Graphite scaler should use latest datapoint, not earliest, returned

[bpinske]

Graphite query responses return values in order of oldest to latest. With the final element of the response array being the most up-to-date timestamp. Graphite's scaler should be on the most recent datapoint, not on data potentially hours old.

https://graphite-api.readthedocs.io/en/latest/api.html#json
https://github.com/kedacore/keda/blob/main/pkg/scalers/graphite_scaler.go#L197

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Fixes #2366

[JorTurFer]

Hi!,
Is this related with any issue? Could you explain a bit the change and it reasons? (Maybe opening an issue)
Thanks! ❤️

[bpinske]

Hi!, Is this related with any issue? Could you explain a bit the change and it reasons? (Maybe opening an issue) Thanks! ❤️

#2366

Here you can see the graphite server response returns values in order of oldest to latest. With the final element of the response array being the most up-to-date timestamp. Graphite's scaler should be acting on the final element of the response array, not the first.

https://graphite-api.readthedocs.io/en/latest/api.html#json
https://github.com/kedacore/keda/blob/main/pkg/scalers/graphite_scaler.go#L197

[JorTurFer]

/run-e2e graphite.test*
Update: You can check the progres here

[JorTurFer]

LGTM, only small nit
Thanks for the contribution :)

[tomkerkhove]

I'm going to be a pain @bpinske, but would you mind updating the PR description to be more complete please?

[zroubalik]

Generaly looking good, one Q.

[zroubalik]

LGTM