I use node MQTT OUT to send messages to a server. This is working well, but I want to add a buffer if for example the receiving server fails. Therefore I like to use the CATCH node, but it does not react on a connection failure of MQTT OUT. I am sure that I select the correct node to react on. Any suggestions to be able to catch such a failure?
I thought this thread may give you what you require or atleast some ideas. [Announce] Improved Guaranteed Delivery flow
[Edit]
Here is link to Colins latest version node-red-guaranteed-delivery (node) - Node-RED
In fact that has been superceded by @colinl/node-red-guaranteed-delivery, which includes an example of how to use it with mqtt.
You can also look at MQTT "Last Will &Testament" messages.
They are set up in the Node-red MQTT broker config. and get sent when it first connects to the broker, but don't "arrive" unless the connection drops.
ie After the connection to the broker goes down, and a timeout period has elapsed (default 60s?) a message, which could be "MQTT lost contact" seems to arrive with the LWT topic.
Hivemq have a video about LWT here
Edit - I'm currently watching that video. Perhaps I misunderstand who gets the LWT message when a client disconnects.
