Allow setting of source CIDR for LB rule

[CodeBleu]

* Annotation added to allow setting of Source CIDR for Load Balancer rule

Adding annotation like the following will create the rule with source CIDR set:

    annotations:
        service.beta.kubernetes.io/cloudstack-load-balancer-source-cidrs: "1.2.3.4/32,5.6.7.8/32"

[kiranchavala]

LGTM

Tested by building a docker image based on the pr

Before the fix

After you expose a service, there is no source cidr list populated

k expose deploy/nginx-deployment --port=80 --type=LoadBalancer

---

After fix, there is source cidr populated on the loadbalancer rule

Tested with normal service.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-deployment2
  namespace: default
  annotations:
    service.beta.kubernetes.io/cloudstack-load-balancer-source-cidrs: "1.2.3.4/32,5.6.7.8/32"
spec:
  type: LoadBalancer
  selector:
    app: nginx
  ports:
    - port: 80
      targetPort: 80
      protocol: TCP
      nodePort: 30558
  externalTrafficPolicy: Cluster
  allocateLoadBalancerNodePorts: true
  sessionAffinity: None

[CodeBleu]

@Pearl1594 Do you mind doing a quick review of this? I believe I need 2 approvals and a test output before I can merge.

[DaanHoogland]

clgtm

[DaanHoogland]

i’d rather see

Suggested change

	// Read the source CIDR annotation
	sourceCIDRs, ok := service.Annotations[ServiceAnnotationLoadBalancerSourceCidrs]
	var cidrList []string
	if ok && sourceCIDRs != "" {
	cidrList = strings.Split(sourceCIDRs, ",")
	for i, cidr := range cidrList {
	cidr = strings.TrimSpace(cidr)
	if _, _, err := net.ParseCIDR(cidr); err != nil {
	return nil, fmt.Errorf("invalid CIDR in annotation %s: %s", ServiceAnnotationLoadBalancerSourceCidrs, cidr)
	}
	cidrList[i] = cidr
	}
	} else {
	cidrList = []string{defaultAllowedCIDR}
	}
	// Set the CIDR list in the parameters
	p.SetCidrlist(cidrList)
	// Set the CIDR list in the parameters
	p.SetCidrlist(readTheSourceCidrAnnotation(service))

and

func readTheSourceCidrAnnotation(service *corev1.Service) []string {
	// Read the source CIDR annotation
	sourceCIDRs, ok := service.Annotations[ServiceAnnotationLoadBalancerSourceCidrs]
	var cidrList []string
	if ok && sourceCIDRs != "" {
		cidrList = strings.Split(sourceCIDRs, ",")
		for i, cidr := range cidrList {
			cidr = strings.TrimSpace(cidr)
			if _, _, err := net.ParseCIDR(cidr); err != nil {
				return nil, fmt.Errorf("invalid CIDR in annotation %s: %s", ServiceAnnotationLoadBalancerSourceCidrs, cidr)
			}
			cidrList[i] = cidr
		}
	} else {
		cidrList = []string{defaultAllowedCIDR}
	}
    return cidrList
}

(no waranty on the syntax)