[processor/resourcedetectionprocessor] Expose Azure resource tags

[rimitchell]

Description:

Adds support to expose regex matched Azure resource tags as opentelemetry resource attributes.

Link to tracking Issue:

Testing:

• Internal regex matching tests added
• Built & deployed to allow verification against deployed Azure resources

Documentation:

• Updated Azure section of the resource detection processor documentation to include a section outlining regex matching usage

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: rimitchell / name: Richard Mitchell (3e1f7a1, 92b19af, 8d97230, dbffdbf, 785ed35, aa887a6, 82f87e0)

[mx-psi]

Thanks for your contribution! We can't accept your contribution unless you sign the CLA

[mx-psi]

Is just adding all tags acceptable in terms of performance and number? i.e. Do Azure instances typically have a lot of tags?

Asking because I would like to keep it simple: if you want to filter, you can do that in a different component in your pipeline like the transform processor

[rimitchell]

Azure supports a max of 50 tags per resource, how many are actually in use of course varies depending on people's use cases.
In terms of "cost", we essentially get the data for free since it is included in the resource's metadata query results, unlike on AWS which requires a secondary rest call to fetch the tag information. So we are only paying the cost of the regex matching.

When implementing this I decided to keep it aligned with how the AWS implementation was exposed to users. The thought there was if someone is in a multi-cloud environment having them both configured the same, makes it easier for them to be used but I am not glued to that implementation choice.

[mx-psi]

Thanks for the detailed reply! I agree it's valuable to be aligned with the AWS detector. I guess we can always add an 'add all of them' setting if needed.

[rimitchell]

You're welcome. As for the all setting. Yup! In the interim, if people wanted to do this it would just require an unrestrictive regex .*

And CLA is finally signed. There was a hiccup on our side.

[mx-psi]

Thanks!