stream: remove Event.Key

Makes Payload a type with FilterByKey so that Payloads can implement
filtering by key. With this approach we don't need to expose a Namespace
field on Event, and we don't need to invest micro formats or require a
bunch of code to be aware of exactly how the key field is encoded.

agent/consul/state/catalog_events.go

@@ -13,6 +13,26 @@ import (
 type EventPayloadCheckServiceNode struct {
 	Op    pbsubscribe.CatalogOp
 	Value *structs.CheckServiceNode
+	// key is used to override the key used to filter the payload. It is set for
+	// events in the connect topic to specify the name of the underlying service
+	// when the change event is for a sidecar or gateway.
+	key string
+}
+
+func (e EventPayloadCheckServiceNode) FilterByKey(key, namespace string) bool {
+	if key == "" && namespace == "" {
+		return true
+	}
+
+	if e.Value.Service == nil {
+		return false
+	}
+
+	name := e.Value.Service.Service
+	if e.key != "" {
+		name = e.key
+	}
+	return key == name && namespace == e.Value.Service.EnterpriseMeta.GetNamespace()
 }
 
 // serviceHealthSnapshot returns a stream.SnapshotFunc that provides a snapshot
@@ -42,10 +62,6 @@ func serviceHealthSnapshot(s *Store, topic stream.Topic) stream.SnapshotFunc {
 				},
 			}
 
-			if n.Service != nil {
-				event.Key = n.Service.Service
-			}
-
 			// append each event as a separate item so that they can be serialized
 			// separately, to prevent the encoding of one massive message.
 			buf.Append([]stream.Event{event})
@@ -252,7 +268,9 @@ func isConnectProxyDestinationServiceChange(idx uint64, before, after *structs.S
 
 	e := newServiceHealthEventDeregister(idx, before)
 	e.Topic = topicServiceHealthConnect
-	e.Key = getPayloadCheckServiceNode(e.Payload).Service.Proxy.DestinationServiceName
+	payload := e.Payload.(EventPayloadCheckServiceNode)
+	payload.key = payload.Value.Service.Proxy.DestinationServiceName
+	e.Payload = payload
 	return e, true
 }
 
@@ -304,7 +322,9 @@ func serviceHealthToConnectEvents(events ...stream.Event) []stream.Event {
 			result = append(result, connectEvent)
 
 		case node.Service.Kind == structs.ServiceKindConnectProxy:
-			connectEvent.Key = node.Service.Proxy.DestinationServiceName
+			payload := event.Payload.(EventPayloadCheckServiceNode)
+			payload.key = node.Service.Proxy.DestinationServiceName
+			connectEvent.Payload = payload
 			result = append(result, connectEvent)
 
 		default:
@@ -316,7 +336,7 @@ func serviceHealthToConnectEvents(events ...stream.Event) []stream.Event {
 	return result
 }
 
-func getPayloadCheckServiceNode(payload interface{}) *structs.CheckServiceNode {
+func getPayloadCheckServiceNode(payload stream.Payload) *structs.CheckServiceNode {
 	ep, ok := payload.(EventPayloadCheckServiceNode)
 	if !ok {
 		return nil
@@ -431,7 +451,6 @@ func newServiceHealthEventRegister(
 	}
 	return stream.Event{
 		Topic: topicServiceHealth,
-		Key:   sn.ServiceName,
 		Index: idx,
 		Payload: EventPayloadCheckServiceNode{
 			Op:    pbsubscribe.CatalogOp_Register,
@@ -458,7 +477,6 @@ func newServiceHealthEventDeregister(idx uint64, sn *structs.ServiceNode) stream
 
 	return stream.Event{
 		Topic: topicServiceHealth,
-		Key:   sn.ServiceName,
 		Index: idx,
 		Payload: EventPayloadCheckServiceNode{
 			Op:    pbsubscribe.CatalogOp_Deregister,

agent/consul/state/catalog_events_test.go

@@ -822,6 +822,7 @@ func TestServiceHealthEventsFromChanges(t *testing.T) {
 
 				return nil
 			},
+
 			WantEvents: []stream.Event{
 				// We should see:
 				//  - service dereg for web and proxy on node2
@@ -832,29 +833,15 @@ func TestServiceHealthEventsFromChanges(t *testing.T) {
 				//  - connect reg for api on node2
 				testServiceHealthDeregistrationEvent(t, "web", evNode2),
 				testServiceHealthDeregistrationEvent(t, "web", evNode2, evSidecar),
-				testServiceHealthDeregistrationEvent(t, "web",
-					evConnectTopic,
-					evNode2,
-					evSidecar,
-				),
+				testServiceHealthDeregistrationEvent(t, "web", evConnectTopic, evNode2, evSidecar),
 
 				testServiceHealthEvent(t, "web", evNodeUnchanged),
 				testServiceHealthEvent(t, "web", evSidecar, evNodeUnchanged),
 				testServiceHealthEvent(t, "web", evConnectTopic, evSidecar, evNodeUnchanged),
 
