Move extensions.LabelSelector to unversioned.

Move type LabelSelector and type LabelSelectorRequirement from pkg/apis/extensions
This avoids an import loop when Job (and later DaemonSet, Deployment, ReplicaSet)
are moved out of extensions to new api groups.

Also Move LabelSelectorAsSelector utility from pkg/apis/extensions/ to pkg/api/unversioned/
Also its test.
Also LabelSelectorOp* constants.
Also the pkg/apis/extensions/validation functions ValidateLabelSelectorRequirement and
ValidateLabelSelector move to pkg/api/unversioned

The related type in pkg/apis/extensions/v1beta1/ is staying there.  I might move
it in another PR if neccessary.

pkg/api/unversioned/helpers.go

@@ -0,0 +1,64 @@
+/*
+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 unversioned
+
+import (
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/labels"
+	"k8s.io/kubernetes/pkg/util/sets"
+)
+
+// LabelSelectorAsSelector converts the LabelSelector api type into a struct that implements
+// labels.Selector
+func LabelSelectorAsSelector(ps *LabelSelector) (labels.Selector, error) {
+	if ps == nil {
+		return labels.Nothing(), nil
+	}
+	if len(ps.MatchLabels)+len(ps.MatchExpressions) == 0 {
+		return labels.Everything(), nil
+	}
+	selector := labels.NewSelector()
+	for k, v := range ps.MatchLabels {
+		r, err := labels.NewRequirement(k, labels.InOperator, sets.NewString(v))
+		if err != nil {
+			return nil, err
+		}
+		selector = selector.Add(*r)
+	}
+	for _, expr := range ps.MatchExpressions {
+		var op labels.Operator
+		switch expr.Operator {
+		case LabelSelectorOpIn:
+			op = labels.InOperator
+		case LabelSelectorOpNotIn:
+			op = labels.NotInOperator
+		case LabelSelectorOpExists:
+			op = labels.ExistsOperator
+		case LabelSelectorOpDoesNotExist:
+			op = labels.DoesNotExistOperator
+		default:
+			return nil, fmt.Errorf("%q is not a valid pod selector operator", expr.Operator)
+		}
+		r, err := labels.NewRequirement(expr.Key, op, sets.NewString(expr.Values...))
+		if err != nil {
+			return nil, err
+		}
+		selector = selector.Add(*r)
+	}
+	return selector, nil
+}

pkg/api/unversioned/helpers_test.go

@@ -0,0 +1,83 @@
+/*
+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 unversioned
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/kubernetes/pkg/labels"
+)
+
+func TestLabelSelectorAsSelector(t *testing.T) {
+	matchLabels := map[string]string{"foo": "bar"}
+	matchExpressions := []LabelSelectorRequirement{{
+		Key:      "baz",
+		Operator: LabelSelectorOpIn,
+		Values:   []string{"qux", "norf"},
+	}}
+	mustParse := func(s string) labels.Selector {
+		out, e := labels.Parse(s)
+		if e != nil {
+			panic(e)
+		}
+		return out
+	}
+	tc := []struct {
+		in        *LabelSelector
+		out       labels.Selector
+		expectErr bool
+	}{
+		{in: nil, out: labels.Nothing()},
+		{in: &LabelSelector{}, out: labels.Everything()},
+		{
+			in:  &LabelSelector{MatchLabels: matchLabels},
+			out: mustParse("foo in (bar)"),
+		},
+		{
+			in:  &LabelSelector{MatchExpressions: matchExpressions},
+			out: mustParse("baz in (norf,qux)"),
+		},
+		{
+			in:  &LabelSelector{MatchLabels: matchLabels, MatchExpressions: matchExpressions},
+			out: mustParse("foo in (bar),baz in (norf,qux)"),
+		},
+		{
+			in: &LabelSelector{
+				MatchExpressions: []LabelSelectorRequirement{{
+					Key:      "baz",
+					Operator: LabelSelectorOpExists,
+					Values:   []string{"qux", "norf"},
+				}},
+			},
+			expectErr: true,
+		},
+	}
+
+	for i, tc := range tc {
+		out, err := LabelSelectorAsSelector(tc.in)
+		if err == nil && tc.expectErr {
+			t.Errorf("[%v]expected error but got none.", i)
+		}
+		if err != nil && !tc.expectErr {
+			t.Errorf("[%v]did not expect error but got: %v", i, err)
+		}
+		if !reflect.DeepEqual(out, tc.out) {
+			t.Errorf("[%v]expected:\n\t%+v\nbut got:\n\t%+v", i, tc.out, out)
+		}
+	}
+}

pkg/api/unversioned/types.go

@@ -15,6 +15,14 @@ limitations under the License.
 */
 
 // Package unversioned contains API types that are common to all versions.
+//
+// The package contains two categories of types:
+// - external (serialized) types that lack their own version (e.g TypeMeta)
+// - internal (never-serialized) types that are needed by several different
+//   api groups, and so live here, to avoid duplication and/or import loops
+//   (e.g. LabelSelector).
+// In the future, we will probably move these categories of objects into
+// separate packages.
 package unversioned
 
 import "strings"
@@ -382,3 +390,46 @@ func (apiVersions APIVersions) GoString() string {
 
