add a PriorityRESTMapper that can choose particular group/version of a resource

pkg/api/meta/priority.go

+/*
+Copyright 2016 The Kubernetes Authors 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 meta
+
+import (
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/api/unversioned"
+)
+
+const (
+	AnyGroup    = "*"
+	AnyVersion  = "*"
+	AnyResource = "*"
+	AnyKind     = "*"
+)
+
+// PriorityRESTMapper is a wrapper for automatically choosing a particular Resource or Kind
+// when multiple matches are possible
+type PriorityRESTMapper struct {
+	// Delegate is the RESTMapper to use to locate all the Kind and Resource matches
+	Delegate RESTMapper
+
+	// ResourcePriority is a list of priority patterns to apply to matching resources.
+	// The list of all matching resources is narrowed based on the patterns until only one remains.
+	// A pattern with no matches is skipped.  A pattern with more than one match uses its
+	// matches as the list to continue matching against.
+	ResourcePriority []unversioned.GroupVersionResource
+
+	// KindPriority is a list of priority patterns to apply to matching kinds.
+	// The list of all matching kinds is narrowed based on the patterns until only one remains.
+	// A pattern with no matches is skipped.  A pattern with more than one match uses its
+	// matches as the list to continue matching against.
+	KindPriority []unversioned.GroupVersionKind
+}
+
+func (m PriorityRESTMapper) String() string {
+	return fmt.Sprintf("PriorityRESTMapper{\n\t%v\n\t%v\n\t%v\n}", m.ResourcePriority, m.KindPriority, m.Delegate)
+}
+
+// ResourceFor finds all resources, then passes them through the ResourcePriority patterns to find a single matching hit.
+func (m PriorityRESTMapper) ResourceFor(partiallySpecifiedResource unversioned.GroupVersionResource) (unversioned.GroupVersionResource, error) {
+	originalGVRs, err := m.Delegate.ResourcesFor(partiallySpecifiedResource)
+	if err != nil {
+		return unversioned.GroupVersionResource{}, err
+	}
+	if len(originalGVRs) == 1 {
+		return originalGVRs[0], nil
+	}
+
+	remainingGVRs := append([]unversioned.GroupVersionResource{}, originalGVRs...)
+	for _, pattern := range m.ResourcePriority {
+		matchedGVRs := []unversioned.GroupVersionResource{}
+		for _, gvr := range remainingGVRs {
+			if resourceMatches(pattern, gvr) {
+				matchedGVRs = append(matchedGVRs, gvr)
+			}
+		}
+
+		switch len(matchedGVRs) {
+		case 0:
+			// if you have no matches, then nothing matched this pattern just move to the next
+			continue
+		case 1:
+			// one match, return
+			return matchedGVRs[0], nil
+		default:
+			// more than one match, use the matched hits as the list moving to the next pattern.
+			// this way you can have a series of selection criteria
+			remainingGVRs = matchedGVRs
+		}
+	}
+
+	return unversioned.GroupVersionResource{}, &AmbiguousResourceError{PartialResource: partiallySpecifiedResource, MatchingResources: originalGVRs}
+}
+
