fix(kuma-cp): don't panic in webhook if k8s object can't convert to c…

…ore resource (#4455)

* fix(kuma-cp): don't panic in webhook if k8s object can't convert to core resource
* refactor: better output on error in mapper

Signed-off-by: Mike Beaumont <mjboamail@gmail.com>

pkg/plugins/policies/donothingpolicy/k8s/v1alpha1/zz_generated.types.go

@@ -54,8 +54,8 @@ func (cb *DoNothingPolicy) SetMesh(mesh string) {
 	cb.Mesh = mesh
 }
 
-func (cb *DoNothingPolicy) GetSpec() proto.Message {
-	return cb.Spec
+func (cb *DoNothingPolicy) GetSpec() (proto.Message, error) {
+	return cb.Spec, nil
 }
 
 func (cb *DoNothingPolicy) SetSpec(spec proto.Message) {

pkg/plugins/resources/k8s/caching_converter.go

@@ -43,14 +43,22 @@ func (c *cachingConverter) ToCoreResource(obj k8s_model.KubernetesObject, out co
 	if obj.GetResourceVersion() == "" {
 		// an absent of the ResourceVersion means we decode 'obj' from webhook request,
 		// all webhooks use SimpleConverter, so this is not supposed to happen
-		if err := out.SetSpec(obj.GetSpec()); err != nil {
+		spec, err := obj.GetSpec()
+		if err != nil {
+			return err
+		}
+		if err := out.SetSpec(spec); err != nil {
 			return err
 		}
 	}
 	if v, ok := c.cache.Get(key); ok {
 		return out.SetSpec(v.(core_model.ResourceSpec))
 	}
-	if err := out.SetSpec(obj.GetSpec()); err != nil {
+	spec, err := obj.GetSpec()
+	if err != nil {
+		return err
+	}
+	if err := out.SetSpec(spec); err != nil {
 		return err
 	}
 	c.cache.SetDefault(key, out.GetSpec())

pkg/plugins/resources/k8s/converter.go

@@ -50,8 +50,11 @@ func (c *SimpleConverter) ToKubernetesList(rl core_model.ResourceList) (k8s_mode
 
 func (c *SimpleConverter) ToCoreResource(obj k8s_model.KubernetesObject, out core_model.Resource) error {
 	out.SetMeta(&KubernetesMetaAdapter{ObjectMeta: *obj.GetObjectMeta(), Mesh: obj.GetMesh()})
-	err := out.SetSpec(obj.GetSpec())
-	return err
+	spec, err := obj.GetSpec()
+	if err != nil {
+		return err
+	}
+	return out.SetSpec(spec)
 }
 
 func (c *SimpleConverter) ToCoreList(in k8s_model.KubernetesList, out core_model.ResourceList, predicate k8s_common.ConverterPredicate) error {