Cache for pod bindings

pkg/controller/volume/persistentvolume/scheduler_binder_cache.go

+/*
+Copyright 2017 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 persistentvolume
+
+import (
+	"sync"
+
+	"k8s.io/api/core/v1"
+)
+
+// podBindingCache stores PV binding decisions per pod per node.
+// Pod entries are removed when the Pod is deleted or updated to
+// no longer be schedulable.
+type PodBindingCache interface {
+	// UpdateBindings will update the cache with the given bindings for the
+	// pod and node.
+	UpdateBindings(pod *v1.Pod, node string, bindings []*bindingInfo)
+
+	// DeleteBindings will remove all cached bindings for the given pod.
+	DeleteBindings(pod *v1.Pod)
+
+	// GetBindings will return the cached bindings for the given pod and node.
+	GetBindings(pod *v1.Pod, node string) []*bindingInfo
+}
+
+type podBindingCache struct {
+	mutex sync.Mutex
+
+	// Key = pod name
+	// Value = nodeBindings
+	bindings map[string]nodeBindings
+}
+
+// Key = nodeName
+// Value = array of bindingInfo
+type nodeBindings map[string][]*bindingInfo
+
+func NewPodBindingCache() PodBindingCache {
+	return &podBindingCache{bindings: map[string]nodeBindings{}}
+}
+
+func (c *podBindingCache) DeleteBindings(pod *v1.Pod) {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	podName := getPodName(pod)
+	delete(c.bindings, podName)
+}
+
+func (c *podBindingCache) UpdateBindings(pod *v1.Pod, node string, bindings []*bindingInfo) {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	podName := getPodName(pod)
+	nodeBinding, ok := c.bindings[podName]
+	if !ok {
+		nodeBinding = nodeBindings{}
+		c.bindings[podName] = nodeBinding
+	}
+	nodeBinding[node] = bindings
+}
+
+func (c *podBindingCache) GetBindings(pod *v1.Pod, node string) []*bindingInfo {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	podName := getPodName(pod)
+	nodeBindings, ok := c.bindings[podName]
+	if !ok {
+		return nil
+	}
+	return nodeBindings[node]
+}

pkg/controller/volume/persistentvolume/scheduler_binder_cache_test.go

+/*
+Copyright 2017 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 persistentvolume
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestUpdateGetBindings(t *testing.T) {
+	scenarios := map[string]struct {
+		updateBindings []*bindingInfo
+		updatePod      string
+		updateNode     string
+
+		getBindings []*bindingInfo
+		getPod      string
+		getNode     string
+	}{
+		"no-pod": {
+			getPod:  "pod1",
+			getNode: "node1",
+		},
+		"no-node": {
+			updatePod:      "pod1",
+			updateNode:     "node1",
+			updateBindings: []*bindingInfo{},
+			getPod:         "pod1",
+			getNode:        "node2",
+		},
+		"binding-exists": {
+			updatePod:      "pod1",
+			updateNode:     "node1",
+			updateBindings: []*bindingInfo{{pvc: &v1.PersistentVolumeClaim{ObjectMeta: metav1.ObjectMeta{Name: "pvc1"}}}},
+			getPod:         "pod1",
+			getNode:        "node1",
+			getBindings:    []*bindingInfo{{pvc: &v1.PersistentVolumeClaim{ObjectMeta: metav1.ObjectMeta{Name: "pvc1"}}}},
+		},
+	}
+
+	for name, scenario := range scenarios {
+		cache := NewPodBindingCache()
+
+		// Perform updates
+		updatePod := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: scenario.updatePod, Namespace: "ns"}}
+		cache.UpdateBindings(updatePod, scenario.updateNode, scenario.updateBindings)
+
+		// Verify updated bindings
+		bindings := cache.GetBindings(updatePod, scenario.updateNode)
+		if !reflect.DeepEqual(bindings, scenario.updateBindings) {
+			t.Errorf("Test %v failed: returned bindings after update different. Got %+v, expected %+v", name, bindings, scenario.updateBindings)
+		}
+
+		// Get bindings
+		getPod := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: scenario.getPod, Namespace: "ns"}}
+		bindings = cache.GetBindings(getPod, scenario.getNode)
+		if !reflect.DeepEqual(bindings, scenario.getBindings) {
+			t.Errorf("Test %v failed: unexpected bindings returned. Got %+v, expected %+v", name, bindings, scenario.updateBindings)
+		}
+	}
+}
+
+func TestDeleteBindings(t *testing.T) {
+	initialBindings := []*bindingInfo{{pvc: &v1.PersistentVolumeClaim{ObjectMeta: metav1.ObjectMeta{Name: "pvc1"}}}}
+	cache := NewPodBindingCache()
+
+	pod := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod1", Namespace: "ns"}}
+
+	// Get nil bindings
+	bindings := cache.GetBindings(pod, "node1")
+	if bindings != nil {
+		t.Errorf("Test failed: expected inital nil bindings, got %+v", bindings)
+	}
+
+	// Delete nothing
+	cache.DeleteBindings(pod)
+
+	// Perform updates
+	cache.UpdateBindings(pod, "node1", initialBindings)
+
+	// Get bindings
+	bindings = cache.GetBindings(pod, "node1")
+	if !reflect.DeepEqual(bindings, initialBindings) {
+		t.Errorf("Test failed: expected bindings %+v, got %+v", initialBindings, bindings)
+	}
+
+	// Delete
+	cache.DeleteBindings(pod)
+
+	// Get bindings
+	bindings = cache.GetBindings(pod, "node1")
+	if bindings != nil {
+		t.Errorf("Test failed: expected nil bindings, got %+v", bindings)
+	}
+}