Migrate all providers to the new interface.

* Providers now should implement ResourcesToIRConverter interface and
  IRToGatewayAPIConverter interface.

pkg/i2gw/ingress2gateway.go

@@ -19,18 +19,13 @@ package i2gw
 import (
 	"context"
 	"fmt"
-	"maps"
 
 	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/notifications"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/config"
-	gatewayv1 "sigs.k8s.io/gateway-api/apis/v1"
-	gatewayv1alpha2 "sigs.k8s.io/gateway-api/apis/v1alpha2"
-	gatewayv1beta1 "sigs.k8s.io/gateway-api/apis/v1beta1"
 )
 
 func ToGatewayAPIResources(ctx context.Context, namespace string, inputFile string, providers []string, providerSpecificFlags map[string]map[string]string) ([]GatewayResources, map[string]string, error) {
@@ -73,7 +68,9 @@ func ToGatewayAPIResources(ctx context.Context, namespace string, inputFile stri
 		errs             field.ErrorList
 	)
 	for _, provider := range providerByName {
-		providerGatewayResources, conversionErrs := provider.ToGatewayAPI()
+		ir, conversionErrs := provider.ToIR()
+		errs = append(errs, conversionErrs...)
+		providerGatewayResources, conversionErrs := provider.ToGatewayResources(ir)
 		errs = append(errs, conversionErrs...)
 		gatewayResources = append(gatewayResources, providerGatewayResources)
 	}
@@ -138,69 +135,6 @@ func GetSupportedProviders() []string {
 	return supportedProviders
 }
 
-// MergeGatewayResources accept multiple GatewayResources and create a unique Resource struct
-// built as follows:
-//   - GatewayClasses, *Routes, and ReferenceGrants are grouped into the same maps
-//   - Gateways may have the same NamespaceName even if they come from different
-//     ingresses, as they have a their GatewayClass' name as name. For this reason,
-//     if there are mutiple gateways named the same, their listeners are merged into
-//     a unique Gateway.
-//
-// This behavior is likely to change after https://github.com/kubernetes-sigs/gateway-api/pull/1863 takes place.
-func MergeGatewayResources(gatewayResources ...GatewayResources) (GatewayResources, field.ErrorList) {
-	mergedGatewayResources := GatewayResources{
-		Gateways:        make(map[types.NamespacedName]gatewayv1.Gateway),
-		GatewayClasses:  make(map[types.NamespacedName]gatewayv1.GatewayClass),
-		HTTPRoutes:      make(map[types.NamespacedName]gatewayv1.HTTPRoute),
-		TLSRoutes:       make(map[types.NamespacedName]gatewayv1alpha2.TLSRoute),
-		TCPRoutes:       make(map[types.NamespacedName]gatewayv1alpha2.TCPRoute),
-		UDPRoutes:       make(map[types.NamespacedName]gatewayv1alpha2.UDPRoute),
-		ReferenceGrants: make(map[types.NamespacedName]gatewayv1beta1.ReferenceGrant),
-	}
-	var errs field.ErrorList
-	mergedGatewayResources.Gateways, errs = mergeGateways(gatewayResources)
-	if len(errs) > 0 {
-		return GatewayResources{}, errs
-	}
-	for _, gr := range gatewayResources {
-		maps.Copy(mergedGatewayResources.GatewayClasses, gr.GatewayClasses)
-		maps.Copy(mergedGatewayResources.HTTPRoutes, gr.HTTPRoutes)
-		maps.Copy(mergedGatewayResources.TLSRoutes, gr.TLSRoutes)
-		maps.Copy(mergedGatewayResources.TCPRoutes, gr.TCPRoutes)
-		maps.Copy(mergedGatewayResources.UDPRoutes, gr.UDPRoutes)
-		maps.Copy(mergedGatewayResources.ReferenceGrants, gr.ReferenceGrants)
-	}
-	return mergedGatewayResources, errs
-}
-
-func mergeGateways(gatewaResources []GatewayResources) (map[types.NamespacedName]gatewayv1.Gateway, field.ErrorList) {
-	newGateways := map[types.NamespacedName]gatewayv1.Gateway{}
-	errs := field.ErrorList{}
-
-	for _, gr := range gatewaResources {
-		for _, g := range gr.Gateways {
-			nn := types.NamespacedName{Namespace: g.Namespace, Name: g.Name}
-			if existingGateway, ok := newGateways[nn]; ok {
-				g.Spec.Listeners = append(g.Spec.Listeners, existingGateway.Spec.Listeners...)
-				g.Spec.Addresses = append(g.Spec.Addresses, existingGateway.Spec.Addresses...)
-			}
-			newGateways[nn] = g
-			// 64 is the maximum number of listeners a Gateway can have
-			if len(g.Spec.Listeners) > 64 {
-				fieldPath := field.NewPath(fmt.Sprintf("%s/%s", nn.Namespace, nn.Name)).Child("spec").Child("listeners")
-				errs = append(errs, field.Invalid(fieldPath, g, "error while merging gateway listeners: a gateway cannot have more than 64 listeners"))
-			}
-			// 16 is the maximum number of addresses a Gateway can have
-			if len(g.Spec.Addresses) > 16 {
-				fieldPath := field.NewPath(fmt.Sprintf("%s/%s", nn.Namespace, nn.Name)).Child("spec").Child("addresses")
-				errs = append(errs, field.Invalid(fieldPath, g, "error while merging gateway listeners: a gateway cannot have more than 16 addresses"))
-			}
-		}
-	}
-
-	return newGateways, errs
-}
-
 func CastToUnstructured(obj runtime.Object) (*unstructured.Unstructured, error) {
 	// Convert the Kubernetes object to unstructured.Unstructured
 	unstructuredObj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(obj)

