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/event.go

@@ -0,0 +1,88 @@
+/*
+ * 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 event
+
+const (
+	// NamespaceFormat - namespace log format used in some event targets.
+	NamespaceFormat = "namespace"
+
+	// AccessFormat - access log format used in some event targets.
+	AccessFormat = "access"
+
+	// AMZTimeFormat - event time format.
+	AMZTimeFormat = "2006-01-02T15:04:05Z"
+)
+
+// Identity represents access key who caused the event.
+type Identity struct {
+	PrincipalID string `json:"principalId"`
+}
+
+// Bucket represents bucket metadata of the event.
+type Bucket struct {
+	Name          string   `json:"name"`
+	OwnerIdentity Identity `json:"ownerIdentity"`
+	ARN           string   `json:"arn"`
+}
+
+// Object represents object metadata of the event.
+type Object struct {
+	Key          string            `json:"key"`
+	Size         int64             `json:"size,omitempty"`
+	ETag         string            `json:"eTag,omitempty"`
+	ContentType  string            `json:"contentType,omitempty"`
+	UserMetadata map[string]string `json:"userMetadata,omitempty"`
+	VersionID    string            `json:"versionId,omitempty"`
+	Sequencer    string            `json:"sequencer"`
+}
+
+// Metadata represents event metadata.
+type Metadata struct {
+	SchemaVersion   string `json:"s3SchemaVersion"`
+	ConfigurationID string `json:"configurationId"`
+	Bucket          Bucket `json:"bucket"`
+	Object          Object `json:"object"`
+}
+
+// Source represents client information who triggered the event.
+type Source struct {
+	Host      string `json:"host"`
+	Port      string `json:"port"`
+	UserAgent string `json:"userAgent"`
+}
+
+// Event represents event notification information defined in
+// http://docs.aws.amazon.com/AmazonS3/latest/dev/notification-content-structure.html.
+type Event struct {
+	EventVersion      string            `json:"eventVersion"`
+	EventSource       string            `json:"eventSource"`
+	AwsRegion         string            `json:"awsRegion"`
+	EventTime         string            `json:"eventTime"`
+	EventName         Name              `json:"eventName"`
+	UserIdentity      Identity          `json:"userIdentity"`
+	RequestParameters map[string]string `json:"requestParameters"`
+	ResponseElements  map[string]string `json:"responseElements"`
+	S3                Metadata          `json:"s3"`
+	Source            Source            `json:"source"`
+}
+
+// Log represents event information for some event targets.
+type Log struct {
+	EventName Name
+	Key       string
+	Records   []Event
+}