feat(zfspv): adding backup and restore support (#162)

This commit adds support for Backup and Restore controller, which will be watching for
the events. The velero plugin will create a Backup CR to create a backup
with the remote location information, the controller will send the data
to that remote location.

In the same way, the velero plugin will create a Restore CR to restore the
volume from the the remote location and the restore controller will restore
the data.

Steps to use velero plugin for ZFS-LocalPV are :

1. install velero

2. add openebs plugin

velero plugin add openebs/velero-plugin:latest

3. Create the volumesnapshot location :

for full backup :-

```yaml
apiVersion: velero.io/v1
kind: VolumeSnapshotLocation
metadata:
  name: default
  namespace: velero
spec:
  provider: openebs.io/zfspv-blockstore
  config:
    bucket: velero
    prefix: zfs
    namespace: openebs
    provider: aws
    region: minio
    s3ForcePathStyle: "true"
    s3Url: http://minio.velero.svc:9000
```

for incremental backup :-

```yaml
apiVersion: velero.io/v1
kind: VolumeSnapshotLocation
metadata:
  name: default
  namespace: velero
spec:
  provider: openebs.io/zfspv-blockstore
  config:
    bucket: velero
    prefix: zfs
    backup: incremental
    namespace: openebs
    provider: aws
    region: minio
    s3ForcePathStyle: "true"
    s3Url: http://minio.velero.svc:9000
```

4. Create backup

velero backup create my-backup --snapshot-volumes --include-namespaces=velero-ns --volume-snapshot-locations=aws-cloud-default --storage-location=default

5. Create Schedule

velero create schedule newschedule  --schedule="*/1 * * * *" --snapshot-volumes --include-namespaces=velero-ns --volume-snapshot-locations=aws-local-default --storage-location=default

6. Restore from backup

velero restore create --from-backup my-backup --restore-volumes=true --namespace-mappings velero-ns:ns1



Signed-off-by: Pawan <pawan@mayadata.io>

pkg/builder/restorebuilder/restore.go

@@ -0,0 +1,117 @@
+// Copyright © 2020 The OpenEBS 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 restorebuilder
+
+import (
+	apis "github.com/openebs/zfs-localpv/pkg/apis/openebs.io/zfs/v1"
+)
+
+// ZFSRestore is a wrapper over
+// ZFSRestore API instance
+type ZFSRestore struct {
+	// ZFSSnap object
+	Object *apis.ZFSRestore
+}
+
+// From returns a new instance of
+// zfsrstr rstrume
+func From(rstr *apis.ZFSRestore) *ZFSRestore {
+	return &ZFSRestore{
+		Object: rstr,
+	}
+}
+
+// Predicate defines an abstraction
+// to determine conditional checks
+// against the provided pod instance
+type Predicate func(*ZFSRestore) bool
+
+// PredicateList holds a list of predicate
+type predicateList []Predicate
+
+// ZFSRestoreList holds the list
+// of zfs restore instances
+type ZFSRestoreList struct {
+	// List contains list of restore
+	List apis.ZFSRestoreList
+}
+
+// Len returns the number of items present
+// in the ZFSRestoreList
+func (rstrList *ZFSRestoreList) Len() int {
+	return len(rstrList.List.Items)
+}
+
+// all returns true if all the predicates
+// succeed against the provided ZFSRestore
+// instance
+func (l predicateList) all(rstr *ZFSRestore) bool {
+	for _, pred := range l {
+		if !pred(rstr) {
+			return false
+		}
+	}
+	return true
+}
+
+// HasLabels returns true if provided labels
+// are present in the provided ZFSRestore instance
+func HasLabels(keyValuePair map[string]string) Predicate {
+	return func(rstr *ZFSRestore) bool {
+		for key, value := range keyValuePair {
+			if !rstr.HasLabel(key, value) {
+				return false
+			}
+		}
+		return true
+	}
+}
+
+// HasLabel returns true if provided label
+// is present in the provided ZFSRestore instance
+func (rstr *ZFSRestore) HasLabel(key, value string) bool {
+	val, ok := rstr.Object.GetLabels()[key]
+	if ok {
+		return val == value
+	}
+	return false
+}
+
+// HasLabel returns true if provided label
+// is present in the provided ZFSRestore instance
+func HasLabel(key, value string) Predicate {
+	return func(rstr *ZFSRestore) bool {
+		return rstr.HasLabel(key, value)
+	}
+}
+
+// IsNil returns true if the zfsrstr rstrume instance
+// is nil
+func (rstr *ZFSRestore) IsNil() bool {
+	return rstr.Object == nil
+}
+
+// IsNil is predicate to filter out nil zfsrstr rstrume
+// instances
+func IsNil() Predicate {
+	return func(rstr *ZFSRestore) bool {
+		return rstr.IsNil()
+	}
+}
+
+// GetAPIObject returns zfsrstr rstrume's API instance
+func (rstr *ZFSRestore) GetAPIObject() *apis.ZFSRestore {
+	return rstr.Object
+}