track latestevent on /peek

federationapi/routing/peek.go

@@ -87,14 +87,17 @@ func Peek(
 		return util.JSONResponse{Code: http.StatusNotFound, JSON: nil}
 	}
 
+	respPeek := gomatrixserverlib.RespPeek{
+		StateEvents: gomatrixserverlib.UnwrapEventHeaders(response.StateEvents),
+		AuthEvents:  gomatrixserverlib.UnwrapEventHeaders(response.AuthChainEvents),
+		RoomVersion: response.RoomVersion,
+		LatestEvent: response.LatestEvent.Unwrap(),
+		RenewalInterval: renewalInterval,
+	}
+
 	return util.JSONResponse{
 		Code: http.StatusOK,
-		JSON: gomatrixserverlib.RespPeek{
-			StateEvents: gomatrixserverlib.UnwrapEventHeaders(response.StateEvents),
-			AuthEvents:  gomatrixserverlib.UnwrapEventHeaders(response.AuthChainEvents),
-			RoomVersion: response.RoomVersion,
-			RenewalInterval: renewalInterval,
-		},
+		JSON: respPeek,
 	}
 }
 

federationapi/routing/send.go

@@ -456,7 +456,7 @@ func (t *txnReq) processEventWithMissingState(ctx context.Context, e gomatrixser
 	// pass the event along with the state to the roomserver using a background context so we don't
 	// needlessly expire
 	headeredEvent := e.Headered(roomVersion)
-	return api.SendEventWithState(context.Background(), t.rsAPI, resolvedState, &headeredEvent, t.haveEventIDs(), roomVersion)
+	return api.SendEventWithState(context.Background(), t.rsAPI, resolvedState, headeredEvent, t.haveEventIDs(), roomVersion)
 }
 
 // lookupStateAfterEvent returns the room state after `eventID`, which is the state before eventID with the state of `eventID` (if it's a state event)

federationsender/consumers/roomserver.go

@@ -118,6 +118,7 @@ func (s *OutputRoomEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
 // processInboundPeek starts tracking a new federated inbound peek (replacing the existing one if any)
 // causing the federationsender to start sending messages to the peeking server
 func (s *OutputRoomEventConsumer) processInboundPeek(orp api.OutputNewInboundPeek) error {
+	// FIXME: do something with orp.LatestEventID to prevent races
   	return s.db.AddInboundPeek(context.TODO(), orp.ServerName, orp.RoomID, orp.PeekID, orp.RenewalInterval)
 }
 
@@ -227,7 +228,7 @@ func (s *OutputRoomEventConsumer) joinedHostsAtEvent(
 	}
 
 	// handle peeking hosts
-	inboundPeeks, err := s.db.GetInboundPeeks(context.TODO(), ore.Event.RoomID())
+	inboundPeeks, err := s.db.GetInboundPeeks(context.TODO(), ore.Event.Event.RoomID())
 	if err != nil {
 		return nil, err
 	}

federationsender/internal/perform.go

@@ -357,7 +357,7 @@ func (r *FederationSenderInternalAPI) performOutboundPeekUsingServer(
 	if err = roomserverAPI.SendEventWithState(
 		ctx, r.rsAPI,
 		&respState,
-		nil, nil,
+		respPeek.LatestEvent.Headered(respPeek.RoomVersion), nil,
 		respPeek.RoomVersion,
 	); err != nil {
 		return fmt.Errorf("r.producer.SendEventWithState: %w", err)

roomserver/api/output.go

@@ -232,6 +232,10 @@ type OutputNewPeek struct {
 type OutputNewInboundPeek struct {
 	RoomID   string
 	PeekID   string
+	// the event ID at which the peek begins (so we can avoid
+	// a race between tracking the state returned by /peek and emitting subsequent
+	// peeked events)
+	LatestEventID string
 	ServerName gomatrixserverlib.ServerName
 	// how often we told the peeking server to renew the peek
 	RenewalInterval int64

roomserver/api/perform.go

@@ -178,4 +178,6 @@ type PerformInboundPeekResponse struct {
 	// The lists will be in an arbitrary order.
 	StateEvents     []gomatrixserverlib.HeaderedEvent `json:"state_events"`
 	AuthChainEvents []gomatrixserverlib.HeaderedEvent `json:"auth_chain_events"`
+	// The event at which this state was captured
+	LatestEvent gomatrixserverlib.HeaderedEvent `json:"latest_event"`
 }

roomserver/api/wrapper.go

@@ -42,11 +42,10 @@ func SendEvents(
 
 // SendEventWithState writes an event with KindNew to the roomserver
 // with the state at the event as KindOutlier before it. Will not send any event that is
-// marked as `true` in haveEventIDs.  The event itself is optional in case
-// hou just want to write outliers to the roomserver.
+// marked as `true` in haveEventIDs.
 func SendEventWithState(
 	ctx context.Context, rsAPI RoomserverInternalAPI, state *gomatrixserverlib.RespState,
-	event *gomatrixserverlib.HeaderedEvent, haveEventIDs map[string]bool,
+	event gomatrixserverlib.HeaderedEvent, haveEventIDs map[string]bool,
 	roomVersion gomatrixserverlib.RoomVersion,
 ) error {
 	outliers, err := state.Events()
@@ -71,15 +70,13 @@ func SendEventWithState(
 		stateEventIDs[i] = state.StateEvents[i].EventID()
 	}
 
-	if event != nil {
-		ires = append(ires, InputRoomEvent{
-			Kind:          KindNew,
-			Event:         *event,
-			AuthEventIDs:  event.AuthEventIDs(),
-			HasState:      true,
-			StateEventIDs: stateEventIDs,
-		})
-	}
+	ires = append(ires, InputRoomEvent{
+		Kind:          KindNew,
+		Event:         event,
+		AuthEventIDs:  event.AuthEventIDs(),
+		HasState:      true,
+		StateEventIDs: stateEventIDs,
+	})
 
 	return SendInputRoomEvents(ctx, rsAPI, ires)
 }

roomserver/internal/perform/perform_inbound_peek.go

@@ -58,15 +58,22 @@ func (r *InboundPeeker) PerformInboundPeek(
 
     var stateEvents []gomatrixserverlib.Event
 
-    // XXX: is this right?
-    roomState := state.NewStateResolution(r.DB, *info)
-
     var currentStateSnapshotNID types.StateSnapshotNID
-    _, currentStateSnapshotNID, _, err =
+    latestEventRefs, currentStateSnapshotNID, _, err :=
             r.DB.LatestEventIDs(ctx, info.RoomNID)
     if err != nil {
             return err
     }
+    // XXX: is this actually the latest of the latest events?
+    latestEvents, err := r.DB.EventsFromIDs(ctx, []string{ latestEventRefs[0].EventID })
+    if err != nil {
+            return err
+    }
+    response.LatestEvent = latestEvents[0].Headered(info.RoomVersion)
+
+    // XXX: do we actually need to do a state resolution here?
+    roomState := state.NewStateResolution(r.DB, *info)
+
     var stateEntries []types.StateEntry
     stateEntries, err = roomState.LoadStateAtSnapshot(
             ctx, currentStateSnapshotNID,
@@ -109,6 +116,7 @@ func (r *InboundPeeker) PerformInboundPeek(
 			NewInboundPeek: &api.OutputNewInboundPeek{
 				RoomID:   request.RoomID,
 				PeekID:   request.PeekID,
+				LatestEventID: latestEvents[0].EventID(),
 				ServerName: request.ServerName,
                 RenewalInterval: request.RenewalInterval,
 			},