/
dnszone_validating_admission_hook.go
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/
dnszone_validating_admission_hook.go
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package validatingwebhooks
import (
"fmt"
"net/http"
"strings"
log "github.com/sirupsen/logrus"
admissionv1beta1 "k8s.io/api/admission/v1beta1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime/schema"
dnsvalidation "k8s.io/apimachinery/pkg/util/validation"
"k8s.io/client-go/rest"
"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
hivev1 "github.com/openshift/hive/pkg/apis/hive/v1"
)
const (
dnsZoneGroup = "hive.openshift.io"
dnsZoneVersion = "v1"
dnsZoneResource = "dnszones"
)
// DNSZoneValidatingAdmissionHook is a struct that is used to reference what code should be run by the generic-admission-server.
type DNSZoneValidatingAdmissionHook struct {
decoder *admission.Decoder
}
// NewDNSZoneValidatingAdmissionHook constructs a new DNSZoneValidatingAdmissionHook
func NewDNSZoneValidatingAdmissionHook(decoder *admission.Decoder) *DNSZoneValidatingAdmissionHook {
return &DNSZoneValidatingAdmissionHook{decoder: decoder}
}
// ValidatingResource is called by generic-admission-server on startup to register the returned REST resource through which the
// webhook is accessed by the kube apiserver.
// For example, generic-admission-server uses the data below to register the webhook on the REST resource "/apis/admission.hive.openshift.io/v1/dnszonevalidators".
// When the kube apiserver calls this registered REST resource, the generic-admission-server calls the Validate() method below.
func (a *DNSZoneValidatingAdmissionHook) ValidatingResource() (plural schema.GroupVersionResource, singular string) {
log.WithFields(log.Fields{
"group": "admission.hive.openshift.io",
"version": "v1",
"resource": "dnszonevalidator",
}).Info("Registering validation REST resource")
// NOTE: This GVR is meant to be different than the DNSZone CRD GVR which has group "hive.openshift.io".
return schema.GroupVersionResource{
Group: "admission.hive.openshift.io",
Version: "v1",
Resource: "dnszonevalidators",
},
"dnszonevalidator"
}
// Initialize is called by generic-admission-server on startup to setup any special initialization that your webhook needs.
func (a *DNSZoneValidatingAdmissionHook) Initialize(kubeClientConfig *rest.Config, stopCh <-chan struct{}) error {
log.WithFields(log.Fields{
"group": "admission.hive.openshift.io",
"version": "v1",
"resource": "dnszonevalidator",
}).Info("Initializing validation REST resource")
return nil // No initialization needed right now.
}
// Validate is called by generic-admission-server when the registered REST resource above is called with an admission request.
// Usually it's the kube apiserver that is making the admission validation request.
func (a *DNSZoneValidatingAdmissionHook) Validate(admissionSpec *admissionv1beta1.AdmissionRequest) *admissionv1beta1.AdmissionResponse {
contextLogger := log.WithFields(log.Fields{
"operation": admissionSpec.Operation,
"group": admissionSpec.Resource.Group,
"version": admissionSpec.Resource.Version,
"resource": admissionSpec.Resource.Resource,
"method": "Validate",
})
if !a.shouldValidate(admissionSpec) {
contextLogger.Info("Skipping validation for request")
// The request object isn't something that this validator should validate.
// Therefore, we say that it's allowed.
return &admissionv1beta1.AdmissionResponse{
Allowed: true,
}
}
contextLogger.Info("Validating request")
if admissionSpec.Operation == admissionv1beta1.Create {
return a.validateCreate(admissionSpec)
}
if admissionSpec.Operation == admissionv1beta1.Update {
return a.validateUpdate(admissionSpec)
}
// We're only validating creates and updates at this time, so all other operations are explicitly allowed.
contextLogger.Info("Successful validation")
return &admissionv1beta1.AdmissionResponse{
Allowed: true,
}
}
// shouldValidate explicitly checks if the request should validated. For example, this webhook may have accidentally been registered to check
// the validity of some other type of object with a different GVR.
func (a *DNSZoneValidatingAdmissionHook) shouldValidate(admissionSpec *admissionv1beta1.AdmissionRequest) bool {
contextLogger := log.WithFields(log.Fields{
"operation": admissionSpec.Operation,
"group": admissionSpec.Resource.Group,
"version": admissionSpec.Resource.Version,
"resource": admissionSpec.Resource.Resource,
"method": "shouldValidate",
})
if admissionSpec.Resource.Group != dnsZoneGroup {
contextLogger.Debug("Returning False, not our group")
return false
}
if admissionSpec.Resource.Version != dnsZoneVersion {
contextLogger.Debug("Returning False, it's our group, but not the right version")
return false
}
if admissionSpec.Resource.Resource != dnsZoneResource {
contextLogger.Debug("Returning False, it's our group and version, but not the right resource")
return false
}
// If we get here, then we're supposed to validate the object.
