Add support for routes

[adleong]

Some resources may break down their traffic metrics into logical groupings of
requests called routes. For example, a web application might break down metrics
by request path. If the route field is set, the traffic metrics apply to that
route only. If the route field is empty, the traffic metrics apply to the
resource as a whole.

[stefanprodan]

Can you please bump the API version to v1alpha3 and squash all commits.

[stefanprodan]

Looks like we have a version mismatch, in the SDK the metrics API is at v1alpha2 and in the spec at v1alpha1 😱

cc @grampelberg

[adleong]

Hey @stefanprodan. I've squashed the commits as you requested. If I'm understanding correctly, smi-metrics in the smi-spec is currently at v1alpha2. Or, at least that's the version listed at the top of traffic-metrics.md; is there somewhere else I should be looking?

It was my intention that this change and all the previous ones I've made to the spec (e.g. support for specifying the "side" and support for traffic splits) would be part of v1alpha2. It doesn't seem reasonable to me to bump the version for each spec PR. We could probably benefit from some concept of cutting releases of the spec so that we can intentionally bump the version when appropriate. But perhaps I'm missing some context for the way this API versioning was intended to work. Please let me know what you think.

[stefanprodan]

is there somewhere else I should be looking?

In your example it's apiVersion: metrics.smi-spec.io/v1alpha1

It was my intention that this change and all the previous ones I've made to the spec (e.g. support for specifying the "side" and support for traffic splits) would be part of v1alpha2.

Got it, I haven't made the connection to the previous PR. Maybe an issue that would link both PRs would've been better.

We could probably benefit from some concept of cutting releases of the spec so that we can intentionally bump the version when appropriate.

Yes we should discuss this at the next meeting.

[stefanprodan]

Can you update the examples from apiVersion: metrics.smi-spec.io/v1alpha1 to apiVersion: metrics.smi-spec.io/v1alpha2?

[adleong]

Ah, you're right, I missed updating one of the exampled. Fixed.

[stefanprodan]

@adleong I was referring to metrics.smi-spec.io/v1alpha1 but you've changed specs.smi-spec.io/v1alpha1

[adleong]

@stefanprodan Gah, you're right, sorry. Technical difficulties on my end :)

Should be all fixed up now!

[stefanprodan]

LGTM

Before merging I would squash all commits.

[adleong]

Squashed!

[michelleN]

Looks great. Thank you. Would you mind rebasing?

[bridgetkromhout]

Closing due to project archival: https://www.cncf.io/blog/2023/10/03/cncf-archives-the-service-mesh-interface-smi-project/)