Merge pull request #3198 from smarterclayton/allow_delete_to_span_resources

Allow delete to work from directories and multiple sources

pkg/kubectl/cmd/cmd_test.go

@@ -153,3 +153,7 @@ func NewAPIFactory() (*Factory, *testFactory, runtime.Codec) {
 func objBody(codec runtime.Codec, obj runtime.Object) io.ReadCloser {
 	return ioutil.NopCloser(bytes.NewReader([]byte(runtime.EncodeOrDie(codec, obj))))
 }
+
+func stringBody(body string) io.ReadCloser {
+	return ioutil.NopCloser(bytes.NewReader([]byte(body)))
+}

pkg/kubectl/cmd/delete.go

@@ -23,10 +23,15 @@ import (
 	"github.com/golang/glog"
 	"github.com/spf13/cobra"
 
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/resource"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 )
 
 func (f *Factory) NewCmdDelete(out io.Writer) *cobra.Command {
+	flags := &struct {
+		Filenames util.StringList
+	}{}
 	cmd := &cobra.Command{
 		Use:   "delete ([-f filename] | (<resource> [(<id> | -l <label>)]",
 		Short: "Delete a resource by filename, stdin or resource and id",
@@ -54,13 +59,18 @@ Examples:
   $ kubectl delete pod 1234-56-7890-234234-456456
   <delete a pod with ID 1234-56-7890-234234-456456>`,
 		Run: func(cmd *cobra.Command, args []string) {
-			filename := GetFlagString(cmd, "filename")
-			schema, err := f.Validator(cmd)
-			checkErr(err)
-			selector := GetFlagString(cmd, "selector")
-			found := 0
 			mapper, typer := f.Object(cmd)
-			ResourcesFromArgsOrFile(cmd, args, filename, selector, typer, mapper, f.RESTClient, schema, true).Visit(func(r *resource.Info) error {
+			r := resource.NewBuilder(mapper, typer, ClientMapperForCommand(cmd, f)).
+				ContinueOnError().
+				NamespaceParam(GetKubeNamespace(cmd)).DefaultNamespace().
+				FilenameParam(flags.Filenames...).
+				SelectorParam(GetFlagString(cmd, "selector")).
+				ResourceTypeOrNameArgs(args...).
+				Flatten().
+				Do()
+
+			found := 0
+			r.IgnoreErrors(errors.IsNotFound).Visit(func(r *resource.Info) error {
 				found++
 				if err := resource.NewHelper(r.Client, r.Mapping).Delete(r.Namespace, r.Name); err != nil {
 					return err
@@ -73,7 +83,7 @@ Examples:
 			}
 		},
 	}
-	cmd.Flags().StringP("filename", "f", "", "Filename or URL to file to use to delete the resource")
+	cmd.Flags().VarP(&flags.Filenames, "filename", "f", "Filename, directory, or URL to a file containing the resource to delete")
 	cmd.Flags().StringP("selector", "l", "", "Selector (label query) to filter on")
 	return cmd
 }

