client: client.MatchingFields support multiple indexes (#2512)

add support for multiple indexes when using client.MatchingFields

Author: halfcrazy

pkg/cache/cache_test.go

@@ -1998,13 +1998,13 @@ func CacheTest(createCacheFunc func(config *rest.Config, opts cache.Options) (ca
 					Expect(err).NotTo(HaveOccurred())
 
 					By("indexing the Namespace objects with fixed values before starting")
-					pod := &corev1.Namespace{}
+					ns := &corev1.Namespace{}
 					indexerValues := []string{"a", "b", "c"}
 					fieldName := "fixedValues"
 					indexFunc := func(obj client.Object) []string {
 						return indexerValues
 					}
-					Expect(informer.IndexField(context.TODO(), pod, fieldName, indexFunc)).To(Succeed())
+					Expect(informer.IndexField(context.TODO(), ns, fieldName, indexFunc)).To(Succeed())
 
 					By("running the cache and waiting for it to sync")
 					go func() {
@@ -2025,6 +2025,51 @@ func CacheTest(createCacheFunc func(config *rest.Config, opts cache.Options) (ca
 					Expect(indexerValues[1]).To(Equal("b"))
 					Expect(indexerValues[2]).To(Equal("c"))
 				})
+
+				It("should be able to matching fields with multiple indexes", func() {
+					By("creating the cache")
+					informer, err := cache.New(cfg, cache.Options{})
+					Expect(err).NotTo(HaveOccurred())
+
+					pod := &corev1.Pod{}
+					By("indexing pods with label before starting")
+					fieldName1 := "indexByLabel"
+					indexFunc1 := func(obj client.Object) []string {
+						return []string{obj.(*corev1.Pod).Labels["common-label"]}
+					}
+					Expect(informer.IndexField(context.TODO(), pod, fieldName1, indexFunc1)).To(Succeed())
+					By("indexing pods with restart policy before starting")
+					fieldName2 := "indexByPolicy"
+					indexFunc2 := func(obj client.Object) []string {
+						return []string{string(obj.(*corev1.Pod).Spec.RestartPolicy)}
+					}
+					Expect(informer.IndexField(context.TODO(), pod, fieldName2, indexFunc2)).To(Succeed())
+
+					By("running the cache and waiting for it to sync")
+					go func() {
+						defer GinkgoRecover()
+						Expect(informer.Start(informerCacheCtx)).To(Succeed())
+					}()
+					Expect(informer.WaitForCacheSync(informerCacheCtx)).To(BeTrue())
+
+					By("listing pods with label index")
+					listObj := &corev1.PodList{}
+					Expect(informer.List(context.Background(), listObj,
+						client.MatchingFields{fieldName1: "common"})).To(Succeed())
+					Expect(listObj.Items).To(HaveLen(2))
+
+					By("listing pods with restart policy index")
+					listObj = &corev1.PodList{}
+					Expect(informer.List(context.Background(), listObj,
+						client.MatchingFields{fieldName2: string(corev1.RestartPolicyNever)})).To(Succeed())
+					Expect(listObj.Items).To(HaveLen(3))
+
+					By("listing pods with both fixed indexers 1 and 2")
+					listObj = &corev1.PodList{}
+					Expect(informer.List(context.Background(), listObj,
+						client.MatchingFields{fieldName1: "common", fieldName2: string(corev1.RestartPolicyNever)})).To(Succeed())
+					Expect(listObj.Items).To(HaveLen(1))
+				})
 			})
 			Context("with unstructured objects", func() {
 				It("should be able to get informer for the object", func() {

pkg/cache/internal/cache_reader.go

@@ -23,6 +23,7 @@ import (
 
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	apimeta "k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -117,16 +118,14 @@ func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...cli
 
