Extend Filter interface with Trigger() and use it for pods and nodes

examples/apiserver/rest/reststorage.go

@@ -38,7 +38,7 @@ func NewREST(s storage.Interface, storageDecorator generic.StorageDecorator) *RE
 	// Usually you should reuse your RESTCreateStrategy.
 	strategy := &NotNamespaceScoped{}
 	storageInterface := storageDecorator(
-		s, 100, &testgroup.TestType{}, prefix, strategy, newListFunc)
+		s, 100, &testgroup.TestType{}, prefix, strategy, newListFunc, storage.NoTriggerPublisher)
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &testgroup.TestType{} },
 		// NewListFunc returns an object capable of storing results of an etcd list.

federation/registry/cluster/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -49,7 +50,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &federation.ClusterList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, 100, &federation.Cluster{}, prefix, cluster.Strategy, newListFunc)
+		opts.Storage,
+		100,
+		&federation.Cluster{},
+		prefix,
+		cluster.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &federation.Cluster{} },

pkg/registry/certificates/etcd/etcd.go

@@ -27,6 +27,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for CertificateSigningRequest against etcd
@@ -39,7 +40,15 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST, *ApprovalREST) {
 	prefix := "/certificatesigningrequests"
 
 	newListFunc := func() runtime.Object { return &certificates.CertificateSigningRequestList{} }
-	storageInterface := opts.Decorator(opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.CertificateSigningRequests), &certificates.CertificateSigningRequest{}, prefix, csrregistry.Strategy, newListFunc)
+	storageInterface := opts.Decorator(
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.CertificateSigningRequests),
+		&certificates.CertificateSigningRequest{},
+		prefix,
+		csrregistry.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &certificates.CertificateSigningRequest{} },

pkg/registry/clusterrole/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for ClusterRole against etcd
@@ -43,6 +44,7 @@ func NewREST(opts generic.RESTOptions) *REST {
 		prefix,
 		clusterrole.Strategy,
 		newListFunc,
+		storage.NoTriggerPublisher,
 	)
 
 	store := &registry.Store{

pkg/registry/clusterrolebinding/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for ClusterRoleBinding against etcd
@@ -43,6 +44,7 @@ func NewREST(opts generic.RESTOptions) *REST {
 		prefix,
 		clusterrolebinding.Strategy,
 		newListFunc,
+		storage.NoTriggerPublisher,
 	)
 
 	store := &registry.Store{

pkg/registry/configmap/etcd/etcd.go

@@ -20,9 +20,9 @@ import (
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/registry/configmap"
 	"k8s.io/kubernetes/pkg/registry/generic"
-	"k8s.io/kubernetes/pkg/runtime"
-
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for ConfigMap against etcd
@@ -36,7 +36,7 @@ func NewREST(opts generic.RESTOptions) *REST {
 
 	newListFunc := func() runtime.Object { return &api.ConfigMapList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, 100, &api.ConfigMap{}, prefix, configmap.Strategy, newListFunc)
+		opts.Storage, 100, &api.ConfigMap{}, prefix, configmap.Strategy, newListFunc, storage.NoTriggerPublisher)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object {

pkg/registry/controller/etcd/etcd.go

@@ -32,6 +32,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // ControllerStorage includes dummy storage for Replication Controllers and for Scale subresource.
@@ -62,7 +63,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &api.ReplicationControllerList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Controllers), &api.ReplicationController{}, prefix, controller.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Controllers),
+		&api.ReplicationController{},
+		prefix,
+		controller.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &api.ReplicationController{} },

pkg/registry/daemonset/etcd/etcd.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // rest implements a RESTStorage for DaemonSets against etcd
@@ -38,7 +39,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &extensions.DaemonSetList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Daemonsets), &extensions.DaemonSet{}, prefix, daemonset.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Daemonsets),
+		&extensions.DaemonSet{},
+		prefix,
+		daemonset.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &extensions.DaemonSet{} },

pkg/registry/deployment/etcd/etcd.go

@@ -63,7 +63,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST, *RollbackREST) {
 
 	newListFunc := func() runtime.Object { return &extensions.DeploymentList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Deployments), &extensions.Deployment{}, prefix, deployment.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Deployments),
+		&extensions.Deployment{},
+		prefix,
+		deployment.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &extensions.Deployment{} },

pkg/registry/endpoint/etcd/etcd.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -35,7 +36,14 @@ func NewREST(opts generic.RESTOptions) *REST {
 
 	newListFunc := func() runtime.Object { return &api.EndpointsList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Endpoints), &api.Endpoints{}, prefix, endpoint.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Endpoints),
+		&api.Endpoints{},
+		prefix,
+		endpoint.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.Endpoints{} },

pkg/registry/generic/matcher.go

@@ -21,6 +21,7 @@ import (
 	"k8s.io/kubernetes/pkg/fields"
 	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // AttrFunc returns label and field sets for List or Watch to compare against, or an error.
@@ -50,9 +51,10 @@ func MergeFieldsSets(source fields.Set, fragment fields.Set) fields.Set {
 // SelectionPredicate implements a generic predicate that can be passed to
 // GenericRegistry's List or Watch methods. Implements the Matcher interface.
 type SelectionPredicate struct {
-	Label    labels.Selector
-	Field    fields.Selector
-	GetAttrs AttrFunc
+	Label       labels.Selector
+	Field       fields.Selector
+	GetAttrs    AttrFunc
+	IndexFields []string
 }
 
