MqttClient.cs - Exception handling on SendReceive Exception

[jvcode1]

In case that the broker terminates the connection "SendReceive" throws a MqttCommunicationException, therefore the Connect-method is exited and "this.isRunning" remains true. Hence the threads are not terminated properly and keep hanging and consuming resources on error.

Example exception when HiveMQ closes the connection (e.g. when too less licenses are available):
uPLibrary.Networking.M2Mqtt.Exceptions.MqttCommunicationException: Eine Ausnahme vom Typ "uPLibrary.Networking.M2Mqtt.Exceptions.MqttCommunicationException" wurde ausgelöst.
bei uPLibrary.Networking.M2Mqtt.MqttClient.SendReceive(Byte[] msgBytes, Int32 timeout) in c:\Users\ppatierno\Source\Repos\m2mqtt\M2Mqtt\MqttClient.cs:Zeile 1094.
bei uPLibrary.Networking.M2Mqtt.MqttClient.SendReceive(MqttMsgBase msg, Int32 timeout) in c:\Users\ppatierno\Source\Repos\m2mqtt\M2Mqtt\MqttClient.cs:Zeile 1117.
bei uPLibrary.Networking.M2Mqtt.MqttClient.Connect(String clientId, String username, String password, Boolean willRetain, Byte willQosLevel, Boolean willFlag, String willTopic, String willMessage, Boolean cleanSession, UInt16 keepAlivePeriod) in c:\Users\ppatierno\Source\Repos\m2mqtt\M2Mqtt\MqttClient.cs:Zeile 567.
bei uPLibrary.Networking.M2Mqtt.MqttClient.Connect(String clientId, String username, String password) in c:\Users\ppatierno\Source\Repos\m2mqtt\M2Mqtt\MqttClient.cs:Zeile 494.

[chriswue]

It would be better to just throw; which preserves the original stack trace

[vroyk]

This solves our problem. Please commit this change. Thanks!

[ppatierno]

Hi,
can you give me an example on how reproduce the problem locally ?
In any case you don't have a valid signed Eclipse CLA you should sign (https://www.eclipse.org/legal/CLA.php)

[vroyk]

Hi,

It is very easy to reproduce:
I have a local ActiveMQ which I have configured for maximum 1 connection.
Now, I start two instances of my application.
The first application connects well, there is no problem.
The second application fails connecting. With each (re)try to connect, the CPU-use rises.
After a few tries, the CPU is 100%. It never recovers, unless we quit the application.

[kjschaef]

@ppatierno This bug bit me in production and caused some major problems by taking down an important PC. It appears that this project has been abandoned, but there are about 10 PR's calling out exactly this same issue. It would be a great service to the community if you could accept one of them and save others from finding it the hard way. Thanks!