feat(parser.prometheusremotewrite, serializer.prometheusremotewrite): Native histogram support end-to-end

[Reimirno]

Summary

Add a configuration field to prometheusremotewrite parser to change its behavior when parsing Prometheus native histogram.

Previously prometheusremotewrite parser parses a native histogram into multiple Telegraf metric (the conversion is not lossless and is irreversible); now it parses it into one single Telegraf metric. Correspondingly, add a code path to prometheusremotewrite serializer to be able to handle this single Telegraf "native histogram" metric and convert back to Prometheus native histogram. NOTE: logic that handles classic histogram is orthogonal and not changed.

This treatment of native histograms is able to preserve its benefits in terms of correctness guarantee (atomicity, no correctness issue due to write batching) and its performance gain (low cardinality, sparse data structure). More importantly, this means Telegraf can supports native histogram end-to-end: ingest a native histogram and write out a native histogram.

Detailed rationale, including a diagram, please see #16120

Test

Previously, using a prometheusremotewrite HTTP listener v2 input to accept prometheus remote write, and a prometheusremotewrite HTTP output, Telegraf ingests prometheus native histogram but writes out several counters, as if this were a classic histogram.

In the query here, a native histogram get translated into several "bucket" metrics (but without _bucket suffix and with a <metric_name>_le tag.

Now, after this PR:

This native histogram now gets correctly written out as a native histogram.

I can add unit test / integration test when the community reaches some agreement on this implementation.

Checklist

• [x] No AI generated code was used in this PR

Related issues

resolves #16120

[telegraf-tiger[bot]]

Thanks so much for the pull request! :handshake: :black_nib: Just a reminder that the CLA has not yet been signed, and we'll need it before merging. Please sign the CLA when you get a chance, then post a comment here saying !signed-cla

[Reimirno]

!signed-cla

[telegraf-tiger[bot]]

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Artifact URLs

DEB	RPM	TAR GZ	ZIP
amd64.deb	aarch64.rpm	darwin_amd64.tar.gz	windows_amd64.zip
arm64.deb	armel.rpm	darwin_arm64.tar.gz	windows_arm64.zip
armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz	windows_i386.zip
armhf.deb	i386.rpm	freebsd_armv7.tar.gz
i386.deb	ppc64le.rpm	freebsd_i386.tar.gz
mips.deb	riscv64.rpm	linux_amd64.tar.gz
mipsel.deb	s390x.rpm	linux_arm64.tar.gz
ppc64el.deb	x86_64.rpm	linux_armel.tar.gz
riscv64.deb		linux_armhf.tar.gz
s390x.deb		linux_i386.tar.gz
		linux_mips.tar.gz
		linux_mipsel.tar.gz
		linux_ppc64le.tar.gz
		linux_riscv64.tar.gz
		linux_s390x.tar.gz

[srebhan]

@Reimirno any update?

[telegraf-tiger[bot]]

Hello! I am closing this issue due to inactivity. I hope you were able to resolve your problem, if not please try posting this question in our Community Slack or Community Forums or provide additional details in this issue and reqeust that it be re-opened. Thank you!

[Hipska]

@srebhan I think they replied to aal of your comments. I think they are waiting on you instead.

[srebhan]

@Hipska we had a conversation on Slack that splitting the histogram into fields is the right thing to do...

@Reimirno if you feel like I owe you a reply to anything, please speak up. Otherwise, if you do want to continue to work on this PR, please reopen or tell me to reopen here...

[Reimirno]

@srebhan Sorry, I dropped the ball due to some changes in life.

I made a new PR implementing the parser side of stuff for this: https://github.com/influxdata/telegraf/pull/16493, accoridng to what we have discussed.

Future contributors interested in taking this up: feel free to ping me if you have questions.