feat(translator): combine services across httproutes expression router

CHANGELOG.md

@@ -219,6 +219,7 @@ Adding a new version? You'll need three changes:
   where `<hash>` is the hash result of the calculated name, like
   `httproute.default.svc.default.a-long-long-long-service-name.80_combined.00001111222233334444aaaabbbbcccc`.
   [#6711](https://github.com/Kong/kubernetes-ingress-controller/pull/6711)
+  [#6766](https://github.com/Kong/kubernetes-ingress-controller/pull/6766)
 - The new tag `k8s-named-route-rule` is added to a Kong Route, in the case when mapped `HTTPRoute`, `GRPCRoute`,
   `TCPRoute`, `TLSRoute` or `UDPRoute` has one or many route rules named (filled `spec.rules[*].name` field),
   those names will be propagated to one or many instances of aforementioned tag.

internal/dataplane/testdata/golden/httproute-example/expression-routes-on_golden.yaml

@@ -1,9 +1,9 @@
 _format_version: "3.0"
 services:
 - connect_timeout: 60000
-  host: httproute.default.httproute-testing._.3
-  id: 23683d37-44ee-559b-add2-a0b650ad36c0
-  name: httproute.default.httproute-testing._.3
+  host: httproute.default.httproute-testing.3
+  id: efb4a7d7-791f-504e-b005-0bd38bf1435e
+  name: httproute.default.httproute-testing.3
   port: 8080
   protocol: http
   read_timeout: 60000
@@ -29,9 +29,9 @@ services:
   - k8s-version:v1
   write_timeout: 60000
 - connect_timeout: 60000
-  host: httproute.default.httproute-testing._.2
-  id: ff054481-b58a-588f-a8c4-e6cedb6cb489
-  name: httproute.default.httproute-testing._.2
+  host: httproute.default.httproute-testing.1
+  id: 672dc964-a7f8-5a80-a518-96fc39500cc8
+  name: httproute.default.httproute-testing.1
   port: 80
   protocol: http
   read_timeout: 60000
@@ -51,21 +51,6 @@ services:
     - k8s-group:gateway.networking.k8s.io
     - k8s-version:v1
     - k8s-named-route-rule:content
-  tags:
-  - k8s-name:httpbin
-  - k8s-namespace:default
-  - k8s-kind:Service
-  - k8s-version:v1
-  write_timeout: 60000
-- connect_timeout: 60000
-  host: httproute.default.httproute-testing._.1
-  id: 13be00e6-9c94-561f-9598-8896cd755468
-  name: httproute.default.httproute-testing._.1
-  port: 80
-  protocol: http
-  read_timeout: 60000
-  retries: 5
-  routes:
   - expression: (http.path == "/echo") || (http.path ^= "/echo/")
     https_redirect_status_code: 426
     id: 88d36cfe-fbb0-5d7a-93c1-df18d1db3a12
@@ -87,9 +72,9 @@ services:
   - k8s-version:v1
   write_timeout: 60000
 - connect_timeout: 60000
-  host: httproute.default.httproute-testing._.0
-  id: 2fad71d1-7599-5c6e-9d4f-4afd44f99587
-  name: httproute.default.httproute-testing._.0
+  host: httproute.default.httproute-testing.0
+  id: 4e3cb785-a8d0-5866-aa05-117f7c64f24d
+  name: httproute.default.httproute-testing.0
   port: 8080
   protocol: http
   read_timeout: 60000
@@ -118,28 +103,21 @@ services:
   write_timeout: 60000
 upstreams:
 - algorithm: round-robin
-  name: httproute.default.httproute-testing._.3
+  name: httproute.default.httproute-testing.3
   tags:
   - k8s-name:nginx
   - k8s-namespace:default
   - k8s-kind:Service
   - k8s-version:v1
 - algorithm: round-robin
-  name: httproute.default.httproute-testing._.2
-  tags:
-  - k8s-name:httpbin
-  - k8s-namespace:default
-  - k8s-kind:Service
-  - k8s-version:v1
-- algorithm: round-robin
-  name: httproute.default.httproute-testing._.1
+  name: httproute.default.httproute-testing.1
   tags:
   - k8s-name:httpbin
   - k8s-namespace:default
   - k8s-kind:Service
   - k8s-version:v1
 - algorithm: round-robin
-  name: httproute.default.httproute-testing._.0
+  name: httproute.default.httproute-testing.0
   tags:
   - k8s-name:httproute-testing
   - k8s-namespace:default

internal/dataplane/testdata/golden/httproute-url-rewrite-path-prefix/expression-routes-on_golden.yaml

