Add NATS notifier (#2795)

cmd/notify-nats.go

@@ -0,0 +1,108 @@
+/*
+ * Minio Cloud Storage, (C) 2016 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 cmd
+
+import (
+	"io/ioutil"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/nats-io/nats"
+)
+
+// natsNotify - represents logrus compatible NATS hook.
+// All fields represent NATS configuration details.
+type natsNotify struct {
+	Enable       bool   `json:"enable"`
+	Address      string `json:"address"`
+	Subject      string `json:"subject"`
+	Username     string `json:"username"`
+	Password     string `json:"password"`
+	Token        string `json:"token"`
+	Secure       bool   `json:"secure"`
+	PingInterval int64  `json:"pingInterval"`
+}
+
+type natsConn struct {
+	params natsNotify
+	*nats.Conn
+}
+
+// dialNATS - dials and returns an natsConn instance,
+// for sending notifications. Returns error if nats logger
+// is not enabled.
+func dialNATS(natsL natsNotify) (natsConn, error) {
+	if !natsL.Enable {
+		return natsConn{}, errNotifyNotEnabled
+	}
+	// Configure and connect to NATS server
+	natsC := nats.DefaultOptions
+	natsC.Url = "nats://" + natsL.Address
+	natsC.User = natsL.Username
+	natsC.Password = natsL.Password
+	natsC.Token = natsL.Token
+	natsC.Secure = natsL.Secure
+	conn, err := natsC.Connect()
+	if err != nil {
+		return natsConn{}, err
+	}
+	return natsConn{Conn: conn, params: natsL}, nil
+}
+
+func newNATSNotify(accountID string) (*logrus.Logger, error) {
+	natsL := serverConfig.GetNATSNotifyByID(accountID)
+
+	// Connect to nats server.
+	natsC, err := dialNATS(natsL)
+	if err != nil {
+		return nil, err
+	}
+
+	natsLog := logrus.New()
+
+	// Disable writing to console.
+	natsLog.Out = ioutil.Discard
+
+	// Add a nats hook.
+	natsLog.Hooks.Add(natsC)
+
+	// Set default JSON formatter.
+	natsLog.Formatter = new(logrus.JSONFormatter)
+
+	// Successfully enabled all NATSs.
+	return natsLog, nil
+}
+
+// Fire is called when an event should be sent to the message broker
+func (n natsConn) Fire(entry *logrus.Entry) error {
+	ch := n.Conn
+	body, err := entry.Reader()
+	if err != nil {
+		return err
+	}
+	err = ch.Publish(n.params.Subject, body.Bytes())
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Levels is available logging levels.
+func (n natsConn) Levels() []logrus.Level {
+	return []logrus.Level{
+		logrus.InfoLevel,
+	}
+}