Reading MQTT subtopics topic with wildcards into a sensor with attributes

Configuration
1

Hi,

I try to read different MQTT subtopics into a sensor with attributes.

In the MQTT-Explorer it looks like this:

Screenshot 2025-03-01 111258
Screenshot 2025-03-01 111258669×240 18.2 KB

I tried following code to read this out:

    - name: "Test Heizung heute Energieverbrauch"
      state_topic: "open3e/vitocal250/680_548_EnergyConsumptionCentralHeating/+"
      state_class: total_increasing
      unique_id: 680_548_TestEnergyConsumptionCentralHeatingToday
      object_id: 548_TestEnergyConsumptionCentralHeatingToday
      device:
        name: "Open3e_Vitocal250A"
        identifiers: !secret vitocal_sn
        manufacturer: "Viessmann"
        model: "Vitocal 250-A"
      icon: mdi:home-lightning-bolt
      value_template: '{{value_json.Today}}'
      unit_of_measurement: "kWh"
      device_class: energy
      json_attributes_topic: "open3e/vitocal250/680_548_EnergyConsumptionCentralHeating/+"
      json_attributes_template: '{{ value_json | tojson }}'

However the sensor remains ‘unknown’ with no contents in the attributes.

What works, is reading all subtopics in single steps and then templating them together in a Helper. While the effort is acceptable with 6 subtopics, it would be favourable to read out more complex Topics in one step automaticly.

Like this one:

Screenshot 2025-03-01 112736
Screenshot 2025-03-01 112736870×1164 45.9 KB

Do you have any ideas?
Best regards
Hendrik

2

By doing this (adding a + to the end of the topic):

open3e/vitocal250/680_548_EnergyConsumptionCentralHeating/+

your MQTT Sensor is subscribed to the following six sub-topics:

Today
Past7Days
CurrentMonth
PastMonth
CurrentYear
PastYear

The value published to each of those topics (the “payload”) is not in JSON format, it is simply a number.

That’s why this template doesn’t work, and produces an unknown result, because it mistakenly assumes the received payload is in JSON format. It’s not.

value_template: '{{value_json.Today}}'

The same problem exists for attributes and that’s why it fails to produce a result.

json_attributes_topic: "open3e/vitocal250/680_548_EnergyConsumptionCentralHeating/+"
json_attributes_template: '{{ value_json | tojson }}'

The variables named value and value_json represent the received payload. By subscribing to six topics, your MQTT Sensor receives six separate payloads (sequentially, not concurrently). You can’t use a JSON oriented template like value_json.Today to distinguish one sub-topic’s received value from another.

If you want the MQTT Sensor to report the Today value you will need to subscribe exclusively to that one topic.

open3e/vitocal250/680_548_EnergyConsumptionCentralHeating/Today

Then either remove the value_template option or set its template to {{ value }}.

In this case, you can’t create attributes for the other 5 sub-topics because json_attributes_topic and json_attributes_template are meant for processing the JSON payload of a single topic.

3

Thanks for the information, that helped me a lot.

I managed, that the MQTT Topic (last Image in first post) delivers now a payload JSON format:

{
  "CurrentMonth": {
    "10": 0,
    "11": 0,
    "12": 0,
    "13": 0,
    "14": 0,
    "15": 0,
    "16": 0,
    "17": 0,
    "18": 0,
    "19": 0,
    "20": 0,
    "21": 0,
    ... and so on

I now used following Code in the mqtt sensor to read the attributes:

      json_attributes_topic: "open3e/vitocal250/680_1294_EnergyConsumptionCentralHeatingMonthMatrix"
      json_attributes_template: >-
        { "10.": {{value_json.CurrentMonth.10}},
          "11.": {{value_json.CurrentMonth.11}},
          "12.": {{value_json.CurrentMonth.12}},
          "13.": {{value_json.CurrentMonth.13}},
          "14.": {{value_json.CurrentMonth.14}},
          "15.": {{value_json.CurrentMonth.15}},
          "16.": {{value_json.CurrentMonth.16}},
          "17.": {{value_json.CurrentMonth.17}},
          "18.": {{value_json.CurrentMonth.18}},
          "19.": {{value_json.CurrentMonth.19}},
          "20.": {{value_json.CurrentMonth.20}},
          "21.": {{value_json.CurrentMonth.21}},
          "22.": {{value_json.CurrentMonth.22}},
          "23.": {{value_json.CurrentMonth.23}},
          "24.": {{value_json.CurrentMonth.24}},
          "25.": {{value_json.CurrentMonth.25}},
          "26.": {{value_json.CurrentMonth.26}},
          "27.": {{value_json.CurrentMonth.27}},
          "28.": {{value_json.CurrentMonth.28}},
          "29.": {{value_json.CurrentMonth.29}},
          "30.": {{value_json.CurrentMonth.30}},
          "31.": {{value_json.CurrentMonth.31}}
           ... and so on }

I get the error message:
TemplateSyntaxError: expected token ‘end of print statement’, got ‘integer’

What did I wrong? Are there too many attributes (31)?
Thanks in advance for your help
Hendrik

4

Not sure if this is the only thing that’s off, but it looks to me like you’re misusing {{ }} print statements.

Although I haven’t worked with json_attributes_template before, I think that at minimum:

  1. You need to enclose the whole dictionary (with the keys “10.”, “11.” etc.) in a single {{ }}.
  2. You need to remove the {{ }} surrounding the individual value_json references.

That’s consistent with the error message.

5

Also, I assume that the ... and so on} is not part of your actual code. In general, it’s not helpful to modify your code with off-syntax edits like that for posting in the forum because it can easily obscure problems or mislead people when they suggest solutions.

6

Hi Dominik,

thanks for your hint. It was not the solution, however goes in the right direction. After consulting other threads in the forum and a lot of trial and error, I found the solution.

The templates work as following:

          "01": {{value_json.CurrentMonth['01']}},

With this, all the attributes are inserted in the sensor entity correctly.

Thank for the support
Hendrik