 // Matches returns true if the given object's labels and fields (as
@@ -79,6 +81,20 @@ func (s *SelectionPredicate) MatchesSingle() (string, bool) {
 	return "", false
 }
 
+// For any index defined by IndexFields, if a matcher can match only (a subset)
+// of objects that return <value> for a given index, a pair (<index name>, <value>)
+// wil be returned.
+// TODO: Consider supporting also labels.
+func (s *SelectionPredicate) MatcherIndex() []storage.MatchValue {
+	var result []storage.MatchValue
+	for _, field := range s.IndexFields {
+		if value, ok := s.Field.RequiresExactMatch(field); ok {
+			result = append(result, storage.MatchValue{IndexName: field, Value: value})
+		}
+	}
+	return result
+}
+
 // Matcher can return true if an object matches the Matcher's selection
 // criteria. If it is known that the matcher will match only a single object
 // then MatchesSingle should return the key of that object and true. This is an
@@ -93,9 +109,10 @@ type Matcher interface {
 	// include the object's namespace.
 	MatchesSingle() (key string, matchesSingleObject bool)
 
-	// TODO: when we start indexing objects, add something like the below:
-	//         MatchesIndices() (indexName []string, indexValue []string)
-	//       where indexName/indexValue are the same length.
+	// For any known index, if a matcher can match only (a subset) of objects
+	// that return <value> for a given index, a pair (<index name>, <value>)
+	// will be returned.
+	MatcherIndex() []storage.MatchValue
 }
 
 // MatcherFunc makes a matcher from the provided function. For easy definition
@@ -117,6 +134,11 @@ func (m matcherFunc) MatchesSingle() (string, bool) {
 	return "", false
 }
 
+// MatcherIndex always returns empty list.
+func (m matcherFunc) MatcherIndex() []storage.MatchValue {
+	return nil
+}
+
 // MatchOnKey returns a matcher that will send only the object matching key
 // through the matching function f. For testing!
 // Note: use SelectionPredicate above for real code!

pkg/registry/generic/registry/storage_factory.go

@@ -30,15 +30,17 @@ func StorageWithCacher(
 	objectType runtime.Object,
 	resourcePrefix string,
 	scopeStrategy rest.NamespaceScopedStrategy,
-	newListFunc func() runtime.Object) storage.Interface {
+	newListFunc func() runtime.Object,
+	triggerFunc storage.TriggerPublisherFunc) storage.Interface {
 
 	config := storage.CacherConfig{
-		CacheCapacity:  capacity,
-		Storage:        storageInterface,
-		Versioner:      etcdstorage.APIObjectVersioner{},
-		Type:           objectType,
-		ResourcePrefix: resourcePrefix,
-		NewListFunc:    newListFunc,
+		CacheCapacity:        capacity,
+		Storage:              storageInterface,
+		Versioner:            etcdstorage.APIObjectVersioner{},
+		Type:                 objectType,
+		ResourcePrefix:       resourcePrefix,
+		NewListFunc:          newListFunc,
+		TriggerPublisherFunc: triggerFunc,
 	}
 	if scopeStrategy.NamespaceScoped() {
 		config.KeyFunc = func(obj runtime.Object) (string, error) {

pkg/registry/generic/registry/store.go

@@ -828,7 +828,7 @@ func (e *Store) createFilter(m generic.Matcher) storage.Filter {
 		}
 		return matches
 	}
-	return storage.NewSimpleFilter(filterFunc)
+	return storage.NewSimpleFilter(filterFunc, m.MatcherIndex)
 }
 
 // calculateTTL is a helper for retrieving the updated TTL for an object or returning an error

pkg/registry/generic/registry/store_test.go

@@ -105,6 +105,10 @@ func (sm setMatcher) MatchesSingle() (string, bool) {
 	return "", false
 }
 
+func (sm setMatcher) MatcherIndex() []storage.MatchValue {
+	return nil
+}
+
 // everythingMatcher matches everything
 type everythingMatcher struct{}
 
@@ -116,6 +120,10 @@ func (everythingMatcher) MatchesSingle() (string, bool) {
 	return "", false
 }
 
+func (everythingMatcher) MatcherIndex() []storage.MatchValue {
+	return nil
+}
+
 func TestStoreList(t *testing.T) {
 	podA := &api.Pod{
 		ObjectMeta: api.ObjectMeta{Namespace: "test", Name: "bar"},

pkg/registry/generic/storage_decorator.go

@@ -30,7 +30,8 @@ type StorageDecorator func(
 	objectType runtime.Object,
 	resourcePrefix string,
 	scopeStrategy rest.NamespaceScopedStrategy,
-	newListFunc func() runtime.Object) storage.Interface
+	newListFunc func() runtime.Object,
+	trigger storage.TriggerPublisherFunc) storage.Interface
 