pkg/kubectl/cmd/delete_test.go

@@ -0,0 +1,221 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 cmd_test
+
+import (
+	"bytes"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+)
+
+func TestDeleteObject(t *testing.T) {
+	pods, _ := testData()
+
+	f, tf, codec := NewAPIFactory()
+	tf.Printer = &testPrinter{}
+	tf.Client = &client.FakeRESTClient{
+		Codec: codec,
+		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
+			switch p, m := req.URL.Path, req.Method; {
+			case p == "/ns/test/pods/redis-master" && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &pods.Items[0])}, nil
+			default:
+				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+	buf := bytes.NewBuffer([]byte{})
+
+	cmd := f.NewCmdDelete(buf)
+	cmd.Flags().String("namespace", "test", "")
+	cmd.Flags().Set("filename", "../../../examples/guestbook/redis-master.json")
+	cmd.Run(cmd, []string{})
+
+	// uses the name from the file, not the response
+	if buf.String() != "redis-master\n" {
+		t.Errorf("unexpected output: %s", buf.String())
+	}
+}
+
+func TestDeleteObjectIgnoreNotFound(t *testing.T) {
+	f, tf, codec := NewAPIFactory()
+	tf.Printer = &testPrinter{}
+	tf.Client = &client.FakeRESTClient{
+		Codec: codec,
+		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
+			switch p, m := req.URL.Path, req.Method; {
+			case p == "/ns/test/pods/redis-master" && m == "DELETE":
+				return &http.Response{StatusCode: 404, Body: stringBody("")}, nil
+			default:
+				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+	buf := bytes.NewBuffer([]byte{})
+
+	cmd := f.NewCmdDelete(buf)
+	cmd.Flags().String("namespace", "test", "")
+	cmd.Flags().Set("filename", "../../../examples/guestbook/redis-master.json")
+	cmd.Run(cmd, []string{})
+
+	if buf.String() != "" {
+		t.Errorf("unexpected output: %s", buf.String())
+	}
+}
+
+func TestDeleteMultipleObject(t *testing.T) {
+	pods, svc := testData()
+
+	f, tf, codec := NewAPIFactory()
+	tf.Printer = &testPrinter{}
+	tf.Client = &client.FakeRESTClient{
+		Codec: codec,
+		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
+			switch p, m := req.URL.Path, req.Method; {
+			case p == "/ns/test/pods/redis-master" && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &pods.Items[0])}, nil
+			case p == "/ns/test/services/frontend" && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &svc.Items[0])}, nil
+			default:
+				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+	buf := bytes.NewBuffer([]byte{})
+
+	cmd := f.NewCmdDelete(buf)
+	cmd.Flags().String("namespace", "test", "")
+	cmd.Flags().Set("filename", "../../../examples/guestbook/redis-master.json")
+	cmd.Flags().Set("filename", "../../../examples/guestbook/frontend-service.json")
+	cmd.Run(cmd, []string{})
+
+	if buf.String() != "redis-master\nfrontend\n" {
+		t.Errorf("unexpected output: %s", buf.String())
+	}
+}
+
+func TestDeleteMultipleObjectIgnoreMissing(t *testing.T) {
+	_, svc := testData()
+
+	f, tf, codec := NewAPIFactory()
+	tf.Printer = &testPrinter{}
+	tf.Client = &client.FakeRESTClient{
+		Codec: codec,
+		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
+			switch p, m := req.URL.Path, req.Method; {
+			case p == "/ns/test/pods/redis-master" && m == "DELETE":
