Add option to specify relative uri for service

[kgibm]

Feature request

One useful addition would be a relative uri option when specifying a service sink.

Use case

It's very common for the CloudEvents endpoint to be at a URI other than /. KafkaSource supports uri in addition to ref:

uri: [...] Relative URIs are resolved using the base URI retrieved from Ref.

I had to use YAML instead:

apiVersion: sources.knative.dev/v1beta1
kind: KafkaSource
metadata:
  name: mysource
spec:
  bootstrapServers:
  - my-cluster-kafka-bootstrap.amq-streams-kafka.svc:9092
  sink:
    ref:
      apiVersion: serving.knative.dev/v1
      kind: Service
      name: myservice
    uri: "/api/cloudevents/mytopic"
  topics:
  - mytopic

UI Example

kn source kafka create mysource --servers my-cluster-kafka-bootstrap.amq-streams-kafka.svc:9092 --topics mytopic --sink myservice --uri /api/cloudevents/mytopic

[dsimansk]

Thanks for the proposal! Indeed this might have been overlooked as an option. We will aim to get it done for Knative 1.12.

[dsimansk]

@Cali0707 @Leo6Leo FYI one of the issues we chatted about in the Slack thread. If you know about anyone interested to work on it, please feel free to share.

[Leo6Leo]

/assign @taniaduggal

[knative-prow]

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[dsimansk]

@Leo6Leo you won't be able to assign issue to non-member of knative/knative-extensions orgs, per the bot's comment.

But it's fine even without a direct assignee on the issue. There's an indication of assignee at least. :)
PR can be still created and merged, given the contrib CLA is signed.

@taniaduggal happy to see new faces around! Please don't hesitate and let us know if you need any assistance or source code pointers to start.