Support multiple index functions, address feedback

pkg/client/cache/index.go

+/*
+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 cache
+
+import (
+	"fmt"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/meta"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+)
+
+// Indexer is a storage interface that lets you list objects using multiple indexing functions
+type Indexer interface {
+	Store
+	// Retrieve list of objects that match on the named indexing function
+	Index(indexName string, obj interface{}) ([]interface{}, error)
+}
+
+// IndexFunc knows how to provide an indexed value for an object.
+type IndexFunc func(obj interface{}) (string, error)
+
+// MetaNamespaceIndexFunc is a default index function that indexes based on an object's namespace
+func MetaNamespaceIndexFunc(obj interface{}) (string, error) {
+	meta, err := meta.Accessor(obj)
+	if err != nil {
+		return "", fmt.Errorf("object has no meta: %v", err)
+	}
+	return meta.Namespace(), nil
+}
+
+// Index maps the indexed value to a set of keys in the store that match on that value
+type Index map[string]util.StringSet
+
+// Indexers maps a name to a IndexFunc
+type Indexers map[string]IndexFunc
+
+// Indices maps a name to an Index
+type Indices map[string]Index

pkg/client/cache/store.go

@@ -60,35 +60,16 @@ func MetaNamespaceKeyFunc(obj interface{}) (string, error) {
 	return meta.Namespace() + "/" + meta.Name(), nil
 }
 
-// Index is a generic object storage interface that lets you list objects by their Index
-type Index interface {
-	Store
-	Index(obj interface{}) ([]interface{}, error)
-}
-
-// IndexFunc knows how to provide an indexed value for an object.
-type IndexFunc func(obj interface{}) (string, error)
-
-// MetaNamespaceIndexFunc is a convenient default IndexFun which knows how to index
-// an object by its namespace.
-func MetaNamespaceIndexFunc(obj interface{}) (string, error) {
-	meta, err := meta.Accessor(obj)
-	if err != nil {
-		return "", fmt.Errorf("object has no meta: %v", err)
-	}
-	return meta.Namespace(), nil
-}
-
 type cache struct {
 	lock  sync.RWMutex
 	items map[string]interface{}
 	// keyFunc is used to make the key for objects stored in and retrieved from items, and
 	// should be deterministic.
 	keyFunc KeyFunc
-	// indexFunc is used to make the index value for objects stored in an retrieved from index
-	indexFunc IndexFunc
-	// maps the indexFunc value for an object to a set whose keys are keys in items
-	index map[string]util.StringSet
+	// indexers maps a name to an IndexFunc
+	indexers Indexers
+	// indices maps a name to an Index
+	indices Indices
 }
 
 // Add inserts an item into the cache.
@@ -100,53 +81,57 @@ func (c *cache) Add(obj interface{}) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	c.items[key] = obj
-	c.updateIndex(obj)
+	c.updateIndices(obj)
 	return nil
 }
 
-// updateIndex adds or modifies an object in the index
-// it is intended to be called from a function that already has a lock on the cache
-func (c *cache) updateIndex(obj interface{}) error {
-	if c.indexFunc == nil {
-		return nil
-	}
+// updateIndices modifies the objects location in the managed indexes
+// updateIndices must be called from a function that already has a lock on the cache
+func (c *cache) updateIndices(obj interface{}) error {
 	key, err := c.keyFunc(obj)
 	if err != nil {
 		return err
 	}
-	indexValue, err := c.indexFunc(obj)
-	if err != nil {
-		return err
-	}
-	set := c.index[indexValue]
-	if set == nil {
-		set = util.StringSet{}
-		c.index[indexValue] = set
+	for name, indexFunc := range c.indexers {
+		indexValue, err := indexFunc(obj)
+		if err != nil {
+			return err
+		}
+		index := c.indices[name]
+		if index == nil {
+			index = Index{}
+			c.indices[name] = index
+		}
+		set := index[indexValue]
+		if set == nil {
+			set = util.StringSet{}
+			index[indexValue] = set
+		}
+		set.Insert(key)
 	}
-	set.Insert(key)
 	return nil
 }
 
-// deleteFromIndex removes an entry from the index
+// deleteFromIndices removes the object from each of the managed indexes
 // it is intended to be called from a function that already has a lock on the cache
-func (c *cache) deleteFromIndex(obj interface{}) error {
-	if c.indexFunc == nil {
-		return nil
-	}
+func (c *cache) deleteFromIndices(obj interface{}) error {
 	key, err := c.keyFunc(obj)
 	if err != nil {
 		return err
 	}
-	indexValue, err := c.indexFunc(obj)
-	if err != nil {
-		return err
-	}
-	set := c.index[indexValue]
-	if set == nil {
-		set = util.StringSet{}
-		c.index[indexValue] = set
+	for name, indexFunc := range c.indexers {
+		indexValue, err := indexFunc(obj)
+		if err != nil {
+			return err
+		}
+		index := c.indices[name]
+		if index != nil {
+			set := index[indexValue]
+			if set != nil {
+				set.Delete(key)
+			}
+		}
 	}
-	set.Delete(key)
 	return nil
 }
 
