make sure to comply with MQTT spec (#14037)

- keep-alive cannot be 0 by default anymore
- client_id cannot be empty

fixes #13993

go.mod

@@ -23,7 +23,7 @@ require (
 	github.com/djherbis/atime v1.0.0
 	github.com/dswarbrick/smart v0.0.0-20190505152634-909a45200d6d
 	github.com/dustin/go-humanize v1.0.0
-	github.com/eclipse/paho.mqtt.golang v1.3.0
+	github.com/eclipse/paho.mqtt.golang v1.3.5
 	github.com/elastic/go-elasticsearch/v7 v7.12.0
 	github.com/fatih/color v1.13.0
 	github.com/go-ldap/ldap/v3 v3.2.4

go.sum

@@ -333,8 +333,8 @@ github.com/eapache/go-xerial-snappy v0.0.0-20180814174437-776d5712da21 h1:YEetp8
 github.com/eapache/go-xerial-snappy v0.0.0-20180814174437-776d5712da21/go.mod h1:+020luEh2TKB4/GOp8oxxtq0Daoen/Cii55CzbTV6DU=
 github.com/eapache/queue v1.1.0 h1:YOEu7KNc61ntiQlcEeUIoDTJ2o8mQznoNvUhiigpIqc=
 github.com/eapache/queue v1.1.0/go.mod h1:6eCeP0CKFpHLu8blIFXhExK/dRa7WDZfr6jVFPTqq+I=
-github.com/eclipse/paho.mqtt.golang v1.3.0 h1:MU79lqr3FKNKbSrGN7d7bNYqh8MwWW7Zcx0iG+VIw9I=
-github.com/eclipse/paho.mqtt.golang v1.3.0/go.mod h1:eTzb4gxwwyWpqBUHGQZ4ABAV7+Jgm1PklsYT/eo8Hcc=
+github.com/eclipse/paho.mqtt.golang v1.3.5 h1:sWtmgNxYM9P2sP+xEItMozsR3w0cqZFlqnNN1bdl41Y=
+github.com/eclipse/paho.mqtt.golang v1.3.5/go.mod h1:eTzb4gxwwyWpqBUHGQZ4ABAV7+Jgm1PklsYT/eo8Hcc=
 github.com/edsrzf/mmap-go v1.0.0/go.mod h1:YO35OhQPt3KJa3ryjFM5Bs14WD66h8eGKpfaBNrHW5M=
 github.com/elastic/go-elasticsearch/v7 v7.12.0 h1:j4tvcMrZJLp39L2NYvBb7f+lHKPqPHSL3nvB8+/DV+s=
 github.com/elastic/go-elasticsearch/v7 v7.12.0/go.mod h1:OJ4wdbtDNk5g503kvlHLyErCgQwwzmDtaFC4XyOxXA4=

internal/event/target/mqtt.go

@@ -209,8 +209,12 @@ func NewMQTTTarget(id string, args MQTTArgs, doneCh <-chan struct{}, loggerOnce
 		args.MaxReconnectInterval = 10 * time.Minute
 	}
 
+	if args.KeepAlive == 0 {
+		args.KeepAlive = 10 * time.Second
+	}
+
 	options := mqtt.NewClientOptions().
-		SetClientID("").
+		SetClientID(id).
 		SetCleanSession(true).
 		SetUsername(args.User).
 		SetPassword(args.Password).