Update the use of sets in EndpointSlice validation

Don't use sets for validating port name and zone hint uniqueness,
since constructing a new set each time is likely to be less efficient
than just doing a linear search.

Keep the sets for supportedAddressTypes and supportedPortProtocols
(since they're only constructed once) but switch to the generic set
API.

Author: danwinship

pkg/apis/discovery/validation/validation.go

@@ -18,6 +18,7 @@ package validation
 
 import (
 	"fmt"
+	"slices"
 
 	corev1 "k8s.io/api/core/v1"
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
@@ -33,15 +34,15 @@ import (
 )
 
 var (
-	supportedAddressTypes = sets.NewString(
-		string(discovery.AddressTypeIPv4),
-		string(discovery.AddressTypeIPv6),
-		string(discovery.AddressTypeFQDN),
+	supportedAddressTypes = sets.New(
+		discovery.AddressTypeIPv4,
+		discovery.AddressTypeIPv6,
+		discovery.AddressTypeFQDN,
 	)
-	supportedPortProtocols = sets.NewString(
-		string(api.ProtocolTCP),
-		string(api.ProtocolUDP),
-		string(api.ProtocolSCTP),
+	supportedPortProtocols = sets.New(
+		api.ProtocolTCP,
+		api.ProtocolUDP,
+		api.ProtocolSCTP,
 	)
 	maxTopologyLabels = 16
 	maxAddresses      = 100
@@ -172,24 +173,26 @@ func validatePorts(endpointPorts []discovery.EndpointPort, fldPath *field.Path)
 		return allErrs
 	}
 
-	portNames := sets.String{}
+	// Even though a sets.Set would be more idiomatic, we use a []string here to avoid
+	// extra allocations (especially since there are presumably only a few ports anyway).
+	portNames := make([]string, 0, len(endpointPorts))
 	for i, endpointPort := range endpointPorts {
 		idxPath := fldPath.Index(i)
 
 		if len(*endpointPort.Name) > 0 {
 			allErrs = append(allErrs, apivalidation.ValidateDNS1123Label(*endpointPort.Name, idxPath.Child("name"))...)
 		}
 
-		if portNames.Has(*endpointPort.Name) {
+		if slices.Contains(portNames, *endpointPort.Name) {
 			allErrs = append(allErrs, field.Duplicate(idxPath.Child("name"), endpointPort.Name))
 		} else {
-			portNames.Insert(*endpointPort.Name)
+			portNames = append(portNames, *endpointPort.Name)
 		}
 
 		if endpointPort.Protocol == nil {
 			allErrs = append(allErrs, field.Required(idxPath.Child("protocol"), ""))
-		} else if !supportedPortProtocols.Has(string(*endpointPort.Protocol)) {
-			allErrs = append(allErrs, field.NotSupported(idxPath.Child("protocol"), *endpointPort.Protocol, supportedPortProtocols.List()))
+		} else if !supportedPortProtocols.Has(*endpointPort.Protocol) {
+			allErrs = append(allErrs, field.NotSupported(idxPath.Child("protocol"), *endpointPort.Protocol, sets.List(supportedPortProtocols)))
 		}
 
 		if endpointPort.AppProtocol != nil {
@@ -205,8 +208,8 @@ func validateAddressType(addressType discovery.AddressType) field.ErrorList {
 
 	if addressType == "" {
 		allErrs = append(allErrs, field.Required(field.NewPath("addressType"), ""))
-	} else if !supportedAddressTypes.Has(string(addressType)) {
-		allErrs = append(allErrs, field.NotSupported(field.NewPath("addressType"), addressType, supportedAddressTypes.List()))
+	} else if !supportedAddressTypes.Has(addressType) {
+		allErrs = append(allErrs, field.NotSupported(field.NewPath("addressType"), addressType, sets.List(supportedAddressTypes)))
 	}
 
 	return allErrs
@@ -221,13 +224,15 @@ func validateHints(endpointHints *discovery.EndpointHints, fldPath *field.Path)
 		return allErrs
 	}
 
-	zoneNames := sets.String{}
+	// Even though a sets.Set would be more idiomatic, we use a []string here to avoid
+	// extra allocations (especially since there is normally only one zone anyway).
+	zoneNames := make([]string, 0, len(endpointHints.ForZones))
 	for i, forZone := range endpointHints.ForZones {
 		zonePath := fzPath.Index(i).Child("name")
-		if zoneNames.Has(forZone.Name) {
+		if slices.Contains(zoneNames, forZone.Name) {
 			allErrs = append(allErrs, field.Duplicate(zonePath, forZone.Name))
 		} else {
-			zoneNames.Insert(forZone.Name)
+			zoneNames = append(zoneNames, forZone.Name)
 		}
 
 		for _, msg := range validation.IsValidLabelValue(forZone.Name) {