docs(processors.ifname): Document better agent tag name

[Hipska]

Required for all PRs

• Updated associated README.md.
• Wrote appropriate unit tests.
• Pull request title or commits are in conventional commit format

Related to #8011 and #4413

[powersj]

@Hipska,

As you know the config should show the default, and you are essentially changing the default if someone takes the default config and modifies it. I don't think we want to do this. If you want to document (i.e. add a comment) about using "source" instead of agent, I think that is cool, but not changing the default.

Thoughts?

[Hipska]

Well, the default isn't actually changed (it is still agent), so current users aren't affected. But as discussed in the original #8011, that default doesn't make much sense as most (if not, all) users need to change it anyway.

FYI, I'm planning to make a new processor which will make the ifname processor deprecated as it will have the same functionality + more.

[powersj]

@Hipska,

This will create confusion. The sample config option no longer shows the default value. The uncommented value is not the default.

What I was trying to say above is that we do have users who use the telegraf config command and/or the sample config to generate their config. They would pick up this change unconsciously, they would not be aware of the change, and it would cause confusion.

[Hipska]

You prefer to have it the other way round? (having example: ... in the comments)

[powersj]

yes

[telegraf-tiger]

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Downloads for additional architectures and packages are available below.

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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]

Thanks @Hipska!