pkg/i2gw/intermediate/provider_apisix.go

@@ -19,3 +19,15 @@ package intermediate
 type ApisixGatewayIR struct{}
 type ApisixHTTPRouteIR struct{}
 type ApisixServiceIR struct{}
+
+func MergeApisixGatewayIR(current, existing *ApisixGatewayIR) *ApisixGatewayIR {
+	var mergedGatewayIR *ApisixGatewayIR
+	// Populate the value of each fields once ApisixGatewayIR is not empty.
+	if existing != nil {
+		mergedGatewayIR = existing
+	}
+	if current != nil {
+		mergedGatewayIR = current
+	}
+	return mergedGatewayIR
+}

pkg/i2gw/intermediate/provider_ingressnginx.go

@@ -19,3 +19,15 @@ package intermediate
 type IngressNginxGatewayIR struct{}
 type IngressNginxHTTPRouteIR struct{}
 type IngressNginxServiceIR struct{}
+
+func MergeIngressNginxGatewayIR(current, existing *IngressNginxGatewayIR) *IngressNginxGatewayIR {
+	var mergedGatewayIR *IngressNginxGatewayIR
+	// Populate the value of each fields once IngressNginxGatewayIR is not empty.
+	if existing != nil {
+		mergedGatewayIR = existing
+	}
+	if current != nil {
+		mergedGatewayIR = current
+	}
+	return mergedGatewayIR
+}

pkg/i2gw/intermediate/provider_istio.go

@@ -19,3 +19,15 @@ package intermediate
 type IstioGatewayIR struct{}
 type IstioHTTPRouteIR struct{}
 type IstioServiceIR struct{}
+
+func MergeIstioGatewayIR(current, existing *IstioGatewayIR) *IstioGatewayIR {
+	var mergedGatewayIR *IstioGatewayIR
+	// Populate the value of each fields once IstioGatewayIR is not empty.
+	if existing != nil {
+		mergedGatewayIR = existing
+	}
+	if current != nil {
+		mergedGatewayIR = current
+	}
+	return mergedGatewayIR
+}

pkg/i2gw/intermediate/provider_kong.go

@@ -19,3 +19,15 @@ package intermediate
 type KongGatewayIR struct{}
 type KongHTTPRouteIR struct{}
 type KongServiceIR struct{}
+
+func MergeKongGatewayIR(current, existing *KongGatewayIR) *KongGatewayIR {
+	var mergedGatewayIR *KongGatewayIR
+	// Populate the value of each fields once KongGatewayIR is not empty.
+	if existing != nil {
+		mergedGatewayIR = existing
+	}
+	if current != nil {
+		mergedGatewayIR = current
+	}
+	return mergedGatewayIR
+}

