Add Slowset Utility From external-resizer

slowset/slowset.go

@@ -0,0 +1,118 @@
+/*
+Copyright 2024 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 slowset
+
+import (
+	"sync"
+	"time"
+)
+
+// SlowSet is a set of API objects that should be synced at slower rate. Key is typically the object
+// namespace + name and value is timestamp when the object was added to the set.
+type SlowSet struct {
+	sync.RWMutex
+	// retentionTime is the time after which an item will be removed from the set
+	// this indicates, how long before an operation on pvc can be retried.
+	retentionTime time.Duration
+
+	resyncPeriod time.Duration
+	workSet      map[string]ObjectData
+}
+
+type ObjectData struct {
+	Timestamp       time.Time
+	StorageClassUID string
+}
+
+func NewSlowSet(retTime time.Duration) *SlowSet {
+	return &SlowSet{
+		retentionTime: retTime,
+		resyncPeriod:  100 * time.Millisecond,
+		workSet:       make(map[string]ObjectData),
+	}
+}
+
+func (s *SlowSet) Add(key string, info ObjectData) bool {
+	s.Lock()
+	defer s.Unlock()
+
+	if _, ok := s.workSet[key]; ok {
+		return false
+	}
+
+	s.workSet[key] = info
+	return true
+}
+
+func (s *SlowSet) Get(key string) (ObjectData, bool) {
+	s.RLock()
+	defer s.RUnlock()
+
+	info, ok := s.workSet[key]
+	return info, ok
+}
+
+func (s *SlowSet) Contains(key string) bool {
+	s.RLock()
+	defer s.RUnlock()
+
+	info, ok := s.workSet[key]
+	if ok && time.Since(info.Timestamp) < s.retentionTime {
+		return true
+	}
+	return false
+}
+
+func (s *SlowSet) Remove(key string) {
+	s.Lock()
+	defer s.Unlock()
+
+	delete(s.workSet, key)
+}
+
+func (s *SlowSet) TimeRemaining(key string) time.Duration {
+	s.RLock()
+	defer s.RUnlock()
+
+	if info, ok := s.workSet[key]; ok {
+		return s.retentionTime - time.Since(info.Timestamp)
+	}
+	return 0
+}
+
+func (s *SlowSet) removeAllExpired() {
+	s.Lock()
+	defer s.Unlock()
+	for key, info := range s.workSet {
+		if time.Since(info.Timestamp) > s.retentionTime {
+			delete(s.workSet, key)
+		}
+	}
+}
+
+func (s *SlowSet) Run(stopCh <-chan struct{}) {
+	ticker := time.NewTicker(s.resyncPeriod)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-stopCh:
+			return
+		case <-ticker.C:
+			s.removeAllExpired()
+		}
+	}
+}

slowset/slowset_test.go

@@ -0,0 +1,118 @@
+/*
+Copyright 2024 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 slowset
+
+import (
+	"testing"
+	"time"
+)
+
+func TestSlowSet(t *testing.T) {
+	tests := []struct {
+		name          string
+		retentionTime time.Duration
+		resyncPeriod  time.Duration
+		testFunc      func(*SlowSet) bool
+	}{
+		{
+			name:         "Should not change time of a key if added multiple times",
+			resyncPeriod: 100 * time.Millisecond,
+			testFunc: func(s *SlowSet) bool {
+				key := "key"
+				info := ObjectData{
+					Timestamp: time.Now(),
+				}
+				s.Add(key, info)
+				time1 := s.workSet[key]
+				s.Add(key, info)
+				time2 := s.workSet[key]
+				return time1 == time2
+			},
+		},
+		{
+			name:          "Should remove key after retention time",
+			retentionTime: 200 * time.Millisecond,
+			resyncPeriod:  100 * time.Millisecond,
+			testFunc: func(s *SlowSet) bool {
+				key := "key"
+				info := ObjectData{
+					Timestamp: time.Now(),
+				}
+				s.Add(key, info)
+				time.Sleep(300 * time.Millisecond)
+				return !s.Contains(key)
+			},
+		},
+		{
+			name:          "Should not remove key before retention time",
+			retentionTime: 200 * time.Millisecond,
+			resyncPeriod:  100 * time.Millisecond,
+			testFunc: func(s *SlowSet) bool {
+				key := "key"
+				info := ObjectData{
+					Timestamp: time.Now(),
+				}
+				s.Add(key, info)
+				time.Sleep(100 * time.Millisecond)
+				return s.Contains(key)
+			},
+		},
+		{
+			name:          "Should return time remaining for added keys",
+			retentionTime: 300 * time.Millisecond,
+			resyncPeriod:  100 * time.Millisecond,
+			testFunc: func(s *SlowSet) bool {
+				key := "key"
+				info := ObjectData{
+					Timestamp: time.Now(),
+				}
+				s.Add(key, info)
+				time.Sleep(100 * time.Millisecond)
+				timeRemaining := s.TimeRemaining(key)
+				return timeRemaining > 0 && timeRemaining < 300*time.Millisecond
+			},
+		},
+		{
+			name:          "should return false for Contains if key is present but expired",
+			resyncPeriod:  200 * time.Millisecond,
+			retentionTime: 300 * time.Millisecond,
+			testFunc: func(s *SlowSet) bool {
+				key := "key"
+				info := ObjectData{
+					Timestamp: time.Now(),
+				}
+				s.Add(key, info)
+				time.Sleep(301 * time.Millisecond)
+				return !s.Contains(key)
+			},
+		},
+	}
+
+	for i := range tests {
+		test := tests[i]
+		t.Run(test.name, func(t *testing.T) {
+			s := NewSlowSet(test.retentionTime)
+			s.resyncPeriod = test.resyncPeriod
+			stopCh := make(chan struct{}, 1)
+			go s.Run(stopCh)
+			defer close(stopCh)
+			if !test.testFunc(s) {
+				t.Errorf("Test failed")
+			}
+		})
+	}
+}