[receiver/prometheus] Summary metrics without quantiles cause scrape errors

[swiatekm]

Component(s)

receiver/prometheus

What happened?

Description

Scraping a Summary type metric without a quantile label causes the Prometheus receiver to error and fail the whole scrape.

Expected Result

The metric should be ingested as-is.

Collector version

0.80.0

Additional context

Originally discussed in #22070

[github-actions]

Pinging code owners:

• receiver/prometheus: @Aneurysm9 @dashpole

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[swiatekm]

@dashpole I think we originally had a misunderstanding about this, in that this was a problem for me not just for the _sum and _count parts, but for all the samples. That is obviously against the Otel spec, so it's correct that the receiver rejects it. #24030 helps with this in that the valid samples in a given scrape can still be collected, but it still makes migrations from Prometheus to Otel a bit more difficult.

If we want to consider trying to accept metrics which aren't up to spec (perhaps as type Unknown?), then we can discuss that in a separate issue and close this one. Is that ok with you?

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• receiver/prometheus: @Aneurysm9 @dashpole

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[github-actions]

This issue has been closed as inactive because it has been stale for 120 days with no activity.