-				testServiceHealthEvent(t, "api",
-					evNode2,
-					evConnectNative,
-					evNodeUnchanged,
-				),
-				testServiceHealthEvent(t, "api",
-					evNode2,
-					evConnectTopic,
-					evConnectNative,
-					evNodeUnchanged,
-				),
+				testServiceHealthEvent(t, "api", evNode2, evConnectNative, evNodeUnchanged),
+				testServiceHealthEvent(t, "api", evNode2, evConnectTopic, evConnectNative, evNodeUnchanged),
 			},
-			WantErr: false,
 		},
 	}
 
@@ -1192,10 +1179,10 @@ func evSidecar(e *stream.Event) error {
 		csn.Checks[1].ServiceName = svc + "_sidecar_proxy"
 	}
 
-	// Update event key to be the proxy service name, but only if this is not
-	// already in the connect topic
-	if e.Topic != topicServiceHealthConnect {
-		e.Key = csn.Service.Service
+	if e.Topic == topicServiceHealthConnect {
+		payload := e.Payload.(EventPayloadCheckServiceNode)
+		payload.key = svc
+		e.Payload = payload
 	}
 	return nil
 }
@@ -1264,15 +1251,13 @@ func evChecksUnchanged(e *stream.Event) error {
 // name but not ID simulating an in-place service rename.
 func evRenameService(e *stream.Event) error {
 	csn := getPayloadCheckServiceNode(e.Payload)
-	isSidecar := csn.Service.Kind == structs.ServiceKindConnectProxy
 
-	if !isSidecar {
+	if csn.Service.Kind != structs.ServiceKindConnectProxy {
 		csn.Service.Service += "_changed"
 		// Update service checks
 		if len(csn.Checks) >= 2 {
 			csn.Checks[1].ServiceName += "_changed"
 		}
-		e.Key += "_changed"
 		return nil
 	}
 	// This is a sidecar, it's not really realistic but lets only update the
@@ -1280,12 +1265,13 @@ func evRenameService(e *stream.Event) error {
 	// we get the right result. This is certainly possible if not likely so a
 	// valid case.
 
-	// We don't need to update out own details, only the name of the destination
+	// We don't need to update our own details, only the name of the destination
 	csn.Service.Proxy.DestinationServiceName += "_changed"
 
-	// If this is the connect topic we need to change the key too
 	if e.Topic == topicServiceHealthConnect {
-		e.Key += "_changed"
+		payload := e.Payload.(EventPayloadCheckServiceNode)
+		payload.key = csn.Service.Proxy.DestinationServiceName
+		e.Payload = payload
 	}
 	return nil
 }
@@ -1373,7 +1359,6 @@ func newTestEventServiceHealthRegister(index uint64, nodeNum int, svc string) st
 
 	return stream.Event{
 		Topic: topicServiceHealth,
-		Key:   svc,
 		Index: index,
 		Payload: EventPayloadCheckServiceNode{
 			Op: pbsubscribe.CatalogOp_Register,
@@ -1444,7 +1429,6 @@ func newTestEventServiceHealthRegister(index uint64, nodeNum int, svc string) st
 func newTestEventServiceHealthDeregister(index uint64, nodeNum int, svc string) stream.Event {
 	return stream.Event{
 		Topic: topicServiceHealth,
-		Key:   svc,
 		Index: index,
 		Payload: EventPayloadCheckServiceNode{
 			Op: pbsubscribe.CatalogOp_Deregister,

agent/consul/state/store_integration_test.go

@@ -395,9 +395,8 @@ func newTestSnapshotHandlers(s *Store) stream.SnapshotHandlers {
 			for _, node := range nodes {
 				event := stream.Event{
 					Topic:   req.Topic,
-					Key:     req.Key,
 					Index:   node.ModifyIndex,
-					Payload: node,
+					Payload: nodePayload{node: node, key: req.Key},
 				}
 				snap.Append([]stream.Event{event})
 			}
@@ -406,6 +405,15 @@ func newTestSnapshotHandlers(s *Store) stream.SnapshotHandlers {
 	}
 }
 
