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/elasticsearch.go

@@ -0,0 +1,132 @@
+/*
+ * 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 (
+	"context"
+	"fmt"
+	"net/url"
+	"time"
+
+	"github.com/minio/minio/pkg/event"
+	xnet "github.com/minio/minio/pkg/net"
+
+	"gopkg.in/olivere/elastic.v5"
+)
+
+// ElasticsearchArgs - Elasticsearch target arguments.
+type ElasticsearchArgs struct {
+	Enable bool     `json:"enable"`
+	Format string   `json:"format"`
+	URL    xnet.URL `json:"url"`
+	Index  string   `json:"index"`
+}
+
+// ElasticsearchTarget - Elasticsearch target.
+type ElasticsearchTarget struct {
+	id     event.TargetID
+	args   ElasticsearchArgs
+	client *elastic.Client
+}
+
+// ID - returns target ID.
+func (target *ElasticsearchTarget) ID() event.TargetID {
+	return target.id
+}
+
+// Send - sends event to Elasticsearch.
+func (target *ElasticsearchTarget) Send(eventData event.Event) (err error) {
+	var key string
+
+	remove := func() error {
+		_, err := target.client.Delete().Index(target.args.Index).Type("event").Id(key).Do(context.Background())
+		return err
+	}
+
+	update := func() error {
+		_, err := target.client.Index().Index(target.args.Index).Type("event").BodyJson(map[string]interface{}{"Records": []event.Event{eventData}}).Id(key).Do(context.Background())
+		return err
+	}
+
+	add := func() error {
+		eventTime, err := time.Parse(event.AMZTimeFormat, eventData.EventTime)
+		if err != nil {
+			return err
+		}
+
+		eventTimeMS := fmt.Sprintf("%d", eventTime.UnixNano()/1000000)
+		_, err = target.client.Index().Index(target.args.Index).Type("event").Timestamp(eventTimeMS).BodyJson(map[string]interface{}{"Records": []event.Event{eventData}}).Do(context.Background())
+		return err
+	}
+
+	if target.args.Format == event.NamespaceFormat {
+		objectName, err := url.QueryUnescape(eventData.S3.Object.Key)
+		if err != nil {
+			return err
+		}
+
+		key = eventData.S3.Bucket.Name + "/" + objectName
+		if eventData.EventName == event.ObjectRemovedDelete {
+			err = remove()
+		} else {
+			err = update()
+		}
+
+		return err
+	}
+
+	if target.args.Format == event.AccessFormat {
+		return add()
+	}
+
+	return nil
+}
+
+// Close - does nothing and available for interface compatibility.
+func (target *ElasticsearchTarget) Close() error {
+	return nil
+}
+
+// NewElasticsearchTarget - creates new Elasticsearch target.
+func NewElasticsearchTarget(id string, args ElasticsearchArgs) (*ElasticsearchTarget, error) {
+	client, err := elastic.NewClient(elastic.SetURL(args.URL.String()), elastic.SetSniff(false), elastic.SetMaxRetries(10))
+	if err != nil {
+		return nil, err
+	}
+
+	exists, err := client.IndexExists(args.Index).Do(context.Background())
+	if err != nil {
+		return nil, err
+	}
+
+	if !exists {
+		var createIndex *elastic.IndicesCreateResult
+		if createIndex, err = client.CreateIndex(args.Index).Do(context.Background()); err != nil {
+			return nil, err
+		}
+
+		if !createIndex.Acknowledged {
+			return nil, fmt.Errorf("index %v not created", args.Index)
+		}
+	}
+
+	return &ElasticsearchTarget{
+		id:     event.TargetID{id, "elasticsearch"},
+		args:   args,
+		client: client,
+	}, nil
+}