 	switch {
 	case listOpts.FieldSelector != nil:
-		// TODO(directxman12): support more complicated field selectors by
-		// combining multiple indices, GetIndexers, etc
-		field, val, requiresExact := selector.RequiresExactMatch(listOpts.FieldSelector)
+		requiresExact := selector.RequiresExactMatch(listOpts.FieldSelector)
 		if !requiresExact {
 			return fmt.Errorf("non-exact field matches are not supported by the cache")
 		}
 		// list all objects by the field selector. If this is namespaced and we have one, ask for the
 		// namespaced index key. Otherwise, ask for the non-namespaced variant by using the fake "all namespaces"
 		// namespace.
-		objs, err = c.indexer.ByIndex(FieldIndexName(field), KeyToNamespacedKey(listOpts.Namespace, val))
+		objs, err = byIndexes(c.indexer, listOpts.FieldSelector.Requirements(), listOpts.Namespace)
 	case listOpts.Namespace != "":
 		objs, err = c.indexer.ByIndex(cache.NamespaceIndex, listOpts.Namespace)
 	default:
@@ -178,6 +177,54 @@ func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...cli
 	return apimeta.SetList(out, runtimeObjs)
 }
 
+func byIndexes(indexer cache.Indexer, requires fields.Requirements, namespace string) ([]interface{}, error) {
+	var (
+		err  error
+		objs []interface{}
+		vals []string
+	)
+	indexers := indexer.GetIndexers()
+	for idx, req := range requires {
+		indexName := FieldIndexName(req.Field)
+		indexedValue := KeyToNamespacedKey(namespace, req.Value)
+		if idx == 0 {
+			// we use first require to get snapshot data
+			// TODO(halfcrazy): use complicated index when client-go provides byIndexes
+			// https://github.com/kubernetes/kubernetes/issues/109329
+			objs, err = indexer.ByIndex(indexName, indexedValue)
+			if err != nil {
+				return nil, err
+			}
+			if len(objs) == 0 {
+				return nil, nil
+			}
+			continue
+		}
+		fn, exist := indexers[indexName]
+		if !exist {
+			return nil, fmt.Errorf("index with name %s does not exist", indexName)
+		}
+		filteredObjects := make([]interface{}, 0, len(objs))
+		for _, obj := range objs {
+			vals, err = fn(obj)
+			if err != nil {
+				return nil, err
+			}
+			for _, val := range vals {
+				if val == indexedValue {
+					filteredObjects = append(filteredObjects, obj)
+					break
+				}
+			}
+		}
+		if len(filteredObjects) == 0 {
+			return nil, nil
+		}
+		objs = filteredObjects
+	}
+	return objs, nil
+}
+
 // objectKeyToStorageKey converts an object key to store key.
 // It's akin to MetaNamespaceKeyFunc. It's separate from
 // String to allow keeping the key format easily in sync with

pkg/client/example_test.go

@@ -262,7 +262,7 @@ func ExampleClient_deleteAllOf() {
 }
 
 // This example shows how to set up and consume a field selector over a pod's volumes' secretName field.
-func ExampleFieldIndexer_secretName() {
+func ExampleFieldIndexer_secretNameNode() {
 	// someIndexer is a FieldIndexer over a Cache
 	_ = someIndexer.IndexField(context.TODO(), &corev1.Pod{}, "spec.volumes.secret.secretName", func(o client.Object) []string {
 		var res []string
@@ -276,8 +276,20 @@ func ExampleFieldIndexer_secretName() {
 		return res
 	})
 
+	_ = someIndexer.IndexField(context.TODO(), &corev1.Pod{}, "spec.NodeName", func(o client.Object) []string {
+		nodeName := o.(*corev1.Pod).Spec.NodeName
+		if nodeName != "" {
+			return []string{nodeName}
+		}
+		return nil
+	})
+
 	// elsewhere (e.g. in your reconciler)
 	mySecretName := "someSecret" // derived from the reconcile.Request, for instance
+	myNode := "master-0"
 	var podsWithSecrets corev1.PodList
-	_ = c.List(context.Background(), &podsWithSecrets, client.MatchingFields{"spec.volumes.secret.secretName": mySecretName})
+	_ = c.List(context.Background(), &podsWithSecrets, client.MatchingFields{
+		"spec.volumes.secret.secretName": mySecretName,
+		"spec.NodeName":                  myNode,
+	})
 }

