Create Helpers for exposing pod/deployment in a cluster

[pablochacin]

When running chaos tests this is common pattern:

• Create a target pod or deployment (commonly, on its own namespace)
• Subject the target pod/deployment to certain attack (e.g. kill replica, stress resources, delay network traffic)
• Submit load to the target and measure behavior

A similar requirement may arise in other contexts, such as integration tests.

However, in order to reach the target from outside a k8s cluster, it must be exposed as a service and optionally (depending on the cluster's infrastructure) the service exposed as an ingress.

Presently the xk6-kubernetes extension offers the basic building blocks for doing so, but requires a considerable programming effort. It can be done by means of applying a raw yaml manifest or by creating a kubernetes service object "manually" and submitting it to the cluster via a create operation. Neither option seems neither convenient nor idiomatic in the context of k6 testing.

Therefore, it would be convenient to create a helper method in the ingress package that allows exposing a pod/deployment as a service and, optionally, as an ingress.

The intended API should look similar to this example below:

 import { kubernetes } from xk6-kubernetes
 
k8s  =  new Kubernetes()

pod = k8s.pods.Create({
  name: "my-pod",
  namespace: "my-namespace",
  image: "my-image",
} )

k8s.helpers.expose({
  selector: { run: "my-app" },
  service: "my-service", 
  type: "ClusterIP",
  port: 80, 
  ingress: "my-ingress",
  path: "/my-app"
})

[pablochacin]

With the introduction of the Generic API and helper functions such as getExternalIP this helper may result redundant.