+// KindFor finds all kinds, then passes them through the KindPriority patterns to find a single matching hit.
+func (m PriorityRESTMapper) KindFor(partiallySpecifiedResource unversioned.GroupVersionResource) (unversioned.GroupVersionKind, error) {
+	originalGVKs, err := m.Delegate.KindsFor(partiallySpecifiedResource)
+	if err != nil {
+		return unversioned.GroupVersionKind{}, err
+	}
+	if len(originalGVKs) == 1 {
+		return originalGVKs[0], nil
+	}
+
+	remainingGVKs := append([]unversioned.GroupVersionKind{}, originalGVKs...)
+	for _, pattern := range m.KindPriority {
+		matchedGVKs := []unversioned.GroupVersionKind{}
+		for _, gvr := range remainingGVKs {
+			if kindMatches(pattern, gvr) {
+				matchedGVKs = append(matchedGVKs, gvr)
+			}
+		}
+
+		switch len(matchedGVKs) {
+		case 0:
+			// if you have no matches, then nothing matched this pattern just move to the next
+			continue
+		case 1:
+			// one match, return
+			return matchedGVKs[0], nil
+		default:
+			// more than one match, use the matched hits as the list moving to the next pattern.
+			// this way you can have a series of selection criteria
+			remainingGVKs = matchedGVKs
+		}
+	}
+
+	return unversioned.GroupVersionKind{}, &AmbiguousResourceError{PartialResource: partiallySpecifiedResource, MatchingKinds: originalGVKs}
+}
+
+func resourceMatches(pattern unversioned.GroupVersionResource, resource unversioned.GroupVersionResource) bool {
+	if pattern.Group != AnyGroup && pattern.Group != resource.Group {
+		return false
+	}
+	if pattern.Version != AnyVersion && pattern.Version != resource.Version {
+		return false
+	}
+	if pattern.Resource != AnyResource && pattern.Resource != resource.Resource {
+		return false
+	}
+
+	return true
+}
+
+func kindMatches(pattern unversioned.GroupVersionKind, kind unversioned.GroupVersionKind) bool {
+	if pattern.Group != AnyGroup && pattern.Group != kind.Group {
+		return false
+	}
+	if pattern.Version != AnyVersion && pattern.Version != kind.Version {
+		return false
+	}
+	if pattern.Kind != AnyKind && pattern.Kind != kind.Kind {
+		return false
+	}
+
+	return true
+}
+
+func (m PriorityRESTMapper) RESTMapping(gk unversioned.GroupKind, versions ...string) (mapping *RESTMapping, err error) {
+	return m.Delegate.RESTMapping(gk, versions...)
+}
+
+func (m PriorityRESTMapper) AliasesForResource(alias string) (aliases []string, ok bool) {
+	return m.Delegate.AliasesForResource(alias)
+}
+
+func (m PriorityRESTMapper) ResourceSingularizer(resource string) (singular string, err error) {
+	return m.Delegate.ResourceSingularizer(resource)
+}
+
+func (m PriorityRESTMapper) ResourcesFor(partiallySpecifiedResource unversioned.GroupVersionResource) ([]unversioned.GroupVersionResource, error) {
+	return m.Delegate.ResourcesFor(partiallySpecifiedResource)
+}
+
+func (m PriorityRESTMapper) KindsFor(partiallySpecifiedResource unversioned.GroupVersionResource) (gvk []unversioned.GroupVersionKind, err error) {
+	return m.Delegate.KindsFor(partiallySpecifiedResource)
+}

