feat(inputs.redfish): adds more chassis tags

[steven-freed]

adds more chassis tags to the redfish input plugin. These chassis tags are applied to the underlying chassis links containing metrics such as Power and Thermal similar to how the implementation for Chassis.Location was done.

Required for all PRs

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

resolves #

[srebhan]

Thanks for your contribution @steven-freed! While the code looks good I do have concerns regarding backward-compatibility on the query side. If you add tags and feed the data to e.g. InfluxDB you can get different results for your query (e.g. when grouping by all tags) let alone the increased cardinality.

Therefore, I suggest to add a setting to add the new tag set with a default of false. I think that is not too hard given your nice cutting of the code... What do you think?

[steven-freed]

@srebhan thanks, happy to be here! I'm thinking of adding a setting called include_parent_tags to include the child link's (e.g. Thermal, Power) parent tags (e.g. Chassis). However, the way the previous version was written includes Chassis.Location tags along with the child link tags. Would it be ok if this compatibility is broken? (Only outputting the location tags if include_parent_tags=true) It would be cleaner and match the API spec more closely but if you'd rather I leave those extra location tags I can do that as well.

Also a good argument to increased cardinality would be that if a client really was concerned with cardinality then they should restrict tags fed to their input plug-in by using the "taginclude" telegraf input settings.

[srebhan]

We cannot break current users @steven-freed. However, how about having something like

  include_tag_set = ["thermal", "power", "chassis.location", ...]

with a granularity that matches what is there and make your tag-set a new element in that array? This way you could set that array to something that matches the current state and we can easily add new tag-sets if necessary...

[steven-freed]

I see. Ok that sounds good. We can default to the current tag sets as you've shown above.

[steven-freed]

I've left out chassis.thermal and chassis.power from tag sets because this would allow for users to include a metric in their telegraf.conf that may not have any tags.
For example:
namepass = ["redfish_thermal_fans"] metric may not have any tags if the user sets include_tag_sets = ["chassis.power"]

To resolve this issue, I've modeled the code so that tag sets can be used to add more tags rather than restrict tags. To ensure backwards compatibility I've defaulted the tag sets to include chassis.location. Thanks for the recommendations!

[srebhan]

@steven-freed some small comments from my side, but the overall code looks quite good already.

[srebhan]

The config should show the actual default values but mention the available options. Did that for you and will push to get this over the finish line.

Thanks for your contribution @steven-freed!

[telegraf-tiger]

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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

[powersj]

Thank you!