Merge pull request #84970 from atlassian/pdzwart/kubernetes/kubernetes/84959

- Delete backing string set from a threadSafeMap index when the string set length reaches 0.

Kubernetes-commit: 41be6d65d88728f443966da83b62d545684576ab

Godeps/Godeps.json

@@ -348,11 +348,11 @@
 		},
 		{
 			"ImportPath": "k8s.io/api",
-			"Rev": "7f9008e52f64"
+			"Rev": "37fc98278a4b"
 		},
 		{
 			"ImportPath": "k8s.io/apimachinery",
-			"Rev": "6eb29fdf75dc"
+			"Rev": "d496f1036126"
 		},
 		{
 			"ImportPath": "k8s.io/gengo",

go.mod

@@ -28,8 +28,8 @@ require (
 	golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45
 	golang.org/x/time v0.0.0-20190308202827-9d24e82272b4
 	google.golang.org/appengine v1.5.0 // indirect
-	k8s.io/api v0.0.0-20191112020540-7f9008e52f64
-	k8s.io/apimachinery v0.0.0-20191111054156-6eb29fdf75dc
+	k8s.io/api v0.0.0-20191114100032-37fc98278a4b
+	k8s.io/apimachinery v0.0.0-20191114095527-d496f1036126
 	k8s.io/klog v1.0.0
 	k8s.io/utils v0.0.0-20191030222137-2b95a09bc58d
 	sigs.k8s.io/yaml v1.1.0
@@ -38,6 +38,6 @@ require (
 replace (
 	golang.org/x/sys => golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a
 	golang.org/x/tools => golang.org/x/tools v0.0.0-20190821162956-65e3620a7ae7
-	k8s.io/api => k8s.io/api v0.0.0-20191112020540-7f9008e52f64
-	k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20191111054156-6eb29fdf75dc
+	k8s.io/api => k8s.io/api v0.0.0-20191114100032-37fc98278a4b
+	k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20191114095527-d496f1036126
 )

go.sum

@@ -191,8 +191,8 @@ gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
-k8s.io/api v0.0.0-20191112020540-7f9008e52f64/go.mod h1:8svLRMiLwQReMTycutfjsaQ0ackWIf8HCT4UcixYLjI=
-k8s.io/apimachinery v0.0.0-20191111054156-6eb29fdf75dc/go.mod h1:+6CX7hP4aLfX2sb91JYDMIp0VqDSog2kZu0BHe+lP+s=
+k8s.io/api v0.0.0-20191114100032-37fc98278a4b/go.mod h1:8svLRMiLwQReMTycutfjsaQ0ackWIf8HCT4UcixYLjI=
+k8s.io/apimachinery v0.0.0-20191114095527-d496f1036126/go.mod h1:+6CX7hP4aLfX2sb91JYDMIp0VqDSog2kZu0BHe+lP+s=
 k8s.io/gengo v0.0.0-20190128074634-0689ccc1d7d6/go.mod h1:ezvh/TsK7cY6rbqRK0oQQ8IAqLxYwwyPxAX1Pzy0ii0=
 k8s.io/klog v0.0.0-20181102134211-b9b56d5dfc92/go.mod h1:Gq+BEi5rUBO/HRz0bTSXDUcqjScdoY3a9IHpCEIOOfk=
 k8s.io/klog v0.3.0/go.mod h1:Gq+BEi5rUBO/HRz0bTSXDUcqjScdoY3a9IHpCEIOOfk=

tools/cache/thread_safe_store.go

@@ -292,6 +292,13 @@ func (c *threadSafeMap) deleteFromIndices(obj interface{}, key string) {
 			set := index[indexValue]
 			if set != nil {
 				set.Delete(key)
+
+				// If we don't delete the set when zero, indices with high cardinality
+				// short lived resources can cause memory to increase over time from
+				// unused empty sets. See `kubernetes/kubernetes/issues/84959`.
+				if len(set) == 0 {
+					delete(index, indexValue)
+				}
 			}
 		}
 	}

tools/cache/thread_safe_store_test.go

@@ -0,0 +1,92 @@
+/*
+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 cache
+
+import (
+	"testing"
+)
+
+func TestThreadSafeStoreDeleteRemovesEmptySetsFromIndex(t *testing.T) {
+	testIndexer := "testIndexer"
+
+	indexers := Indexers{
+		testIndexer: func(obj interface{}) (strings []string, e error) {
+			indexes := []string{obj.(string)}
+			return indexes, nil
+		},
+	}
+
+	indices := Indices{}
+	store := NewThreadSafeStore(indexers, indices).(*threadSafeMap)
+
+	testKey := "testKey"
+
+	store.Add(testKey, testKey)
+
+	// Assumption check, there should be a set for the `testKey` with one element in the added index
+	set := store.indices[testIndexer][testKey]
+
+	if len(set) != 1 {
+		t.Errorf("Initial assumption of index backing string set having 1 element failed. Actual elements: %d", len(set))
+		return
+	}
+
+	store.Delete(testKey)
+	set, present := store.indices[testIndexer][testKey]
+
+	if present {
+		t.Errorf("Index backing string set not deleted from index. Set length: %d", len(set))
+	}
+}
+
+func TestThreadSafeStoreAddKeepsNonEmptySetPostDeleteFromIndex(t *testing.T) {
+	testIndexer := "testIndexer"
+	testIndex := "testIndex"
+
+	indexers := Indexers{
+		testIndexer: func(obj interface{}) (strings []string, e error) {
+			indexes := []string{testIndex}
+			return indexes, nil
+		},
+	}
+
+	indices := Indices{}
+	store := NewThreadSafeStore(indexers, indices).(*threadSafeMap)
+
+	store.Add("retain", "retain")
+	store.Add("delete", "delete")
+
+	// Assumption check, there should be a set for the `testIndex` with two elements
+	set := store.indices[testIndexer][testIndex]
+
+	if len(set) != 2 {
+		t.Errorf("Initial assumption of index backing string set having 2 elements failed. Actual elements: %d", len(set))
+		return
+	}
+
+	store.Delete("delete")
+	set, present := store.indices[testIndexer][testIndex]
+
+	if !present {
+		t.Errorf("Index backing string set erroneously deleted from index.")
+		return
+	}
+
+	if len(set) != 1 {
+		t.Errorf("Index backing string set has incorrect length, expect 1. Set length: %d", len(set))
+	}
+}