pkg/i2gw/intermediate/provider_openapi3.go

@@ -19,3 +19,15 @@ package intermediate
 type Openapi3GatewayIR struct{}
 type Openapi3HTTPRouteIR struct{}
 type Openapi3ServiceIR struct{}
+
+func MergeOpenapi3GatewayIR(current, existing *Openapi3GatewayIR) *Openapi3GatewayIR {
+	var mergedGatewayIR *Openapi3GatewayIR
+	// Populate the value of each fields once Openapi3GatewayIR is not empty.
+	if existing != nil {
+		mergedGatewayIR = existing
+	}
+	if current != nil {
+		mergedGatewayIR = current
+	}
+	return mergedGatewayIR
+}

pkg/i2gw/provider.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"sync"
 
+	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/intermediate"
 	networkingv1 "k8s.io/api/networking/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/types"
@@ -55,7 +56,8 @@ type ProviderConf struct {
 // be used.
 type Provider interface {
 	CustomResourceReader
-	ResourceConverter
+	ResourcesToIRConverter
+	IRToGatewayAPIConverter
 }
 
 type CustomResourceReader interface {
@@ -69,13 +71,19 @@ type CustomResourceReader interface {
 	ReadResourcesFromFile(ctx context.Context, filename string) error
 }
 
-// The ResourceConverter interface specifies all the implemented Gateway API resource
-// conversion functions.
-type ResourceConverter interface {
+// The ResourcesToIRConverter interface specifies conversion functions from Ingress
+// and extensions into IR.
+type ResourcesToIRConverter interface {
+	// ToIR converts stored API entities associated with the Provider into IR.
+	ToIR() (intermediate.IR, field.ErrorList)
+}
 
-	// ToGatewayAPIResources converts stored API entities associated
-	// with the Provider into GatewayResources.
-	ToGatewayAPI() (GatewayResources, field.ErrorList)
+// The IRToGatewayAPIConverter interface specifies conversion functions from IR
+// into Gateway and Gateway extensions.
+type IRToGatewayAPIConverter interface {
+	// ToGatewayResources converts stored IR with the Provider into
+	// Gateway API resources and extensions
+	ToGatewayResources(intermediate.IR) (GatewayResources, field.ErrorList)
 }
 
 // ImplementationSpecificHTTPPathTypeMatchConverter is an option to customize the ingress implementationSpecific
@@ -110,7 +118,7 @@ type GatewayResources struct {
 //
 // Different FeatureParsers will run in undetermined order. The function must
 // modify / create only the required fields of the gateway resources and nothing else.
-type FeatureParser func([]networkingv1.Ingress, *GatewayResources) field.ErrorList
+type FeatureParser func([]networkingv1.Ingress, *intermediate.IR) field.ErrorList
 
 var providerSpecificFlagDefinitions = providerSpecificFlags{
 	flags: make(map[ProviderName]map[string]ProviderSpecificFlag),

pkg/i2gw/providers/apisix/apisix.go

@@ -21,6 +21,8 @@ import (
 	"fmt"
 
 	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw"
+	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/intermediate"
+	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/providers/common"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 )
 
@@ -34,24 +36,28 @@ func init() {
 
 // Provider implements the i2gw.Provider interface.
 type Provider struct {
-	storage        *storage
-	resourceReader *resourceReader
-	converter      *converter
+	storage                *storage
+	resourceReader         *resourceReader
+	resourcesToIRConverter *resourcesToIRConverter
 }
 
 // NewProvider constructs and returns the apisix implementation of i2gw.Provider.
 func NewProvider(conf *i2gw.ProviderConf) i2gw.Provider {
 	return &Provider{
-		storage:        newResourcesStorage(),
-		resourceReader: newResourceReader(conf),
-		converter:      newConverter(),
+		storage:                newResourcesStorage(),
+		resourceReader:         newResourceReader(conf),
+		resourcesToIRConverter: newResourcesToIRConverter(),
 	}
 }
 
