Multiple sensors on a single mqtt connection

[romoloman]

Is it possible to have multiple sensors on a single mqtt connection, ie publishing a BME680 sensor as 4 different sensors ?
It will be interesting to have 4 devices (with unique_id xxxxxxxx_t xxxxxxxx_p xxxxxxxx_h xxxxxxxx_a for temperature pressure humidity and air quality) but a single mqtt_client in the code.
At the moment hamqtt has to be initialized as (client, device), so a single device for mqtt, but (If I have not misunderstood) that means that I need 4 different connections to the broker.
Am'I wrong ?

[romoloman]

I have seen that indeed is possible, You got 1 device and 4 entities (and that make sense)
just to leave some hint to other users, on an esp32 I have:

in declarations:

WiFiClient client;
HADevice device;
HAMqtt mqtt(client, device);
HASensor temperature("TEMPERATURE");
HASensor pressure("PRESSURE");
HASensor humidity("HUMIDIDY");
HASensor aiq("AIQ");

in setup()

  device.setUniqueId(mac, sizeof(mac)); // mac get derived from ESP.getEfuseMac();
  // set device's details (optional)
  device.setName(sysname.c_str());
  device.setSoftwareVersion("1.0.0");
  temperature.setUnitOfMeasurement("°C");
  temperature.setDeviceClass("temperature");
  temperature.setName("Temperature");
  pressure.setUnitOfMeasurement("hPa");
  pressure.setDeviceClass("pressure");
  pressure.setName("Pressure");
  humidity.setUnitOfMeasurement("%");
  humidity.setDeviceClass("humidity");
  humidity.setName("Humidity");      
  aiq.setUnitOfMeasurement("AIQ");
  aiq.setDeviceClass("aqi");
  aiq.setName("AirQuality");

  mqtt.begin(mqttsrv, mqttuser.c_str(), mqttpwd.c_str()); 

and in loop():

  mqtt.loop();
  if (now - lastForceMsg > 300000) {
    lastForceMsg = now;
    forceMsg = true;
    Serial.println("Forcing publish every 5 minutes...");
  }
  if (checkBound(newTemp, temp, diff) || forceMsg) {
    temp = newTemp;
    temperature.setValue(temp);
  }
  if (checkBound(newHum, hum, diff) || forceMsg) {
    hum = newHum;
    humidity.setValue(hum);
  }
  if (checkBound(newBaro, baro, diff) || forceMsg) {
    baro = newBaro;
    pressure.setValue(baro);
  }
  if (checkBound(newiaq, iaq, 5) || forceMsg) {
    iaq = newiaq;
    aiq.setValue(iaq);
  }

1 device and 4 sensor entities get automatically configured in home assistant.
really easier than i was thinking about....