make admission plugins handle mutating spec of uninitialized pods

pkg/kubeapiserver/admission/BUILD

@@ -42,6 +42,7 @@ filegroup(
     srcs = [
         ":package-srcs",
         "//pkg/kubeapiserver/admission/configuration:all-srcs",
+        "//pkg/kubeapiserver/admission/util:all-srcs",
     ],
     tags = ["automanaged"],
 )

pkg/kubeapiserver/admission/util/BUILD

@@ -0,0 +1,31 @@
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["initializer.go"],
+    tags = ["automanaged"],
+    deps = [
+        "//vendor/k8s.io/apimachinery/pkg/api/meta:go_default_library",
+        "//vendor/k8s.io/apiserver/pkg/admission:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)

pkg/kubeapiserver/admission/util/initializer.go

@@ -0,0 +1,56 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+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 util
+
+import (
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apiserver/pkg/admission"
+)
+
+// IsUpdatingInitializedObject returns if the operation is trying to update an
+// already initialized object.
+func IsUpdatingInitializedObject(a admission.Attributes) (bool, error) {
+	if a.GetOperation() != admission.Update {
+		return false, nil
+	}
+	oldObj := a.GetOldObject()
+	accessor, err := meta.Accessor(oldObj)
+	if err != nil {
+		return false, err
+	}
+	if accessor.GetInitializers() == nil {
+		return true, nil
+	}
+	return false, nil
+}
+
+// IsUpdatingUninitializedObject returns if the operation is trying to update an
+// object that is not initialized yet.
+func IsUpdatingUninitializedObject(a admission.Attributes) (bool, error) {
+	if a.GetOperation() != admission.Update {
+		return false, nil
+	}
+	oldObj := a.GetOldObject()
+	accessor, err := meta.Accessor(oldObj)
+	if err != nil {
+		return false, err
+	}
+	if accessor.GetInitializers() == nil {
+		return false, nil
+	}
+	return true, nil
+}