Peer RPCs for bucket notifications (#2877)

* Implements a Peer RPC router that sends info to all Minio servers in the cluster.
* Bucket notifications are propagated to all nodes via this RPC router.
* Bucket listener configuration is persisted to separate object layer
  file (`listener.json`) and peer RPCs are used to communicate changes
  throughout the cluster.
* When events are generated, RPC calls to send them to other servers
  where bucket listeners may be connected is implemented.
* Some bucket notification tests are now disabled as they cannot work in
  the new design.
* Minor fix in `funcFromPC` to use `path.Join`

cmd/s3-peer-rpc-handlers.go

@@ -0,0 +1,123 @@
+/*
+ * Minio Cloud Storage, (C) 2014-2016 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 cmd
+
+import "time"
+
+func (s3 *s3PeerAPIHandlers) LoginHandler(args *RPCLoginArgs, reply *RPCLoginReply) error {
+	jwt, err := newJWT(defaultInterNodeJWTExpiry)
+	if err != nil {
+		return err
+	}
+	if err = jwt.Authenticate(args.Username, args.Password); err != nil {
+		return err
+	}
+	token, err := jwt.GenerateToken(args.Username)
+	if err != nil {
+		return err
+	}
+	reply.Token = token
+	reply.ServerVersion = Version
+	reply.Timestamp = time.Now().UTC()
+	return nil
+}
+
+// SetBNPArgs - Arguments collection to SetBucketNotificationPeer RPC
+// call
+type SetBNPArgs struct {
+	// For Auth
+	GenericArgs
+
+	Bucket string
+
+	// Notification config for the given bucket.
+	NCfg *notificationConfig
+}
+
+func (s3 *s3PeerAPIHandlers) SetBucketNotificationPeer(args *SetBNPArgs, reply *GenericReply) error {
+	// check auth
+	if !isRPCTokenValid(args.Token) {
+		return errInvalidToken
+	}
+
+	// check if object layer is available.
+	objAPI := s3.ObjectAPI()
+	if objAPI == nil {
+		return errServerNotInitialized
+	}
+
+	// Update in-memory notification config.
+	globalEventNotifier.SetBucketNotificationConfig(args.Bucket, args.NCfg)
+
+	return nil
+}
+
+// SetBLPArgs - Arguments collection to SetBucketListenerPeer RPC call
+type SetBLPArgs struct {
+	// For Auth
+	GenericArgs
+
+	Bucket string
+
+	// Listener config for a given bucket.
+	LCfg []listenerConfig
+}
+
+func (s3 *s3PeerAPIHandlers) SetBucketListenerPeer(args SetBLPArgs, reply *GenericReply) error {
+	// check auth
+	if !isRPCTokenValid(args.Token) {
+		return errInvalidToken
+	}
+
+	// check if object layer is available.
+	objAPI := s3.ObjectAPI()
+	if objAPI == nil {
+		return errServerNotInitialized
+	}
+
+	// Update in-memory notification config.
+	return globalEventNotifier.SetBucketListenerConfig(args.Bucket, args.LCfg)
+}
+
+// EventArgs - Arguments collection for Event RPC call
+type EventArgs struct {
+	// For Auth
+	GenericArgs
+
+	// event being sent
+	Event []NotificationEvent
+
+	// client that it is meant for
+	Arn string
+}
+
+// submit an event to the receiving server.
+func (s3 *s3PeerAPIHandlers) Event(args *EventArgs, reply *GenericReply) error {
+	// check auth
+	if !isRPCTokenValid(args.Token) {
+		return errInvalidToken
+	}
+
+	// check if object layer is available.
+	objAPI := s3.ObjectAPI()
+	if objAPI == nil {
+		return errServerNotInitialized
+	}
+
+	err := globalEventNotifier.SendListenerEvent(args.Arn, args.Event)
+	return err
+}