+				return &http.Response{StatusCode: 404, Body: stringBody("")}, nil
+			case p == "/ns/test/services/frontend" && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &svc.Items[0])}, nil
+			default:
+				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+	buf := bytes.NewBuffer([]byte{})
+
+	cmd := f.NewCmdDelete(buf)
+	cmd.Flags().String("namespace", "test", "")
+	cmd.Flags().Set("filename", "../../../examples/guestbook/redis-master.json")
+	cmd.Flags().Set("filename", "../../../examples/guestbook/frontend-service.json")
+	cmd.Run(cmd, []string{})
+
+	if buf.String() != "frontend\n" {
+		t.Errorf("unexpected output: %s", buf.String())
+	}
+}
+
+func TestDeleteDirectory(t *testing.T) {
+	pods, svc := testData()
+
+	f, tf, codec := NewAPIFactory()
+	tf.Printer = &testPrinter{}
+	tf.Client = &client.FakeRESTClient{
+		Codec: codec,
+		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
+			switch p, m := req.URL.Path, req.Method; {
+			case strings.HasPrefix(p, "/ns/test/pods/") && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &pods.Items[0])}, nil
+			case strings.HasPrefix(p, "/ns/test/services/") && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &svc.Items[0])}, nil
+			case strings.HasPrefix(p, "/ns/test/replicationcontrollers/") && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &svc.Items[0])}, nil
+			default:
+				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+	buf := bytes.NewBuffer([]byte{})
+
+	cmd := f.NewCmdDelete(buf)
+	cmd.Flags().String("namespace", "test", "")
+	cmd.Flags().Set("filename", "../../../examples/guestbook")
+	cmd.Run(cmd, []string{})
+
+	if buf.String() != "frontendController\nfrontend\nredis-master\nredis-master\nredisSlaveController\nredisslave\n" {
+		t.Errorf("unexpected output: %s", buf.String())
+	}
+}
+
+func TestDeleteMultipleSelector(t *testing.T) {
+	pods, svc := testData()
+
+	f, tf, codec := NewAPIFactory()
+	tf.Printer = &testPrinter{}
+	tf.Client = &client.FakeRESTClient{
+		Codec: codec,
+		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
+			switch p, m := req.URL.Path, req.Method; {
+			case p == "/ns/test/pods" && m == "GET":
+				if req.URL.Query().Get("labels") != "a=b" {
+					t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				}
+				return &http.Response{StatusCode: 200, Body: objBody(codec, pods)}, nil
+			case p == "/ns/test/services" && m == "GET":
+				if req.URL.Query().Get("labels") != "a=b" {
+					t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				}
+				return &http.Response{StatusCode: 200, Body: objBody(codec, svc)}, nil
+			case strings.HasPrefix(p, "/ns/test/pods/") && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &pods.Items[0])}, nil
+			case strings.HasPrefix(p, "/ns/test/services/") && m == "DELETE":
+				return &http.Response{StatusCode: 200, Body: objBody(codec, &svc.Items[0])}, nil
+			default:
+				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+	buf := bytes.NewBuffer([]byte{})
+
+	cmd := f.NewCmdDelete(buf)
+	cmd.Flags().String("namespace", "test", "")
+	cmd.Flags().Set("selector", "a=b")
+	cmd.Run(cmd, []string{"pods,services"})
+
+	if buf.String() != "foo\nbar\nbaz\n" {
+		t.Errorf("unexpected output: %s", buf.String())
+	}
+}