+type nodePayload struct {
+	key  string
+	node *structs.ServiceNode
+}
+
+func (p nodePayload) FilterByKey(key, _ string) bool {
+	return p.key == key
+}
+
 func createTokenAndWaitForACLEventPublish(t *testing.T, s *Store) *structs.ACLToken {
 	token := &structs.ACLToken{
 		AccessorID:  "3af117a9-2233-4cf4-8ff8-3c749c9906b4",

agent/consul/stream/event.go

@@ -14,15 +14,23 @@ type Topic fmt.Stringer
 // EventPublisher and returned to Subscribers.
 type Event struct {
 	Topic   Topic
-	Key     string
 	Index   uint64
-	Payload interface{}
+	Payload Payload
+}
+
+type Payload interface {
+	// FilterByKey must return true if the Payload should be included in a subscription
+	// requested with the key and namespace.
+	// Generally this means that the payload matches the key and namespace or
+	// the payload is a special framing event that should be returned to every
+	// subscription.
+	FilterByKey(key, namespace string) bool
 }
 
 // Len returns the number of events contained within this event. If the Payload
 // is a []Event, the length of that slice is returned. Otherwise 1 is returned.
 func (e Event) Len() int {
-	if batch, ok := e.Payload.([]Event); ok {
+	if batch, ok := e.Payload.(PayloadEvents); ok {
 		return len(batch)
 	}
 	return 1
@@ -31,7 +39,7 @@ func (e Event) Len() int {
 // Filter returns an Event filtered to only those Events where f returns true.
 // If the second return value is false, every Event was removed by the filter.
 func (e Event) Filter(f func(Event) bool) (Event, bool) {
-	batch, ok := e.Payload.([]Event)
+	batch, ok := e.Payload.(PayloadEvents)
 	if !ok {
 		return e, f(e)
 	}
@@ -50,7 +58,7 @@ func (e Event) Filter(f func(Event) bool) (Event, bool) {
 		return e, size != 0
 	}
 
-	filtered := make([]Event, 0, size)
+	filtered := make(PayloadEvents, 0, size)
 	for idx := range batch {
 		event := batch[idx]
 		if f(event) {
@@ -64,6 +72,20 @@ func (e Event) Filter(f func(Event) bool) (Event, bool) {
 	return e, true
 }
 
+// PayloadEvents is an Payload which contains multiple Events.
+type PayloadEvents []Event
+
+// TODO: this method is not called, but needs to exist so that we can store
+// a slice of events as a payload. In the future we should be able to refactor
+// Event.Filter so that this FilterByKey includes the re-slicing.
+func (e PayloadEvents) FilterByKey(_, _ string) bool {
+	return true
+}
+
+func (e PayloadEvents) Events() []Event {
+	return e
+}
+
 // IsEndOfSnapshot returns true if this is a framing event that indicates the
 // snapshot has completed. Subsequent events from Subscription.Next will be
 // streamed as they occur.
@@ -80,12 +102,24 @@ func (e Event) IsNewSnapshotToFollow() bool {
 
 type endOfSnapshot struct{}
 
+func (endOfSnapshot) FilterByKey(string, string) bool {
+	return true
+}
+
 type newSnapshotToFollow struct{}
 
+func (newSnapshotToFollow) FilterByKey(string, string) bool {
+	return true
+}
+
 type closeSubscriptionPayload struct {
 	tokensSecretIDs []string
 }
 
+func (closeSubscriptionPayload) FilterByKey(string, string) bool {
+	return true
+}
+
 // NewCloseSubscriptionEvent returns a special Event that is handled by the
 // stream package, and is never sent to subscribers. EventProcessor handles
 // these events, and closes any subscriptions which were created using a token

agent/consul/stream/event_publisher.go

@@ -185,7 +185,6 @@ func (e *EventPublisher) Subscribe(req *SubscribeRequest) (*Subscription, error)
 	if req.Index > 0 {
 		snap.buffer.Append([]Event{{
 			Topic:   req.Topic,
-			Key:     req.Key,
 			Payload: newSnapshotToFollow{},
 		}})
 

agent/consul/stream/event_publisher_test.go

@@ -43,24 +43,37 @@ func TestEventPublisher_SubscribeWithIndex0(t *testing.T) {
 
 	events := []Event{{
 		Topic:   testTopic,
-		Key:     "sub-key",
-		Payload: "the-published-event-payload",
+		Payload: simplePayload{key: "sub-key", value: "the-published-event-payload"},
 	}}
 	publisher.Publish(events)
 