 // Returns given 'storageInterface' without any decoration.
 func UndecoratedStorage(
@@ -39,6 +40,7 @@ func UndecoratedStorage(
 	objectType runtime.Object,
 	resourcePrefix string,
 	scopeStrategy rest.NamespaceScopedStrategy,
-	newListFunc func() runtime.Object) storage.Interface {
+	newListFunc func() runtime.Object,
+	trigger storage.TriggerPublisherFunc) storage.Interface {
 	return storageInterface
 }

pkg/registry/horizontalpodautoscaler/etcd/etcd.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/horizontalpodautoscaler"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -37,7 +38,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &autoscaling.HorizontalPodAutoscalerList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.HorizontalPodAutoscalers), &autoscaling.HorizontalPodAutoscaler{}, prefix, horizontalpodautoscaler.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.HorizontalPodAutoscalers),
+		&autoscaling.HorizontalPodAutoscaler{},
+		prefix,
+		horizontalpodautoscaler.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &autoscaling.HorizontalPodAutoscaler{} },

pkg/registry/ingress/etcd/etcd.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	ingress "k8s.io/kubernetes/pkg/registry/ingress"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // rest implements a RESTStorage for replication controllers against etcd
@@ -38,7 +39,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &extensions.IngressList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Ingress), &extensions.Ingress{}, prefix, ingress.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Ingress),
+		&extensions.Ingress{},
+		prefix,
+		ingress.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &extensions.Ingress{} },

pkg/registry/job/etcd/etcd.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/job"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for jobs against etcd
@@ -38,7 +39,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &batch.JobList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Jobs), &batch.Job{}, prefix, job.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Jobs),
+		&batch.Job{},
+		prefix,
+		job.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &batch.Job{} },

pkg/registry/limitrange/etcd/etcd.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/limitrange"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -35,7 +36,14 @@ func NewREST(opts generic.RESTOptions) *REST {
 
 	newListFunc := func() runtime.Object { return &api.LimitRangeList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.LimitRanges), &api.LimitRange{}, prefix, limitrange.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.LimitRanges),
+		&api.LimitRange{},
+		prefix,
+		limitrange.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.LimitRange{} },

pkg/registry/namespace/etcd/etcd.go

@@ -54,7 +54,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST, *FinalizeREST) {
 
 	newListFunc := func() runtime.Object { return &api.NamespaceList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Namespaces), &api.Namespace{}, prefix, namespace.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Namespaces),
+		&api.Namespace{},
+		prefix,
+		namespace.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.Namespace{} },

pkg/registry/networkpolicy/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/networkpolicy"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // rest implements a RESTStorage for network policies against etcd
@@ -37,7 +38,14 @@ func NewREST(opts generic.RESTOptions) *REST {
 
 	newListFunc := func() runtime.Object { return &extensionsapi.NetworkPolicyList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.NetworkPolicys), &extensionsapi.NetworkPolicy{}, prefix, networkpolicy.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.NetworkPolicys),
+		&extensionsapi.NetworkPolicy{},
+		prefix,
+		networkpolicy.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &extensionsapi.NetworkPolicy{} },

pkg/registry/node/etcd/etcd.go

@@ -70,7 +70,13 @@ func NewStorage(opts generic.RESTOptions, connection client.ConnectionInfoGetter
 
 	newListFunc := func() runtime.Object { return &api.NodeList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Nodes), &api.Node{}, prefix, node.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Nodes),
+		&api.Node{},
+		prefix,
+		node.Strategy,
+		newListFunc,
+		node.NodeNameTriggerFunc)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.Node{} },

pkg/registry/node/strategy.go

@@ -32,6 +32,7 @@ import (
 	"k8s.io/kubernetes/pkg/master/ports"
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/runtime"
+	pkgstorage "k8s.io/kubernetes/pkg/storage"
 	utilnet "k8s.io/kubernetes/pkg/util/net"
 	nodeutil "k8s.io/kubernetes/pkg/util/node"
 	"k8s.io/kubernetes/pkg/util/validation/field"
@@ -157,9 +158,16 @@ func MatchNode(label labels.Selector, field fields.Selector) generic.Matcher {
 			}
 			return labels.Set(nodeObj.ObjectMeta.Labels), NodeToSelectableFields(nodeObj), nil
 		},
+		IndexFields: []string{"metadata.name"},
 	}
 }
 
+func NodeNameTriggerFunc(obj runtime.Object) []pkgstorage.MatchValue {
+	node := obj.(*api.Node)
+	result := pkgstorage.MatchValue{IndexName: "metadata.name", Value: node.ObjectMeta.Name}
+	return []pkgstorage.MatchValue{result}
+}
+
 // ResourceLocation returns an URL and transport which one can use to send traffic for the specified node.
 func ResourceLocation(getter ResourceGetter, connection client.ConnectionInfoGetter, proxyTransport http.RoundTripper, ctx api.Context, id string) (*url.URL, http.RoundTripper, error) {
 	schemeReq, name, portReq, valid := utilnet.SplitSchemeNamePort(id)

pkg/registry/persistentvolume/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/persistentvolume"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -36,7 +37,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &api.PersistentVolumeList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.PersistentVolumes), &api.PersistentVolume{}, prefix, persistentvolume.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.PersistentVolumes),
+		&api.PersistentVolume{},
+		prefix,
+		persistentvolume.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.PersistentVolume{} },

pkg/registry/persistentvolumeclaim/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/persistentvolumeclaim"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -36,7 +37,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &api.PersistentVolumeClaimList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.PersistentVolumeClaims), &api.PersistentVolumeClaim{}, prefix, persistentvolumeclaim.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.PersistentVolumeClaims),
+		&api.PersistentVolumeClaim{},
+		prefix,
+		persistentvolumeclaim.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.PersistentVolumeClaim{} },