pkg/kubectl/resource/builder.go

@@ -21,16 +21,13 @@ import (
 	"io"
 	"net/url"
 	"os"
-	"reflect"
 	"strings"
 
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/meta"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
 )
 
 // Builder provides convenience functions for taking arguments and parameters
@@ -408,156 +405,6 @@ func (b *Builder) Do() *Result {
 	return r
 }
 
-// Result contains helper methods for dealing with the outcome of a Builder.
-type Result struct {
-	err     error
-	visitor Visitor
-
-	sources  []Visitor
-	singular bool
-
-	// populated by a call to Infos
-	info []*Info
-}
-
-// Err returns one or more errors (via a util.ErrorList) that occurred prior
-// to visiting the elements in the visitor. To see all errors including those
-// that occur during visitation, invoke Infos().
-func (r *Result) Err() error {
-	return r.err
-}
-
-// Visit implements the Visitor interface on the items described in the Builder.
-// Note that some visitor sources are not traversable more than once, or may
-// return different results.  If you wish to operate on the same set of resources
-// multiple times, use the Infos() method.
-func (r *Result) Visit(fn VisitorFunc) error {
-	if r.err != nil {
-		return r.err
-	}
-	return r.visitor.Visit(fn)
-}
-
-// IntoSingular sets the provided boolean pointer to true if the Builder input
-// reflected a single item, or multiple.
-func (r *Result) IntoSingular(b *bool) *Result {
-	*b = r.singular
-	return r
-}
-
-// Infos returns an array of all of the resource infos retrieved via traversal.
-// Will attempt to traverse the entire set of visitors only once, and will return
-// a cached list on subsequent calls.
-func (r *Result) Infos() ([]*Info, error) {
-	if r.err != nil {
-		return nil, r.err
-	}
-	if r.info != nil {
-		return r.info, nil
-	}
-	infos := []*Info{}
-	err := r.visitor.Visit(func(info *Info) error {
-		infos = append(infos, info)
-		return nil
-	})
-	r.info, r.err = infos, err
-	return infos, err
-}
-
-// Object returns a single object representing the output of a single visit to all
-// found resources.  If the Builder was a singular context (expected to return a
-// single resource by user input) and only a single resource was found, the resource
-// will be returned as is.  Otherwise, the returned resources will be part of an
-// api.List. The ResourceVersion of the api.List will be set only if it is identical
-// across all infos returned.
-func (r *Result) Object() (runtime.Object, error) {
-	infos, err := r.Infos()
-	if err != nil {
-		return nil, err
-	}
-
-	versions := util.StringSet{}
-	objects := []runtime.Object{}
-	for _, info := range infos {
-		if info.Object != nil {
-			objects = append(objects, info.Object)
-			versions.Insert(info.ResourceVersion)
-		}
-	}
-
-	if len(objects) == 1 {
-		if r.singular {
-			return objects[0], nil
-		}
-		// if the item is a list already, don't create another list
-		if _, err := runtime.GetItemsPtr(objects[0]); err == nil {
-			return objects[0], nil
-		}
-	}
-
-	version := ""
-	if len(versions) == 1 {
-		version = versions.List()[0]
-	}
-	return &api.List{
-		ListMeta: api.ListMeta{
-			ResourceVersion: version,
-		},
-		Items: objects,
-	}, err
-}
-
-// ResourceMapping returns a single meta.RESTMapping representing the
-// resources located by the builder, or an error if more than one
-// mapping was found.
-func (r *Result) ResourceMapping() (*meta.RESTMapping, error) {
-	if r.err != nil {
-		return nil, r.err
-	}
-	mappings := map[string]*meta.RESTMapping{}
-	for i := range r.sources {
-		m, ok := r.sources[i].(ResourceMapping)
-		if !ok {
-			return nil, fmt.Errorf("a resource mapping could not be loaded from %v", reflect.TypeOf(r.sources[i]))
-		}
-		mapping := m.ResourceMapping()
-		mappings[mapping.Resource] = mapping
-	}
-	if len(mappings) != 1 {
-		return nil, fmt.Errorf("expected only a single resource type")
-	}
-	for _, mapping := range mappings {
-		return mapping, nil
-	}
-	return nil, nil
-}
-
-// Watch retrieves changes that occur on the server to the specified resource.
-// It currently supports watching a single source - if the resource source
-// (selectors or pure types) can be watched, they will be, otherwise the list
-// will be visited (equivalent to the Infos() call) and if there is a single
-// resource present, it will be watched, otherwise an error will be returned.
-func (r *Result) Watch(resourceVersion string) (watch.Interface, error) {
-	if r.err != nil {
-		return nil, r.err
-	}
-	if len(r.sources) != 1 {
-		return nil, fmt.Errorf("you may only watch a single resource or type of resource at a time")
-	}
-	w, ok := r.sources[0].(Watchable)
-	if !ok {
-		info, err := r.Infos()
-		if err != nil {
-			return nil, err
-		}
-		if len(info) != 1 {
-			return nil, fmt.Errorf("watch is only supported on a single resource - %d resources were found", len(info))
-		}
-		return info[0].Watch(resourceVersion)
-	}
-	return w.Watch(resourceVersion)
-}
-
 func SplitResourceArgument(arg string) []string {
 	set := util.NewStringSet()
 	set.Insert(strings.Split(arg, ",")...)

