fix(trait): controller strategy default service port name

[squakez]

Using a func that determine the default port name based on the controller strategy adopted.

Close #5409

Release Note

fix(trait): controller strategy default service port name

[squakez]

@lburgazzoli do you know if this change may create any problem for other deployment strategy or other clusters (ie, Openshift) by any chance?

[lburgazzoli]

In general if you use a service, it should not be an issue, however it may break customer deployment if they were using such name in any external tool for any reason i.e. in prometheus' PodMonitor

apiVersion: monitoring.coreos.com/v1
kind: PodMonitor
metadata:
  name: example-app
  labels:
    team: frontend
spec:
  selector:
    matchLabels:
      app: example-app
  podMetricsEndpoints:
  - port: http

I wonder if we should make this change knative only at least for now and eventually failing the integration if the use changes the port name for a Knative deployment.

[lburgazzoli]

As side note, this would probably cause all the integration Pods to be restarted when the operator gets upgraded

[squakez]

In general if you use a service, it should not be an issue, however it may break customer deployment if they were using such name in any external tool for any reason i.e. in prometheus' PodMonitor

Yes, if the monitoring is external, then, we cannot control that. I'll move this change to apply exclusively to Knative, however, there are several places where this is happening, so we need to make more verification about it.

[squakez]

Should be good to go now. I've worked to define a more generic approach and let any trait requiring to know the port name to use a function that will return the default based on the controller strategy used. It should be compatible with the existing Deployment as will still return http conversely to the previous commit.