pkg/registry/petset/etcd/etcd.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/petset"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // rest implements a RESTStorage for replication controllers against etcd
@@ -38,7 +39,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &appsapi.PetSetList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.PetSet), &appsapi.PetSet{}, prefix, petset.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.PetSet),
+		&appsapi.PetSet{},
+		prefix,
+		petset.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &appsapi.PetSet{} },

pkg/registry/pod/etcd/etcd.go

@@ -61,7 +61,14 @@ func NewStorage(opts generic.RESTOptions, k client.ConnectionInfoGetter, proxyTr
 
 	newListFunc := func() runtime.Object { return &api.PodList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Pods), &api.Pod{}, prefix, pod.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Pods),
+		&api.Pod{},
+		prefix,
+		pod.Strategy,
+		newListFunc,
+		pod.NodeNameTriggerFunc,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.Pod{} },

pkg/registry/pod/strategy.go

@@ -33,6 +33,7 @@ import (
 	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/registry/generic"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 	utilnet "k8s.io/kubernetes/pkg/util/net"
 	"k8s.io/kubernetes/pkg/util/validation/field"
 )
@@ -177,9 +178,16 @@ func MatchPod(label labels.Selector, field fields.Selector) generic.Matcher {
 			}
 			return podLabels, podFields, nil
 		},
+		IndexFields: []string{"spec.nodeName"},
 	}
 }
 
+func NodeNameTriggerFunc(obj runtime.Object) []storage.MatchValue {
+	pod := obj.(*api.Pod)
+	result := storage.MatchValue{IndexName: "spec.nodeName", Value: pod.Spec.NodeName}
+	return []storage.MatchValue{result}
+}
+
 // PodToSelectableFields returns a field set that represents the object
 // TODO: fields are not labels, and the validation rules for them do not apply.
 func PodToSelectableFields(pod *api.Pod) fields.Set {

pkg/registry/poddisruptionbudget/etcd/etcd.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/poddisruptionbudget"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // rest implements a RESTStorage for pod disruption budgets against etcd
@@ -38,7 +39,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &policyapi.PodDisruptionBudgetList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.PodDisruptionBudget), &policyapi.PodDisruptionBudget{}, prefix, poddisruptionbudget.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.PodDisruptionBudget),
+		&policyapi.PodDisruptionBudget{},
+		prefix,
+		poddisruptionbudget.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &policyapi.PodDisruptionBudget{} },

pkg/registry/podsecuritypolicy/etcd/etcd.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/podsecuritypolicy"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for PodSecurityPolicies against etcd.
@@ -36,7 +37,14 @@ const Prefix = "/podsecuritypolicies"
 func NewREST(opts generic.RESTOptions) *REST {
 	newListFunc := func() runtime.Object { return &extensions.PodSecurityPolicyList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, 100, &extensions.PodSecurityPolicy{}, Prefix, podsecuritypolicy.Strategy, newListFunc)
+		opts.Storage,
+		100,
+		&extensions.PodSecurityPolicy{},
+		Prefix,
+		podsecuritypolicy.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &extensions.PodSecurityPolicy{} },

pkg/registry/podtemplate/etcd/etcd.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/podtemplate"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -35,7 +36,14 @@ func NewREST(opts generic.RESTOptions) *REST {
 
 	newListFunc := func() runtime.Object { return &api.PodTemplateList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.PodTemplates), &api.PodTemplate{}, prefix, podtemplate.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.PodTemplates),
+		&api.PodTemplate{},
+		prefix,
+		podtemplate.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.PodTemplate{} },

pkg/registry/replicaset/etcd/etcd.go

@@ -31,6 +31,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/replicaset"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // ReplicaSetStorage includes dummy storage for ReplicaSets and for Scale subresource.
@@ -61,7 +62,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &extensions.ReplicaSetList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Replicasets), &extensions.ReplicaSet{}, prefix, replicaset.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Replicasets),
+		&extensions.ReplicaSet{},
+		prefix,
+		replicaset.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc: func() runtime.Object { return &extensions.ReplicaSet{} },

pkg/registry/resourcequota/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/resourcequota"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -36,7 +37,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &api.ResourceQuotaList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.ResourceQuotas), &api.ResourceQuota{}, prefix, resourcequota.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.ResourceQuotas),
+		&api.ResourceQuota{},
+		prefix,
+		resourcequota.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.ResourceQuota{} },

pkg/registry/role/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/role"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for Role against etcd
@@ -43,6 +44,7 @@ func NewREST(opts generic.RESTOptions) *REST {
 		prefix,
 		role.Strategy,
 		newListFunc,
+		storage.NoTriggerPublisher,
 	)
 
 	store := &registry.Store{

pkg/registry/rolebinding/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/rolebinding"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 // REST implements a RESTStorage for RoleBinding against etcd
@@ -43,6 +44,7 @@ func NewREST(opts generic.RESTOptions) *REST {
 		prefix,
 		rolebinding.Strategy,
 		newListFunc,
+		storage.NoTriggerPublisher,
 	)
 
 	store := &registry.Store{

pkg/registry/secret/etcd/etcd.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/secret"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -35,7 +36,14 @@ func NewREST(opts generic.RESTOptions) *REST {
 
 	newListFunc := func() runtime.Object { return &api.SecretList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Secrets), &api.Secret{}, prefix, secret.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Secrets),
+		&api.Secret{},
+		prefix,
+		secret.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.Secret{} },