 	// Subscriber should see the published event
 	next = getNextEvent(t, eventCh)
-	expected := Event{Payload: "the-published-event-payload", Key: "sub-key", Topic: testTopic}
+	expected := Event{
+		Topic:   testTopic,
+		Payload: simplePayload{key: "sub-key", value: "the-published-event-payload"},
+	}
 	require.Equal(t, expected, next)
 }
 
 var testSnapshotEvent = Event{
 	Topic:   testTopic,
-	Payload: "snapshot-event-payload",
-	Key:     "sub-key",
+	Payload: simplePayload{key: "sub-key", value: "snapshot-event-payload"},
 	Index:   1,
 }
 
+type simplePayload struct {
+	key   string
+	value string
+}
+
+func (p simplePayload) FilterByKey(key, _ string) bool {
+	if key == "" {
+		return true
+	}
+	return p.key == key
+}
+
 func newTestSnapshotHandlers() SnapshotHandlers {
 	return SnapshotHandlers{
 		testTopic: func(req SubscribeRequest, buf SnapshotAppender) (uint64, error) {
@@ -193,8 +206,7 @@ func TestEventPublisher_SubscribeWithIndex0_FromCache(t *testing.T) {
 
 	expected := Event{
 		Topic:   testTopic,
-		Key:     "sub-key",
-		Payload: "the-published-event-payload",
+		Payload: simplePayload{key: "sub-key", value: "the-published-event-payload"},
 		Index:   3,
 	}
 	publisher.Publish([]Event{expected})
@@ -243,9 +255,8 @@ func TestEventPublisher_SubscribeWithIndexNotZero_CanResume(t *testing.T) {
 
 		expected := Event{
 			Topic:   testTopic,
-			Key:     "sub-key",
 			Index:   3,
-			Payload: "event-3",
+			Payload: simplePayload{key: "sub-key", value: "event-3"},
 		}
 		publisher.publishEvent([]Event{expected})
 
@@ -284,9 +295,8 @@ func TestEventPublisher_SubscribeWithIndexNotZero_NewSnapshot(t *testing.T) {
 
 	nextEvent := Event{
 		Topic:   testTopic,
-		Key:     "sub-key",
 		Index:   3,
-		Payload: "event-3",
+		Payload: simplePayload{key: "sub-key", value: "event-3"},
 	}
 
 	runStep(t, "publish an event while unsubed", func(t *testing.T) {
@@ -341,9 +351,8 @@ func TestEventPublisher_SubscribeWithIndexNotZero_NewSnapshotFromCache(t *testin
 
 	nextEvent := Event{
 		Topic:   testTopic,
-		Key:     "sub-key",
 		Index:   3,
-		Payload: "event-3",
+		Payload: simplePayload{key: "sub-key", value: "event-3"},
 	}
 
 	runStep(t, "publish an event while unsubed", func(t *testing.T) {

agent/consul/stream/event_snapshot.go

@@ -37,7 +37,6 @@ func (s *eventSnapshot) appendAndSplice(req SubscribeRequest, fn SnapshotFunc, t
 	}
 	s.buffer.Append([]Event{{
 		Topic:   req.Topic,
-		Key:     req.Key,
 		Index:   idx,
 		Payload: endOfSnapshot{},
 	}})

agent/consul/stream/event_snapshot_test.go

@@ -129,9 +129,9 @@ func TestEventSnapshot(t *testing.T) {
 				e := curItem.Events[0]
 				switch {
 				case snapDone:
-					payload, ok := e.Payload.(string)
+					payload, ok := e.Payload.(simplePayload)
 					require.True(t, ok, "want health event got: %#v", e.Payload)
-					updateIDs = append(updateIDs, payload)
+					updateIDs = append(updateIDs, payload.value)
 					if len(updateIDs) == tc.updatesAfterSnap {
 						// We're done!
 						break RECV
@@ -139,9 +139,9 @@ func TestEventSnapshot(t *testing.T) {
 				case e.IsEndOfSnapshot():
 					snapDone = true
 				default:
-					payload, ok := e.Payload.(string)
+					payload, ok := e.Payload.(simplePayload)
 					require.True(t, ok, "want health event got: %#v", e.Payload)
-					snapIDs = append(snapIDs, payload)
+					snapIDs = append(snapIDs, payload.value)
 				}
 			}
 