pkg/api/meta/priority_test.go

+/*
+Copyright 2016 The Kubernetes Authors 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 meta
+
+import (
+	"strings"
+	"testing"
+
+	"k8s.io/kubernetes/pkg/api/unversioned"
+)
+
+func TestPriorityRESTMapperResourceForErrorHandling(t *testing.T) {
+	tcs := []struct {
+		name string
+
+		delegate         RESTMapper
+		resourcePatterns []unversioned.GroupVersionResource
+		result           unversioned.GroupVersionResource
+		err              string
+	}{
+		{
+			name:     "single hit",
+			delegate: fixedRESTMapper{resourcesFor: []unversioned.GroupVersionResource{{Resource: "single-hit"}}},
+			result:   unversioned.GroupVersionResource{Resource: "single-hit"},
+		},
+		{
+			name: "ambiguous match",
+			delegate: fixedRESTMapper{resourcesFor: []unversioned.GroupVersionResource{
+				{Group: "one", Version: "a", Resource: "first"},
+				{Group: "two", Version: "b", Resource: "second"},
+			}},
+			err: "matches multiple resources",
+		},
+		{
+			name: "group selection",
+			delegate: fixedRESTMapper{resourcesFor: []unversioned.GroupVersionResource{
+				{Group: "one", Version: "a", Resource: "first"},
+				{Group: "two", Version: "b", Resource: "second"},
+			}},
+			resourcePatterns: []unversioned.GroupVersionResource{
+				{Group: "one", Version: AnyVersion, Resource: AnyResource},
+			},
+			result: unversioned.GroupVersionResource{Group: "one", Version: "a", Resource: "first"},
+		},
+		{
+			name: "empty match continues",
+			delegate: fixedRESTMapper{resourcesFor: []unversioned.GroupVersionResource{
+				{Group: "one", Version: "a", Resource: "first"},
+				{Group: "two", Version: "b", Resource: "second"},
+			}},
+			resourcePatterns: []unversioned.GroupVersionResource{
+				{Group: "fail", Version: AnyVersion, Resource: AnyResource},
+				{Group: "one", Version: AnyVersion, Resource: AnyResource},
+			},
+			result: unversioned.GroupVersionResource{Group: "one", Version: "a", Resource: "first"},
+		},
+		{
+			name: "group followed by version selection",
+			delegate: fixedRESTMapper{resourcesFor: []unversioned.GroupVersionResource{
+				{Group: "one", Version: "a", Resource: "first"},
+				{Group: "two", Version: "b", Resource: "second"},
+				{Group: "one", Version: "c", Resource: "third"},
+			}},
+			resourcePatterns: []unversioned.GroupVersionResource{
+				{Group: "one", Version: AnyVersion, Resource: AnyResource},
+				{Group: AnyGroup, Version: "a", Resource: AnyResource},
+			},
+			result: unversioned.GroupVersionResource{Group: "one", Version: "a", Resource: "first"},
+		},
+		{
+			name: "resource selection",
+			delegate: fixedRESTMapper{resourcesFor: []unversioned.GroupVersionResource{
+				{Group: "one", Version: "a", Resource: "first"},
+				{Group: "one", Version: "a", Resource: "second"},
+			}},
+			resourcePatterns: []unversioned.GroupVersionResource{
+				{Group: AnyGroup, Version: AnyVersion, Resource: "second"},
+			},
+			result: unversioned.GroupVersionResource{Group: "one", Version: "a", Resource: "second"},
+		},
+	}
+
+	for _, tc := range tcs {
+		mapper := PriorityRESTMapper{Delegate: tc.delegate, ResourcePriority: tc.resourcePatterns}
+
+		actualResult, actualErr := mapper.ResourceFor(unversioned.GroupVersionResource{})
+		if e, a := tc.result, actualResult; e != a {
+			t.Errorf("%s: expected %v, got %v", tc.name, e, a)
+		}
+		if len(tc.err) == 0 && actualErr == nil {
+			continue
+		}