pkg/registry/service/etcd/etcd.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/service"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -36,7 +37,14 @@ func NewREST(opts generic.RESTOptions) (*REST, *StatusREST) {
 
 	newListFunc := func() runtime.Object { return &api.ServiceList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.Services), &api.Service{}, prefix, service.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.Services),
+		&api.Service{},
+		prefix,
+		service.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.Service{} },

pkg/registry/serviceaccount/etcd/etcd.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/kubernetes/pkg/registry/generic/registry"
 	"k8s.io/kubernetes/pkg/registry/serviceaccount"
 	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/storage"
 )
 
 type REST struct {
@@ -35,7 +36,14 @@ func NewREST(opts generic.RESTOptions) *REST {
 
 	newListFunc := func() runtime.Object { return &api.ServiceAccountList{} }
 	storageInterface := opts.Decorator(
-		opts.Storage, cachesize.GetWatchCacheSizeByResource(cachesize.ServiceAccounts), &api.ServiceAccount{}, prefix, serviceaccount.Strategy, newListFunc)
+		opts.Storage,
+		cachesize.GetWatchCacheSizeByResource(cachesize.ServiceAccounts),
+		&api.ServiceAccount{},
+		prefix,
+		serviceaccount.Strategy,
+		newListFunc,
+		storage.NoTriggerPublisher,
+	)
 
 	store := &registry.Store{
 		NewFunc:     func() runtime.Object { return &api.ServiceAccount{} },

pkg/storage/cacher.go

@@ -59,11 +59,67 @@ type CacherConfig struct {
 	// KeyFunc is used to get a key in the underyling storage for a given object.
 	KeyFunc func(runtime.Object) (string, error)
 
+	// TriggerPublisherFunc is used for optimizing amount of watchers that
+	// needs to process an incoming event.
+	TriggerPublisherFunc TriggerPublisherFunc
+
 	// NewList is a function that creates new empty object storing a list of
 	// objects of type Type.
 	NewListFunc func() runtime.Object
 }
 
+type watchersMap map[int]*cacheWatcher
+
+func (wm watchersMap) addWatcher(w *cacheWatcher, number int) {
+	wm[number] = w
+}
+
+func (wm watchersMap) deleteWatcher(number int) {
+	delete(wm, number)
+}
+
+func (wm watchersMap) terminateAll() {
+	for key, watcher := range wm {
+		delete(wm, key)
+		watcher.stop()
+	}
+}
+
+type indexedWatchers struct {
+	allWatchers   watchersMap
+	valueWatchers map[string]watchersMap
+}
+
+func (i *indexedWatchers) addWatcher(w *cacheWatcher, number int, value string, supported bool) {
+	if supported {
+		if _, ok := i.valueWatchers[value]; !ok {
+			i.valueWatchers[value] = watchersMap{}
+		}
+		i.valueWatchers[value].addWatcher(w, number)
+	} else {
+		i.allWatchers.addWatcher(w, number)
+	}
+}
+
+func (i *indexedWatchers) deleteWatcher(number int, value string, supported bool) {
+	if supported {
+		i.valueWatchers[value].deleteWatcher(number)
+		if len(i.valueWatchers[value]) == 0 {
+			delete(i.valueWatchers, value)
+		}
+	} else {
+		i.allWatchers.deleteWatcher(number)
+	}
+}
+
+func (i *indexedWatchers) terminateAll() {
+	i.allWatchers.terminateAll()
+	for index, watchers := range i.valueWatchers {
+		watchers.terminateAll()
+		delete(i.valueWatchers, index)
+	}
+}
+
 // Cacher is responsible for serving WATCH and LIST requests for a given
 // resource from its internal cache and updating its cache in the background
 // based on the underlying storage contents.
@@ -87,16 +143,20 @@ type Cacher struct {
 	watchCache *watchCache
 	reflector  *cache.Reflector
 
-	// Registered watchers.
-	watcherIdx int
-	watchers   map[int]*cacheWatcher
-
 	// Versioner is used to handle resource versions.
 	versioner Versioner
 
 	// keyFunc is used to get a key in the underyling storage for a given object.
 	keyFunc func(runtime.Object) (string, error)
 
+	// triggerFunc is used for optimizing amount of watchers that needs to process
+	// an incoming event.
+	triggerFunc TriggerPublisherFunc
+	// watchers is mapping from the value of trigger function that a
+	// watcher is interested into the watchers
+	watcherIdx int
+	watchers   indexedWatchers
+
 	// Handling graceful termination.
 	stopLock sync.RWMutex
 	stopped  bool
@@ -120,13 +180,18 @@ func NewCacherFromConfig(config CacherConfig) *Cacher {
 	}
 
 	cacher := &Cacher{
-		ready:      newReady(),
-		storage:    config.Storage,
-		watchCache: watchCache,
-		reflector:  cache.NewReflector(listerWatcher, config.Type, watchCache, 0),
-		watchers:   make(map[int]*cacheWatcher),
-		versioner:  config.Versioner,
-		keyFunc:    config.KeyFunc,
+		ready:       newReady(),
+		storage:     config.Storage,
+		watchCache:  watchCache,
+		reflector:   cache.NewReflector(listerWatcher, config.Type, watchCache, 0),
+		versioner:   config.Versioner,
+		keyFunc:     config.KeyFunc,
+		triggerFunc: config.TriggerPublisherFunc,
+		watcherIdx:  0,
+		watchers: indexedWatchers{
+			allWatchers:   make(map[int]*cacheWatcher),
+			valueWatchers: make(map[string]watchersMap),
+		},
 		// We need to (potentially) stop both:
 		// - wait.Until go-routine
 		// - reflector.ListAndWatch
@@ -223,10 +288,20 @@ func (c *Cacher) Watch(ctx context.Context, key string, resourceVersion string,
 		return newErrWatcher(err), nil
 	}
 
