Introduce gvk package to isolate apimachinery schema.

pkg/gvk/gvk.go

@@ -0,0 +1,132 @@
+/*
+Copyright 2018 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 gvk
+
+import (
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+// Gvk identifies a Kubernetes API type.
+// https://github.com/kubernetes/community/blob/master/contributors/design-proposals/api-machinery/api-group.md
+type Gvk struct {
+	Group   string `json:"group,omitempty" yaml:"group,omitempty"`
+	Version string `json:"version,omitempty" yaml:"version,omitempty"`
+	Kind    string `json:"kind,omitempty" yaml:"kind,omitempty"`
+}
+
+// FromKind makes a Gvk with only the kind specified.
+func FromKind(k string) Gvk {
+	return Gvk{
+		Kind: k,
+	}
+}
+
+// FromSchemaGvk converts from a schema.GroupVersionKind.
+func FromSchemaGvk(x schema.GroupVersionKind) Gvk {
+	return Gvk{
+		Group:   x.Group,
+		Version: x.Version,
+		Kind:    x.Kind,
+	}
+}
+
+// ToSchemaGvk converts to a schema.GroupVersionKind.
+func (x Gvk) ToSchemaGvk() schema.GroupVersionKind {
+	return schema.GroupVersionKind{
+		Group:   x.Group,
+		Version: x.Version,
+		Kind:    x.Kind,
+	}
+}
+
+// String returns a string representation of the GVK.
+func (x Gvk) String() string {
+	if x.Group == "" {
+		return x.Version + "_" + x.Kind
+	}
+	return x.Group + "_" + x.Version + "_" + x.Kind
+}
+
+// Equals returns true if the Gvk's have equal fields.
+func (x Gvk) Equals(o Gvk) bool {
+	return x.Group == o.Group && x.Version == o.Version && x.Kind == o.Kind
+}
+
+var order = []string{
+	"Namespace",
+	"CustomResourceDefinition",
+	"ServiceAccount",
+	"Role",
+	"ClusterRole",
+	"RoleBinding",
+	"ClusterRoleBinding",
+	"ConfigMap",
+	"Secret",
+	"Service",
+}
+var typeOrders = func() map[string]int {
+	m := map[string]int{}
+	for i, n := range order {
+		m[n] = i
+	}
+	return m
+}()
+
+// IsLessThan returns true if self is less than the argument.
+func (x Gvk) IsLessThan(o Gvk) bool {
+	indexI, foundI := typeOrders[x.Kind]
+	indexJ, foundJ := typeOrders[o.Kind]
+	if foundI && foundJ {
+		return indexI < indexJ
+	}
+	if foundI && !foundJ {
+		return true
+	}
+	if !foundI && foundJ {
+		return false
+	}
+	return x.String() < o.String()
+}
+
+// IsSelected returns true if `selector` selects `x`; otherwise, false.
+// If `selector` and `x` are the same, return true.
+// If `selector` is nil, it is considered as a wildcard and always return true.
+// e.g. selector <Group: "", Version: "", Kind: "Deployment"> CAN select
+// <Group: "extensions", Version: "v1beta1", Kind: "Deployment">.
+// selector <Group: "apps", Version: "", Kind: "Deployment"> CANNOT select
+// <Group: "extensions", Version: "v1beta1", Kind: "Deployment">.
+func (x Gvk) IsSelected(selector *Gvk) bool {
+	if selector == nil {
+		return true
+	}
+	if len(selector.Group) > 0 {
+		if x.Group != selector.Group {
+			return false
+		}
+	}
+	if len(selector.Version) > 0 {
+		if x.Version != selector.Version {
+			return false
+		}
+	}
+	if len(selector.Kind) > 0 {
+		if x.Kind != selector.Kind {
+			return false
+		}
+	}
+	return true
+}