Grep in Flux Language for InfluxDB 2+

I'm collecting various data from my house's KNX system (temperature, switches and so on). Initially, I had it collected in a MySQL database but, since this is a time series data and it's only interesting for statistics, I've decided to use InfluxDB. My measurements include the data type (DPT 9.001), name, description... as tags.

Initially, I used InfluxDB's query builder to select the fields:

The results are OK:

The query though is not at all elegant, not flexible:

from(bucket: "my_bucket")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "KNX-DPST 9.1")
  |> filter(fn: (r) => r["name"] == "Valve1 - 5 Dining heating [CTEMP 2.1.8]" or r["name"] == "Valve1 - 6 Living heating [CTEMP 2.1.10]" or r["name"] == "Valve1 - 6 Living heating [CTEMP 2.1.11]" or r["name"] == "Valve1 - 6 Living heating [CTEMP 2.1.13]" or r["name"] == "Valve1-1 Media [CTEMP 1.3.10]" or r["name"] == "Valve1-2 Lounge [CTEMP 2.3.1]" or r["name"] == "Valve1-3 Guest [CTEMP 2.1.1]" or r["name"] == "Valve1-4 Shower [CTEMP 2.1.7]" or r["name"] == "Valve1-X Kitchen front [CTEMP 2.1.14]" or r["name"] == "Valve1-X Slider [CTEMP 2.1.12]" or r["name"] == "Valve2-1 Bathroom [CTEMP 2.2.3]" or r["name"] == "Valve2-2 Master bed [CTEMP 2.2.1]" or r["name"] == "Valve2-3 Study [CTEMP 2.2.4]" or r["name"] == "Valve2-4 Child [CTEMP 2.2.2]")
  |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: false)
  |> yield(name: "mean")

As you can see, I'd have to change the query every time when I add a new temperature measurement (all switches I have in the house have temperature sensors!).

Enhancing the query

I remember that SQL has a string matching function, so I figured flux language must also have one. It does so, via strings.containsStr. I can then do something like this:

|> filter(fn: (r) => strings.containsStr(v: r["name"], substr: "CTEMP"))

... and all my CTEMP (current temperature) measures are collected automatically.

Final Query

The final query I have is:

import "strings"
from(bucket: "my_bucket")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "KNX-DPST 9.1")
  |> filter(fn: (r) => strings.containsStr(v: r["name"], substr: "CTEMP"))
  |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: false)
  |> yield(name: "mean")

This gives me something like:

You can see the update I did in hte middle of the graph (yellow dots to green) where I had a typo in the description and I've fixed it.

HTH,