Simplify RateLimitPolicy

[eguzki]

What

Make some fields of the RateLimitPolicy optional to make the required CR object smaller and simpler. After this changes, the simplest RLP instance looks like this:

---
apiVersion: kuadrant.io/v1beta1
kind: RateLimitPolicy
metadata:
  name: toystore
spec:
  targetRef:
    group: gateway.networking.k8s.io
    kind: HTTPRoute
    name: toystore
  rateLimits:
    - limits:
        - maxValue: 5
          seconds: 10

Only targetRef and one limit object is required. Furthermore, the limit object does not require conditions and variables fields.

When the Kuadrant control plane finds a rate limit policy that does not specify any action configuration, the Kuadrant control plane
will assign a generic default action configuration for the traffic related to the targeted network resource. This default action configuration allows defining global limits for all the traffic related to the targeted network resource.

[BREAKING CHANGE] (or maybe not). Technically this is breaking the current v1beta1 API. However, I do not expect issues at all. The changes switch some fields from required to optional. Thus, any existing "old" RLP instance will still be valid with the "new" CRD. No need to conversion either.

TODO:

• unittests and e2e tests
• Doc

Fixes #133

Verification steps

run dev env

make local-setup

Create kuadrant CR

k apply -f - <<EOF
---
apiVersion: kuadrant.io/v1beta1
kind: Kuadrant
metadata:
  name: kuadrant
spec: {}
EOF

Deploy toystore upstream service

kubectl apply -f examples/toystore/toystore.yaml

Create HTTPRoute

k apply -f examples/toystore/httproute.yaml

Check toystore HTTPRoute works

kubectl port-forward -n istio-system service/istio-ingressgateway 9080:80 &
curl -v -H 'Host: api.toystore.com' http://localhost:9080/toy

It should return 200 OK.

Create simplified RLP

k apply -f - <<EOF
---
apiVersion: kuadrant.io/v1beta1
kind: RateLimitPolicy
metadata:
  name: toystore
spec:
  targetRef:
    group: gateway.networking.k8s.io
    kind: HTTPRoute
    name: toystore
  rateLimits:
    - limits:
        - maxValue: 5
          seconds: 10
EOF

Wait for the policy to be available (and avoid possible errors)

k wait --for=condition=available ratelimitpolicy/toystore

Validating the rate limit policy

Only 5 requests every 10 secs on rate-limited.toystore.com allowed.

curl -v -H 'Host: rate-limited.toystore.com' http://localhost:9080/toy

[eguzki]

ready for review @Kuadrant/engineering

[maleck13]

@eguzki I don't feel qualified to approve the PR but I love this change and take a look through it looks reasonable

[didierofrivia]

The verification steps are working 👍🏼

[guicassolato]

Thanks for addressing the comments. I think this is only still relevant, but even so I'm guessing it won't matter for too long.

Verification steps work. Approved.