pkg/kubectl/resource/result.go

@@ -0,0 +1,202 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 resource
+
+import (
+	"fmt"
+	"reflect"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/meta"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
+)
+
+// ErrMatchFunc can be used to filter errors that may not be true failures.
+type ErrMatchFunc func(error) bool
+
+// Result contains helper methods for dealing with the outcome of a Builder.
+type Result struct {
+	err     error
+	visitor Visitor
+
+	sources  []Visitor
+	singular bool
+
+	ignoreErrors []errors.Matcher
+
+	// populated by a call to Infos
+	info []*Info
+}
+
+// IgnoreErrors will filter errors that occur when by visiting the result
+// (but not errors that occur by creating the result in the first place),
+// eliminating any that match fns. This is best used in combination with
+// Builder.ContinueOnError(), where the visitors accumulate errors and return
+// them after visiting as a slice of errors. If no errors remain after
+// filtering, the various visitor methods on Result will return nil for
+// err.
+func (r *Result) IgnoreErrors(fns ...ErrMatchFunc) *Result {
+	for _, fn := range fns {
+		r.ignoreErrors = append(r.ignoreErrors, errors.Matcher(fn))
+	}
+	return r
+}
+
+// Err returns one or more errors (via a util.ErrorList) that occurred prior
+// to visiting the elements in the visitor. To see all errors including those
+// that occur during visitation, invoke Infos().
+func (r *Result) Err() error {
+	return r.err
+}
+
+// Visit implements the Visitor interface on the items described in the Builder.
+// Note that some visitor sources are not traversable more than once, or may
+// return different results.  If you wish to operate on the same set of resources
+// multiple times, use the Infos() method.
+func (r *Result) Visit(fn VisitorFunc) error {
+	if r.err != nil {
+		return r.err
+	}
+	err := r.visitor.Visit(fn)
+	return errors.FilterOut(err, r.ignoreErrors...)
+}
+
+// IntoSingular sets the provided boolean pointer to true if the Builder input
+// reflected a single item, or multiple.
+func (r *Result) IntoSingular(b *bool) *Result {
+	*b = r.singular
+	return r
+}
+
+// Infos returns an array of all of the resource infos retrieved via traversal.
+// Will attempt to traverse the entire set of visitors only once, and will return
+// a cached list on subsequent calls.
+func (r *Result) Infos() ([]*Info, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	if r.info != nil {
+		return r.info, nil
+	}
+
+	infos := []*Info{}
+	err := r.visitor.Visit(func(info *Info) error {
+		infos = append(infos, info)
+		return nil
+	})
+	err = errors.FilterOut(err, r.ignoreErrors...)
+
+	r.info, r.err = infos, err
+	return infos, err
+}
+
+// Object returns a single object representing the output of a single visit to all
+// found resources.  If the Builder was a singular context (expected to return a
+// single resource by user input) and only a single resource was found, the resource
+// will be returned as is.  Otherwise, the returned resources will be part of an
+// api.List. The ResourceVersion of the api.List will be set only if it is identical
+// across all infos returned.
+func (r *Result) Object() (runtime.Object, error) {
+	infos, err := r.Infos()
+	if err != nil {
+		return nil, err
+	}
+
+	versions := util.StringSet{}
+	objects := []runtime.Object{}
+	for _, info := range infos {
+		if info.Object != nil {
+			objects = append(objects, info.Object)
+			versions.Insert(info.ResourceVersion)
+		}
+	}
+
+	if len(objects) == 1 {
+		if r.singular {
+			return objects[0], nil
+		}
+		// if the item is a list already, don't create another list
+		if _, err := runtime.GetItemsPtr(objects[0]); err == nil {
+			return objects[0], nil
+		}
+	}
+
+	version := ""
+	if len(versions) == 1 {
+		version = versions.List()[0]
+	}
+	return &api.List{
+		ListMeta: api.ListMeta{
+			ResourceVersion: version,
+		},
+		Items: objects,
+	}, err
+}
+
+// ResourceMapping returns a single meta.RESTMapping representing the
+// resources located by the builder, or an error if more than one
+// mapping was found.
+func (r *Result) ResourceMapping() (*meta.RESTMapping, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	mappings := map[string]*meta.RESTMapping{}
+	for i := range r.sources {
+		m, ok := r.sources[i].(ResourceMapping)
+		if !ok {
+			return nil, fmt.Errorf("a resource mapping could not be loaded from %v", reflect.TypeOf(r.sources[i]))
+		}
+		mapping := m.ResourceMapping()
+		mappings[mapping.Resource] = mapping
+	}
+	if len(mappings) != 1 {
+		return nil, fmt.Errorf("expected only a single resource type")
+	}
+	for _, mapping := range mappings {
+		return mapping, nil
+	}
+	return nil, nil
+}
+
+// Watch retrieves changes that occur on the server to the specified resource.
+// It currently supports watching a single source - if the resource source
+// (selectors or pure types) can be watched, they will be, otherwise the list
+// will be visited (equivalent to the Infos() call) and if there is a single
+// resource present, it will be watched, otherwise an error will be returned.
+func (r *Result) Watch(resourceVersion string) (watch.Interface, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	if len(r.sources) != 1 {
+		return nil, fmt.Errorf("you may only watch a single resource or type of resource at a time")
+	}
+	w, ok := r.sources[0].(Watchable)
+	if !ok {
+		info, err := r.Infos()
+		if err != nil {
+			return nil, err
+		}
+		if len(info) != 1 {
+			return nil, fmt.Errorf("watch is only supported on a single resource - %d resources were found", len(info))
+		}
+		return info[0].Watch(resourceVersion)
+	}
+	return w.Watch(resourceVersion)
+}