@@ -176,6 +176,6 @@ func newDefaultHealthEvent(index uint64, n int) Event {
 	return Event{
 		Index:   index,
 		Topic:   testTopic,
-		Payload: fmt.Sprintf("test-event-%03d", n),
+		Payload: simplePayload{value: fmt.Sprintf("test-event-%03d", n)},
 	}
 }

agent/consul/stream/subscription.go

@@ -53,9 +53,21 @@ type Subscription struct {
 // SubscribeRequest identifies the types of events the subscriber would like to
 // receiver. Topic and Token are required.
 type SubscribeRequest struct {
+	// Topic to subscribe to
 	Topic Topic
-	Key   string
+	// Key used to filter events in the topic. Only events matching the key will
+	// be returned by the subscription. A blank key will return all events. Key
+	// is generally the name of the resource.
+	Key string
+	// Namespace used to filter events in the topic. Only events matching the
+	// namespace will be returned by the subscription.
+	Namespace string
+	// Token that was used to authenticate the request. If any ACL policy
+	// changes impact the token the subscription will be forcefully closed.
 	Token string
+	// Index is the last index the client received. If non-zero the
+	// subscription will be resumed from this index. If the index is out-of-date
+	// a NewSnapshotToFollow event will be sent.
 	Index uint64
 }
 
@@ -115,9 +127,8 @@ func newEventFromBatch(req SubscribeRequest, events []Event) Event {
 	}
 	return Event{
 		Topic:   req.Topic,
-		Key:     req.Key,
 		Index:   first.Index,
-		Payload: events,
+		Payload: PayloadEvents(events),
 	}
 }
 
@@ -128,7 +139,7 @@ func filterByKey(req SubscribeRequest, events []Event) (Event, bool) {
 	}
 
 	fn := func(e Event) bool {
-		return req.Key == e.Key
+		return e.Payload.FilterByKey(req.Key, req.Namespace)
 	}
 	return event.Filter(fn)
 }

agent/consul/stream/subscription_test.go

@@ -69,7 +69,7 @@ func TestSubscription(t *testing.T) {
 	require.True(t, elapsed < 200*time.Millisecond,
 		"Event should have been delivered immediately, took %s", elapsed)
 	require.Equal(t, index, got.Index)
-	require.Equal(t, "test", got.Key)
+	require.Equal(t, "test", got.Payload.(simplePayload).key)
 
 	// Cancelling the subscription context should unblock Next
 	start = time.Now()
@@ -130,20 +130,17 @@ func TestSubscription_Close(t *testing.T) {
 }
 
 func publishTestEvent(index uint64, b *eventBuffer, key string) {
-	// Don't care about the event payload for now just the semantics of publishing
-	// something. This is not a valid stream in the end-to-end streaming protocol
-	// but enough to test subscription mechanics.
 	e := Event{
-		Index: index,
-		Topic: testTopic,
-		Key:   key,
+		Index:   index,
+		Topic:   testTopic,
+		Payload: simplePayload{key: key},
 	}
 	b.Append([]Event{e})
 }
 
 func TestFilter_NoKey(t *testing.T) {
-	events := make([]Event, 0, 5)
-	events = append(events, Event{Key: "One", Index: 102}, Event{Key: "Two"})
+	events := make(PayloadEvents, 0, 5)
+	events = append(events, newSimpleEvent("One", 102), newSimpleEvent("Two", 102))
 
 	req := SubscribeRequest{Topic: testTopic}
 	actual, ok := filterByKey(req, events)
@@ -151,26 +148,33 @@ func TestFilter_NoKey(t *testing.T) {
 	require.Equal(t, Event{Topic: testTopic, Index: 102, Payload: events}, actual)
 
