Adding support for TopologyAwareHints to kube-proxy

pkg/proxy/topology.go

@@ -19,11 +19,80 @@ package proxy
 import (
 	v1 "k8s.io/api/core/v1"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/klog/v2"
 	"k8s.io/kubernetes/pkg/features"
 )
 
-// FilterTopologyEndpoint returns the appropriate endpoints based on the cluster
-// topology.
+// FilterEndpoints filters endpoints based on Service configuration, node
+// labels, and enabled feature gates. This is primarily used to enable topology
+// aware routing.
+func FilterEndpoints(endpoints []Endpoint, svcInfo ServicePort, nodeLabels map[string]string) []Endpoint {
+	if svcInfo.NodeLocalExternal() || !utilfeature.DefaultFeatureGate.Enabled(features.EndpointSliceProxying) {
+		return endpoints
+	}
+
+	if utilfeature.DefaultFeatureGate.Enabled(features.ServiceTopology) {
+		return deprecatedTopologyFilter(nodeLabels, svcInfo.TopologyKeys(), endpoints)
+	}
+
+	if utilfeature.DefaultFeatureGate.Enabled(features.ServiceInternalTrafficPolicy) && svcInfo.NodeLocalInternal() {
+		return filterEndpointsInternalTrafficPolicy(svcInfo.InternalTrafficPolicy(), endpoints)
+	}
+
+	if utilfeature.DefaultFeatureGate.Enabled(features.TopologyAwareHints) {
+		return filterEndpointsWithHints(endpoints, svcInfo.HintsAnnotation(), nodeLabels)
+	}
+
+	return endpoints
+}
+
+// filterEndpointsWithHints provides filtering based on the hints included in
+// EndpointSlices. If any of the following are true, the full list of endpoints
+// will be returned without any filtering:
+// * The AnnotationTopologyAwareHints annotation is not set to "auto" for this
+//   Service.
+// * No zone is specified in node labels.
+// * No endpoints for this Service have a hint pointing to the zone this
+//   instance of kube-proxy is running in.
+// * One or more endpoints for this Service do not have hints specified.
+func filterEndpointsWithHints(endpoints []Endpoint, hintsAnnotation string, nodeLabels map[string]string) []Endpoint {
+	if hintsAnnotation != "auto" {
+		if hintsAnnotation != "" && hintsAnnotation != "disabled" {
+			klog.Warningf("Skipping topology aware endpoint filtering since Service has unexpected value for %s annotation: %s", v1.AnnotationTopologyAwareHints, hintsAnnotation)
+		}
+		return endpoints
+	}
+
+	zone, ok := nodeLabels[v1.LabelTopologyZone]
+	if !ok || zone == "" {
+		klog.Warningf("Skipping topology aware endpoint filtering since node is missing %s label", v1.LabelTopologyZone)
+		return endpoints
+	}
+
+	filteredEndpoints := []Endpoint{}
+
+	for _, endpoint := range endpoints {
+		if endpoint.GetZoneHints().Len() == 0 {
+			klog.Warningf("Skipping topology aware endpoint filtering since one or more endpoints is missing a zone hint")
+			return endpoints
+		}
+		if endpoint.GetZoneHints().Has(zone) {
+			filteredEndpoints = append(filteredEndpoints, endpoint)
+		}
+	}
+
+	if len(filteredEndpoints) > 0 {
+		klog.Warningf("Skipping topology aware endpoint filtering since no hints were provided for zone %s", zone)
+		return filteredEndpoints
+	}
+
+	return endpoints
+}
+
+// deprecatedTopologyFilter returns the appropriate endpoints based on the
+// cluster topology. This will be removed in an upcoming release along with the
+// ServiceTopology feature gate.
+//
 // This uses the current node's labels, which contain topology information, and
 // the required topologyKeys to find appropriate endpoints. If both the endpoint's
 // topology and the current node have matching values for topologyKeys[0], the
@@ -40,7 +109,7 @@ import (
 //
 // If topologyKeys is not specified or empty, no topology constraints will be
 // applied and this will return all endpoints.
-func FilterTopologyEndpoint(nodeLabels map[string]string, topologyKeys []string, endpoints []Endpoint) []Endpoint {
+func deprecatedTopologyFilter(nodeLabels map[string]string, topologyKeys []string, endpoints []Endpoint) []Endpoint {
 	// Do not filter endpoints if service has no topology keys.
 	if len(topologyKeys) == 0 {
 		return endpoints
@@ -81,13 +150,13 @@ func FilterTopologyEndpoint(nodeLabels map[string]string, topologyKeys []string,
 	return filteredEndpoints
 }
 
-// FilterLocalEndpoint returns the node local endpoints based on configured
-// InternalTrafficPolicy.
+// filterEndpointsInternalTrafficPolicy returns the node local endpoints based
+// on configured InternalTrafficPolicy.
 //
 // If ServiceInternalTrafficPolicy feature gate is off, returns the original
-// endpoints slice.
+// EndpointSlice.
 // Otherwise, if InternalTrafficPolicy is Local, only return the node local endpoints.
-func FilterLocalEndpoint(internalTrafficPolicy *v1.ServiceInternalTrafficPolicyType, endpoints []Endpoint) []Endpoint {
+func filterEndpointsInternalTrafficPolicy(internalTrafficPolicy *v1.ServiceInternalTrafficPolicyType, endpoints []Endpoint) []Endpoint {
 	if !utilfeature.DefaultFeatureGate.Enabled(features.ServiceInternalTrafficPolicy) {
 		return endpoints
 	}