Mqtt out node not able to generate a will message

#1

Hello,

I am writing my question here, because I haven’t found anything on the forum that is similar to my problem.

I am trying to set a will message (QoS 1, retained) to an mqtt out node in my flow, but apparently the Broker is not being notified about it. To be specific, when I force a disconnection (by stopping node-red), if I watch the messages on the mqtt Broker (using a different machine as an mqtt client), I don’t see the will message. However if I connect to the same Broker with the use of MQTTBox (after having set the will topic and message on it), when I disconnect from the Broker, the will message (and topic) appears on it. Am I missing something or is this the normal behavior of the mqtt out node?

I hope my question is not a dumb one…

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#2

could you provide your flow? (export it and paste it into a reply.

what version of NR, node?
what machine/os?

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#3

LWT only fires on an unexpected disconnect.

Within the latest version of Node-RED the MQTT node includes a “Message sent before disconnecting (close message)”

I’d try updating and see if it does what you want it to.

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#4

Can you export the mqtt out node config (by selecting it, and click Ctrl-E) and paste it here please.

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#5

Ignore me, @ukmoose is right, the LWT message is not sent on a normal shutdown. It would be if you unplugged the network for example, assuming there is a network between node red and the broker. That is how it is supposed to work according to the MQTT spec.

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#6

Thanks, I will look at it, including updating node-red.

I will also try it by just unplugging the machine from the network.

But anyway, the answer is that this is normal, expected behavior.

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