How to use mosquitto_pub to create new mqtt device? With answer

Configuration
1

Hello. My OBD device does not send discovery topic, so instead of editing configuration.yaml and restarting server, I would like to use mosquitto_pub to create device. But is not working. My _pub command is:

mosquitto_pub -h 10.0.0.54 -u <user> -P <password> -t "homeassistant/sensor/AndrOBD/config" -m '{"name": "ECU voltage", "device_class": "voltage", "state_topic": "AndrOBD/ecu_voltage"}'

The message is sent correctly, I can see it in mosquitto_sub:

homeassistant/sensor/AndrOBD/config {"name": "ECU voltage", "device_class": "voltage", "state_topic": "AndrOBD/ecu_voltage"}

But no sensor is created. The actual message sent by device is

AndrOBD/ecu_voltage 8.994

Does anyone know how to register new device with mosquitto_pub?

I posted an answer few more messages down.

2

Try it with escaped quotes.

mosquitto_pub -h 10.0.0.54 -u <user> -P <password> -t "homeassistant/sensor/AndrOBD/config" -m '\"name\": \"ECU voltage\", \"device_class\": \"voltage\", \"state_topic\": \"AndrOBD/ecu_voltage\"}'
3

As an FYI, there are a couple of Forum threads that do this using HA’s MQTT publish service call in a script. Here is one such thread:

1 Like
4

Why so complicated with scripts? Simple command can do it, I have debugged it and it works:

mosquitto_pub -h <IP address> -u <user> -P <password> -t "homeassistant/sensor/AndrOBD/ecu_voltage/config" -m '{"name": "ECU voltage", "device_class": "voltage", "state_topic": "AndrOBD/ecu_voltage", "unit_of_measurement": "V"}'

Just remember one thing. After I restarted Home Assistant, entity definition is lost and I have to publish this event again. I created init-mqtt.sh script for that.

5

Where do you enter this command? it doesn’t explain it clearly in the Doc’s

6

Sorry I thought it is clear. I use linux and I installed clients with sudo apt-get install mosquitto-clients

Then you use linux terminal basically on any machine where you installed mosquitto-clients from which you can access HA and use IP address of mosquitto broker that is running in your HA instance (you get IP somewhere in system info).

I do not know how it works in non-linux environments. It could also be possible from mqtt explorer, which is graphical app.

7

Oh thank you, HA core has a ssh/terminal add-on I guess i could use that … Maybe?
And mqtt explorer, I have that so ill look into that one too.
Thanks for the info.

8

Actually, I think you can publish events straight from Home Assistant. With new update, it moved somewhere I cannot find it, but there is sumple GUI for listening and publishing straight inside HA. If you find it, please post the path, thanks.

9

Ok great thanks
Yes that’s in the mqtt integration configure menu.

10

Just remember one thing. After I restarted Home Assistant, entity definition is lost and I have to publish this event again. I created init-mqtt.sh script for that.

11

Thanks @janbenes
Can you show me where you save that file so it runs the script every boot.
And is there a down side to using the retain flag. Is not another way of retaining the definition of the enities?

12

I run that script manually on my laptop after I reboot HA computer. I am not familiar, I think RETAIN serves to populat value after you restart HA and before sensor sends its first reading. Then retain shows last valid value pulled out from mqtt broker.