@@ -1,9 +1,9 @@
 _format_version: "3.0"
 services:
 - connect_timeout: 60000
-  host: httproute.default.httproute-testing._.0
-  id: 2fad71d1-7599-5c6e-9d4f-4afd44f99587
-  name: httproute.default.httproute-testing._.0
+  host: httproute.default.httproute-testing.0
+  id: 4e3cb785-a8d0-5866-aa05-117f7c64f24d
+  name: httproute.default.httproute-testing.0
   port: 8080
   protocol: http
   read_timeout: 60000
@@ -42,7 +42,7 @@ services:
   write_timeout: 60000
 upstreams:
 - algorithm: round-robin
-  name: httproute.default.httproute-testing._.0
+  name: httproute.default.httproute-testing.0
   tags:
   - k8s-name:httproute-testing
   - k8s-namespace:default

internal/dataplane/translator/subtranslator/httproute.go

@@ -54,23 +54,52 @@ type HTTPRoutesTranslationResult struct {
 	HTTPRouteNameToTranslationErrors map[k8stypes.NamespacedName][]error
 }
 
+type splitHTTPRouteMatchesWithPrioritiesGroupedByRule map[string][]SplitHTTPRouteMatchToKongRoutePriority
+
 // TranslateHTTPRoutesToKongstateServices translates a set of HTTPRoutes to kongstate services,
 // and collect the translation errors in the process of translating.
 func TranslateHTTPRoutesToKongstateServices(
 	logger logr.Logger,
 	storer store.Storer,
 	routes []*gatewayapi.HTTPRoute,
 	combinedServicesFromDifferentHTTPRoutes bool,
+	expressionRoutes bool,
 ) HTTPRoutesTranslationResult {
 	serviceNameToRules := groupRulesFromHTTPRoutesByKongServiceName(routes, combinedServicesFromDifferentHTTPRoutes)
 
+	// When feature flag expression routes is enabled, we need first split the matches and assign priorities to them
+	// to set proper priorities to the translated Kong routes for satisfying the specification of priorities of HTTPRoute matches:
+	// https://gateway-api.sigs.k8s.io/reference/spec/#gateway.networking.k8s.io/v1.HTTPRouteRule
+	var ruleToSplitMatchesWithPriorities splitHTTPRouteMatchesWithPrioritiesGroupedByRule
+	if expressionRoutes {
+		ruleToSplitMatchesWithPriorities = groupHTTPRouteMatchesWithPrioritiesByRule(logger, routes)
+	}
+
 	kongstateServiceCache := map[string]kongstate.Service{}
 	routeTranslationErrors := map[k8stypes.NamespacedName][]error{}
 	for serviceName, rulesMeta := range serviceNameToRules {
 		if len(rulesMeta) == 0 {
 			continue
 		}
-		service, err := translateHTTPRouteRulesMetaToKongstateService(logger, storer, serviceName, rulesMeta)
+
+		// Sort the rules according to the namespace, name and rule number to guarantee a fixed order.
+		sort.SliceStable(rulesMeta, func(i, j int) bool {
+			return rulesMeta[i].getRuleKey() < rulesMeta[j].getRuleKey()
+		})
+
+		var matchesWithPriorities []SplitHTTPRouteMatchToKongRoutePriority
+		if expressionRoutes {
+			for _, ruleMeta := range rulesMeta {
+				ruleKey := ruleMeta.getRuleKey()
+				matchesWithPriorities = append(matchesWithPriorities, ruleToSplitMatchesWithPriorities[ruleKey]...)
+			}
+		}
+		service, err := translateHTTPRouteRulesMetaToKongstateService(
+			logger, storer, serviceName, rulesMeta,
+			expressionRoutes,
+			matchesWithPriorities,
+		)
+		// Set translation errors for involved HTTPRoutes on failure of translation.
 		if err != nil {
 			httpRoutes := extractUniqueHTTPRoutes(rulesMeta)
 			for _, route := range httpRoutes {
@@ -82,6 +111,7 @@ func TranslateHTTPRoutesToKongstateServices(
 			}
 			continue
 		}
+
 		kongstateServiceCache[serviceName] = service
 	}
 
