[grafana-sampling] metrics generation configuration

[maximelaboisson]

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Adding metrics flush interval, expiration, and buckets configuration for metrics generation

[CLAassistant]

All committers have signed the CLA.

[maximelaboisson]

👋 I'm not sure if I'm tagging the right people here since there's no codeowner for this chart, but I can see from previous PR that @petewall & @rlankfo reviewed most of them 😄 I'm wondering if I did something wrong since some CI checks do not seem to be running? Is there anything else missing for me to be able to ask for review?

[rlankfo]

hey @maximelaboisson, thanks for the PR! I'll re-open this and see if I can approve and run the workflows.

[a-abella]

Just commenting that this is a highly valuable change and would love to see it merged. I am currently hacking around the lack of metrics expiration with a helm hook patching the configmap. Expiration is basically a required feature of metrics generation otherwise the cardinality implications make metrics generation unusable in larger workloads.

[a-abella]

Another PR was merged recently that enables configuration of the metric expiration value, #3613

[maximelaboisson]

For some reasons I'm just seeing the notifications for the PR being reopened now 😅

In the end, I decided to just run a fork of the chart on my side since I ended up making more changes. I'm happy to fix this PR to make things work though if the maintainers think it's valuable?