How to troubleshoot MQTT?

I am new to MQTT and getting the hang of OpenHAB.

I have what I think should be a working MQTT configuration for my first item, but can’t get it to work.

Where can I see what messages are being exchanged? From the command line, I can see published messages showing up with the client (I know this is different than OpenHAB).

My mqtt.cfg looks like this:

orchestrate.url=tcp://192.168.0.205:1883
orchestrate.clientId=openhab

And my only device looks like this:

String test_topic “Test Item: [%s]” {mqtt="<[orchestrate:/test/topic:state:default]"}

but the only things I see in openhab.log is

2016-04-10 20:52:53.268 [INFO ] [t.mqtt.internal.MqttBrokerConnection] - Starting MQTT broker connection 'orchestrate’
2016-04-10 20:52:54.978 [WARN ] [mqtt.internal.MqttPersistenceService] - mqtt-persistence:broker
2016-04-10 20:52:54.981 [WARN ] [mqtt.internal.MqttPersistenceService] - mqtt-persistence:topic
2016-04-10 20:52:54.984 [WARN ] [mqtt.internal.MqttPersistenceService] - mqtt-persistence:message

and when I send an update from another machine, I don’t see any change in events.log or openhab.log. I’m surprised I haven’t figured it out in the process of composing this message (as often is the case) but any tips would be greatly appreciated.

I seem to have figured it out. I think it was because I was publishing a leading slash in the pub, but I’m not 100% sure…

Got some help from the thread here… changing the topic to match his in my test made it work.