Provide access to admission.Request in custom validator/defaulter

Author: sbueringer

pkg/builder/webhook_test.go

@@ -694,6 +694,14 @@ func (dv *TestDefaultValidator) ValidateDelete() error {
 type TestCustomDefaulter struct{}
 
 func (*TestCustomDefaulter) Default(ctx context.Context, obj runtime.Object) error {
+	req, err := admission.RequestFromContext(ctx)
+	if err != nil {
+		return fmt.Errorf("expected admission.Request in ctx: %v", err)
+	}
+	if req.Kind.Kind != "TestDefaulter" {
+		return fmt.Errorf("expected Kind TestDefaulter got %q", req.Kind.Kind)
+	}
+
 	d := obj.(*TestDefaulter) //nolint:ifshort
 	if d.Replica < 2 {
 		d.Replica = 2
@@ -708,6 +716,14 @@ var _ admission.CustomDefaulter = &TestCustomDefaulter{}
 type TestCustomValidator struct{}
 
 func (*TestCustomValidator) ValidateCreate(ctx context.Context, obj runtime.Object) error {
+	req, err := admission.RequestFromContext(ctx)
+	if err != nil {
+		return fmt.Errorf("expected admission.Request in ctx: %v", err)
+	}
+	if req.Kind.Kind != "TestValidator" {
+		return fmt.Errorf("expected Kind TestValidator got %q", req.Kind.Kind)
+	}
+
 	v := obj.(*TestValidator) //nolint:ifshort
 	if v.Replica < 0 {
 		return errors.New("number of replica should be greater than or equal to 0")
@@ -716,6 +732,14 @@ func (*TestCustomValidator) ValidateCreate(ctx context.Context, obj runtime.Obje
 }
 
 func (*TestCustomValidator) ValidateUpdate(ctx context.Context, oldObj, newObj runtime.Object) error {
+	req, err := admission.RequestFromContext(ctx)
+	if err != nil {
+		return fmt.Errorf("expected admission.Request in ctx: %v", err)
+	}
+	if req.Kind.Kind != "TestValidator" {
+		return fmt.Errorf("expected Kind TestValidator got %q", req.Kind.Kind)
+	}
+
 	v := newObj.(*TestValidator)
 	old := oldObj.(*TestValidator) //nolint:ifshort
 	if v.Replica < 0 {
@@ -728,6 +752,14 @@ func (*TestCustomValidator) ValidateUpdate(ctx context.Context, oldObj, newObj r
 }
 
 func (*TestCustomValidator) ValidateDelete(ctx context.Context, obj runtime.Object) error {
+	req, err := admission.RequestFromContext(ctx)
+	if err != nil {
+		return fmt.Errorf("expected admission.Request in ctx: %v", err)
+	}
+	if req.Kind.Kind != "TestValidator" {
+		return fmt.Errorf("expected Kind TestValidator got %q", req.Kind.Kind)
+	}
+
 	v := obj.(*TestValidator) //nolint:ifshort
 	if v.Replica > 0 {
 		return errors.New("number of replica should be less than or equal to 0 to delete")

pkg/webhook/admission/defaulter_custom.go

@@ -19,7 +19,6 @@ package admission
 import (
 	"context"
 	"encoding/json"
-
 	"errors"
 	"net/http"
 
@@ -61,6 +60,8 @@ func (h *defaulterForType) Handle(ctx context.Context, req Request) Response {
 		panic("object should never be nil")
 	}
 
+	ctx = NewContextWithRequest(ctx, req)
+
 	// Get the object in the request
 	obj := h.object.DeepCopyObject()
 	if err := h.decoder.Decode(req, obj); err != nil {

pkg/webhook/admission/validator_custom.go

@@ -64,6 +64,8 @@ func (h *validatorForType) Handle(ctx context.Context, req Request) Response {
 		panic("object should never be nil")
 	}
 
+	ctx = NewContextWithRequest(ctx, req)
+
 	// Get the object in the request
 	obj := h.object.DeepCopyObject()
 

pkg/webhook/admission/webhook.go

@@ -253,3 +253,21 @@ func StandaloneWebhook(hook *Webhook, opts StandaloneOptions) (http.Handler, err
 	}
 	return metrics.InstrumentedHook(opts.MetricsPath, hook), nil
 }
+
+// requestContextKey is how we find the admission.Request in a context.Context.
+type requestContextKey struct{}
+
+// RequestFromContext returns an admission.Request from ctx.
+func RequestFromContext(ctx context.Context) (Request, error) {
+	if v, ok := ctx.Value(requestContextKey{}).(Request); ok {
+		return v, nil
+	}
+
+	return Request{}, errors.New("admission.Request not found in context")
+}
+
+// NewContextWithRequest returns a new Context, derived from ctx, which carries the
+// provided admission.Request.
+func NewContextWithRequest(ctx context.Context, req Request) context.Context {
+	return context.WithValue(ctx, requestContextKey{}, req)
+}

pkg/webhook/admission/webhook_test.go

@@ -194,6 +194,21 @@ var _ = Describe("Admission Webhooks", func() {
 	})
 })
 
+var _ = Describe("Should be able to write/read admission.Request to/from context", func() {
+	ctx := context.Background()
+	testRequest := Request{
+		admissionv1.AdmissionRequest{
+			UID: "test-uid",
+		},
+	}
+
+	ctx = NewContextWithRequest(ctx, testRequest)
+
+	gotRequest, err := RequestFromContext(ctx)
+	Expect(err).To(Not(HaveOccurred()))
+	Expect(gotRequest).To(Equal(testRequest))
+})
+
 type stringInjector interface {
 	InjectString(s string) error
 }