Fixing Potential Race Condition in EndpointSlice Controller.

This adds a new EndpointSlice tracker to keep track of the expected resource versions of EndpointSlices associated with each Service managed by the EndpointSlice controller. This should prevent a potential race where a syncService call could happen with an incomplete view of EndpointSlices if additions or deletions hadn't fully propagated to the cache yet. Additionally, this ensures that external changes to EndpointSlices will be handled by the EndpointSlice controller.

pkg/controller/endpointslice/endpointslice_tracker_test.go

@@ -0,0 +1,174 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package endpointslice
+
+import (
+	"testing"
+
+	discovery "k8s.io/api/discovery/v1beta1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestEndpointSliceTrackerUpdate(t *testing.T) {
+	epSlice1 := &discovery.EndpointSlice{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:            "example-1",
+			Namespace:       "ns1",
+			ResourceVersion: "rv1",
+			Labels:          map[string]string{discovery.LabelServiceName: "svc1"},
+		},
+	}
+
+	epSlice1DifferentNS := epSlice1.DeepCopy()
+	epSlice1DifferentNS.Namespace = "ns2"
+
+	epSlice1DifferentService := epSlice1.DeepCopy()
+	epSlice1DifferentService.Labels[discovery.LabelServiceName] = "svc2"
+
+	epSlice1DifferentRV := epSlice1.DeepCopy()
+	epSlice1DifferentRV.ResourceVersion = "rv2"
+
+	testCases := map[string]struct {
+		updateParam *discovery.EndpointSlice
+		checksParam *discovery.EndpointSlice
+		expectHas   bool
+		expectStale bool
+	}{
+		"same slice": {
+			updateParam: epSlice1,
+			checksParam: epSlice1,
+			expectHas:   true,
+			expectStale: false,
+		},
+		"different namespace": {
+			updateParam: epSlice1,
+			checksParam: epSlice1DifferentNS,
+			expectHas:   false,
+			expectStale: true,
+		},
+		"different service": {
+			updateParam: epSlice1,
+			checksParam: epSlice1DifferentService,
+			expectHas:   false,
+			expectStale: true,
+		},
+		"different resource version": {
+			updateParam: epSlice1,
+			checksParam: epSlice1DifferentRV,
+			expectHas:   true,
+			expectStale: true,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			esTracker := newEndpointSliceTracker()
+			esTracker.Update(tc.updateParam)
+			if esTracker.Has(tc.checksParam) != tc.expectHas {
+				t.Errorf("tc.tracker.Has(%+v) == %t, expected %t", tc.checksParam, esTracker.Has(tc.checksParam), tc.expectHas)
+			}
+			if esTracker.Stale(tc.checksParam) != tc.expectStale {
+				t.Errorf("tc.tracker.Stale(%+v) == %t, expected %t", tc.checksParam, esTracker.Stale(tc.checksParam), tc.expectStale)
+			}
+		})
+	}
+}
+
+func TestEndpointSliceTrackerDelete(t *testing.T) {
+	epSlice1 := &discovery.EndpointSlice{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:            "example-1",
+			Namespace:       "ns1",
+			ResourceVersion: "rv1",
+			Labels:          map[string]string{discovery.LabelServiceName: "svc1"},
+		},
+	}
+
+	epSlice1DifferentNS := epSlice1.DeepCopy()
+	epSlice1DifferentNS.Namespace = "ns2"
+
+	epSlice1DifferentService := epSlice1.DeepCopy()
+	epSlice1DifferentService.Labels[discovery.LabelServiceName] = "svc2"
+
+	epSlice1DifferentRV := epSlice1.DeepCopy()
+	epSlice1DifferentRV.ResourceVersion = "rv2"
+
+	testCases := map[string]struct {
+		deleteParam *discovery.EndpointSlice
+		checksParam *discovery.EndpointSlice
+		expectHas   bool
+		expectStale bool
+	}{
+		"same slice": {
+			deleteParam: epSlice1,
+			checksParam: epSlice1,
+			expectHas:   false,
+			expectStale: true,
+		},
+		"different namespace": {
+			deleteParam: epSlice1DifferentNS,
+			checksParam: epSlice1DifferentNS,
+			expectHas:   false,
+			expectStale: true,
+		},
+		"different namespace, check original ep slice": {
+			deleteParam: epSlice1DifferentNS,
+			checksParam: epSlice1,
+			expectHas:   true,
+			expectStale: false,
+		},
+		"different service": {
+			deleteParam: epSlice1DifferentService,
+			checksParam: epSlice1DifferentService,
+			expectHas:   false,
+			expectStale: true,
+		},
+		"different service, check original ep slice": {
+			deleteParam: epSlice1DifferentService,
+			checksParam: epSlice1,
+			expectHas:   true,
+			expectStale: false,
+		},
+		"different resource version": {
+			deleteParam: epSlice1DifferentRV,
+			checksParam: epSlice1DifferentRV,
+			expectHas:   false,
+			expectStale: true,
+		},
+		"different resource version, check original ep slice": {
+			deleteParam: epSlice1DifferentRV,
+			checksParam: epSlice1,
+			expectHas:   false,
+			expectStale: true,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			esTracker := newEndpointSliceTracker()
+			esTracker.Update(epSlice1)
+
+			esTracker.Delete(tc.deleteParam)
+			if esTracker.Has(tc.checksParam) != tc.expectHas {
+				t.Errorf("esTracker.Has(%+v) == %t, expected %t", tc.checksParam, esTracker.Has(tc.checksParam), tc.expectHas)
+			}
+			if esTracker.Stale(tc.checksParam) != tc.expectStale {
+				t.Errorf("esTracker.Stale(%+v) == %t, expected %t", tc.checksParam, esTracker.Stale(tc.checksParam), tc.expectStale)
+			}
+		})
+	}
+}