Filter List in Storage level to avoid additional copies.

pkg/registry/generic/etcd/etcd.go

@@ -150,6 +150,7 @@ func (e *Etcd) List(ctx api.Context, label labels.Selector, field fields.Selecto
 func (e *Etcd) ListPredicate(ctx api.Context, m generic.Matcher) (runtime.Object, error) {
 	list := e.NewListFunc()
 	trace := util.NewTrace("List " + reflect.TypeOf(list).String())
+	filterFunc := e.filterAndDecorateFunction(m)
 	defer trace.LogIfLong(600 * time.Millisecond)
 	if name, ok := m.MatchesSingle(); ok {
 		trace.Step("About to read single object")
@@ -157,21 +158,20 @@ func (e *Etcd) ListPredicate(ctx api.Context, m generic.Matcher) (runtime.Object
 		if err != nil {
 			return nil, err
 		}
-		err = e.Storage.GetToList(key, list)
+		err = e.Storage.GetToList(key, filterFunc, list)
 		trace.Step("Object extracted")
 		if err != nil {
 			return nil, err
 		}
 	} else {
 		trace.Step("About to list directory")
-		err := e.Storage.List(e.KeyRootFunc(ctx), list)
+		err := e.Storage.List(e.KeyRootFunc(ctx), filterFunc, list)
 		trace.Step("List extracted")
 		if err != nil {
 			return nil, err
 		}
 	}
-	defer trace.Step("List filtered")
-	return generic.FilterList(list, m, generic.DecoratorFunc(e.Decorator))
+	return list, nil
 }
 
 // Create inserts a new item according to the unique key from the object.
@@ -449,8 +449,21 @@ func (e *Etcd) WatchPredicate(ctx api.Context, m generic.Matcher, resourceVersio
 	if err != nil {
 		return nil, err
 	}
+	filterFunc := e.filterAndDecorateFunction(m)
 
-	filterFunc := func(obj runtime.Object) bool {
+	if name, ok := m.MatchesSingle(); ok {
+		key, err := e.KeyFunc(ctx, name)
+		if err != nil {
+			return nil, err
+		}
+		return e.Storage.Watch(key, version, filterFunc)
+	}
+
+	return e.Storage.WatchList(e.KeyRootFunc(ctx), version, filterFunc)
+}
+
+func (e *Etcd) filterAndDecorateFunction(m generic.Matcher) func(runtime.Object) bool {
+	return func(obj runtime.Object) bool {
 		matches, err := m.Matches(obj)
 		if err != nil {
 			glog.Errorf("unable to match watch: %v", err)
@@ -464,16 +477,6 @@ func (e *Etcd) WatchPredicate(ctx api.Context, m generic.Matcher, resourceVersio
 		}
 		return matches
 	}
-
-	if name, ok := m.MatchesSingle(); ok {
-		key, err := e.KeyFunc(ctx, name)
-		if err != nil {
-			return nil, err
-		}
-		return e.Storage.Watch(key, version, filterFunc)
-	}
-
-	return e.Storage.WatchList(e.KeyRootFunc(ctx), version, filterFunc)
 }
 
 // calculateTTL is a helper for retrieving the updated TTL for an object or returning an error

pkg/registry/generic/matcher.go

@@ -118,38 +118,3 @@ var (
 	_ = Matcher(&SelectionPredicate{})
 	_ = Matcher(matcherFunc(nil))
 )
-
-// DecoratorFunc can mutate the provided object prior to being returned.
-type DecoratorFunc func(obj runtime.Object) error
-
-// FilterList filters any list object that conforms to the api conventions,
-// provided that 'm' works with the concrete type of list. d is an optional
-// decorator for the returned functions. Only matching items are decorated.
-func FilterList(list runtime.Object, m Matcher, d DecoratorFunc) (filtered runtime.Object, err error) {
-	// TODO: push a matcher down into tools.etcdHelper to avoid all this
-	// nonsense. This is a lot of unnecessary copies.
-	items, err := runtime.ExtractList(list)
-	if err != nil {
-		return nil, err
-	}
-	var filteredItems []runtime.Object
-	for _, obj := range items {
-		match, err := m.Matches(obj)
-		if err != nil {
-			return nil, err
-		}
-		if match {
-			if d != nil {
-				if err := d(obj); err != nil {
-					return nil, err
-				}
-			}
-			filteredItems = append(filteredItems, obj)
-		}
-	}
-	err = runtime.SetList(list, filteredItems)
-	if err != nil {
-		return nil, err
-	}
-	return list, nil
-}

pkg/registry/generic/matcher_test.go

@@ -18,7 +18,6 @@ package generic
 
 import (
 	"errors"
-	"reflect"
 	"testing"
 
 	"k8s.io/kubernetes/pkg/fields"
@@ -118,44 +117,6 @@ func TestSelectionPredicate(t *testing.T) {
 	}
 }
 
-func TestFilterList(t *testing.T) {
-	try := &IgnoredList{
-		Items: []Ignored{
-			{"foo"},
-			{"bar"},
-			{"baz"},
-			{"qux"},
-			{"zot"},
-		},
-	}
-	expect := &IgnoredList{
-		Items: []Ignored{
-			{"bar"},
-			{"baz"},
-		},
-	}
-
-	m := MatcherFunc(func(obj runtime.Object) (bool, error) {
-		i, ok := obj.(*Ignored)
-		if !ok {
-			return false, errors.New("wrong type")
-		}
-		return i.ID[0] == 'b', nil
-	})
-	if _, matchesSingleObject := m.MatchesSingle(); matchesSingleObject {
-		t.Errorf("matcher unexpectedly matches only a single object.")
-	}
-
-	got, err := FilterList(try, m, nil)
-	if err != nil {
-		t.Fatalf("Unexpected error %v", err)
-	}
-
-	if e, a := expect, got; !reflect.DeepEqual(e, a) {
-		t.Errorf("Expected %#v, got %#v", e, a)
-	}
-}
-
 func TestSingleMatch(t *testing.T) {
 	m := MatchOnKey("pod-name-here", func(obj runtime.Object) (bool, error) { return true, nil })
 	got, ok := m.MatchesSingle()