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/webhook.go

@@ -0,0 +1,113 @@
+/*
+ * 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 (
+	"bytes"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/minio/minio/pkg/event"
+	xnet "github.com/minio/minio/pkg/net"
+)
+
+// WebhookArgs - Webhook target arguments.
+type WebhookArgs struct {
+	Enable   bool           `json:"enable"`
+	Endpoint xnet.URL       `json:"endpoint"`
+	RootCAs  *x509.CertPool `json:"-"`
+}
+
+// WebhookTarget - Webhook target.
+type WebhookTarget struct {
+	id         event.TargetID
+	args       WebhookArgs
+	httpClient *http.Client
+}
+
+// ID - returns target ID.
+func (target WebhookTarget) ID() event.TargetID {
+	return target.id
+}
+
+// Send - sends event to Webhook.
+func (target *WebhookTarget) 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
+	}
+
+	req, err := http.NewRequest("POST", target.args.Endpoint.String(), bytes.NewReader(data))
+	if err != nil {
+		return err
+	}
+
+	// req.Header.Set("User-Agent", globalServerUserAgent)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := target.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+
+	// FIXME: log returned error. ignore time being.
+	_ = resp.Body.Close()
+
+	switch resp.StatusCode {
+	case http.StatusOK, http.StatusAccepted, http.StatusContinue:
+		return nil
+	default:
+		return fmt.Errorf("sending event failed with %v", resp.Status)
+	}
+}
+
+// Close - does nothing and available for interface compatibility.
+func (target *WebhookTarget) Close() error {
+	return nil
+}
+
+// NewWebhookTarget - creates new Webhook target.
+func NewWebhookTarget(id string, args WebhookArgs) *WebhookTarget {
+	return &WebhookTarget{
+		id:   event.TargetID{id, "webhook"},
+		args: args,
+		httpClient: &http.Client{
+			Transport: &http.Transport{
+				TLSClientConfig: &tls.Config{RootCAs: args.RootCAs},
+				DialContext: (&net.Dialer{
+					Timeout:   5 * time.Second,
+					KeepAlive: 5 * time.Second,
+				}).DialContext,
+				TLSHandshakeTimeout:   3 * time.Second,
+				ResponseHeaderTimeout: 3 * time.Second,
+				ExpectContinueTimeout: 2 * time.Second,
+			},
+		},
+	}
+}