Initial commit

Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>

third_party/kubernetes/pkg/kubectl/cmd/util/shortcut_expander.go

@@ -0,0 +1,174 @@
+/*
+Copyright 2016 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 (
+	"errors"
+	"strings"
+
+	"github.com/golang/glog"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/discovery"
+)
+
+// ResourceShortcuts represents a structure that holds the information how to
+// transition from resource's shortcut to its full name.
+type ResourceShortcuts struct {
+	ShortForm schema.GroupResource
+	LongForm  schema.GroupResource
+}
+
+// shortcutExpander is a RESTMapper that can be used for Kubernetes resources.   It expands the resource first, then invokes the wrapped
+type shortcutExpander struct {
+	RESTMapper meta.RESTMapper
+
+	discoveryClient discovery.DiscoveryInterface
+}
+
+var _ meta.RESTMapper = &shortcutExpander{}
+
+func NewShortcutExpander(delegate meta.RESTMapper, client discovery.DiscoveryInterface) (shortcutExpander, error) {
+	if client == nil {
+		return shortcutExpander{}, errors.New("Please provide discovery client to shortcut expander")
+	}
+	return shortcutExpander{RESTMapper: delegate, discoveryClient: client}, nil
+}
+
+func (e shortcutExpander) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
+	return e.RESTMapper.KindFor(e.expandResourceShortcut(resource))
+}
+
+func (e shortcutExpander) KindsFor(resource schema.GroupVersionResource) ([]schema.GroupVersionKind, error) {
+	return e.RESTMapper.KindsFor(e.expandResourceShortcut(resource))
+}
+
+func (e shortcutExpander) ResourcesFor(resource schema.GroupVersionResource) ([]schema.GroupVersionResource, error) {
+	return e.RESTMapper.ResourcesFor(e.expandResourceShortcut(resource))
+}
+
+func (e shortcutExpander) ResourceFor(resource schema.GroupVersionResource) (schema.GroupVersionResource, error) {
+	return e.RESTMapper.ResourceFor(e.expandResourceShortcut(resource))
+}
+
+func (e shortcutExpander) ResourceSingularizer(resource string) (string, error) {
+	return e.RESTMapper.ResourceSingularizer(e.expandResourceShortcut(schema.GroupVersionResource{Resource: resource}).Resource)
+}
+
+func (e shortcutExpander) RESTMapping(gk schema.GroupKind, versions ...string) (*meta.RESTMapping, error) {
+	return e.RESTMapper.RESTMapping(gk, versions...)
+}
+
+func (e shortcutExpander) RESTMappings(gk schema.GroupKind, versions ...string) ([]*meta.RESTMapping, error) {
+	return e.RESTMapper.RESTMappings(gk, versions...)
+}
+
+// getShortcutMappings returns a set of tuples which holds short names for resources.
+// First the list of potential resources will be taken from the API server.
+// Next we will append the hardcoded list of resources - to be backward compatible with old servers.
+// NOTE that the list is ordered by group priority.
+func (e shortcutExpander) getShortcutMappings() ([]ResourceShortcuts, error) {
+	// TODO delete this once discovery is working for svc and netpol
+	haveSvc := false
+	haveNetpol := false
+
+	res := []ResourceShortcuts{}
+	// get server resources
+	apiResList, err := e.discoveryClient.ServerResources()
+	if err == nil {
+		for _, apiResources := range apiResList {
+			for _, apiRes := range apiResources.APIResources {
+				for _, shortName := range apiRes.ShortNames {
+					gv, err := schema.ParseGroupVersion(apiResources.GroupVersion)
+					if err != nil {
+						glog.V(1).Infof("Unable to parse groupversion = %s due to = %s", apiResources.GroupVersion, err.Error())
+						continue
+					}
+					rs := ResourceShortcuts{
+						ShortForm: schema.GroupResource{Group: gv.Group, Resource: shortName},
+						LongForm:  schema.GroupResource{Group: gv.Group, Resource: apiRes.Name},
+					}
+					res = append(res, rs)
+					if shortName == "svc" {
+						haveSvc = true
+					}
+					if shortName == "netpol" {
+						haveNetpol = true
+					}
+				}
+			}
+		}
+	}
+
+	// 'svc' is not exposed due to the way the services rest storage handler is installed.
+	// 'netpol' is not currently in discovery.
+	// add these 2 shortcuts until they're actually in discovery.
+	if !haveSvc {
+		res = append(res,
+			ResourceShortcuts{
+				ShortForm: schema.GroupResource{Group: "", Resource: "svc"},
+				LongForm:  schema.GroupResource{Group: "", Resource: "services"},
+			},
+		)
+	}
+	if !haveNetpol {
+		res = append(res,
+			ResourceShortcuts{
+				ShortForm: schema.GroupResource{Group: "extensions", Resource: "netpol"},
+				LongForm:  schema.GroupResource{Group: "extensions", Resource: "networkpolicies"},
+			},
+		)
+	}
+
+	return res, nil
+}
+
+// expandResourceShortcut will return the expanded version of resource
+// (something that a pkg/api/meta.RESTMapper can understand), if it is
+// indeed a shortcut. If no match has been found, we will match on group prefixing.
+// Lastly we will return resource unmodified.
+func (e shortcutExpander) expandResourceShortcut(resource schema.GroupVersionResource) schema.GroupVersionResource {
+	// get the shortcut mappings and return on first match.
+	if resources, err := e.getShortcutMappings(); err == nil {
+		for _, item := range resources {
+			if len(resource.Group) != 0 && resource.Group != item.ShortForm.Group {
+				continue
+			}
+			if resource.Resource == item.ShortForm.Resource {
+				resource.Resource = item.LongForm.Resource
+				return resource
+			}
+		}
+
+		// we didn't find exact match so match on group prefixing. This allows autoscal to match autoscaling
+		if len(resource.Group) == 0 {
+			return resource
+		}
+		for _, item := range resources {
+			if !strings.HasPrefix(item.ShortForm.Group, resource.Group) {
+				continue
+			}
+			if resource.Resource == item.ShortForm.Resource {
+				resource.Resource = item.LongForm.Resource
+				return resource
+			}
+		}
+	}
+
+	return resource
+}