Improve messaging on resize

- we now provide clear message to user what to do when cloudprovider resizing is finished
  and file system resizing is needed.
- add a event when resizing is successful.
- Use Patch for updating PVCs in both kubelet and controller-manager
- Extract updating pvc util function in one place.
- Only update resize conditions on progress

pkg/volume/util/resize_util.go

@@ -0,0 +1,125 @@
+/*
+Copyright 2018 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 util
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/strategicpatch"
+	clientset "k8s.io/client-go/kubernetes"
+)
+
+var (
+	knownResizeConditions map[v1.PersistentVolumeClaimConditionType]bool = map[v1.PersistentVolumeClaimConditionType]bool{
+		v1.PersistentVolumeClaimFileSystemResizePending: true,
+		v1.PersistentVolumeClaimResizing:                true,
+	}
+)
+
+type resizeProcessStatus struct {
+	condition v1.PersistentVolumeClaimCondition
+	processed bool
+}
+
+// ClaimToClaimKey return namespace/name string for pvc
+func ClaimToClaimKey(claim *v1.PersistentVolumeClaim) string {
+	return fmt.Sprintf("%s/%s", claim.Namespace, claim.Name)
+}
+
+// MarkFSResizeFinished marks file system resizing as done
+func MarkFSResizeFinished(
+	pvc *v1.PersistentVolumeClaim,
+	capacity v1.ResourceList,
+	kubeClient clientset.Interface) error {
+	newPVC := pvc.DeepCopy()
+	newPVC.Status.Capacity = capacity
+	newPVC = MergeResizeConditionOnPVC(newPVC, []v1.PersistentVolumeClaimCondition{})
+	_, err := PatchPVCStatus(pvc /*oldPVC*/, newPVC, kubeClient)
+	return err
+}
+
+// PatchPVCStatus updates PVC status using PATCH verb
+func PatchPVCStatus(
+	oldPVC *v1.PersistentVolumeClaim,
+	newPVC *v1.PersistentVolumeClaim,
+	kubeClient clientset.Interface) (*v1.PersistentVolumeClaim, error) {
+	pvcName := oldPVC.Name
+
+	oldData, err := json.Marshal(oldPVC)
+	if err != nil {
+		return nil, fmt.Errorf("PatchPVCStatus.Failed to marshal oldData for pvc %q with %v", pvcName, err)
+	}
+
+	newData, err := json.Marshal(newPVC)
+	if err != nil {
+		return nil, fmt.Errorf("PatchPVCStatus.Failed to marshal newData for pvc %q with %v", pvcName, err)
+	}
+
+	patchBytes, err := strategicpatch.CreateTwoWayMergePatch(oldData, newData, oldPVC)
+	if err != nil {
+		return nil, fmt.Errorf("PatchPVCStatus.Failed to CreateTwoWayMergePatch for pvc %q with %v ", pvcName, err)
+	}
+	updatedClaim, updateErr := kubeClient.CoreV1().PersistentVolumeClaims(oldPVC.Namespace).
+		Patch(pvcName, types.StrategicMergePatchType, patchBytes, "status")
+	if updateErr != nil {
+		return nil, fmt.Errorf("PatchPVCStatus.Failed to patch PVC %q with %v", pvcName, updateErr)
+	}
+	return updatedClaim, nil
+}
+
+// MergeResizeConditionOnPVC updates pvc with requested resize conditions
+// leaving other conditions untouched.
+func MergeResizeConditionOnPVC(
+	pvc *v1.PersistentVolumeClaim,
+	resizeConditions []v1.PersistentVolumeClaimCondition) *v1.PersistentVolumeClaim {
+	resizeConditionMap := map[v1.PersistentVolumeClaimConditionType]*resizeProcessStatus{}
+
+	for _, condition := range resizeConditions {
+		resizeConditionMap[condition.Type] = &resizeProcessStatus{condition, false}
+	}
+
+	oldConditions := pvc.Status.Conditions
+	newConditions := []v1.PersistentVolumeClaimCondition{}
+	for _, condition := range oldConditions {
+		// If Condition is of not resize type, we keep it.
+		if _, ok := knownResizeConditions[condition.Type]; !ok {
+			newConditions = append(newConditions, condition)
+			continue
+		}
+
+		if newCondition, ok := resizeConditionMap[condition.Type]; ok {
+			if newCondition.condition.Status != condition.Status {
+				newConditions = append(newConditions, newCondition.condition)
+			} else {
+				newConditions = append(newConditions, condition)
+			}
+			newCondition.processed = true
+		}
+	}
+
+	// append all unprocessed conditions
+	for _, newCondition := range resizeConditionMap {
+		if !newCondition.processed {
+			newConditions = append(newConditions, newCondition.condition)
+		}
+	}
+	pvc.Status.Conditions = newConditions
+	return pvc
+}