feat: Parser plugin restructuring

[srebhan]

Required for all PRs:

• Associated README.md updated.
• Has appropriate unit tests.

This PR restructures the parser plugin infrastructure to match those of other plugins (e.g. input, aggregators,...) with a central registry and config definitions (including TOML tags) in the parser code itself. This reliefs new parsers for spraying the code all over the project and allow them to keep all in one place (the parser code).

By using the new infrastructure you get some goodies for free like support of logging via definition of Log telegraf.Logger 'toml:"-"' and internal plugin statistics metrics_parsed and parse_time_ns. We keep backward compatibility so parsers not ported yet are still supported.
This PR currently only converts the CSV parser to the new interface as a PoC and fixes the fallout.

The main benefit is that now, implementing new parser plugins has the same procedure as all other plugins. You write your self-contained parser in a sub-directory below plugins/parsers , add it to plugins/parsers/all/all.go and update the documentation. No need anymore to add TOML exceptions in config or fight with plugins/parsers/registration.go.

[telegraf-tiger]

🤝 ✅ CLA has been signed. Thank you!

[ssoroka]

overall I think it's headed in the right direction. some thoughts:

• I don't think you can remove parsers.Parsers without breaking backwards compatibility, it's part of the contract we maintain to plugins.
• I don't feel like giving parsers their own runners makes sense in the way it does for inputs/etc, because they really belong to the plugin using them.
• FYI there's future parser work related to stream parsers, and supporting multiple parsers per input plugin at some point.

[srebhan]

@sspaink, @reimda, @powersj, @MyaLongmire here is the discussed update. Would love to get your feedback!

[sspaink]

Great work! I think this looks good.

[etycomputer]

Hi @srebhan,
You have been very busy.
The only suggestion that I can make is to add a new test to the exec input plugin to cover the #10347 scenario.
Cheers

[telegraf-tiger]

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

📦 Looks like new artifacts were built from this PR.

Expand this list to get them here ! 🐯

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_i386.zip
armel.deb	armv6hl.rpm	freebsd_amd64.tar.gz
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
		static_linux_amd64.tar.gz

[reimda]

Looks good to me. Thanks for working on this. It will be nice to switch them all over to the new system and then remove the old compatibility code!

[srebhan]

@etycomputer could you please submit a PR adding this as a test-case? Your help would be very much appreciated!