Make rabbitmq federation plugin optional

[pabigot]

Required for all PRs:

• Updated associated README.md.
• Wrote appropriate unit tests.

resolves #9489

Do not record an error for a 404 return for api/federation-links.

[telegraf-tiger]

Looks like new artifacts were built from this PR. Get them here!

Artifact URLs

• darwin_amd64.tar.gz

• windows_amd64.zip

• windows_i386.zip

• armv6hl.rpm

• freebsd_armv7.tar.gz

• linux_armhf.tar.gz

• armhf.deb

• armel.rpm

• linux_armel.tar.gz

• armel.deb

• ppc64le.rpm

• linux_ppc64le.tar.gz

• ppc64el.deb

• x86_64.rpm

• freebsd_amd64.tar.gz

• linux_amd64.tar.gz

• amd64.deb

• linux_mipsel.tar.gz

• mipsel.deb

• s390x.rpm

• linux_s390x.tar.gz

• s390x.deb

• aarch64.rpm

• linux_arm64.tar.gz

• arm64.deb

• i386.rpm

• freebsd_i386.tar.gz

• linux_i386.tar.gz

• i386.deb

• static_linux_amd64.tar.gz

• linux_mips.tar.gz

• mips.deb

[srebhan]

Hey @pabigot, thanks for submitting this PR!

I wonder why you can't use metric_include or metric_exclude introduced in PR #9443 using e.g.

metric_exclude = ["federation"]

to disable collection of federation information. Can you please explain the use-case this PR is covering that is beyond the above solution. It's for me to understand how those two things interact...

[pabigot]

I wonder why you can't use metric_include or metric_exclude introduced in PR #9443

Because I didn't know about it. That feature isn't mentioned anywhere in #9383 no, it is, I just missed it, nor in the commit message that resolved it, and my scan of the changes to the source didn't pick it up.

It does work, though. Thanks.

[srebhan]

@pabigot no worries and yes I could have documented the feature better. Sorry about this. I just wanted to make sure I don't miss something on your PR that is not covered by the referenced change. Have fun using telegraf!

[Dmaina5054]

metric_exclude = ["federation"]
Worked for me running influxdb:2.0.7