Вы правы, не было в системе модуля. Теперь все ок. Данные в базе есть.
Для отладки запустил с параметром window и вот что на экране в консоли.
Результат такой: sudo -u mqtt-agent /media/mqttMySqlClient.py window
2019-07-23 00:57:03 connecting to MQTT broker...
2019-07-23 00:57:03 mysql connected
2019-07-23 00:57:03 mqtt connected
client id: mqttMySqlClient
2019-07-23 00:57:03 mqtt subscribe on "#"
2019-07-23 00:57:03 mqtt subscribe on "$SYS/#"
2019-07-23 00:57:03 mysql disconnect
2019-07-23 00:57:03 connecting to MQTT broker...
2019-07-23 00:57:03 mqtt connected
client id: mqttMySqlClient
2019-07-23 00:57:03 mqtt subscribe on "#"
2019-07-23 00:57:03 mqtt subscribe on "$SYS/#"
2019-07-23 00:57:03 mysql [2006]
2019-07-23 00:57:03 mysql [2006]
2019-07-23 00:57:03 mysql [2006]
2019-07-23 00:57:03 mysql [2006]
2019-07-23 00:57:03 mysql ping fail [2006]
2019-07-23 00:57:03
unexpected termination of the program
Traceback (most recent call last):
File "/media/mqttMySqlClient.py", line 305, in <module>
start()
File "/media/mqttMySqlClient.py", line 188, in start
alert('\nunexpected termination of the program', True)
File "/media/mqttMySqlClient.py", line 46, in alert
with open(mysql_log_file, 'a+') as log:
IOError: [Errno 13] Permission denied: '/var/log/mqttMySqlClient.log'
esp-master@mqtt:~$