ingestion/gateway-api: Map backend weight to model

[sayboras]

Description

This commit is to make sure the weightage value is propagated to internal model.

Relates: 58c8aff

Reported-by: Nico Vibert nicolas.vibert@isovalent.com
Signed-off-by: Tam Mach tam.mach@cilium.io

Testing

Verification is done by checking envoy config dump, then run-time behavior is confirmed.

HTTP route config

---
apiVersion: gateway.networking.k8s.io/v1alpha2
kind: HTTPRoute
metadata:
  name: example-route-1
spec:
  parentRefs:
  - name: my-example-gateway
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /echo
    backendRefs:
    - kind: Service
      name: echo-1
      port: 8080
      weight: 100
    - kind: Service
      name: echo-2
      port: 8090
      weight: 0

Envoy Config dump

# Before (weight values are always 1)
"route": {
 "weighted_clusters": {
  "clusters": [
   {
    "name": "default/echo-1:8080",
    "weight": 1
   },
   {
    "name": "default/echo-2:8090",
    "weight": 1
   }
  ],
  "total_weight": 2
 },
           
# After
"route": {
 "weighted_clusters": {
  "clusters": [
   {
    "name": "default/echo-1:8080",
    "weight": 100
   },
   {
    "name": "default/echo-2:8090",
    "weight": 0
   }
  ],
  "total_weight": 100
 },        

Runtime behavior

$ curl -s http://$lb/echo | grep "Hostname: echo-"
Hostname: echo-1-7b499f4578-7j9dr

...
$ curl -s http://$lb/echo | grep "Hostname: echo-"
Hostname: echo-1-7b499f4578-7j9dr

[sayboras]

Full CI is not required, the changes are covered by Gateway API conformance test.

[sayboras]

This changes are only for Gateway API, full CI is not required. Conformance test is passed, in addition to manual verification. Mark this ready to merge.