@@ -165,6 +195,8 @@ func translateHTTPRouteRulesMetaToKongstateService(
 	storer store.Storer,
 	serviceName string,
 	rulesMeta []httpRouteRuleMeta,
+	expressionRoutes bool,
+	matchesWithPriorities []SplitHTTPRouteMatchToKongRoutePriority,
 ) (kongstate.Service, error) {
 	// Fill in the common fields of the kongstate.Service.
 	service := kongstate.Service{
@@ -235,13 +267,19 @@ func translateHTTPRouteRulesMetaToKongstateService(
 		applyTimeoutToServiceFromHTTPRouteRule(&service, ruleMeta.Rule)
 	}
 
-	routes, err := translateHTTPRouteRulesMetaToKongstateRoutes(rulesMeta)
-	if err != nil {
-		return kongstate.Service{}, err
+	if expressionRoutes {
+		routes, err := translateSplitHTTPRouteMatchesToKongstateRoutesWithExpression(matchesWithPriorities)
+		if err != nil {
+			return kongstate.Service{}, err
+		}
+		service.Routes = routes
+	} else {
+		routes, err := translateHTTPRouteRulesMetaToKongstateRoutes(rulesMeta)
+		if err != nil {
+			return kongstate.Service{}, err
+		}
+		service.Routes = routes
 	}
-	// preallocate slice for the routes.
-	service.Routes = make([]kongstate.Route, 0, len(routes))
-	service.Routes = append(service.Routes, routes...)
 
 	return service, nil
 }
@@ -428,6 +466,10 @@ func (m httpRouteRuleMeta) getHTTPBackendRefsKey() string {
 	return getSortedItemsString(m.Rule.BackendRefs)
 }
 
+func (m httpRouteRuleMeta) getRuleKey() string {
+	return fmt.Sprintf("%s/%s.%d", m.parentRoute.Namespace, m.parentRoute.Name, m.RuleNumber)
+}
+
 // getFiltersKey computes a key from a list of filters.
 // The order of the filters is not important.
 func (m httpRouteRuleMeta) getFiltersKey() string {
@@ -490,7 +532,6 @@ func (m httpRouteRuleMeta) getKongServiceNameByBackendRefs() string {
 		hash := sha256.Sum256([]byte(name))
 		// We have already returned when there are no backends in the rule, so it is safe to use backendNames[0].
 		trimmedName := fmt.Sprintf("httproute.%s.svc.%s_combined.%x", m.parentRoute.Namespace, backendNames[0], hash)
-		// REVIEW: should we emit a log here to tell that the name is trimmed? And should we record the original long name?
 		return trimmedName
 	}
 	return name

internal/dataplane/translator/subtranslator/httproute_atc.go

@@ -175,9 +175,6 @@ func pathMatcherFromHTTPPathMatch(pathMatch *gatewayapi.HTTPPathMatch) atc.Match
 			atc.NewPredicateHTTPPath(atc.OpPrefixMatch, path+"/"),
 		)
 	case gatewayapi.PathMatchRegularExpression:
-		// TODO: for compatibility with kong traditional routes, here we append the ^ prefix to match the path from beginning.
-		// Could we allow the regex to match any part of the path?
-		// https://github.com/Kong/kubernetes-ingress-controller/issues/3983
 		return atc.NewPredicateHTTPPath(atc.OpRegexMatch, appendRegexBeginIfNotExist(path))
 	}
 
@@ -454,14 +451,14 @@ func (t HTTPRoutePriorityTraits) EncodeToPriority() RoutePriorityType {
 	return priority
 }
 
-// AssignRoutePriorityToSplitHTTPRouteMatches assigns priority to
+// assignRoutePriorityToSplitHTTPRouteMatches assigns priority to
 // ALL split matches from ALL HTTPRoutes in the cache.
 // Firstly assign "fixed" bits by the following fields of the match:
 // hostname, path type, path length, method match, number of header matches, number of query param matches.
 // If ties exists in the first step, where multiple matches has the same priority
 // calculated from the fields, we run a sort for the matches in the tie
 // and assign the bits for "relative order" according to the sorting result of these matches.
-func AssignRoutePriorityToSplitHTTPRouteMatches(
+func assignRoutePriorityToSplitHTTPRouteMatches(
 	logger logr.Logger,
 	splitHTTPRouteMatches []SplitHTTPRouteMatch,
 ) []SplitHTTPRouteMatchToKongRoutePriority {
@@ -544,9 +541,9 @@ func compareSplitHTTPRouteMatchesRelativePriority(match1, match2 SplitHTTPRouteM
 	return true
 }
 
