kube-proxy: update internal endpoints map with 'serving' and 'terminating' condition from EndpointSlice

Signed-off-by: Andrew Sy Kim <kim.andrewsy@gmail.com>

pkg/proxy/endpoints.go

@@ -49,6 +49,23 @@ type BaseEndpointInfo struct {
 	// IsLocal indicates whether the endpoint is running in same host as kube-proxy.
 	IsLocal  bool
 	Topology map[string]string
+
+	// Ready indicates whether this endpoint is ready and NOT terminating.
+	// For pods, this is true if a pod has a ready status and a nil deletion timestamp.
+	// This is only set when watching EndpointSlices. If using Endpoints, this is always
+	// true since only ready endpoints are read from Endpoints.
+	// TODO: Ready can be inferred from Serving and Terminating below when enabled by default.
+	Ready bool
+	// Serving indiciates whether this endpoint is ready regardless of its terminating state.
+	// For pods this is true if it has a ready status regardless of its deletion timestamp.
+	// This is only set when watching EndpointSlices. If using Endpoints, this is always
+	// true since only ready endpoints are read from Endpoints.
+	Serving bool
+	// Terminating indicates whether this endpoint is terminating.
+	// For pods this is true if it has a non-nil deletion timestamp.
+	// This is only set when watching EndpointSlices. If using Endpoints, this is always
+	// false since terminating endpoints are always excluded from Endpoints.
+	Terminating bool
 }
 
 var _ Endpoint = &BaseEndpointInfo{}
@@ -63,6 +80,23 @@ func (info *BaseEndpointInfo) GetIsLocal() bool {
 	return info.IsLocal
 }
 
+// IsReady returns true if an endpoint is ready and not terminating.
+func (info *BaseEndpointInfo) IsReady() bool {
+	return info.Ready
+}
+
+// IsServing returns true if an endpoint is ready, regardless of if the
+// endpoint is terminating.
+func (info *BaseEndpointInfo) IsServing() bool {
+	return info.Serving
+}
+
+// IsTerminating retruns true if an endpoint is terminating. For pods,
+// that is any pod with a deletion timestamp.
+func (info *BaseEndpointInfo) IsTerminating() bool {
+	return info.Terminating
+}
+
 // GetTopology returns the topology information of the endpoint.
 func (info *BaseEndpointInfo) GetTopology() map[string]string {
 	return info.Topology
@@ -83,11 +117,15 @@ func (info *BaseEndpointInfo) Equal(other Endpoint) bool {
 	return info.String() == other.String() && info.GetIsLocal() == other.GetIsLocal()
 }
 
-func newBaseEndpointInfo(IP string, port int, isLocal bool, topology map[string]string) *BaseEndpointInfo {
+func newBaseEndpointInfo(IP string, port int, isLocal bool, topology map[string]string,
+	ready, serving, terminating bool) *BaseEndpointInfo {
 	return &BaseEndpointInfo{
-		Endpoint: net.JoinHostPort(IP, strconv.Itoa(port)),
-		IsLocal:  isLocal,
-		Topology: topology,
+		Endpoint:    net.JoinHostPort(IP, strconv.Itoa(port)),
+		IsLocal:     isLocal,
+		Topology:    topology,
+		Ready:       ready,
+		Serving:     serving,
+		Terminating: terminating,
 	}
 }
 
@@ -383,8 +421,14 @@ func (ect *EndpointChangeTracker) endpointsToEndpointsMap(endpoints *v1.Endpoint
 					continue
 				}
 
+				// it is safe to assume that any address in endpoints.subsets[*].addresses is
+				// ready and NOT terminating
+				isReady := true
+				isServing := true
+				isTerminating := false
 				isLocal := addr.NodeName != nil && *addr.NodeName == ect.hostname
-				baseEndpointInfo := newBaseEndpointInfo(addr.IP, int(port.Port), isLocal, nil)
+
+				baseEndpointInfo := newBaseEndpointInfo(addr.IP, int(port.Port), isLocal, nil, isReady, isServing, isTerminating)
 				if ect.makeEndpointInfo != nil {
 					endpointsMap[svcPortName] = append(endpointsMap[svcPortName], ect.makeEndpointInfo(baseEndpointInfo))
 				} else {