+	triggerValue, triggerSupported := "", false
+	// TODO: Currently we assume that in a given Cacher object, any <filter> that is
+	// passed here is aware of exactly the same trigger (at most one).
+	// Thus, either 0 or 1 values will be returned.
+	if matchValues := filter.Trigger(); len(matchValues) > 0 {
+		triggerValue, triggerSupported = matchValues[0].Value, true
+	}
+
 	c.Lock()
 	defer c.Unlock()
-	watcher := newCacheWatcher(watchRV, initEvents, filterFunction(key, c.keyFunc, filter), forgetWatcher(c, c.watcherIdx))
-	c.watchers[c.watcherIdx] = watcher
+	forget := forgetWatcher(c, c.watcherIdx, triggerValue, triggerSupported)
+	watcher := newCacheWatcher(watchRV, initEvents, filterFunction(key, c.keyFunc, filter), forget)
+
+	c.watchers.addWatcher(watcher, c.watcherIdx, triggerValue, triggerSupported)
 	c.watcherIdx++
 	return watcher, nil
 }
@@ -307,21 +382,68 @@ func (c *Cacher) Codec() runtime.Codec {
 	return c.storage.Codec()
 }
 
+func (c *Cacher) triggerValues(event *watchCacheEvent) ([]string, bool) {
+	// TODO: Currently we assume that in a given Cacher object, its <c.triggerFunc>
+	// is aware of exactly the same trigger (at most one). Thus calling:
+	//   c.triggerFunc(<some object>)
+	// can return only 0 or 1 values.
+	// That means, that triggerValues itself may return up to 2 different values.
+	if c.triggerFunc == nil {
+		return nil, false
+	}
+	result := make([]string, 0, 2)
+	matchValues := c.triggerFunc(event.Object)
+	if len(matchValues) > 0 {
+		result = append(result, matchValues[0].Value)
+	}
+	if event.PrevObject == nil {
+		return result, len(result) > 0
+	}
+	prevMatchValues := c.triggerFunc(event.PrevObject)
+	if len(prevMatchValues) > 0 {
+		if len(result) == 0 || result[0] != prevMatchValues[0].Value {
+			result = append(result, prevMatchValues[0].Value)
+		}
+	}
+	return result, len(result) > 0
+}
+
 func (c *Cacher) processEvent(event watchCacheEvent) {
+	triggerValues, supported := c.triggerValues(&event)
+
 	c.Lock()
 	defer c.Unlock()
-	for _, watcher := range c.watchers {
+	// Iterate over "allWatchers" no matter what the trigger function is.
+	for _, watcher := range c.watchers.allWatchers {
 		watcher.add(event)
 	}
+	if supported {
+		// Iterate over watchers interested in the given values of the trigger.
+		for _, triggerValue := range triggerValues {
+			for _, watcher := range c.watchers.valueWatchers[triggerValue] {
+				watcher.add(event)
+			}
+		}
+	} else {
+		// supported equal to false generally means that trigger function
+		// is not defined (or not aware of any indexes). In this case,
+		// watchers filters should generally also don't generate any
+		// trigger values, but can cause problems in case of some
+		// misconfiguration. Thus we paranoidly leave this branch.
+
+		// Iterate over watchers interested in exact values for all values.
+		for _, watchers := range c.watchers.valueWatchers {
+			for _, watcher := range watchers {
+				watcher.add(event)
+			}
+		}
+	}
 }
 
 func (c *Cacher) terminateAllWatchers() {
 	c.Lock()
 	defer c.Unlock()
-	for key, watcher := range c.watchers {
-		delete(c.watchers, key)
-		watcher.stop()
-	}
+	c.watchers.terminateAll()
 }
 
 func (c *Cacher) isStopped() bool {
@@ -338,15 +460,15 @@ func (c *Cacher) Stop() {
 	c.stopWg.Wait()
 }
 
-func forgetWatcher(c *Cacher, index int) func(bool) {
+func forgetWatcher(c *Cacher, index int, triggerValue string, triggerSupported bool) func(bool) {
 	return func(lock bool) {
 		if lock {
 			c.Lock()
 			defer c.Unlock()
 		}
-		// It's possible that the watcher is already not in the map (e.g. in case of
+		// It's possible that the watcher is already not in the structure (e.g. in case of
 		// simulaneous Stop() and terminateAllWatchers(), but it doesn't break anything.
-		delete(c.watchers, index)
+		c.watchers.deleteWatcher(index, triggerValue, triggerSupported)
 	}
 }
 
@@ -362,7 +484,7 @@ func filterFunction(key string, keyFunc func(runtime.Object) (string, error), fi
 		}
 		return filter.Filter(obj)
 	}
-	return NewSimpleFilter(filterFunc)
+	return NewSimpleFilter(filterFunc, filter.Trigger)
 }
 
