fix(config): Error on invalid tagpass/tagdrop list syntax

[calvinmachado20]

Summary

Address open issue: #16398

People work sloppily and try to match metrics with a tagpass = ["mymarkertag"] when the correct version would be tagpass = { "markertag" = ["mymarkertag"] } or similar.
Telegraf doesn't error out, though, and processors and outputs still process and put out the affected metrics because no working tagpass means matching every metric.

But it also matches metrics it shouldn't match and those end up in databases where they shouldn't end up.

Expected behavior
Error out with a config syntax error because tagpass expects a dictionary

Actual behavior
No erroring out and just matching everything leading to metrics in places where they don't belong.

Checklist

• No AI generated code was used in this PR

Related issues

resolves #16398

[skartikey]

@calvinmachado20 Thanks for the PR!
This is a breaking change for users with incorrect configurations, but that's appropriate since those configs were already broken and causing data integrity issues. The clear error message will help them quickly fix their configuration.

[calvinmachado20]

@skartikey thanks for having a look at this, I agree with what you said

[calvinmachado20]

@skartikey any update on this or is this change good?

[skartikey]

It’s worth pointing out that this PR fixes #16398 but does not fix #17500. They may look similar at first, but they are different problems:

• Tagpass with a list doesn't trigger error and just matches everything #16398 → Wrong data type for tagpass/tagdrop (list vs. table) - Fixed here
• processors.rename - weird behaviour in regards to "tags"-option #17500 → processors.rename ignoring global tags option - Needs larger architectural changes

[telegraf-tiger]

Download PR build artifacts for linux_amd64.tar.gz, darwin_arm64.tar.gz, and windows_amd64.zip.
Downloads for additional architectures and packages are available below.

☺️ This pull request doesn't significantly change the Telegraf binary size (less than 1%)

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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

[telegraf-tiger]

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!

[calvinmachado20]

@skartikey can this PR be opened again? Are there any issues you think with these changes?

[srebhan]

Sorry for closing this @calvinmachado20! Are you willing to drive this over the finish line? If so, please rebase the PR on latest master!

[calvinmachado20]

Yes, happy to do so. Let me do that and comment back