78 lines
2.5 KiB
Go
78 lines
2.5 KiB
Go
package webhook
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import (
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"fmt"
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"net"
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"net/url"
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corev1 "k8s.io/api/core/v1"
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apierrors "k8s.io/apimachinery/pkg/api/errors"
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webhookutil "k8s.io/apiserver/pkg/util/webhook"
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corev1lister "k8s.io/client-go/listers/core/v1"
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)
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// ServiceResolver knows how to convert a service reference into an actual location.
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type ServiceResolver interface {
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ResolveEndpoint(namespace, name string, port int32) (*url.URL, error)
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}
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// NewServiceResolver returns a ServiceResolver that parses service first,
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// if service not exist, constructs a service URL from a given namespace and name.
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func NewServiceResolver(services corev1lister.ServiceLister) ServiceResolver {
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return &serviceResolver{
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services: services,
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defaultResolver: webhookutil.NewDefaultServiceResolver(),
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}
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}
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type serviceResolver struct {
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services corev1lister.ServiceLister
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defaultResolver ServiceResolver
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}
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func (r *serviceResolver) ResolveEndpoint(namespace, name string, port int32) (*url.URL, error) {
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svc, err := r.services.Services(namespace).Get(name)
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if err != nil {
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if apierrors.IsNotFound(err) {
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return r.defaultResolver.ResolveEndpoint(namespace, name, port)
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}
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return nil, err
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}
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return resolveCluster(svc, port)
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}
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// resolveCluster parses Service resource to url.
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func resolveCluster(svc *corev1.Service, port int32) (*url.URL, error) {
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switch {
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case svc.Spec.Type == corev1.ServiceTypeClusterIP && svc.Spec.ClusterIP == corev1.ClusterIPNone:
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return nil, fmt.Errorf(`cannot route to service with ClusterIP "None"`)
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// use IP from a clusterIP for these service types
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case svc.Spec.Type == corev1.ServiceTypeClusterIP, svc.Spec.Type == corev1.ServiceTypeLoadBalancer, svc.Spec.Type == corev1.ServiceTypeNodePort:
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svcPort, err := findServicePort(svc, port)
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if err != nil {
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return nil, err
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}
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return &url.URL{
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Scheme: "https",
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Host: net.JoinHostPort(svc.Spec.ClusterIP, fmt.Sprintf("%d", svcPort.Port)),
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}, nil
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case svc.Spec.Type == corev1.ServiceTypeExternalName:
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return &url.URL{
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Scheme: "https",
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Host: net.JoinHostPort(svc.Spec.ExternalName, fmt.Sprintf("%d", port)),
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}, nil
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default:
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return nil, fmt.Errorf("unsupported service type %q", svc.Spec.Type)
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}
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}
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// findServicePort finds the service port by name or numerically.
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func findServicePort(svc *corev1.Service, port int32) (*corev1.ServicePort, error) {
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for _, svcPort := range svc.Spec.Ports {
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if svcPort.Port == port {
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return &svcPort, nil
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}
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}
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return nil, apierrors.NewServiceUnavailable(fmt.Sprintf("no service port %d found for service %q", port, svc.Name))
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}
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