add dnsStore interface for upcoming operator webhook (#10077)

cmd/config/etcd/dns/etcd_dns.go

@@ -48,8 +48,9 @@ func newCoreDNSMsg(ip string, port string, ttl uint32, t time.Time) ([]byte, err
 }
 
 // Close closes the internal etcd client and cannot be used further
-func (c *CoreDNS) Close() {
+func (c *CoreDNS) Close() error {
 	c.etcdClient.Close()
+	return nil
 }
 
 // List - Retrieves list of DNS entries for the domain.
@@ -259,7 +260,7 @@ func CoreDNSPath(prefix string) Option {
 }
 
 // NewCoreDNS - initialize a new coreDNS set/unset values.
-func NewCoreDNS(cfg clientv3.Config, setters ...Option) (*CoreDNS, error) {
+func NewCoreDNS(cfg clientv3.Config, setters ...Option) (Store, error) {
 	etcdClient, err := clientv3.New(cfg)
 	if err != nil {
 		return nil, err

cmd/config/etcd/dns/store.go

@@ -0,0 +1,27 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * 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 dns
+
+// Store dns record store
+type Store interface {
+	Put(bucket string) error
+	Get(bucket string) ([]SrvRecord, error)
+	Delete(bucket string) error
+	List() (map[string][]SrvRecord, error)
+	DeleteRecord(record SrvRecord) error
+	Close() error
+}