pkg/client/fake/client.go

@@ -588,9 +588,7 @@ func (c *fakeClient) filterList(list []runtime.Object, gvk schema.GroupVersionKi
 }
 
 func (c *fakeClient) filterWithFields(list []runtime.Object, gvk schema.GroupVersionKind, fs fields.Selector) ([]runtime.Object, error) {
-	// We only allow filtering on the basis of a single field to ensure consistency with the
-	// behavior of the cache reader (which we're faking here).
-	fieldKey, fieldVal, requiresExact := selector.RequiresExactMatch(fs)
+	requiresExact := selector.RequiresExactMatch(fs)
 	if !requiresExact {
 		return nil, fmt.Errorf("field selector %s is not in one of the two supported forms \"key==val\" or \"key=val\"",
 			fs)
@@ -599,15 +597,24 @@ func (c *fakeClient) filterWithFields(list []runtime.Object, gvk schema.GroupVer
 	// Field selection is mimicked via indexes, so there's no sane answer this function can give
 	// if there are no indexes registered for the GroupVersionKind of the objects in the list.
 	indexes := c.indexes[gvk]
-	if len(indexes) == 0 || indexes[fieldKey] == nil {
-		return nil, fmt.Errorf("List on GroupVersionKind %v specifies selector on field %s, but no "+
-			"index with name %s has been registered for GroupVersionKind %v", gvk, fieldKey, fieldKey, gvk)
+	for _, req := range fs.Requirements() {
+		if len(indexes) == 0 || indexes[req.Field] == nil {
+			return nil, fmt.Errorf("List on GroupVersionKind %v specifies selector on field %s, but no "+
+				"index with name %s has been registered for GroupVersionKind %v", gvk, req.Field, req.Field, gvk)
+		}
 	}
 
-	indexExtractor := indexes[fieldKey]
 	filteredList := make([]runtime.Object, 0, len(list))
 	for _, obj := range list {
-		if c.objMatchesFieldSelector(obj, indexExtractor, fieldVal) {
+		matches := true
+		for _, req := range fs.Requirements() {
+			indexExtractor := indexes[req.Field]
+			if !c.objMatchesFieldSelector(obj, indexExtractor, req.Value) {
+				matches = false
+				break
+			}
+		}
+		if matches {
 			filteredList = append(filteredList, obj)
 		}
 	}

pkg/client/fake/client_test.go

@@ -1333,14 +1333,15 @@ var _ = Describe("Fake client", func() {
 					Expect(list.Items).To(BeEmpty())
 				})
 
-				It("errors when field selector uses two requirements", func() {
+				It("no error when field selector uses two requirements", func() {
 					listOpts := &client.ListOptions{
 						FieldSelector: fields.AndSelectors(
 							fields.OneTermEqualSelector("spec.replicas", "1"),
 							fields.OneTermEqualSelector("spec.strategy.type", string(appsv1.RecreateDeploymentStrategyType)),
 						)}
-					err := cl.List(context.Background(), &appsv1.DeploymentList{}, listOpts)
-					Expect(err).To(HaveOccurred())
+					list := &appsv1.DeploymentList{}
+					Expect(cl.List(context.Background(), list, listOpts)).To(Succeed())
+					Expect(list.Items).To(ConsistOf(*dep))
 				})
 			})
 		})

pkg/client/options.go

@@ -419,7 +419,7 @@ type ListOptions struct {
 	LabelSelector labels.Selector
 	// FieldSelector filters results by a particular field.  In order
 	// to use this with cache-based implementations, restrict usage to
-	// a single field-value pair that's been added to the indexers.
+	// exact match field-value pair that's been added to the indexers.
 	FieldSelector fields.Selector
 
