Enhance(webhook): add skip validations checks via annotations

There are some cases like volume migration where we need to delete
the old pvc and create new based on CSI, in such cases we need
to ignore/skip the validations.

Signed-off-by: prateekpandey14 <prateek.pandey@mayadata.io>

pkg/webhook/webhook.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/http"
+	"strings"
 
 	snapshot "github.com/openebs/maya/pkg/apis/openebs.io/snapshot/v1"
 	"github.com/openebs/maya/pkg/apis/openebs.io/v1alpha1"
@@ -63,6 +64,7 @@ var (
 		metav1.NamespacePublic,
 	}
 	snapshotAnnotation = "snapshot.alpha.kubernetes.io/snapshot"
+	skipValidation     = "openebs.io/skip-validations"
 )
 
 // webhook implements a validating webhook.
@@ -183,7 +185,20 @@ func admissionRequired(ignoredList []string, metadata *metav1.ObjectMeta) bool {
 			return false
 		}
 	}
-	return true
+
+	annotations := metadata.GetAnnotations()
+	if annotations == nil {
+		annotations = map[string]string{}
+	}
+
+	var required bool
+	switch strings.ToLower(annotations[skipValidation]) {
+	default:
+		required = true
+	case "n", "no", "false", "off":
+		required = false
+	}
+	return required
 }
 
 func validationRequired(ignoredList []string, metadata *metav1.ObjectMeta) bool {
@@ -230,6 +245,12 @@ func (wh *webhook) validatePVCDeleteRequest(req *v1beta1.AdmissionRequest) *v1be
 		return response
 	}
 
+	// skip pvc validation if skip-validations annotation has been set
+	if _, ok := pvc.GetAnnotations()[skipValidation]; ok {
+		klog.Infof("Skipping validations for %s/%s due to PVC has skip validation", pvc.Namespace, pvc.Name)
+		return response
+	}
+
 	// If PVC is not yet bound to PV then don't even perform any checks
 	if pvc.Spec.VolumeName == "" {
 		klog.Infof("Skipping validations for %s/%s due to PVC is not yet bound", pvc.Namespace, pvc.Name)

pkg/webhook/webhook_test.go

@@ -282,6 +282,51 @@ func TestValidatePVCDeleteRequest(t *testing.T) {
 			isRequiresPVCCreation: true,
 			expectedResponse:      true,
 		},
+		"Skip PVC validations if skip-validaions annotations set even snapshotData exists": {
+			pvc: &corev1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:        "PVC7",
+					Namespace:   "test",
+					Annotations: map[string]string{skipValidation: "true"},
+				},
+				Spec: corev1.PersistentVolumeClaimSpec{
+					VolumeName: "PV1",
+				},
+			},
+			snapshotData: &snapshotapi.VolumeSnapshotData{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "SnapData1",
+				},
+				Spec: snapshotapi.VolumeSnapshotDataSpec{
+					PersistentVolumeRef: &corev1.ObjectReference{
+						Name: "PV1",
+					},
+				},
+			},
+			isRequiresPVCCreation: true,
+			expectedResponse:      true,
+		},
+		"Skip pvc validaion if skipValidation annotations set even snapshot exists": {
+			pvc: &corev1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:        "PVC8",
+					Namespace:   "test",
+					Annotations: map[string]string{skipValidation: "true"},
+				},
+				Spec: corev1.PersistentVolumeClaimSpec{
+					VolumeName: "PV1",
+				},
+			},
+			snapshot: &snapshotapi.VolumeSnapshot{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "Snap1",
+					Namespace: "test",
+					Labels:    map[string]string{snapshotMetadataPVName: "PV1"},
+				},
+			},
+			isRequiresPVCCreation: true,
+			expectedResponse:      true,
+		},
 	}
 	for name, test := range tests {
 		name, test := name, test