Add validating admission webhook

* Add validating admission webhook HTTP server application
* Handle incoming AdmissionReview requests and validate their correctness, handle errors if any
* Validate Network Attachment Definition objects
* Send AdmissionReview response with allowed/denied decision and its reason
* In case of any other errors (malformed HTTP request, empty body, etc.) send proper HTTP error code
* Use TLS encryption
* Add some basic unit tests for Network Attachment Definition objects validation
* Build Docker image with webhook application

Signed-off-by: Przemyslaw Lal <przemyslawx.lal@intel.com>

webhook/webhook_suite_test.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2017 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestWebhook(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Webhook Suite")
+}