-// KongExpressionRouteFromHTTPRouteMatchWithPriority translates a split HTTPRoute match into expression
+// kongExpressionRouteFromHTTPRouteMatchWithPriority translates a split HTTPRoute match into expression
 // based kong route with assigned priority.
-func KongExpressionRouteFromHTTPRouteMatchWithPriority(
+func kongExpressionRouteFromHTTPRouteMatchWithPriority(
 	httpRouteMatchWithPriority SplitHTTPRouteMatchToKongRoutePriority,
 ) (*kongstate.Route, error) {
 	match := httpRouteMatchWithPriority.Match
@@ -610,20 +607,44 @@ func KongExpressionRouteFromHTTPRouteMatchWithPriority(
 	return r, nil
 }
 
-// KongServiceNameFromSplitHTTPRouteMatch generates service name from split HTTPRoute match.
-// since one HTTPRoute may be split by hostname and rule, the service name will be generated
-// in the format "httproute.<namespace>.<name>.<hostname>.<rule index>".
-// For example: `httproute.default.example.foo.com.0`.
-func KongServiceNameFromSplitHTTPRouteMatch(match SplitHTTPRouteMatch) string {
-	httproute := match.Source
-	hostname := "_"
-	if len(match.Hostname) > 0 {
-		hostname = strings.ReplaceAll(match.Hostname, "*", "_")
+// groupHTTPRouteMatchesWithPrioritiesByRule groups split HTTPRoute matches that has priorities assigned by the source HTTPRoute rule,.
+func groupHTTPRouteMatchesWithPrioritiesByRule(
+	logger logr.Logger, routes []*gatewayapi.HTTPRoute,
+) splitHTTPRouteMatchesWithPrioritiesGroupedByRule {
+	splitHTTPRouteMatches := []SplitHTTPRouteMatch{}
+	for _, route := range routes {
+		splitHTTPRouteMatches = append(splitHTTPRouteMatches, SplitHTTPRoute(route)...)
+	}
+	// assign priorities to split HTTPRoutes.
+	splitHTTPRouteMatchesWithPriorities := assignRoutePriorityToSplitHTTPRouteMatches(logger, splitHTTPRouteMatches)
+
+	// group the matches with priorities by its source HTTPRoute rule.
+	ruleToSplitMatchesWithPriorities := splitHTTPRouteMatchesWithPrioritiesGroupedByRule{}
+	for _, matchWithPriority := range splitHTTPRouteMatchesWithPriorities {
+		sourceRoute := matchWithPriority.Match.Source
+		ruleKey := fmt.Sprintf("%s/%s.%d", sourceRoute.Namespace, sourceRoute.Name, matchWithPriority.Match.RuleIndex)
+		ruleToSplitMatchesWithPriorities[ruleKey] = append(ruleToSplitMatchesWithPriorities[ruleKey], matchWithPriority)
+	}
+	return ruleToSplitMatchesWithPriorities
+}
+
+// translateSplitHTTPRouteMatchesToKongstateRoutesWithExpression translates a list of split HTTPRoute matches with assigned priorities
+// that are poiting to the same service to list of kongstate route with expressions.
+func translateSplitHTTPRouteMatchesToKongstateRoutesWithExpression(
+	matchesWithPriorities []SplitHTTPRouteMatchToKongRoutePriority,
+) ([]kongstate.Route, error) {
+	routes := make([]kongstate.Route, 0, len(matchesWithPriorities))
+	for _, matchWithPriority := range matchesWithPriorities {
+		// Since each match is assigned a deterministic priority, we have to generate one route for each split match
+		// because every match have a different priority.
+		// TODO: update the algorithm to assign priorities to matches to make it possible to consolidate some matches.
+		// For example, we can assign the same priority to multiple matches from the same rule if they tie on the priority from the fixed fields:
+		// https://github.com/Kong/kubernetes-ingress-controller/issues/6807
+		route, err := kongExpressionRouteFromHTTPRouteMatchWithPriority(matchWithPriority)
+		if err != nil {
+			return []kongstate.Route{}, err
+		}
+		routes = append(routes, *route)
 	}
-	return fmt.Sprintf("httproute.%s.%s.%s.%d",
-		httproute.Namespace,
-		httproute.Name,
-		hostname,
-		match.RuleIndex,
-	)
+	return routes, nil
 }