Python function returns none

InfluxDB 1
1

If I do this query in Influxdb 1.8:

SELECT Watt from kWh WHERE groep='Droger' ORDER by time DESC LIMIT 1

It gives this result:

time Watt

2025-01-31T21:33:46.962262637Z 18.16

If I do the same using this query:

def read_energy_data(groep):
    client = InfluxDBClient(host='192.168.178.999', port=8086, username='admin', 
    password='Willem1584')
    client.switch_database('FamilieBot')
    results = client.query(("SELECT Watt from kWh WHERE groep= %s  ORDER by 
    time DESC LIMIT 1") % (groep))
    points = results.get_points()
    for item in points:
        return item[groep]

print(read_energy_data("Droger"))

It returns None

What am I doing wrong?

2

Hello @Aziona,
What errors are you getting?

Can you run this example?

 python

>>> from influxdb import InfluxDBClient

>>> json_body = [
    {
        "measurement": "cpu_load_short",
        "tags": {
            "host": "server01",
            "region": "us-west"
        },
        "time": "2009-11-10T23:00:00Z",
        "fields": {
            "value": 0.64
        }
    }
]

>>> client = InfluxDBClient('localhost', 8086, 'root', 'root', 'example')

>>> client.create_database('example')

>>> client.write_points(json_body)

>>> result = client.query('select value from cpu_load_short;')

>>> print("Result: {0}".format(result))

Or try a

SHOW MEASUREMENT

query instead? Explore your schema using InfluxQL | InfluxDB OSS v1 Documentation

I don’t think you shoul dhave to use switch_databases I’d try just initializing with the database you want to query from.

3

Did you check if your client actually connects? The IP address is invalid, since it ends in 999.

1 Like
4

Good point, I changed the IP and the username/password for the post only. I was finally able to do it but by changing how I pass the variable. I made it work using this. There is a tag named [groep] which contains a.o. Dryer and Oven. The measurement is named kDh.

from influxdb import InfluxDBClient

def read_energy_data(test):
client = InfluxDBClient(host=‘192.168.178.106’, port=8086, username=‘admin’, password=‘Hello1234’)
client.switch_database(‘FamilieBot’)
results = client.query((“SELECT last(Watt),groep from kWh Group by groep ORDER by time DESC LIMIT 1”) )
points = results.get_points(tags={“groep”:test})
for item in points:
return item[‘last’]
print(item[‘last’])

print(read_energy_data(‘Dryer’))
print(read_energy_data(‘Oven’))

infclient.close()

5

Thank you for the initialize database comment, I have now added it to the connect string. Apparently the keyword is database (and not dbname or databasename). I could not find that in the documentation on github but found it on the forum.