make notification as separate package (#5294)

* Remove old notification files

* Add net package

* Add event package

* Modify minio to take new notification system

pkg/event/target/nats.go

@@ -0,0 +1,143 @@
+/*
+ * Minio Cloud Storage, (C) 2018 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 target
+
+import (
+	"encoding/json"
+	"net/url"
+
+	"github.com/minio/minio/pkg/event"
+	xnet "github.com/minio/minio/pkg/net"
+	"github.com/nats-io/go-nats-streaming"
+	"github.com/nats-io/nats"
+)
+
+// NATSArgs - NATS target arguments.
+type NATSArgs struct {
+	Enable       bool      `json:"enable"`
+	Address      xnet.Host `json:"address"`
+	Subject      string    `json:"subject"`
+	Username     string    `json:"username"`
+	Password     string    `json:"password"`
+	Token        string    `json:"token"`
+	Secure       bool      `json:"secure"`
+	PingInterval int64     `json:"pingInterval"`
+	Streaming    struct {
+		Enable             bool   `json:"enable"`
+		ClusterID          string `json:"clusterID"`
+		ClientID           string `json:"clientID"`
+		Async              bool   `json:"async"`
+		MaxPubAcksInflight int    `json:"maxPubAcksInflight"`
+	} `json:"streaming"`
+}
+
+// NATSTarget - NATS target.
+type NATSTarget struct {
+	id       event.TargetID
+	args     NATSArgs
+	natsConn *nats.Conn
+	stanConn stan.Conn
+}
+
+// ID - returns target ID.
+func (target *NATSTarget) ID() event.TargetID {
+	return target.id
+}
+
+// Send - sends event to NATS.
+func (target *NATSTarget) Send(eventData event.Event) (err error) {
+	objectName, err := url.QueryUnescape(eventData.S3.Object.Key)
+	if err != nil {
+		return err
+	}
+	key := eventData.S3.Bucket.Name + "/" + objectName
+
+	data, err := json.Marshal(event.Log{eventData.EventName, key, []event.Event{eventData}})
+	if err != nil {
+		return err
+	}
+
+	if target.stanConn != nil {
+		if target.args.Streaming.Async {
+			_, err = target.stanConn.PublishAsync(target.args.Subject, data, nil)
+		} else {
+			err = target.stanConn.Publish(target.args.Subject, data)
+		}
+	} else {
+		err = target.natsConn.Publish(target.args.Subject, data)
+	}
+
+	return err
+}
+
+// Close - closes underneath connections to NATS server.
+func (target *NATSTarget) Close() (err error) {
+	if target.stanConn != nil {
+		err = target.stanConn.Close()
+	}
+
+	if target.natsConn != nil {
+		target.natsConn.Close()
+	}
+
+	return err
+}
+
+// NewNATSTarget - creates new NATS target.
+func NewNATSTarget(id string, args NATSArgs) (*NATSTarget, error) {
+	var natsConn *nats.Conn
+	var stanConn stan.Conn
+	var err error
+
+	if args.Streaming.Enable {
+		scheme := "nats"
+		if args.Secure {
+			scheme = "tls"
+		}
+		addressURL := scheme + "://" + args.Username + ":" + args.Password + "@" + args.Address.String()
+
+		clientID := args.Streaming.ClientID
+		if clientID == "" {
+			clientID = mustGetNewUUID()
+		}
+
+		connOpts := []stan.Option{stan.NatsURL(addressURL)}
+		if args.Streaming.MaxPubAcksInflight > 0 {
+			connOpts = append(connOpts, stan.MaxPubAcksInflight(args.Streaming.MaxPubAcksInflight))
+		}
+
+		stanConn, err = stan.Connect(args.Streaming.ClusterID, clientID, connOpts...)
+	} else {
+		options := nats.DefaultOptions
+		options.Url = "nats://" + args.Address.String()
+		options.User = args.Username
+		options.Password = args.Password
+		options.Token = args.Token
+		options.Secure = args.Secure
+		natsConn, err = options.Connect()
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return &NATSTarget{
+		id:       event.TargetID{id, "nats"},
+		args:     args,
+		stanConn: stanConn,
+		natsConn: natsConn,
+	}, nil
+}