Setup Mosquitto to treat all messages as retained

Mosquitto MQTT Broker
1

Hello. I am using Mosquitto broker and tty2mqtt as a serial bridge. The problem is that this bridge is not able to send a retained messages. My question is it possible to set up Mosquitto to treat all incoming messages as retained?

2

Assuming you are using Mosquitto 2.0.x, the answer is yes!

I’ve just created an example plugin that does this: mosquitto/plugins/examples/force-retain at develop · eclipse/mosquitto · GitHub

If you’re on Linux and happy with compiling things, then the following command line commands should work:

git clone https://github.com/eclipse/mosquitto
cd mosquitto
git checkout develop
cd plugins/examples/force-retain
make
sudo cp mosquitto_force_retain.so /usr/local/lib

Then add the following to your mosquitto.conf:

plugin /usr/local/lib/mosquitto_force_retain.so

If you need help with any of the compiling stage please let me know.

Regards,

Roger

3

Hello Roger,

Thank you very much for the quick response with the solution. I use Mosquitto 2.0 on Linux. But, the thing is the developer of the tty2mqtt Siegfried Steiner has implemented retained flag in the bridge.
I am sure, this plugging will be useful for someone else.
Really appreciate your help/