Adding Math functions to line_format

[Leosirth]

Is your feature request related to a problem? Please describe.
I have a scenario where AccessLogs from my reverse proxy have the duration logged as nanoseconds.
It would be great if I could format the extracted label "duration" as milliseconds (dividing it by 1000000).

Describe the solution you'd like
Having the Math and Conversion functions from sprig available on line_format as a follow-up of #2822 PR
Something like:

{log_type="access_log"}
| json
| line_format "{{.ClientHost}}\t{{.OriginStatus}}\t{{div (.Duration | int) 1000000}}\t{{.RequestScheme}}\t{{.RequestAddr}}\t{{.RequestPath}}"

Describe alternatives you've considered
Using Grafana to graph it as a metric

Additional context
http://masterminds.github.io/sprig/math.html
http://masterminds.github.io/sprig/conversion.html

[cyriltovena]

I'm not against that.

/cc @grafana/loki-team who vouch for or against ?

I intentionally added strings functions only for now, wanted that we selectively choose what we add as we go.

[owen-d]

I can see this being a nice thing to have.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 30 days. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.

[Leosirth]

Good bot, keep it open

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 30 days. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.

[Leosirth]

Good bot, keep it open

[m4ver1k]

@cyriltovena is someone working on this ?
if not is it something I can give a try ?

[cyriltovena]

We want to do it but we did not yet had the time so yeah go ahead