 // Returns resource version to which the underlying cache is synced.

pkg/storage/cacher_test.go

@@ -340,7 +340,7 @@ func TestFiltering(t *testing.T) {
 		}
 		return selector.Matches(labels.Set(metadata.GetLabels()))
 	}
-	filter := storage.NewSimpleFilter(filterFunc)
+	filter := storage.NewSimpleFilter(filterFunc, storage.NoTriggerFunc)
 	watcher, err := cacher.Watch(context.TODO(), "pods/ns/foo", fooCreated.ResourceVersion, filter)
 	if err != nil {
 		t.Fatalf("Unexpected error: %v", err)

pkg/storage/etcd/etcd_helper_test.go

@@ -158,7 +158,7 @@ func TestListFiltered(t *testing.T) {
 		pod := obj.(*api.Pod)
 		return pod.Name == "bar"
 	}
-	filter := storage.NewSimpleFilter(filterFunc)
+	filter := storage.NewSimpleFilter(filterFunc, storage.NoTriggerFunc)
 
 	var got api.PodList
 	err := helper.List(context.TODO(), key, "", filter, &got)

pkg/storage/etcd/etcd_watcher_test.go

@@ -56,6 +56,10 @@ func (f *firstLetterIsB) Filter(obj runtime.Object) bool {
 	return obj.(*api.Pod).Name[0] == 'b'
 }
 
+func (f *firstLetterIsB) Trigger() []storage.MatchValue {
+	return nil
+}
+
 func TestWatchInterpretations(t *testing.T) {
 	codec := testapi.Default.Codec()
 	// Declare some pods to make the test cases compact.
@@ -230,7 +234,7 @@ func TestSendResultDeleteEventHaveLatestIndex(t *testing.T) {
 	filterFunc := func(obj runtime.Object) bool {
 		return obj.(*api.Pod).Name != "bar"
 	}
-	filter := storage.NewSimpleFilter(filterFunc)
+	filter := storage.NewSimpleFilter(filterFunc, storage.NoTriggerFunc)
 	w := newEtcdWatcher(false, false, nil, filter, codec, versioner, nil, &fakeEtcdCache{})
 
 	eventChan := make(chan watch.Event, 1)

pkg/storage/etcd3/store_test.go

@@ -227,14 +227,17 @@ func TestGetToList(t *testing.T) {
 	tests := []struct {
 		key         string
 		filter      func(runtime.Object) bool
+		trigger     func() []storage.MatchValue
 		expectedOut []*api.Pod
 	}{{ // test GetToList on existing key
 		key:         key,
 		filter:      storage.EverythingFunc,
+		trigger:     storage.NoTriggerFunc,
 		expectedOut: []*api.Pod{storedObj},
 	}, { // test GetToList on non-existing key
 		key:         "/non-existing",
 		filter:      storage.EverythingFunc,
+		trigger:     storage.NoTriggerFunc,
 		expectedOut: nil,
 	}, { // test GetToList with filter to reject the pod
 		key: "/non-existing",
@@ -245,12 +248,13 @@ func TestGetToList(t *testing.T) {
 			}
 			return pod.Name != storedObj.Name
 		},
+		trigger:     storage.NoTriggerFunc,
 		expectedOut: nil,
 	}}
 
 	for i, tt := range tests {
 		out := &api.PodList{}
-		filter := storage.NewSimpleFilter(tt.filter)
+		filter := storage.NewSimpleFilter(tt.filter, tt.trigger)
 		err := store.GetToList(ctx, tt.key, filter, out)
 		if err != nil {
 			t.Fatalf("GetToList failed: %v", err)
@@ -489,14 +493,17 @@ func TestList(t *testing.T) {
 	tests := []struct {
 		prefix      string
 		filter      func(runtime.Object) bool
+		trigger     func() []storage.MatchValue
 		expectedOut []*api.Pod
 	}{{ // test List on existing key
 		prefix:      "/one-level/",
 		filter:      storage.EverythingFunc,
+		trigger:     storage.NoTriggerFunc,
 		expectedOut: []*api.Pod{preset[0].storedObj},
 	}, { // test List on non-existing key
 		prefix:      "/non-existing/",
 		filter:      storage.EverythingFunc,
+		trigger:     storage.NoTriggerFunc,
 		expectedOut: nil,
 	}, { // test List with filter
 		prefix: "/one-level/",
@@ -507,16 +514,18 @@ func TestList(t *testing.T) {
 			}
 			return pod.Name != preset[0].storedObj.Name
 		},
+		trigger:     storage.NoTriggerFunc,
 		expectedOut: nil,
 	}, { // test List with multiple levels of directories and expect flattened result
 		prefix:      "/two-level/",
 		filter:      storage.EverythingFunc,
+		trigger:     storage.NoTriggerFunc,
 		expectedOut: []*api.Pod{preset[1].storedObj, preset[2].storedObj},
 	}}
 
 	for i, tt := range tests {
 		out := &api.PodList{}
-		filter := storage.NewSimpleFilter(tt.filter)
+		filter := storage.NewSimpleFilter(tt.filter, tt.trigger)
 		err := store.List(ctx, tt.prefix, "0", filter, out)
 		if err != nil {
 			t.Fatalf("List failed: %v", err)