+		if len(tc.err) > 0 && actualErr == nil {
+			t.Errorf("%s: missing expected err: %v", tc.name, tc.err)
+			continue
+		}
+		if !strings.Contains(actualErr.Error(), tc.err) {
+			t.Errorf("%s: expected %v, got %v", tc.name, tc.err, actualErr)
+		}
+	}
+}
+
+func TestPriorityRESTMapperKindForErrorHandling(t *testing.T) {
+	tcs := []struct {
+		name string
+
+		delegate     RESTMapper
+		kindPatterns []unversioned.GroupVersionKind
+		result       unversioned.GroupVersionKind
+		err          string
+	}{
+		{
+			name:     "single hit",
+			delegate: fixedRESTMapper{kindsFor: []unversioned.GroupVersionKind{{Kind: "single-hit"}}},
+			result:   unversioned.GroupVersionKind{Kind: "single-hit"},
+		},
+		{
+			name: "ambiguous match",
+			delegate: fixedRESTMapper{kindsFor: []unversioned.GroupVersionKind{
+				{Group: "one", Version: "a", Kind: "first"},
+				{Group: "two", Version: "b", Kind: "second"},
+			}},
+			err: "matches multiple kinds",
+		},
+		{
+			name: "group selection",
+			delegate: fixedRESTMapper{kindsFor: []unversioned.GroupVersionKind{
+				{Group: "one", Version: "a", Kind: "first"},
+				{Group: "two", Version: "b", Kind: "second"},
+			}},
+			kindPatterns: []unversioned.GroupVersionKind{
+				{Group: "one", Version: AnyVersion, Kind: AnyKind},
+			},
+			result: unversioned.GroupVersionKind{Group: "one", Version: "a", Kind: "first"},
+		},
+		{
+			name: "empty match continues",
+			delegate: fixedRESTMapper{kindsFor: []unversioned.GroupVersionKind{
+				{Group: "one", Version: "a", Kind: "first"},
+				{Group: "two", Version: "b", Kind: "second"},
+			}},
+			kindPatterns: []unversioned.GroupVersionKind{
+				{Group: "fail", Version: AnyVersion, Kind: AnyKind},
+				{Group: "one", Version: AnyVersion, Kind: AnyKind},
+			},
+			result: unversioned.GroupVersionKind{Group: "one", Version: "a", Kind: "first"},
+		},
+		{
+			name: "group followed by version selection",
+			delegate: fixedRESTMapper{kindsFor: []unversioned.GroupVersionKind{
+				{Group: "one", Version: "a", Kind: "first"},
+				{Group: "two", Version: "b", Kind: "second"},
+				{Group: "one", Version: "c", Kind: "third"},
+			}},
+			kindPatterns: []unversioned.GroupVersionKind{
+				{Group: "one", Version: AnyVersion, Kind: AnyKind},
+				{Group: AnyGroup, Version: "a", Kind: AnyKind},
+			},
+			result: unversioned.GroupVersionKind{Group: "one", Version: "a", Kind: "first"},
+		},
+		{
+			name: "kind selection",
+			delegate: fixedRESTMapper{kindsFor: []unversioned.GroupVersionKind{
+				{Group: "one", Version: "a", Kind: "first"},
+				{Group: "one", Version: "a", Kind: "second"},
+			}},
+			kindPatterns: []unversioned.GroupVersionKind{
+				{Group: AnyGroup, Version: AnyVersion, Kind: "second"},
+			},
+			result: unversioned.GroupVersionKind{Group: "one", Version: "a", Kind: "second"},
+		},
+	}
+
+	for _, tc := range tcs {
+		mapper := PriorityRESTMapper{Delegate: tc.delegate, KindPriority: tc.kindPatterns}
+
+		actualResult, actualErr := mapper.KindFor(unversioned.GroupVersionResource{})
+		if e, a := tc.result, actualResult; e != a {
+			t.Errorf("%s: expected %v, got %v", tc.name, e, a)
+		}
+		if len(tc.err) == 0 && actualErr == nil {
+			continue
+		}
+		if len(tc.err) > 0 && actualErr == nil {
+			t.Errorf("%s: missing expected err: %v", tc.name, tc.err)
+			continue
+		}
+		if !strings.Contains(actualErr.Error(), tc.err) {
+			t.Errorf("%s: expected %v, got %v", tc.name, tc.err, actualErr)
+		}
+	}
+}

