adds WithNamespace ability to contexts

apis/contexts.go

@@ -141,6 +141,22 @@ func IsWithinParent(ctx context.Context) bool {
 	return ok
 }
 
+type namespaceKey struct{}
+// WithNamespace attaches the request's namespace. Intended to be used
+// where defaulting depends on the namespace (eventing channels, brokers)
+// and the client may not provide it in the resource ObjectMeta
+func WithNamespace(ctx context.Context, ns string) context.Context {
+	return context.WithValue(ctx, namespaceKey{}, ns)
+}
+
+func GetNamespace(ctx context.Context) string {
+	if ns, ok := ctx.Value(namespaceKey{}).(string); ok {
+		return ns
+	}
+
+	return ""
+}
+
 // ParentMeta accesses the ObjectMeta of the enclosing parent resource
 // from the context.  See WithinParent for how to attach the parent's
 // ObjectMeta to the context.

apis/contexts_test.go

@@ -241,3 +241,18 @@ func TestGetHTTPRequest(t *testing.T) {
 		t.Errorf("GetHTTPRequest() = %v, wanted %v", got, want)
 	}
 }
+
+func TestGetNamespace(t *testing.T) {
+	ctx := context.Background()
+
+	if got := GetNamespace(ctx); got != "" {
+		t.Errorf("GetNamespace() = \"%v\", wanted \"\"", got)
+	}
+
+	ns := "some-namespace"
+	ctx = WithNamespace(ctx, ns)
+
+	if want, got := ns, GetNamespace(ctx); got != want {
+		t.Errorf("GetNamespace() = \"%v\", wanted \"%v\"", got, want)
+	}
+}

webhook/resourcesemantics/defaulting/defaulting.go

@@ -288,7 +288,7 @@ func (ac *reconciler) mutate(ctx context.Context, req *admissionv1.AdmissionRequ
 		ctx = apis.WithinCreate(ctx)
 	}
 	ctx = apis.WithUserInfo(ctx, &req.UserInfo)
-
+	ctx = apis.WithNamespace(ctx, req.Namespace)
 	// Default the new object.
 	if patches, err = setDefaults(ctx, patches, newObj); err != nil {
 		logger.Errorw("Failed the resource specific defaulter", zap.Error(err))