Trying to create JSON structure for MQTT

Configuration
1

Objective
Pass solar power data from HA via MQTT to Victron system using JSON data structure.

The receiver is expecting a data structure like this:

{
    "pv": {
        "power": 0.0,
        "voltage": 0.0,
        "current": 0.0,
        "energy_forward": 0.0,
        "L1": {
            "power": 0.0,
            "voltage": 0.0,
            "current": 0.0,
            "frequency": 0.0,
            "energy_forward": 0.0,
        },
    }
}

I am attempting to create this using a template helper. So far I have assembled the
basic data thus: (Note: the values for pv are the same as L1)

I am completely stuck creating the final output. This is the best I have so far:

{% set pwr ={ 'power':states('sensor.growatt_grid_active_power')} %}
{% set voltage ={ 'voltage':states('sensor.growatt_output_voltage')} %}
{% set current ={ 'current':states('sensor.growatt_output_current')} %}
{% set energy ={ 'energy_forward':states('sensor.growatt_todays_generation')} %}

{% set first ={ 'pv' :[ pwr , voltage , current , energy ]} %} 
{% set second ={ 'L1' :[ pwr , voltage , current , energy ]} %}

{% set output = first , second    %}
{{ output|tojson }}

Any help or pointers to some documentation on this very welcome.
Thankyou.

2

Format your code correctly. Then you’re likely to get people helping you because they can copy and paste it.

Edit: that’s better :slightly_smiling_face:

Note that pv and L1 should be dictionaries but you are creating them as lists.

Just do it directly:

{% set output = {
  "pv": {
    "power": states('sensor.growatt_grid_active_power'),
    "voltage": states('sensor.growatt_output_voltage'),
    "L1": {
    }
  }|tojson
%}

… with the other values filled in appropriately.

1 Like
3

Thank you for your suggestion, I think I’ve improved the formatting.
Is that what you were suggesting?
Eric

1 Like
4

This creates an array, but the JSON you posted originally is what Jinja would consider to be a dict.

Personally I would just do:

{
  "pv": {
    "power": {{ states('sensor.growatt_grid_active_power') }},
    "voltage": {{ states('sensor.growatt_output_voltage') }},
    "current": {{ states('sensor.growatt_output_current') }},
    "energy_forward": {{ states('sensor.growatt_todays_generation') }},
    "L1": {
      "power": {{ states('sensor.growatt_grid_active_power') }},
      "voltage": {{ states('sensor.growatt_output_voltage') }},
      "current": {{ states('sensor.growatt_output_current') }},
      "energy_forward": {{ states('sensor.growatt_todays_generation') }}
    }
  }
}

You don’t need to convert to JSON, just output something that is valid JSON in the structure you want.

1 Like