-// ToGatewayAPI converts stored Apisix API entities to i2gw.GatewayResources
+// ToIR converts stored Apisix API entities to intermediate.IR
 // including the apisix specific features.
-func (p *Provider) ToGatewayAPI() (i2gw.GatewayResources, field.ErrorList) {
-	return p.converter.convert(p.storage)
+func (p *Provider) ToIR() (intermediate.IR, field.ErrorList) {
+	return p.resourcesToIRConverter.convertToIR(p.storage)
+}
+
+func (p *Provider) ToGatewayResources(ir intermediate.IR) (i2gw.GatewayResources, field.ErrorList) {
+	return common.ToGatewayResources(ir)
 }
 
 func (p *Provider) ReadResourcesFromCluster(ctx context.Context) error {

pkg/i2gw/providers/apisix/converter.go

@@ -18,20 +18,21 @@ package apisix
 
 import (
 	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw"
+	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/intermediate"
 	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/providers/common"
 	networkingv1 "k8s.io/api/networking/v1"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 )
 
-// converter implements the ToGatewayAPI function of i2gw.ResourceConverter interface.
-type converter struct {
+// resourcesToIRConverter implements the ToIR function of i2gw.ResourcesToIRConverter interface.
+type resourcesToIRConverter struct {
 	featureParsers                []i2gw.FeatureParser
 	implementationSpecificOptions i2gw.ProviderImplementationSpecificOptions
 }
 
-// newConverter returns an apisix converter instance.
-func newConverter() *converter {
-	return &converter{
+// newResourcesToIRConverter returns an apisix resourcesToIRConverter instance.
+func newResourcesToIRConverter() *resourcesToIRConverter {
+	return &resourcesToIRConverter{
 		featureParsers: []i2gw.FeatureParser{
 			httpToHTTPSFeature,
 		},
@@ -41,24 +42,24 @@ func newConverter() *converter {
 	}
 }
 
-func (c *converter) convert(storage *storage) (i2gw.GatewayResources, field.ErrorList) {
+func (c *resourcesToIRConverter) convertToIR(storage *storage) (intermediate.IR, field.ErrorList) {
 	ingressList := []networkingv1.Ingress{}
 	for _, ing := range storage.Ingresses {
 		ingressList = append(ingressList, *ing)
 	}
 	// Convert plain ingress resources to gateway resources, ignoring all
 	// provider-specific features.
-	gatewayResources, errs := common.ToGateway(ingressList, c.implementationSpecificOptions)
+	ir, errs := common.ToIR(ingressList, c.implementationSpecificOptions)
 	if len(errs) > 0 {
-		return i2gw.GatewayResources{}, errs
+		return intermediate.IR{}, errs
 	}
 
 	for _, parseFeatureFunc := range c.featureParsers {
 		// Apply the feature parsing function to the gateway resources, one by one.
-		parseErrs := parseFeatureFunc(ingressList, &gatewayResources)
+		parseErrs := parseFeatureFunc(ingressList, &ir)
 		// Append the parsing errors to the error list.
 		errs = append(errs, parseErrs...)
 	}
 
-	return gatewayResources, errs
+	return ir, errs
 }

pkg/i2gw/providers/apisix/http_to_https.go

@@ -19,7 +19,7 @@ package apisix
 import (
 	"fmt"
 
-	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw"
+	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/intermediate"
 	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/notifications"
 	"github.com/kubernetes-sigs/ingress2gateway/pkg/i2gw/providers/common"
 	networkingv1 "k8s.io/api/networking/v1"
@@ -29,7 +29,7 @@ import (
 	gatewayv1 "sigs.k8s.io/gateway-api/apis/v1"
 )
 
-func httpToHTTPSFeature(ingresses []networkingv1.Ingress, gatewayResources *i2gw.GatewayResources) field.ErrorList {
+func httpToHTTPSFeature(ingresses []networkingv1.Ingress, ir *intermediate.IR) field.ErrorList {
 	var errs field.ErrorList
 	httpToHTTPSAnnotation := apisixAnnotation("http-to-https")
 	ruleGroups := common.GetRuleGroups(ingresses)
@@ -40,7 +40,7 @@ func httpToHTTPSFeature(ingresses []networkingv1.Ingress, gatewayResources *i2gw
 					continue
 				}
 				key := types.NamespacedName{Namespace: rule.Ingress.Namespace, Name: common.RouteName(rg.Name, rg.Host)}
-				httpRoute, ok := gatewayResources.HTTPRoutes[key]
+				httpRoute, ok := ir.HTTPRoutes[key]
 				if !ok {
 					errs = append(errs, field.NotFound(field.NewPath("HTTPRoute"), key))
 				}