@@ -159,7 +144,7 @@ func (c *cache) Update(obj interface{}) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	c.items[key] = obj
-	c.updateIndex(obj)
+	c.updateIndices(obj)
 	return nil
 }
 
@@ -172,7 +157,7 @@ func (c *cache) Delete(obj interface{}) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	delete(c.items, key)
-	c.deleteFromIndex(obj)
+	c.deleteFromIndices(obj)
 	return nil
 }
 
@@ -190,15 +175,21 @@ func (c *cache) List() []interface{} {
 
 // Index returns a list of items that match on the index function
 // Index is thread-safe so long as you treat all items as immutable
-func (c *cache) Index(obj interface{}) ([]interface{}, error) {
+func (c *cache) Index(indexName string, obj interface{}) ([]interface{}, error) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 
-	indexKey, err := c.indexFunc(obj)
+	indexFunc := c.indexers[indexName]
+	if indexFunc == nil {
+		return nil, fmt.Errorf("Index with name %s does not exist", indexName)
+	}
+
+	indexKey, err := indexFunc(obj)
 	if err != nil {
 		return nil, err
 	}
-	set := c.index[indexKey]
+	index := c.indices[indexName]
+	set := index[indexKey]
 	list := make([]interface{}, 0, set.Len())
 	for _, key := range set.List() {
 		list = append(list, c.items[key])
@@ -243,9 +234,9 @@ func (c *cache) Replace(list []interface{}) error {
 	c.items = items
 
 	// rebuild any index
-	c.index = map[string]util.StringSet{}
+	c.indices = Indices{}
 	for _, item := range c.items {
-		c.updateIndex(item)
+		c.updateIndices(item)
 	}
 
 	return nil
@@ -253,10 +244,10 @@ func (c *cache) Replace(list []interface{}) error {
 
 // NewStore returns a Store implemented simply with a map and a lock.
 func NewStore(keyFunc KeyFunc) Store {
-	return &cache{items: map[string]interface{}{}, keyFunc: keyFunc}
+	return &cache{items: map[string]interface{}{}, keyFunc: keyFunc, indexers: Indexers{}, indices: Indices{}}
 }
 
-// NewIndex returns an Index implemented simply with a map and a lock.
-func NewIndex(keyFunc KeyFunc, indexFunc IndexFunc) Index {
-	return &cache{items: map[string]interface{}{}, keyFunc: keyFunc, indexFunc: indexFunc, index: map[string]util.StringSet{}}
+// NewIndexer returns an Indexer implemented simply with a map and a lock.
+func NewIndexer(keyFunc KeyFunc, indexers Indexers) Indexer {
+	return &cache{items: map[string]interface{}{}, keyFunc: keyFunc, indexers: indexers, indices: Indices{}}
 }

pkg/client/cache/store_test.go

@@ -87,7 +87,7 @@ func doTestStore(t *testing.T, store Store) {
 }
 
 // Test public interface
-func doTestIndex(t *testing.T, index Index) {
+func doTestIndex(t *testing.T, indexer Indexer) {
 	mkObj := func(id string, val string) testStoreObject {
 		return testStoreObject{id: id, val: val}
 	}
@@ -97,14 +97,14 @@ func doTestIndex(t *testing.T, index Index) {
 	expected["b"] = util.NewStringSet("a", "c")
 	expected["f"] = util.NewStringSet("e")
 	expected["h"] = util.NewStringSet("g")
-	index.Add(mkObj("a", "b"))
-	index.Add(mkObj("c", "b"))
-	index.Add(mkObj("e", "f"))
-	index.Add(mkObj("g", "h"))
+	indexer.Add(mkObj("a", "b"))
+	indexer.Add(mkObj("c", "b"))
+	indexer.Add(mkObj("e", "f"))
+	indexer.Add(mkObj("g", "h"))
 	{
 		for k, v := range expected {
 			found := util.StringSet{}
-			indexResults, err := index.Index(mkObj("", k))
+			indexResults, err := indexer.Index("by_val", mkObj("", k))
 			if err != nil {
 				t.Errorf("Unexpected error %v", err)
 			}
@@ -127,6 +127,12 @@ func testStoreIndexFunc(obj interface{}) (string, error) {
 	return obj.(testStoreObject).val, nil
 }
 
+func testStoreIndexers() Indexers {
+	indexers := Indexers{}
+	indexers["by_val"] = testStoreIndexFunc
+	return indexers
+}
+
 type testStoreObject struct {
 	id  string
 	val string
@@ -146,5 +152,5 @@ func TestUndeltaStore(t *testing.T) {
 }
 
 func TestIndex(t *testing.T) {
-	doTestIndex(t, NewIndex(testStoreKeyFunc, testStoreIndexFunc))
+	doTestIndex(t, NewIndexer(testStoreKeyFunc, testStoreIndexers()))
 }