pkg/storage/etcd3/watcher_test.go

@@ -58,15 +58,18 @@ func testWatch(t *testing.T, recursive bool) {
 	tests := []struct {
 		key        string
 		filter     func(runtime.Object) bool
+		trigger    func() []storage.MatchValue
 		watchTests []*testWatchStruct
 	}{{ // create a key
 		key:        "/somekey-1",
 		watchTests: []*testWatchStruct{{podFoo, true, watch.Added}},
 		filter:     storage.EverythingFunc,
+		trigger:    storage.NoTriggerFunc,
 	}, { // create a key but obj gets filtered
 		key:        "/somekey-2",
 		watchTests: []*testWatchStruct{{podFoo, false, ""}},
 		filter:     func(runtime.Object) bool { return false },
+		trigger:    storage.NoTriggerFunc,
 	}, { // create a key but obj gets filtered. Then update it with unfiltered obj
 		key:        "/somekey-3",
 		watchTests: []*testWatchStruct{{podFoo, false, ""}, {podBar, true, watch.Added}},
@@ -74,10 +77,12 @@ func testWatch(t *testing.T, recursive bool) {
 			pod := obj.(*api.Pod)
 			return pod.Name == "bar"
 		},
+		trigger: storage.NoTriggerFunc,
 	}, { // update
 		key:        "/somekey-4",
 		watchTests: []*testWatchStruct{{podFoo, true, watch.Added}, {podBar, true, watch.Modified}},
 		filter:     storage.EverythingFunc,
+		trigger:    storage.NoTriggerFunc,
 	}, { // delete because of being filtered
 		key:        "/somekey-5",
 		watchTests: []*testWatchStruct{{podFoo, true, watch.Added}, {podBar, true, watch.Deleted}},
@@ -85,9 +90,10 @@ func testWatch(t *testing.T, recursive bool) {
 			pod := obj.(*api.Pod)
 			return pod.Name != "bar"
 		},
+		trigger: storage.NoTriggerFunc,
 	}}
 	for i, tt := range tests {
-		filter := storage.NewSimpleFilter(tt.filter)
+		filter := storage.NewSimpleFilter(tt.filter, tt.trigger)
 		w, err := store.watch(ctx, tt.key, "0", filter, recursive)
 		if err != nil {
 			t.Fatalf("Watch failed: %v", err)

pkg/storage/interfaces.go

@@ -51,11 +51,30 @@ type ResponseMeta struct {
 	ResourceVersion uint64
 }
 
+// MatchValue defines a pair (<index name>, <value for that index>).
+type MatchValue struct {
+	IndexName string
+	Value     string
+}
+
+// TriggerPublisherFunc is a function that takes an object, and returns a list of pairs
+// (<index name>, <index value for the given object>) for all indexes known
+// to that function.
+type TriggerPublisherFunc func(obj runtime.Object) []MatchValue
+
 // Filter is interface that is used to pass filtering mechanism.
 type Filter interface {
 	// Filter is a predicate which takes an API object and returns true
 	// if and only if the object should remain in the set.
 	Filter(obj runtime.Object) bool
+	// For any triggers known to the Filter, if Filter() can return only
+	// (a subset of) objects for which indexing function returns <value>,
+	// (<index name>, <value> pair would be returned.
+	//
+	// This is optimization to avoid computing Filter() function (which are
+	// usually relatively expensive) in case we are sure they will return
+	// false anyway.
+	Trigger() []MatchValue
 }
 
 // Everything is a Filter which accepts all objects.
@@ -65,10 +84,14 @@ var Everything Filter = everything{}
 type everything struct {
 }
 
-func (e everything) Filter(_ runtime.Object) bool {
+func (e everything) Filter(runtime.Object) bool {
 	return true
 }
 
+func (e everything) Trigger() []MatchValue {
+	return nil
+}
+
 // Pass an UpdateFunc to Interface.GuaranteedUpdate to make an update
 // that is guaranteed to succeed.
 // See the comment for GuaranteedUpdate for more details.

pkg/storage/util.go

@@ -38,16 +38,24 @@ func SimpleUpdate(fn SimpleUpdateFunc) UpdateFunc {
 
 // SimpleFilter implements Filter interface.
 type SimpleFilter struct {
-	filterFunc func(runtime.Object) bool
+	filterFunc  func(runtime.Object) bool
+	triggerFunc func() []MatchValue
 }
 
 func (s *SimpleFilter) Filter(obj runtime.Object) bool {
 	return s.filterFunc(obj)
 }
 
-func NewSimpleFilter(filterFunc func(runtime.Object) bool) Filter {
+func (s *SimpleFilter) Trigger() []MatchValue {
+	return s.triggerFunc()
+}
+
+func NewSimpleFilter(
+	filterFunc func(runtime.Object) bool,
+	triggerFunc func() []MatchValue) Filter {
 	return &SimpleFilter{
-		filterFunc: filterFunc,
+		filterFunc:  filterFunc,
+		triggerFunc: triggerFunc,
 	}
 }
 
@@ -55,6 +63,14 @@ func EverythingFunc(runtime.Object) bool {
 	return true
 }
 
+func NoTriggerFunc() []MatchValue {
+	return nil
+}
+
+func NoTriggerPublisher(runtime.Object) []MatchValue {
+	return nil
+}
+
 // ParseWatchResourceVersion takes a resource version argument and converts it to
 // the etcd version we should pass to helper.Watch(). Because resourceVersion is
 // an opaque value, the default watch behavior for non-zero watch is to watch