Support canary routing based on multiple upstream according to weight and total weight

[lianglli]

Support canary routing based on multiple upstream according to weight and total weight

[lianglli]

Main ingress with nginx.ingress.kubernetes.io/canary-weight-total: "1000"

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    nginx.ingress.kubernetes.io/canary-weight-total: "1000"
    nginx.ingress.kubernetes.io/ssl-redirect: "false"
  creationTimestamp: "2023-10-30T09:33:15Z"
  generation: 1
  name: tengine-ingress-echo-ing
  namespace: default
  resourceVersion: "28591137"
  uid: 34ff03fa-0e52-4ff4-b992-3b3625664cba
spec:
  ingressClassName: opensource-ingress
  rules:
  - host: echo.w1.com
    http:
      paths:
      - backend:
          service:
            name: tengine-ingress-echo-service
            port:
              number: 80
        path: /
        pathType: Prefix
  tls:
  - hosts:
    - echo.w1.com
    secretName: https-server-1
status:
  loadBalancer:
    ingress:
    - {}

Canary ingress with nginx.ingress.kubernetes.io/canary-weight: "20"

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    nginx.ingress.kubernetes.io/canary: "true"
    nginx.ingress.kubernetes.io/canary-weight: "20"
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
  creationTimestamp: "2023-11-01T11:46:03Z"
  generation: 2
  name: tengine-ingress-hello-weight-ing
  namespace: default
  resourceVersion: "28589548"
  uid: ea56cd6a-7d65-48fd-affd-f102199c12ff
spec:
  ingressClassName: opensource-ingress
  rules:
  - host: echo.w1.com
    http:
      paths:
      - backend:
          service:
            name: tengine-ingress-hello5-service
            port:
              number: 80
        path: /
        pathType: Prefix
  tls:
  - hosts:
    - echo.w1.com
    secretName: https-server-1
status:
  loadBalancer:
    ingress:
    - {}

Expect results:
20 / 1000 ---> upstream tengine-ingress-hello5-service
980 /1000 ---> upstream tengine-ingress-echo-service

for i in {1..1000}; do curl -i -k https://echo.w1.com ;  done > weight.txt

984 times: ups-target-key: default-tengine-ingress-echo-service-80
16 times: ups-target-key: default-tengine-ingress-hello5-service-80