 	// test that a new array was not allocated
-	require.Equal(t, cap(actual.Payload.([]Event)), 5)
+	require.Equal(t, cap(actual.Payload.(PayloadEvents)), 5)
+}
+
+func newSimpleEvent(key string, index uint64) Event {
+	return Event{Index: index, Payload: simplePayload{key: key}}
 }
 
 func TestFilter_WithKey_AllEventsMatch(t *testing.T) {
-	events := make([]Event, 0, 5)
-	events = append(events, Event{Key: "Same", Index: 103}, Event{Key: "Same"})
+	events := make(PayloadEvents, 0, 5)
+	events = append(events, newSimpleEvent("Same", 103), newSimpleEvent("Same", 103))
 
 	req := SubscribeRequest{Topic: testTopic, Key: "Same"}
 	actual, ok := filterByKey(req, events)
 	require.True(t, ok)
-	expected := Event{Topic: testTopic, Index: 103, Key: "Same", Payload: events}
+	expected := Event{Topic: testTopic, Index: 103, Payload: events}
 	require.Equal(t, expected, actual)
 
 	// test that a new array was not allocated
-	require.Equal(t, 5, cap(actual.Payload.([]Event)))
+	require.Equal(t, 5, cap(actual.Payload.(PayloadEvents)))
 }
 
 func TestFilter_WithKey_SomeEventsMatch(t *testing.T) {
 	events := make([]Event, 0, 5)
-	events = append(events, Event{Key: "Same", Index: 104}, Event{Key: "Other"}, Event{Key: "Same"})
+	events = append(events,
+		newSimpleEvent("Same", 104),
+		newSimpleEvent("Other", 0),
+		newSimpleEvent("Same", 0))
 
 	req := SubscribeRequest{Topic: testTopic, Key: "Same"}
 	actual, ok := filterByKey(req, events)
@@ -178,18 +182,17 @@ func TestFilter_WithKey_SomeEventsMatch(t *testing.T) {
 	expected := Event{
 		Topic:   testTopic,
 		Index:   104,
-		Key:     "Same",
-		Payload: []Event{{Key: "Same", Index: 104}, {Key: "Same"}},
+		Payload: PayloadEvents{newSimpleEvent("Same", 104), newSimpleEvent("Same", 0)},
 	}
 	require.Equal(t, expected, actual)
 
 	// test that a new array was allocated with the correct size
-	require.Equal(t, cap(actual.Payload.([]Event)), 2)
+	require.Equal(t, cap(actual.Payload.(PayloadEvents)), 2)
 }
 
 func TestFilter_WithKey_NoEventsMatch(t *testing.T) {
 	events := make([]Event, 0, 5)
-	events = append(events, Event{Key: "Same"}, Event{Key: "Same"})
+	events = append(events, newSimpleEvent("Same", 0), newSimpleEvent("Same", 0))
 
 	req := SubscribeRequest{Topic: testTopic, Key: "Other"}
 	_, ok := filterByKey(req, events)

agent/rpc/subscribe/subscribe.go

@@ -153,9 +153,9 @@ func newEventFromStreamEvent(event stream.Event) *pbsubscribe.Event {
 	return e
 }
 
-func setPayload(e *pbsubscribe.Event, payload interface{}) {
+func setPayload(e *pbsubscribe.Event, payload stream.Payload) {
 	switch p := payload.(type) {
-	case []stream.Event:
+	case stream.PayloadEvents:
 		e.Payload = &pbsubscribe.Event_EventBatch{
 			EventBatch: &pbsubscribe.EventBatch{
 				Events: batchEventsFromEventSlice(p),

agent/rpc/subscribe/subscribe_test.go

@@ -915,7 +915,7 @@ func TestNewEventFromSteamEvent(t *testing.T) {
 			name: "event batch",
 			event: stream.Event{
 				Index: 2002,
-				Payload: []stream.Event{
+				Payload: stream.PayloadEvents{
 					{
 						Index: 2002,
 						Payload: state.EventPayloadCheckServiceNode{

agent/structs/structs_oss.go

@@ -74,6 +74,11 @@ func (_ *EnterpriseMeta) FillAuthzContext(_ *acl.AuthorizerContext) {}
 
 func (_ *EnterpriseMeta) Normalize() {}
 
+// GetNamespace always returns the empty string.
+func (_ *EnterpriseMeta) GetNamespace() string {
+	return ""
+}
+
 // FillAuthzContext stub
 func (_ *DirEntry) FillAuthzContext(_ *acl.AuthorizerContext) {}