plugin/metrics: Update metrics in-place when possible #1277
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Fixes #1276. Currently, the way we update these node metrics is by removing all the old ones, then adding back the current values. If metrics are scraped in between removing the old and adding the new, we can end up with single-datapoint gaps for one node at a time. So to fix this, we should avoid removing the old metrics if and only if the labels are unchanged -- which we can check just by storing the previous labels we used.
sharnoff
requested review from
a team and
petuhovskiy
and removed request for
a team
No changes to the coverage.
HTML Report |
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question (to gain more project context): why do we delete metrics for previous node? |
We include some node labels in the metrics, and if those node labels change, the metrics update needs to also remove the series with the old labels. |
petuhovskiy
reviewed
Feb 25, 2025
petuhovskiy
approved these changes
Feb 26, 2025
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Fixes #1276.
Currently, the way we update these node metrics is by removing all the old ones, then adding back the current values. We do it that way so that the old values can be cleaned up when there's label changes.
However: if metrics are scraped in between removing the old and adding the new, we can end up with single-datapoint gaps for one node at a time.
So to fix this, we should avoid removing the old metrics if and only if the labels are unchanged -- which we can check just by storing the previous labels we used.