HA discovery schema doesn't respect field1 values

[Sebastian Muszynski]

Description

I tried to set the ReducedSetTemp of my Weishaupt WTC-25 setup using this 3rd party configuration: https://github.com/J0EK3R/ebusd-configuration-weishaupt

Home Assistant complained about the structure of the MQTT payload:

2024-01-03 18:00:54.919 ERROR (MainThread) [homeassistant.helpers.template] Template variable error: 'dict object' has no attribute '_16_Temp10' when rendering '{{value_json["_16_Temp10"].value}}'
2024-01-03 18:00:54.920 ERROR (MainThread) [homeassistant.helpers.template] Error parsing value: 'dict object' has no attribute '_16_Temp10' (value: {
     "ReducedSetTemp": {"value": 14.0}}, template: {{value_json["_16_Temp10"].value}})

The schema description of the auto discovery looks like this:

homeassistant/number/ebusd_hc1_ReducedSetTemp__16_Temp10/config {
  "unique_id":"ebusd_hc1_ReducedSetTemp__16_Temp10",
  "name":"ReducedSetTemp _16_Temp10",
  "device":{
   "identifiers":"ebusd_hc1",
   "manufacturer":"ebusd.eu",
   "name":"ebusd hc1",
   "via_device":"ebusd",
   "sw_version":"23.3",
   "suggested_area":"Heating"
  },
  "value_template":"{{value_json[\"_16_Temp10\"].value}}",
  "state_topic":"ebusd/hc1/ReducedSetTemp",
  "command_topic":"ebusd/hc1/ReducedSetTemp/set",
  "min":-3276.7,
  "max":3276.7,
  "step":0.1,
  "unit_of_measurement":"°C",
  "device_class":"temperature"
 }

The value_template definition doesn't match with the MQTT payload:

ebusd/hc1/ReducedSetTemp {
     "ReducedSetTemp": {"value": 14.0}
}

It looks like the MQTT payload uses the field1 value as object key. The Home Assistant discovery schema applies the template value instead.

Actual behavior

The MQTT payload uses the field1 value as object key. HA tries to access the template value as object key.

Expected behavior

Both should be in sync. If I remove the speaking field1 value from the configuration ebusd uses the template value instead. This is the new and HA compatible payload:

ebusd/hc1/ReducedSetTemp {
     "_16_Temp10": {"value": 14.0}
}

ebusd version

23.3

ebusd arguments

--jsonformat

Operating system

Debian 12 (Bookworm) / Ubuntu 22-23 / Raspberry Pi OS 12 (including lite)

CPU architecture

x64

Dockerized

None

Hardware interface

adapter 5 via USB

Related integration

MQTT Home Assistant via mqtt-hassio.cfg

Logs

2024-01-03 18:25:47.693 [update notice] sent read hc1 ReducedSetTemp QQ=31: 14.0

[John]

the issue is the message definition here which differs between the read and write. the read specifies the field name but the write does not and as a consequence, the template name is used instead. this then does not match with the expectation from discovery.
so either remove the field1 name from the read message or add it to the write message. it would be better anyway, to combine such definitions into a single line using "rw" in the first column to avoid exactly such.

[Sebastian Muszynski]

Thanks for your analysis! Let's close this issue because it's resolved.