 // Patch is provided to give a concrete name and type to the Kubernetes PATCH request body.
 type Patch struct{}
+
+// Note:
+// There are two different styles of label selectors used in versioned types:
+// an older style which is represented as just a string in versioned types, and a
+// newer style that is structured.  LabelSelector is an internal representation for the
+// latter style.
+
+// A label selector is a label query over a set of resources. The result of matchLabels and
+// matchExpressions are ANDed. An empty label selector matches all objects. A null
+// label selector matches no objects.
+type LabelSelector struct {
+	// matchLabels is a map of {key,value} pairs. A single {key,value} in the matchLabels
+	// map is equivalent to an element of matchExpressions, whose key field is "key", the
+	// operator is "In", and the values array contains only "value". The requirements are ANDed.
+	MatchLabels map[string]string `json:"matchLabels,omitempty"`
+	// matchExpressions is a list of label selector requirements. The requirements are ANDed.
+	MatchExpressions []LabelSelectorRequirement `json:"matchExpressions,omitempty"`
+}
+
+// A label selector requirement is a selector that contains values, a key, and an operator that
+// relates the key and values.
+type LabelSelectorRequirement struct {
+	// key is the label key that the selector applies to.
+	Key string `json:"key" patchStrategy:"merge" patchMergeKey:"key"`
+	// operator represents a key's relationship to a set of values.
+	// Valid operators ard In, NotIn, Exists and DoesNotExist.
+	Operator LabelSelectorOperator `json:"operator"`
+	// values is an array of string values. If the operator is In or NotIn,
+	// the values array must be non-empty. If the operator is Exists or DoesNotExist,
+	// the values array must be empty. This array is replaced during a strategic
+	// merge patch.
+	Values []string `json:"values,omitempty"`
+}
+
+// A label selector operator is the set of operators that can be used in a selector requirement.
+type LabelSelectorOperator string
+
+const (
+	LabelSelectorOpIn           LabelSelectorOperator = "In"
+	LabelSelectorOpNotIn        LabelSelectorOperator = "NotIn"
+	LabelSelectorOpExists       LabelSelectorOperator = "Exists"
+	LabelSelectorOpDoesNotExist LabelSelectorOperator = "DoesNotExist"
+)

pkg/api/unversioned/validation/validation.go

@@ -0,0 +1,53 @@
+/*
+Copyright 2015 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 validation
+
+import (
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	apivalidation "k8s.io/kubernetes/pkg/api/validation"
+	"k8s.io/kubernetes/pkg/util/validation/field"
+)
+
+func ValidateLabelSelector(ps *unversioned.LabelSelector, fldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+	if ps == nil {
+		return allErrs
+	}
+	allErrs = append(allErrs, apivalidation.ValidateLabels(ps.MatchLabels, fldPath.Child("matchLabels"))...)
+	for i, expr := range ps.MatchExpressions {
+		allErrs = append(allErrs, ValidateLabelSelectorRequirement(expr, fldPath.Child("matchExpressions").Index(i))...)
+	}
+	return allErrs
+}
+
+func ValidateLabelSelectorRequirement(sr unversioned.LabelSelectorRequirement, fldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+	switch sr.Operator {
+	case unversioned.LabelSelectorOpIn, unversioned.LabelSelectorOpNotIn:
+		if len(sr.Values) == 0 {
+			allErrs = append(allErrs, field.Required(fldPath.Child("values"), "must be specified when `operator` is 'In' or 'NotIn'"))
+		}
+	case unversioned.LabelSelectorOpExists, unversioned.LabelSelectorOpDoesNotExist:
+		if len(sr.Values) > 0 {
+			allErrs = append(allErrs, field.Forbidden(fldPath.Child("values"), "may not be specified when `operator` is 'Exists' or 'DoesNotExist'"))
+		}
+	default:
+		allErrs = append(allErrs, field.Invalid(fldPath.Child("operator"), sr.Operator, "not a valid selector operator"))
+	}
+	allErrs = append(allErrs, apivalidation.ValidateLabelName(sr.Key, fldPath.Child("key"))...)
+	return allErrs
+}