Add Snapshot Controller

This PR adds external snapshot controller and main package under cmd.

pkg/controller/util.go

@@ -0,0 +1,123 @@
+/*
+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 controller
+
+import (
+	"fmt"
+	"github.com/golang/glog"
+	crdv1 "github.com/kubernetes-csi/external-snapshotter/pkg/apis/volumesnapshot/v1alpha1"
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/tools/cache"
+	"strconv"
+	"strings"
+)
+
+var (
+	keyFunc = cache.DeletionHandlingMetaNamespaceKeyFunc
+)
+
+// GetNameAndNameSpaceFromSnapshotName retrieves the namespace and
+// the short name of a snapshot from its full name
+func GetNameAndNameSpaceFromSnapshotName(name string) (string, string, error) {
+	strs := strings.Split(name, "/")
+	if len(strs) != 2 {
+		return "", "", fmt.Errorf("invalid snapshot name")
+	}
+	return strs[0], strs[1], nil
+}
+
+func snapshotKey(vs *crdv1.VolumeSnapshot) string {
+	return fmt.Sprintf("%s/%s", vs.Namespace, vs.Name)
+}
+
+func snapshotRefKey(vsref *v1.ObjectReference) string {
+	return fmt.Sprintf("%s/%s", vsref.Namespace, vsref.Name)
+}
+
+// storeObjectUpdate updates given cache with a new object version from Informer
+// callback (i.e. with events from etcd) or with an object modified by the
+// controller itself. Returns "true", if the cache was updated, false if the
+// object is an old version and should be ignored.
+func storeObjectUpdate(store cache.Store, obj interface{}, className string) (bool, error) {
+	objName, err := keyFunc(obj)
+	if err != nil {
+		return false, fmt.Errorf("Couldn't get key for object %+v: %v", obj, err)
+	}
+	oldObj, found, err := store.Get(obj)
+	if err != nil {
+		return false, fmt.Errorf("Error finding %s %q in controller cache: %v", className, objName, err)
+	}
+
+	objAccessor, err := meta.Accessor(obj)
+	if err != nil {
+		return false, err
+	}
+
+	if !found {
+		// This is a new object
+		glog.V(4).Infof("storeObjectUpdate: adding %s %q, version %s", className, objName, objAccessor.GetResourceVersion())
+		if err = store.Add(obj); err != nil {
+			return false, fmt.Errorf("error adding %s %q to controller cache: %v", className, objName, err)
+		}
+		return true, nil
+	}
+
+	oldObjAccessor, err := meta.Accessor(oldObj)
+	if err != nil {
+		return false, err
+	}
+
+	objResourceVersion, err := strconv.ParseInt(objAccessor.GetResourceVersion(), 10, 64)
+	if err != nil {
+		return false, fmt.Errorf("error parsing ResourceVersion %q of %s %q: %s", objAccessor.GetResourceVersion(), className, objName, err)
+	}
+	oldObjResourceVersion, err := strconv.ParseInt(oldObjAccessor.GetResourceVersion(), 10, 64)
+	if err != nil {
+		return false, fmt.Errorf("error parsing old ResourceVersion %q of %s %q: %s", oldObjAccessor.GetResourceVersion(), className, objName, err)
+	}
+
+	// Throw away only older version, let the same version pass - we do want to
+	// get periodic sync events.
+	if oldObjResourceVersion > objResourceVersion {
+		glog.V(4).Infof("storeObjectUpdate: ignoring %s %q version %s", className, objName, objAccessor.GetResourceVersion())
+		return false, nil
+	}
+
+	glog.V(4).Infof("storeObjectUpdate updating %s %q with version %s", className, objName, objAccessor.GetResourceVersion())
+	if err = store.Update(obj); err != nil {
+		return false, fmt.Errorf("error updating %s %q in controller cache: %v", className, objName, err)
+	}
+	return true, nil
+}
+
+// GetSnapshotContentNameForSnapshot returns SnapshotData.Name for the create VolumeSnapshotContent.
+// The name must be unique.
+func GetSnapshotContentNameForSnapshot(snapshot *crdv1.VolumeSnapshot) string {
+	return "snapdata-" + string(snapshot.UID)
+}
+
+// IsDefaultAnnotation returns a boolean if
+// the annotation is set
+func IsDefaultAnnotation(obj metav1.ObjectMeta) bool {
+	if obj.Annotations[IsDefaultSnapshotClassAnnotation] == "true" {
+		return true
+	}
+
+	return false
+}