Template variables in aggregators

[fbeneventi]

Hi,

I need to use a template variable in an aggregator expression as for example:

$N = 24

and then in aggregator I try to do:

scale($N)

where $N is a "custom" type template variable.

Executing this query I have the following error:

query.metric[1].aggregators[1].factor For input string: "$N"

It seems that variables are not interpolated in aggregators. Is there a way/plan to do this?

thanks!
Francesco

[jifwin]

Hi Francesco
Thanks for reporting that. Would you submit a PR?

[gucharbon]

@jifwin We are also really interested in this feature ! Do you think this represent a big effort ? I was able to do that like 1 month ago but I don't remember which datasource or Grafana version I was using.
I can try investigating as we need this feature in our project.

[jifwin]

Templating of aggregators parameters is a bit more tricky, but definitely doable. The question is how to handle multi-value variables with many aggregators defined. E.g.

var1=[1,2,3], AVG($var1,HOUR) + MAX($var1, HOUR)
Would you expect 9 series (cartesian) or 3 (1-to-1 matching)?

Or maybe multivalue variables shouldn't be allowed allowed at all?

[gucharbon]

I'm not sure I understood your point.
I'm okay with not allowing multi variables for variable in Aggregators.
If we wanted to create several visualizations based on each unit or value of aggregator it would make sense, but this seems far too complicated and not really useful.
We would already gain an awesome feature if we could use Single variable in aggregators

[fbeneventi]

Yes, currently only "custom" variables seem not working in aggregators and for now it should be ok to support just single value variables.

[gucharbon]

Oh really ? That means that if I use any other variable, like store my desired Units in a mysql table I can query them and use them in the query builder ? I didn't know that

[jifwin]

I don't think so. It doesn't matter what type of variable it is.

[jifwin]

@gucharbon Are you OK with support for single-value variables?

[gucharbon]

@jifwin Definitely ! 👍

[fbeneventi]

Sorry,
I was talking about the old version (v2.0.1) where I switched to. Also there, custom variables does not work. Other variables I need (Interval) work perfectly in aggregators in v2.0.1, but I found they do not in the latest version.
If it is possible to restore also this kind of variable it would be great!
Thanks!