contextLogger.Debug("Returning True, passed all prerequisites.")
return true
}
// validateCreate specifically validates create operations for DNSZone objects.
func (a *DNSZoneValidatingAdmissionHook) validateCreate(admissionSpec *admissionv1beta1.AdmissionRequest) *admissionv1beta1.AdmissionResponse {
contextLogger := log.WithFields(log.Fields{
"operation": admissionSpec.Operation,
"group": admissionSpec.Resource.Group,
"version": admissionSpec.Resource.Version,
"resource": admissionSpec.Resource.Resource,
"method": "validateCreate",
})
newObject := &hivev1.DNSZone{}
if err := a.decoder.DecodeRaw(admissionSpec.Object, newObject); err != nil {
contextLogger.Errorf("Failed unmarshaling Object: %v", err.Error())
return &admissionv1beta1.AdmissionResponse{
Allowed: false,
Result: &metav1.Status{
Status: metav1.StatusFailure, Code: http.StatusBadRequest, Reason: metav1.StatusReasonBadRequest,
Message: err.Error(),
},
}
}
// Add the new data to the contextLogger
contextLogger.Data["object.Name"] = newObject.Name
strErrs := dnsvalidation.IsDNS1123Subdomain(newObject.Spec.Zone)
if len(strErrs) != 0 {
message := fmt.Sprintf("Failed validation: %v", strings.Join(strErrs, ";"))
contextLogger.Infof(message)
return &admissionv1beta1.AdmissionResponse{
Allowed: false,
Result: &metav1.Status{
Status: metav1.StatusFailure, Code: http.StatusBadRequest, Reason: metav1.StatusReasonBadRequest,
Message: message,
},
}
}
// If we get here, then all checks passed, so the object is valid.
contextLogger.Info("Successful validation")
return &admissionv1beta1.AdmissionResponse{
Allowed: true,
}
}
// validateUpdate specifically validates update operations for DNSZone objects.
func (a *DNSZoneValidatingAdmissionHook) validateUpdate(admissionSpec *admissionv1beta1.AdmissionRequest) *admissionv1beta1.AdmissionResponse {
contextLogger := log.WithFields(log.Fields{
"operation": admissionSpec.Operation,
"group": admissionSpec.Resource.Group,
"version": admissionSpec.Resource.Version,
"resource": admissionSpec.Resource.Resource,
"method": "validateUpdate",
})
newObject := &hivev1.DNSZone{}
if err := a.decoder.DecodeRaw(admissionSpec.Object, newObject); err != nil {
contextLogger.Errorf("Failed unmarshaling Object: %v", err.Error())
return &admissionv1beta1.AdmissionResponse{
Allowed: false,
Result: &metav1.Status{
Status: metav1.StatusFailure, Code: http.StatusBadRequest, Reason: metav1.StatusReasonBadRequest,
Message: err.Error(),
},
}
}
// Add the new data to the contextLogger
contextLogger.Data["object.Name"] = newObject.Name
oldObject := &hivev1.DNSZone{}
if err := a.decoder.DecodeRaw(admissionSpec.OldObject, oldObject); err != nil {
contextLogger.Errorf("Failed unmarshaling OldObject: %v", err.Error())
return &admissionv1beta1.AdmissionResponse{
Allowed: false,
Result: &metav1.Status{
Status: metav1.StatusFailure, Code: http.StatusBadRequest, Reason: metav1.StatusReasonBadRequest,
Message: err.Error(),
},
}
}
// Add the new data to the contextLogger
contextLogger.Data["oldObject.Name"] = oldObject.Name
if oldObject.Spec.Zone != newObject.Spec.Zone {
message := "DNSZone.Spec.Zone is immutable"
contextLogger.Infof("Failed validation: %v", message)
return &admissionv1beta1.AdmissionResponse{
Allowed: false,
Result: &metav1.Status{
Status: metav1.StatusFailure, Code: http.StatusBadRequest, Reason: metav1.StatusReasonBadRequest,
Message: message,
},
}
}
// If we get here, then all checks passed, so the object is valid.
contextLogger.Info("Successful validation")
return &admissionv1beta1.AdmissionResponse{
Allowed: true,
}
}