allow resource.version.group in kubectl

hack/test-cmd.sh

@@ -728,7 +728,7 @@ __EOF__
   # Command: autoscale rc "frontend"
   kubectl autoscale -f hack/testdata/frontend-controller.yaml --save-config "${kube_flags[@]}" --max=2
   # Post-Condition: hpa "frontend" has configuration annotation
-  [[ "$(kubectl get hpa.extensions frontend -o yaml "${kube_flags[@]}" | grep kubectl.kubernetes.io/last-applied-configuration)" ]]
+  [[ "$(kubectl get hpa.v1beta1.extensions frontend -o yaml "${kube_flags[@]}" | grep kubectl.kubernetes.io/last-applied-configuration)" ]]
   # Ensure we can interact with HPA objects in lists through both the extensions/v1beta1 and autoscaling/v1 APIs  
   output_message=$(kubectl get hpa -o=jsonpath='{.items[0].apiVersion}' 2>&1 "${kube_flags[@]}")
   kube::test::if_has_string "${output_message}" 'extensions/v1beta1'

pkg/api/unversioned/group_version.go

@@ -22,6 +22,21 @@ import (
 	"strings"
 )
 
+// ParseResourceArg takes the common style of string which may be either `resource.group.com` or `resource.version.group.com`
+// and parses it out into both possibilities.  This code takes no responsibility for knowing which representation was intended
+// but with a knowledge of all GroupVersions, calling code can take a very good guess.  If there are only two segments, then
+// `*GroupVersionResource` is nil.
+// `resource.group.com` -> `group=com, version=group, resource=resource` and `group=group.com, resource=resource`
+func ParseResourceArg(arg string) (*GroupVersionResource, GroupResource) {
+	var gvr *GroupVersionResource
+	s := strings.SplitN(arg, ".", 3)
+	if len(s) == 3 {
+		gvr = &GroupVersionResource{Group: s[2], Version: s[1], Resource: s[0]}
+	}
+
+	return gvr, ParseGroupResource(arg)
+}
+
 // GroupResource specifies a Group and a Resource, but does not force a version.  This is useful for identifying
 // concepts during lookup stages without having partially valid types
 //

pkg/kubectl/cmd/explain.go

@@ -79,9 +79,16 @@ func RunExplain(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []st
 	}
 
 	// TODO: We should deduce the group for a resource by discovering the supported resources at server.
-	gvk, err := mapper.KindFor(unversioned.ParseGroupResource(inModel).WithVersion(""))
+	fullySpecifiedGVR, groupResource := unversioned.ParseResourceArg(inModel)
-	if err != nil {
+	gvk := unversioned.GroupVersionKind{}
-		return err
+	if fullySpecifiedGVR != nil {
+		gvk, _ = mapper.KindFor(*fullySpecifiedGVR)
+	}
+	if gvk.IsEmpty() {
+		gvk, err = mapper.KindFor(groupResource.WithVersion(""))
+		if err != nil {
+			return err
+		}
 	}
 
 	if len(apiVersionString) == 0 {

pkg/kubectl/resource/builder.go

@@ -433,20 +433,36 @@ func (b *Builder) SingleResourceType() *Builder {
 	return b
 }
 
+// mappingFor returns the RESTMapping for the Kind referenced by the resource.
+// prefers a fully specified GroupVersionResource match.  If we don't have one match on GroupResource
+func (b *Builder) mappingFor(resourceArg string) (*meta.RESTMapping, error) {
+	fullySpecifiedGVR, groupResource := unversioned.ParseResourceArg(resourceArg)
+	gvk := unversioned.GroupVersionKind{}
+	if fullySpecifiedGVR != nil {
+		gvk, _ = b.mapper.KindFor(*fullySpecifiedGVR)
+	}
+	if gvk.IsEmpty() {
+		var err error
+		gvk, err = b.mapper.KindFor(groupResource.WithVersion(""))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return b.mapper.RESTMapping(gvk.GroupKind(), gvk.Version)
+}
+
 func (b *Builder) resourceMappings() ([]*meta.RESTMapping, error) {
 	if len(b.resources) > 1 && b.singleResourceType {
 		return nil, fmt.Errorf("you may only specify a single resource type")
 	}
 	mappings := []*meta.RESTMapping{}
 	for _, r := range b.resources {
-		gvk, err := b.mapper.KindFor(unversioned.ParseGroupResource(r).WithVersion(""))
+		mapping, err := b.mappingFor(r)
-		if err != nil {
-			return nil, err
-		}
-		mapping, err := b.mapper.RESTMapping(gvk.GroupKind(), gvk.Version)
 		if err != nil {
 			return nil, err
 		}
+
 		mappings = append(mappings, mapping)
 	}
 	return mappings, nil
@@ -459,14 +475,11 @@ func (b *Builder) resourceTupleMappings() (map[string]*meta.RESTMapping, error)
 		if _, ok := mappings[r.Resource]; ok {
 			continue
 		}
-		gvk, err := b.mapper.KindFor(unversioned.ParseGroupResource(r.Resource).WithVersion(""))
+		mapping, err := b.mappingFor(r.Resource)
-		if err != nil {
-			return nil, err
-		}
-		mapping, err := b.mapper.RESTMapping(gvk.GroupKind(), gvk.Version)
 		if err != nil {
 			return nil, err
 		}
+
 		mappings[mapping.Resource] = mapping
 		mappings[r.Resource] = mapping
 		canonical[mapping.Resource] = struct{}{}