pkg/kubectl/cmd/cmd_test.go

@@ -180,7 +180,16 @@ func NewTestFactory() (*cmdutil.Factory, *testFactory, runtime.Codec) {
 	}
 	return &cmdutil.Factory{
 		Object: func() (meta.RESTMapper, runtime.ObjectTyper) {
-			return t.Mapper, t.Typer
+			priorityRESTMapper := meta.PriorityRESTMapper{
+				Delegate: t.Mapper,
+				ResourcePriority: []unversioned.GroupVersionResource{
+					{Group: meta.AnyGroup, Version: "v1", Resource: meta.AnyResource},
+				},
+				KindPriority: []unversioned.GroupVersionKind{
+					{Group: meta.AnyGroup, Version: "v1", Kind: meta.AnyKind},
+				},
+			}
+			return priorityRESTMapper, t.Typer
 		},
 		ClientForMapping: func(*meta.RESTMapping) (resource.RESTClient, error) {
 			return t.Client, t.Err
@@ -212,7 +221,16 @@ func NewTestFactory() (*cmdutil.Factory, *testFactory, runtime.Codec) {
 func NewMixedFactory(apiClient resource.RESTClient) (*cmdutil.Factory, *testFactory, runtime.Codec) {
 	f, t, c := NewTestFactory()
 	f.Object = func() (meta.RESTMapper, runtime.ObjectTyper) {
-		return meta.MultiRESTMapper{t.Mapper, testapi.Default.RESTMapper()}, runtime.MultiObjectTyper{t.Typer, api.Scheme}
+		priorityRESTMapper := meta.PriorityRESTMapper{
+			Delegate: meta.MultiRESTMapper{t.Mapper, testapi.Default.RESTMapper()},
+			ResourcePriority: []unversioned.GroupVersionResource{
+				{Group: meta.AnyGroup, Version: "v1", Resource: meta.AnyResource},
+			},
+			KindPriority: []unversioned.GroupVersionKind{
+				{Group: meta.AnyGroup, Version: "v1", Kind: meta.AnyKind},
+			},
+		}
+		return priorityRESTMapper, runtime.MultiObjectTyper{t.Typer, api.Scheme}
 	}
 	f.ClientForMapping = func(m *meta.RESTMapping) (resource.RESTClient, error) {
 		if m.ObjectConvertor == api.Scheme {

pkg/kubectl/cmd/util/factory.go

@@ -43,6 +43,7 @@ import (
 	"k8s.io/kubernetes/pkg/apis/autoscaling"
 	"k8s.io/kubernetes/pkg/apis/batch"
 	"k8s.io/kubernetes/pkg/apis/extensions"
+	"k8s.io/kubernetes/pkg/apis/metrics"
 	clientset "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
 	client "k8s.io/kubernetes/pkg/client/unversioned"
 	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
@@ -202,7 +203,24 @@ func NewFactory(optionalClientConfig clientcmd.ClientConfig) *Factory {
 				cmdApiVersion = *cfg.GroupVersion
 			}
 
-			return kubectl.OutputVersionMapper{RESTMapper: mapper, OutputVersions: []unversioned.GroupVersion{cmdApiVersion}}, api.Scheme
+			outputRESTMapper := kubectl.OutputVersionMapper{RESTMapper: mapper, OutputVersions: []unversioned.GroupVersion{cmdApiVersion}}
+
+			// eventually this should allow me choose a group priority based on the order of the discovery doc, for now hardcode a given order
+			priorityRESTMapper := meta.PriorityRESTMapper{
+				Delegate: outputRESTMapper,
+				ResourcePriority: []unversioned.GroupVersionResource{
+					{Group: api.GroupName, Version: meta.AnyVersion, Resource: meta.AnyResource},
+					{Group: extensions.GroupName, Version: meta.AnyVersion, Resource: meta.AnyResource},
+					{Group: metrics.GroupName, Version: meta.AnyVersion, Resource: meta.AnyResource},
+				},
+				KindPriority: []unversioned.GroupVersionKind{
+					{Group: api.GroupName, Version: meta.AnyVersion, Kind: meta.AnyKind},
+					{Group: extensions.GroupName, Version: meta.AnyVersion, Kind: meta.AnyKind},
+					{Group: metrics.GroupName, Version: meta.AnyVersion, Kind: meta.AnyKind},
+				},
+			}
+
+			return priorityRESTMapper, api.Scheme
 		},
 		Client: func() (*client.Client, error) {
 			return clients.ClientForVersion(nil)