1 /* 2 Copyright 2014 The Kubernetes Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package cache 18 19 import ( 20 "fmt" 21 22 "k8s.io/apimachinery/pkg/api/meta" 23 "k8s.io/apimachinery/pkg/util/sets" 24 ) 25 26 // Indexer extends Store with multiple indices and restricts each 27 // accumulator to simply hold the current object (and be empty after 28 // Delete). 29 // 30 // There are three kinds of strings here: 31 // 1. a storage key, as defined in the Store interface, 32 // 2. a name of an index, and 33 // 3. an "indexed value", which is produced by an IndexFunc and 34 // can be a field value or any other string computed from the object. 35 type Indexer interface { 36 Store 37 // Index returns the stored objects whose set of indexed values 38 // intersects the set of indexed values of the given object, for 39 // the named index 40 Index(indexName string, obj interface{}) ([]interface{}, error) 41 // IndexKeys returns the storage keys of the stored objects whose 42 // set of indexed values for the named index includes the given 43 // indexed value 44 IndexKeys(indexName, indexedValue string) ([]string, error) 45 // ListIndexFuncValues returns all the indexed values of the given index 46 ListIndexFuncValues(indexName string) []string 47 // ByIndex returns the stored objects whose set of indexed values 48 // for the named index includes the given indexed value 49 ByIndex(indexName, indexedValue string) ([]interface{}, error) 50 // GetIndexers return the indexers 51 GetIndexers() Indexers 52 53 // AddIndexers adds more indexers to this store. This supports adding indexes after the store already has items. 54 AddIndexers(newIndexers Indexers) error 55 } 56 57 // IndexFunc knows how to compute the set of indexed values for an object. 58 type IndexFunc func(obj interface{}) ([]string, error) 59 60 // IndexFuncToKeyFuncAdapter adapts an indexFunc to a keyFunc. This is only useful if your index function returns 61 // unique values for every object. This conversion can create errors when more than one key is found. You 62 // should prefer to make proper key and index functions. 63 func IndexFuncToKeyFuncAdapter(indexFunc IndexFunc) KeyFunc { 64 return func(obj interface{}) (string, error) { 65 indexKeys, err := indexFunc(obj) 66 if err != nil { 67 return "", err 68 } 69 if len(indexKeys) > 1 { 70 return "", fmt.Errorf("too many keys: %v", indexKeys) 71 } 72 if len(indexKeys) == 0 { 73 return "", fmt.Errorf("unexpected empty indexKeys") 74 } 75 return indexKeys[0], nil 76 } 77 } 78 79 const ( 80 // NamespaceIndex is the lookup name for the most common index function, which is to index by the namespace field. 81 NamespaceIndex string = "namespace" 82 ) 83 84 // MetaNamespaceIndexFunc is a default index function that indexes based on an object's namespace 85 func MetaNamespaceIndexFunc(obj interface{}) ([]string, error) { 86 meta, err := meta.Accessor(obj) 87 if err != nil { 88 return []string{""}, fmt.Errorf("object has no meta: %v", err) 89 } 90 return []string{meta.GetNamespace()}, nil 91 } 92 93 // Index maps the indexed value to a set of keys in the store that match on that value 94 type Index map[string]sets.String 95 96 // Indexers maps a name to an IndexFunc 97 type Indexers map[string]IndexFunc 98 99 // Indices maps a name to an Index 100 type Indices map[string]Index 101