(map[httpBackendRefsKey][]gatewayv1beta1.HTTPRouteRule),
+	}
+}
+
+// addRoute an HTTPRoute to the index, grouping the rules by their backendRefs.
+func (i *httpRouteTranslationIndex) addRoute(route *gatewayv1beta1.HTTPRoute) {
+	for _, rule := range route.Spec.Rules {
+		backendRefsKey := getHTTPBackendRefsKey(rule.BackendRefs...)
+		i.backendsRules[backendRefsKey] = append(i.backendsRules[backendRefsKey], rule)
+	}
+}
+
+// translate the index into a list of HTTPRouteTranslationMeta objects.
+func (i *httpRouteTranslationIndex) translate() []*HTTPRouteTranslationMeta {
+	translations := make([]*HTTPRouteTranslationMeta, 0)
+	for _, rules := range i.backendsRules {
+		// get the backendRefs from any rule, as they are all the same
+		backendRefs := rules[0].BackendRefs
+
+		translations = append(translations, &HTTPRouteTranslationMeta{
+			BackendRefs: backendRefs,
+			Rules:       rules,
+		})
+	}
+
+	return translations
+}
+
+// -----------------------------------------------------------------------------
+// HttpRoute Translation - Private - Metadata
+// -----------------------------------------------------------------------------
+
+// httpBackendRefsKey is a key computed from a list of backendRefs.
+type httpBackendRefsKey string
+
+// getHTTPBackendRefsKey computes a key from a list of backendRefs.
+func getHTTPBackendRefsKey(backendRefs ...gatewayv1beta1.HTTPBackendRef) httpBackendRefsKey {
+	backendKeys := make([]string, 0, len(backendRefs))
+
+	// create a list of backend keys
+	for _, backendRef := range backendRefs {
+		var backendKey strings.Builder
+
+		if backendRef.Group != nil {
+			backendKey.WriteString(string(*backendRef.Group))
+		}
+		backendKey.WriteString(".")
+
+		if backendRef.Kind != nil {
+			backendKey.WriteString(string(*backendRef.Kind))
+		}
+		backendKey.WriteString(".")
+
+		if backendRef.Namespace != nil {
+			backendKey.WriteString(string(*backendRef.Namespace))
+		}
+		backendKey.WriteString(".")
+
+		backendKey.WriteString(string(backendRef.Name))
+		backendKey.WriteString(".")
+
+		if backendRef.Port != nil {
+			backendKey.WriteString(strconv.Itoa(int(*backendRef.Port)))
+		}
+		backendKey.WriteString(".")
+
+		if backendRef.Weight != nil {
+			backendKey.WriteString(strconv.Itoa(int(*backendRef.Weight)))
+		}
+
+		backendKeys = append(backendKeys, backendKey.String())
+	}
+	sort.Strings(backendKeys)
+
+	// create a string representation of the backend keys
+	var keyBuilder strings.Builder
+	for _, backendKey := range backendKeys {
+		keyBuilder.WriteString(backendKey)
+		keyBuilder.WriteString(";")
+	}
+
+	return httpBackendRefsKey(keyBuilder.String())
+}