Grafana DB node authentication

hi, could you provide for me description for config file /etc/bigclown/mqtt2influxdb.yml.
I would like to use authentication for connection to influx database “node”.

mqtt:
host: 127.0.0.1
port: 1883

influxdb:
host: 127.0.0.1
port: 8086
database: node - how can I setup user and password for connection to db?
Thx
Petr