 	// Namespace represents the namespace to list for, or empty for

pkg/internal/field/selector/utils.go

@@ -22,14 +22,16 @@ import (
 )
 
 // RequiresExactMatch checks if the given field selector is of the form `k=v` or `k==v`.
-func RequiresExactMatch(sel fields.Selector) (field, val string, required bool) {
+func RequiresExactMatch(sel fields.Selector) bool {
 	reqs := sel.Requirements()
-	if len(reqs) != 1 {
-		return "", "", false
+	if len(reqs) == 0 {
+		return false
 	}
-	req := reqs[0]
-	if req.Operator != selection.Equals && req.Operator != selection.DoubleEquals {
-		return "", "", false
+
+	for _, req := range reqs {
+		if req.Operator != selection.Equals && req.Operator != selection.DoubleEquals {
+			return false
+		}
 	}
-	return req.Field, req.Value, true
+	return true
 }

pkg/internal/field/selector/utils_test.go

@@ -27,62 +27,32 @@ import (
 var _ = Describe("RequiresExactMatch function", func() {
 
 	It("Returns false when the selector matches everything", func() {
-		_, _, requiresExactMatch := RequiresExactMatch(fields.Everything())
+		requiresExactMatch := RequiresExactMatch(fields.Everything())
 		Expect(requiresExactMatch).To(BeFalse())
 	})
 
 	It("Returns false when the selector matches nothing", func() {
-		_, _, requiresExactMatch := RequiresExactMatch(fields.Nothing())
+		requiresExactMatch := RequiresExactMatch(fields.Nothing())
 		Expect(requiresExactMatch).To(BeFalse())
 	})
 
 	It("Returns false when the selector has the form key!=val", func() {
-		_, _, requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key!=val"))
+		requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key!=val"))
 		Expect(requiresExactMatch).To(BeFalse())
 	})
 
-	It("Returns false when the selector has the form key1==val1,key2==val2", func() {
-		_, _, requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key1==val1,key2==val2"))
-		Expect(requiresExactMatch).To(BeFalse())
+	It("Returns true when the selector has the form key1==val1,key2==val2", func() {
+		requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key1==val1,key2==val2"))
+		Expect(requiresExactMatch).To(BeTrue())
 	})
 
 	It("Returns true when the selector has the form key==val", func() {
-		_, _, requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key==val"))
+		requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key==val"))
 		Expect(requiresExactMatch).To(BeTrue())
 	})
 
 	It("Returns true when the selector has the form key=val", func() {
-		_, _, requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key=val"))
+		requiresExactMatch := RequiresExactMatch(fields.ParseSelectorOrDie("key=val"))
 		Expect(requiresExactMatch).To(BeTrue())
 	})
-
-	It("Returns empty key and value when the selector matches everything", func() {
-		key, val, _ := RequiresExactMatch(fields.Everything())
-		Expect(key).To(Equal(""))
-		Expect(val).To(Equal(""))
-	})
-
-	It("Returns empty key and value when the selector matches nothing", func() {
-		key, val, _ := RequiresExactMatch(fields.Nothing())
-		Expect(key).To(Equal(""))
-		Expect(val).To(Equal(""))
-	})
-
-	It("Returns empty key and value when the selector has the form key!=val", func() {
-		key, val, _ := RequiresExactMatch(fields.ParseSelectorOrDie("key!=val"))
-		Expect(key).To(Equal(""))
-		Expect(val).To(Equal(""))
-	})
-
-	It("Returns key and value when the selector has the form key==val", func() {
-		key, val, _ := RequiresExactMatch(fields.ParseSelectorOrDie("key==val"))
-		Expect(key).To(Equal("key"))
-		Expect(val).To(Equal("val"))
-	})
-
-	It("Returns key and value when the selector has the form key=val", func() {
-		key, val, _ := RequiresExactMatch(fields.ParseSelectorOrDie("key=val"))
-		Expect(key).To(Equal("key"))
-		Expect(val).To(Equal("val"))
-	})
 })