[pkg/ottl] Accept dynamic lists in keep_keys

[francois07]

Component(s)

pkg/ottl

Is your feature request related to a problem? Please describe.

When using keep_keys, It would be very convenient to be able to pass it a dynamic list of keys to keep. For example to filter datapoint labels dynamically based on a resource attribute.

Describe the solution you'd like

Make it possible for keep_keys to accept a dynamic list of keys, for example keep_key(datapoint.attributes, resource.attributes["labels"])

Describe alternatives you've considered

No response

Additional context

PSliceGetter from #40193 would be useful here

[github-actions]

Pinging code owners:

• pkg/ottl: @TylerHelmuth @evan-bradley @edmocosta

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[edmocosta]

Hi @francois07! Thanks for filling this issue. I support adding this functionality, but I'd do that only after getting #40222 done, so we can implement it without introducing a performance regression.

[francois07]

Hi @francois07! Thanks for filling this issue. I support adding this functionality, but I'd do that only after getting #40222 done, so we can implement it without introducing a performance regression.

I agree, I did some tests on my side and came to the same conclusion, I didn't know #40222 existed ! In fact I think it would make sense for most functions to accept dynamic values once it's implemented. I'll wait for it to be done and do a pull request then 👍