clientID removed in the MQTT config (#7157)

More than one client can't use the same clientID for MQTT connection. 
This causes problem in distributed deployments where config is shared 
across nodes, as each Minio instance tries to connect to MQTT using the
same clientID.

This commit removes the clientID field in config, and allows
MQTT client to create random clientID for each node.

cmd/admin-handlers_test.go

@@ -119,7 +119,6 @@ var (
         "broker": "",
         "topic": "",
         "qos": 0,
-        "clientId": "",
         "username": "",
         "password": "",
         "reconnectInterval": 0,

cmd/config-current_test.go

@@ -233,7 +233,7 @@ func TestValidateConfig(t *testing.T) {
 		{`{"version": "` + v + `", "credential": { "accessKey": "minio", "secretKey": "minio123" }, "region": "us-east-1", "browser": "on", "notify": { "redis": { "1": { "enable": true, "format": "namespace", "address": "example.com:80", "password": "xxx", "key": "key1" } }}}`, true},
 
 		// Test 27 - Test MQTT
-		{`{"version": "` + v + `", "credential": { "accessKey": "minio", "secretKey": "minio123" }, "region": "us-east-1", "browser": "on", "notify": { "mqtt": { "1": { "enable": true, "broker": "",  "topic": "", "qos": 0, "clientId": "", "username": "", "password": "", "queueDir": ""}}}}`, false},
+		{`{"version": "` + v + `", "credential": { "accessKey": "minio", "secretKey": "minio123" }, "region": "us-east-1", "browser": "on", "notify": { "mqtt": { "1": { "enable": true, "broker": "",  "topic": "", "qos": 0, "username": "", "password": "", "queueDir": ""}}}}`, false},
 
 		// Test 28 - Test NSQ
 		{`{"version": "` + v + `", "credential": { "accessKey": "minio", "secretKey": "minio123" }, "region": "us-east-1", "browser": "on", "notify": { "nsq": { "1": { "enable": true, "nsqdAddress": "", "topic": ""} }}}`, false},

cmd/config-versions.go

@@ -893,7 +893,7 @@ type serverConfigV32 struct {
 	} `json:"policy"`
 }
 
-// serverConfigV33 is just like version '32', removes clientID from NATS and adds queueDir with MQTT.
+// serverConfigV33 is just like version '32', removes clientID from NATS and MQTT, and adds queueDir with MQTT.
 type serverConfigV33 struct {
 	quick.Config `json:"-"` // ignore interfaces
 

docs/bucket/notifications/README.md

@@ -160,7 +160,6 @@ The Minio server configuration file is stored on the backend in json format. The
 | `broker` | _string_ | (Required) MQTT server endpoint, e.g. `tcp://localhost:1883` |
 | `topic` | _string_ | (Required) Name of the MQTT topic to publish on, e.g. `minio` |
 | `qos` | _int_ | Set the Quality of Service Level |
-| `clientId` | _string_ | Unique ID for the MQTT broker to identify Minio |
 | `username` | _string_ | Username to connect to the MQTT server (if required) |
 | `password` | _string_ | Password to connect to the MQTT server (if required) |
 | `queueDir` | _string_ | Persistent store for events when MQTT broker is offline |
@@ -174,7 +173,6 @@ An example configuration for MQTT is shown below:
         "broker": "tcp://localhost:1883",
         "topic": "minio",
         "qos": 1,
-        "clientId": "minio",
         "username": "",
         "password": "",
         "queueDir": ""
@@ -222,12 +220,14 @@ import paho.mqtt.client as mqtt
 
 def on_connect(client, userdata, flags, rc):
   print("Connected with result code "+str(rc))
-  client.subscribe("minio")
+  # qos level is set to 1
+  client.subscribe("minio", 1)
 
 def on_message(client, userdata, msg):
     print(msg.payload)
 
-client = mqtt.Client()
+# client_id is a randomly generated unique ID for the mqtt broker to identify the connection.
+client = mqtt.Client(client_id="myclientid",clean_session=False)
 
 client.on_connect = on_connect
 client.on_message = on_message

docs/config/config.sample.json

@@ -82,7 +82,6 @@
 				"broker": "",
 				"topic": "",
 				"qos": 0,
-				"clientId": "",
 				"username": "",
 				"password": "",
 				"reconnectInterval": 0,

pkg/event/target/mqtt.go

@@ -36,7 +36,6 @@ type MQTTArgs struct {
 	Broker               xnet.URL       `json:"broker"`
 	Topic                string         `json:"topic"`
 	QoS                  byte           `json:"qos"`
-	ClientID             string         `json:"clientId"`
 	User                 string         `json:"username"`
 	Password             string         `json:"password"`
 	MaxReconnectInterval time.Duration  `json:"reconnectInterval"`
@@ -59,9 +58,15 @@ func (m MQTTArgs) Validate() error {
 	default:
 		return errors.New("unknown protocol in broker address")
 	}
-	if m.QueueDir != "" && !filepath.IsAbs(m.QueueDir) {
+	if m.QueueDir != "" {
+		if !filepath.IsAbs(m.QueueDir) {
 			return errors.New("queueDir path should be absolute")
 		}
+		if m.QoS == 0 {
+			return errors.New("qos should be set to 1 or 2 if queueDir is set")
+		}
+	}
+
 	return nil
 }
 
@@ -120,7 +125,7 @@ func (target *MQTTTarget) Close() error {
 // NewMQTTTarget - creates new MQTT target.
 func NewMQTTTarget(id string, args MQTTArgs) (*MQTTTarget, error) {
 	options := mqtt.NewClientOptions().
-		SetClientID(args.ClientID).
+		SetClientID("").
 		SetCleanSession(true).
 		SetUsername(args.User).
 		SetPassword(args.Password).