I've also tried posting a couple times to the weewx-user google group but my posts get instantly deleted there for some unknown reason.
Debian / weewx 3.9.1 with mqtt extension / belchertown / nginx / david vantage pro2
Here is the issue in short:
MQTT appears to be working internally but the payload is too large and prevents the website from updating. A smaller fake payload used for testing is successful. How do I truncate the data in the MQTT payload? things like soil and leaf wetness are not required.
-------
Example from current setting obtained at the terminal
mosquitto_sub -h localhost -t weather/#
{"windSpeed10_kph": "0.0", "monthET": "0.0", "cloudbase_meter": "610.078192345", "outHumidity": "73.0", "pressure_mbar": "1004.21031119", "rain_cm": "0.0", "dayET": "0.0", "barometer_mbar": "1013.30892876", "yearRain_cm": "0.0", "consBatteryVoltage_volt": "1.25", "dewpoint_C": "-2.64673607144", "insideAlarm": "0.0", "inHumidity": "27.0", "sunrise": "1554924300.0", "windGust_kph": "0.0", "heatindex_C": "1.66666666667", "dayRain_cm": "0.0", "outsideAlarm1": "0.0", "forecastIcon": "6.0", "outsideAlarm2": "0.0", "windSpeed_kph": "0.0", "forecastRule": "45.0", "rainAlarm": "0.0", "altimeter_mbar": "1012.55702971", "windchill_C": "1.66666666667", "appTemp_C": "-0.674718834607", "outTemp_C": "1.66666666667", "extraAlarm1": "0.0", "extraAlarm2": "0.0", "extraAlarm3": "0.0", "extraAlarm4": "0.0", "extraAlarm5": "0.0", "extraAlarm6": "0.0", "extraAlarm7": "0.0", "extraAlarm8": "0.0", "humidex_C": "1.66666666667", "rain24_cm": "0.0", "hourRain_cm": "0.0", "inTemp_C": "23.5", "soilLeafAlarm4": "0.0", "trendIcon": "20.0", "soilLeafAlarm2": "0.0", "soilLeafAlarm3": "0.0", "usUnits": "16.0", "soilLeafAlarm1": "0.0", "leafWet4": "0.0", "txBatteryStatus": "1.0", "yearET": "0.0", "monthRain_cm": "0.0", "rainRate_cm_per_hour": "0.0", "dateTime": "1554913274.0", "stormRain_cm": "0.0", "sunset": "1554885600.0", "inDewpoint_C": "3.41268318248"}
The website site just shows "Connected. Waiting for data.", no errors, no updates
--------
Using MQTT-admin I can see payload size errors:
https://i.imgur.com/skL3x35.png---------
Sending a smaller fake payload from the terminal successfully updates the website:
mosquitto_pub -h localhost -t "weather" -m '{"UV": "0.68", "barometer_inHg": "30.4306066431", "outHumidity": "45.8", "maxSolarRad": "399.067737313", "dewpoint_F": "17.6078693897", "cloudbase_foot": "4723.66604779", "heatindex_F": "36.5", "altimeter_inHg": "30.3995019668", "dayRain_in": "0.0", "outTemp_F": "36.5", "appTemp_F": "31.2879264251", "windchill_F": "15.5", "hourRain_in": "0.0", "humidex_F": "36.5", "rainRate_inch_per_hour": "0.0", "pressure_inHg": "29.9401590264", "usUnits": "1.0", "txBatteryStatus": "0.0", "windSpeed_mph": "55.0", "rain24_in": "5.0", "dateTime": "1542561977", "radiation_Wpm2": "124.813456"}' -u weewx -P weewx
https://i.imgur.com/lnVyexP.png