use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

vendor/sigs.k8s.io/controller-runtime/pkg/webhook/admission/decode.go

@@ -17,32 +17,60 @@ limitations under the License.
 package admission
 
 import (
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
-	"sigs.k8s.io/controller-runtime/pkg/webhook/admission/types"
+	"k8s.io/apimachinery/pkg/util/json"
 )
 
-// DecodeFunc is a function that implements the Decoder interface.
-type DecodeFunc func(types.Request, runtime.Object) error
-
-var _ types.Decoder = DecodeFunc(nil)
-
-// Decode implements the Decoder interface.
-func (f DecodeFunc) Decode(req types.Request, obj runtime.Object) error {
-	return f(req, obj)
-}
-
-type decoder struct {
+// Decoder knows how to decode the contents of an admission
+// request into a concrete object.
+type Decoder struct {
 	codecs serializer.CodecFactory
 }
 
 // NewDecoder creates a Decoder given the runtime.Scheme
-func NewDecoder(scheme *runtime.Scheme) (types.Decoder, error) {
-	return decoder{codecs: serializer.NewCodecFactory(scheme)}, nil
+func NewDecoder(scheme *runtime.Scheme) (*Decoder, error) {
+	return &Decoder{codecs: serializer.NewCodecFactory(scheme)}, nil
 }
 
 // Decode decodes the inlined object in the AdmissionRequest into the passed-in runtime.Object.
-func (d decoder) Decode(req types.Request, into runtime.Object) error {
-	deserializer := d.codecs.UniversalDeserializer()
-	return runtime.DecodeInto(deserializer, req.AdmissionRequest.Object.Raw, into)
+// If you want decode the OldObject in the AdmissionRequest, use DecodeRaw.
+// It errors out if req.Object.Raw is empty i.e. containing 0 raw bytes.
+func (d *Decoder) Decode(req Request, into runtime.Object) error {
+	// we error out if rawObj is an empty object.
+	if len(req.Object.Raw) == 0 {
+		return fmt.Errorf("there is no content to decode")
+	}
+	return d.DecodeRaw(req.Object, into)
+}
+
+// DecodeRaw decodes a RawExtension object into the passed-in runtime.Object.
+// It errors out if rawObj is empty i.e. containing 0 raw bytes.
+func (d *Decoder) DecodeRaw(rawObj runtime.RawExtension, into runtime.Object) error {
+	// NB(directxman12): there's a bug/weird interaction between decoders and
+	// the API server where the API server doesn't send a GVK on the embedded
+	// objects, which means the unstructured decoder refuses to decode.  It
+	// also means we can't pass the unstructured directly in, since it'll try
+	// and call unstructured's special Unmarshal implementation, which calls
+	// back into that same decoder :-/
+	// See kubernetes/kubernetes#74373.
+
+	// we error out if rawObj is an empty object.
+	if len(rawObj.Raw) == 0 {
+		return fmt.Errorf("there is no content to decode")
+	}
+	if unstructuredInto, isUnstructured := into.(*unstructured.Unstructured); isUnstructured {
+		// unmarshal into unstructured's underlying object to avoid calling the decoder
+		if err := json.Unmarshal(rawObj.Raw, &unstructuredInto.Object); err != nil {
+			return err
+		}
+
+		return nil
+	}
+
+	deserializer := d.codecs.UniversalDeserializer()
+	return runtime.DecodeInto(deserializer, rawObj.Raw, into)
 }