Revert webhook handler methods with nil pointer fix

Signed-off-by: Abhijit Mukherjee <abhijit.mukherjee@infracloud.io>

go.mod

@@ -179,7 +179,7 @@ require (
 	go.opentelemetry.io/otel v1.23.0 // indirect
 	go.opentelemetry.io/otel/sdk v1.22.0 // indirect
 	go.opentelemetry.io/otel/trace v1.23.0 // indirect
-	go.starlark.net v0.0.0-20200306205701-8dd3e2ee1dd5 // indirect
+	go.starlark.net v0.0.0-20230525235612-a134d8f9ddca // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/crypto v0.19.0 // indirect
 	golang.org/x/exp v0.0.0-20231006140011-7918f672742d // indirect

go.sum

@@ -775,7 +775,6 @@ google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98
 google.golang.org/genproto v0.0.0-20190911173649-1774047e7e51/go.mod h1:IbNlFCBrqXvoKpeg0TB2l7cyZUmoaFKYIwrEpbDKLA8=
 google.golang.org/genproto v0.0.0-20191230161307-f3c370f40bfb/go.mod h1:n3cpQtvxv34hfy77yVDNjmbRyujviMdxYliBSkLhpCc=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
-google.golang.org/genproto v0.0.0-20201019141844-1ed22bb0c154/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20240125205218-1f4bbc51befe h1:USL2DhxfgRchafRvt/wYyyQNzwgL7ZiURcozOE/Pkvo=
 google.golang.org/genproto v0.0.0-20240125205218-1f4bbc51befe/go.mod h1:cc8bqMqtv9gMOr0zHg2Vzff5ULhhL2IXP4sbcn32Dro=
 google.golang.org/genproto/googleapis/api v0.0.0-20240116215550-a9fa1716bcac h1:OZkkudMUu9LVQMCoRUbI/1p5VCo9BOrlvkqMvWtqa6s=

pkg/handler/handler.go

@@ -27,7 +27,6 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/webhook"
 	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
 
-	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
 	"github.com/kanisterio/kanister/pkg/validatingwebhook"
 	"github.com/kanisterio/kanister/pkg/version"
 	"github.com/pkg/errors"
@@ -71,11 +70,14 @@ func RunWebhookServer(c *rest.Config) error {
 	if err != nil {
 		return errors.Wrapf(err, "Failed to create new webhook manager")
 	}
+	bpValidator := &validatingwebhook.BlueprintValidator{}
+	if err = bpValidator.InjectDecoder(admission.NewDecoder(mgr.GetScheme())); err != nil {
+		return errors.Wrapf(err, "Failed to inject decoder")
+	}
 
 	hookServerOptions := webhook.Options{CertDir: validatingwebhook.WHCertsDir}
 	hookServer := webhook.NewServer(hookServerOptions)
-	hook := admission.WithCustomValidator(mgr.GetScheme(), &crv1alpha1.Blueprint{}, &validatingwebhook.BlueprintValidator{})
-	hookServer.Register(whHandlePath, hook)
+	hookServer.Register(whHandlePath, &webhook.Admission{Handler: bpValidator})
 	hookServer.Register(healthCheckPath, &healthCheckHandler{})
 	hookServer.Register(metricsPath, promhttp.Handler())
 

pkg/validatingwebhook/blueprint_handler.go

@@ -4,44 +4,34 @@ import (
 	"context"
 	"fmt"
 
-	"k8s.io/apimachinery/pkg/runtime"
-	logf "sigs.k8s.io/controller-runtime/pkg/log"
-	"sigs.k8s.io/controller-runtime/pkg/webhook"
 	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
 
 	kanister "github.com/kanisterio/kanister/pkg"
 	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
 	"github.com/kanisterio/kanister/pkg/blueprint/validate"
+	"net/http"
 )
 
-//+kubebuilder:webhook:path=validate/v1alpha1/blueprint,mutating=false,failurePolicy=fail,sideEffects=None,groups=cr.kanister.io,resources=blueprints,verbs=create,versions=v1alpha1,name=blueprint.cr.kanister.io
-
-type BlueprintValidator struct{}
-
-var _ webhook.CustomValidator = &BlueprintValidator{}
+type BlueprintValidator struct {
+	decoder *admission.Decoder
+}
 
-func (b *BlueprintValidator) validate(ctx context.Context, obj runtime.Object) (admission.Warnings, error) {
-	log := logf.FromContext(ctx)
-	bp, ok := obj.(*crv1alpha1.Blueprint)
-	if !ok {
-		return nil, fmt.Errorf("expected a Blueprint but got a %T", obj)
+func (b *BlueprintValidator) Handle(ctx context.Context, r admission.Request) admission.Response {
+	bp := &crv1alpha1.Blueprint{}
+	err := b.decoder.Decode(r, bp)
+	if err != nil {
+		return admission.Errored(http.StatusBadRequest, err)
 	}
-	log.Info("Validating blueprint")
+
 	if err := validate.Do(bp, kanister.DefaultVersion); err != nil {
-		return nil, fmt.Errorf("invalid blueprint, %s", err.Error())
+		return admission.Denied(fmt.Sprintf("Invalid blueprint, %s\n", err.Error()))
 	}
 
-	return nil, nil
-}
-
-func (b *BlueprintValidator) ValidateCreate(ctx context.Context, obj runtime.Object) (warnings admission.Warnings, err error) {
-	return b.validate(ctx, obj)
-}
-
-func (b *BlueprintValidator) ValidateUpdate(ctx context.Context, oldObj, newObj runtime.Object) (warnings admission.Warnings, err error) {
-	return b.validate(ctx, newObj)
+	return admission.Allowed("")
 }
 
-func (b BlueprintValidator) ValidateDelete(ctx context.Context, obj runtime.Object) (warnings admission.Warnings, err error) {
-	return b.validate(ctx, obj)
+// InjectDecoder injects the decoder.
+func (b *BlueprintValidator) InjectDecoder(d *admission.Decoder) error {
+	b.decoder = d
+	return nil
 }