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/amqp.go

@@ -0,0 +1,150 @@
+/*
+ * 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"
+	"net/url"
+	"sync"
+
+	"github.com/minio/minio/pkg/event"
+	xnet "github.com/minio/minio/pkg/net"
+	"github.com/streadway/amqp"
+)
+
+// AMQPArgs - AMQP target arguments.
+type AMQPArgs struct {
+	Enable       bool     `json:"enable"`
+	URL          xnet.URL `json:"url"`
+	Exchange     string   `json:"exchange"`
+	RoutingKey   string   `json:"routingKey"`
+	ExchangeType string   `json:"exchangeType"`
+	DeliveryMode uint8    `json:"deliveryMode"`
+	Mandatory    bool     `json:"mandatory"`
+	Immediate    bool     `json:"immediate"`
+	Durable      bool     `json:"durable"`
+	Internal     bool     `json:"internal"`
+	NoWait       bool     `json:"noWait"`
+	AutoDeleted  bool     `json:"autoDeleted"`
+}
+
+// AMQPTarget - AMQP target
+type AMQPTarget struct {
+	id        event.TargetID
+	args      AMQPArgs
+	conn      *amqp.Connection
+	connMutex sync.Mutex
+}
+
+// ID - returns TargetID.
+func (target *AMQPTarget) ID() event.TargetID {
+	return target.id
+}
+
+func (target *AMQPTarget) channel() (*amqp.Channel, error) {
+	isAMQPClosedErr := func(err error) bool {
+		if err == amqp.ErrClosed {
+			return true
+		}
+
+		if nerr, ok := err.(*net.OpError); ok {
+			return (nerr.Err.Error() == "use of closed network connection")
+		}
+
+		return false
+	}
+
+	target.connMutex.Lock()
+	defer target.connMutex.Unlock()
+
+	ch, err := target.conn.Channel()
+	if err == nil {
+		return ch, nil
+	}
+
+	if !isAMQPClosedErr(err) {
+		return nil, err
+	}
+
+	var conn *amqp.Connection
+	if conn, err = amqp.Dial(target.args.URL.String()); err != nil {
+		return nil, err
+	}
+
+	if ch, err = conn.Channel(); err != nil {
+		return nil, err
+	}
+
+	target.conn = conn
+
+	return ch, nil
+}
+
+// Send - sends event to AMQP.
+func (target *AMQPTarget) Send(eventData event.Event) error {
+	ch, err := target.channel()
+	if err != nil {
+		return err
+	}
+	defer func() {
+		// FIXME: log returned error. ignore time being.
+		_ = ch.Close()
+	}()
+
+	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 err = ch.ExchangeDeclare(target.args.Exchange, target.args.ExchangeType, target.args.Durable,
+		target.args.AutoDeleted, target.args.Internal, target.args.NoWait, nil); err != nil {
+		return err
+	}
+
+	return ch.Publish(target.args.Exchange, target.args.RoutingKey, target.args.Mandatory,
+		target.args.Immediate, amqp.Publishing{
+			ContentType:  "application/json",
+			DeliveryMode: target.args.DeliveryMode,
+			Body:         data,
+		})
+}
+
+// Close - does nothing and available for interface compatibility.
+func (target *AMQPTarget) Close() error {
+	return nil
+}
+
+// NewAMQPTarget - creates new AMQP target.
+func NewAMQPTarget(id string, args AMQPArgs) (*AMQPTarget, error) {
+	conn, err := amqp.Dial(args.URL.String())
+	if err != nil {
+		return nil, err
+	}
+
+	return &AMQPTarget{
+		id:   event.TargetID{id, "amqp"},
+		args: args,
+		conn: conn,
+	}, nil
+}