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/kafka.go

@@ -0,0 +1,97 @@
+/*
+ * 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"
+
+	sarama "gopkg.in/Shopify/sarama.v1"
+)
+
+// KafkaArgs - Kafka target arguments.
+type KafkaArgs struct {
+	Enable  bool        `json:"enable"`
+	Brokers []xnet.Host `json:"brokers"`
+	Topic   string      `json:"topic"`
+}
+
+// KafkaTarget - Kafka target.
+type KafkaTarget struct {
+	id       event.TargetID
+	args     KafkaArgs
+	producer sarama.SyncProducer
+}
+
+// ID - returns target ID.
+func (target *KafkaTarget) ID() event.TargetID {
+	return target.id
+}
+
+// Send - sends event to Kafka.
+func (target *KafkaTarget) Send(eventData event.Event) 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
+	}
+
+	msg := sarama.ProducerMessage{
+		Topic: target.args.Topic,
+		Key:   sarama.StringEncoder(key),
+		Value: sarama.ByteEncoder(data),
+	}
+	_, _, err = target.producer.SendMessage(&msg)
+
+	return err
+}
+
+// Close - closes underneath kafka connection.
+func (target *KafkaTarget) Close() error {
+	return target.producer.Close()
+}
+
+// NewKafkaTarget - creates new Kafka target.
+func NewKafkaTarget(id string, args KafkaArgs) (*KafkaTarget, error) {
+	config := sarama.NewConfig()
+	config.Producer.RequiredAcks = sarama.WaitForAll
+	config.Producer.Retry.Max = 10
+	config.Producer.Return.Successes = true
+
+	brokers := []string{}
+	for _, broker := range args.Brokers {
+		brokers = append(brokers, broker.String())
+	}
+	producer, err := sarama.NewSyncProducer(brokers, config)
+	if err != nil {
+		return nil, err
+	}
+
+	return &KafkaTarget{
+		id:       event.TargetID{id, "kafka"},
+		args:     args,
+		producer: producer,
+	}, nil
+}