Send presence to newly added servers (#2869)

This should make `New federated private chats get full presence
information (SYN-115)` happy.

federationapi/consumers/roomserver.go

@@ -18,6 +18,10 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"strconv"
+	"time"
+
+	syncAPITypes "github.com/matrix-org/dendrite/syncapi/types"
 
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/nats-io/nats.go"
@@ -38,10 +42,12 @@ type OutputRoomEventConsumer struct {
 	cfg           *config.FederationAPI
 	rsAPI         api.FederationRoomserverAPI
 	jetstream     nats.JetStreamContext
+	natsClient    *nats.Conn
 	durable       string
 	db            storage.Database
 	queues        *queue.OutgoingQueues
 	topic         string
+	topicPresence string
 }
 
 // NewOutputRoomEventConsumer creates a new OutputRoomEventConsumer. Call Start() to begin consuming from room servers.
@@ -49,6 +55,7 @@ func NewOutputRoomEventConsumer(
 	process *process.ProcessContext,
 	cfg *config.FederationAPI,
 	js nats.JetStreamContext,
+	natsClient *nats.Conn,
 	queues *queue.OutgoingQueues,
 	store storage.Database,
 	rsAPI api.FederationRoomserverAPI,
@@ -57,11 +64,13 @@ func NewOutputRoomEventConsumer(
 		ctx:           process.Context(),
 		cfg:           cfg,
 		jetstream:     js,
+		natsClient:    natsClient,
 		db:            store,
 		queues:        queues,
 		rsAPI:         rsAPI,
 		durable:       cfg.Matrix.JetStream.Durable("FederationAPIRoomServerConsumer"),
 		topic:         cfg.Matrix.JetStream.Prefixed(jetstream.OutputRoomEvent),
+		topicPresence: cfg.Matrix.JetStream.Prefixed(jetstream.RequestPresence),
 	}
 }
 
@@ -146,6 +155,7 @@ func (s *OutputRoomEventConsumer) processInboundPeek(orp api.OutputNewInboundPee
 // processMessage updates the list of currently joined hosts in the room
 // and then sends the event to the hosts that were joined before the event.
 func (s *OutputRoomEventConsumer) processMessage(ore api.OutputNewRoomEvent, rewritesState bool) error {
+
 	addsStateEvents, missingEventIDs := ore.NeededStateEventIDs()
 
 	// Ask the roomserver and add in the rest of the results into the set.
@@ -184,6 +194,14 @@ func (s *OutputRoomEventConsumer) processMessage(ore api.OutputNewRoomEvent, rew
 		return err
 	}
 
+	// If we added new hosts, inform them about our known presence events for this room
+	if len(addsJoinedHosts) > 0 && ore.Event.Type() == gomatrixserverlib.MRoomMember && ore.Event.StateKey() != nil {
+		membership, _ := ore.Event.Membership()
+		if membership == gomatrixserverlib.Join {
+			s.sendPresence(ore.Event.RoomID(), addsJoinedHosts)
+		}
+	}
+
 	if oldJoinedHosts == nil {
 		// This means that there is nothing to update as this is a duplicate
 		// message.
@@ -213,6 +231,76 @@ func (s *OutputRoomEventConsumer) processMessage(ore api.OutputNewRoomEvent, rew
 	)
 }
 
+func (s *OutputRoomEventConsumer) sendPresence(roomID string, addedJoined []types.JoinedHost) {
+	joined := make([]gomatrixserverlib.ServerName, len(addedJoined))
+	for _, added := range addedJoined {
+		joined = append(joined, added.ServerName)
+	}
+
+	// get our locally joined users
+	var queryRes api.QueryMembershipsForRoomResponse
+	err := s.rsAPI.QueryMembershipsForRoom(s.ctx, &api.QueryMembershipsForRoomRequest{
+		JoinedOnly: true,
+		LocalOnly:  true,
+		RoomID:     roomID,
+	}, &queryRes)
+	if err != nil {
+		log.WithError(err).Error("failed to calculate joined rooms for user")
+		return
+	}
+
+	// send every presence we know about to the remote server
+	content := types.Presence{}
+	for _, ev := range queryRes.JoinEvents {
+		msg := nats.NewMsg(s.topicPresence)
+		msg.Header.Set(jetstream.UserID, ev.Sender)
+
+		var presence *nats.Msg
+		presence, err = s.natsClient.RequestMsg(msg, time.Second*10)
+		if err != nil {
+			log.WithError(err).Errorf("unable to get presence")
+			continue
+		}
+
+		statusMsg := presence.Header.Get("status_msg")
+		e := presence.Header.Get("error")
+		if e != "" {
+			continue
+		}
+		var lastActive int
+		lastActive, err = strconv.Atoi(presence.Header.Get("last_active_ts"))
+		if err != nil {
+			continue
+		}
+
+		p := syncAPITypes.PresenceInternal{LastActiveTS: gomatrixserverlib.Timestamp(lastActive)}
+
+		content.Push = append(content.Push, types.PresenceContent{
+			CurrentlyActive: p.CurrentlyActive(),
+			LastActiveAgo:   p.LastActiveAgo(),
+			Presence:        presence.Header.Get("presence"),
+			StatusMsg:       &statusMsg,
+			UserID:          ev.Sender,
+		})
+	}
+
+	if len(content.Push) == 0 {
+		return
+	}
+
+	edu := &gomatrixserverlib.EDU{
+		Type:   gomatrixserverlib.MPresence,
+		Origin: string(s.cfg.Matrix.ServerName),
+	}
+	if edu.Content, err = json.Marshal(content); err != nil {
+		log.WithError(err).Error("failed to marshal EDU JSON")
+		return
+	}
+	if err := s.queues.SendEDU(edu, s.cfg.Matrix.ServerName, joined); err != nil {
+		log.WithError(err).Error("failed to send EDU")
+	}
+}
+
 // joinedHostsAtEvent works out a list of matrix servers that were joined to
 // the room at the event (including peeking ones)
 // It is important to use the state at the event for sending messages because:

federationapi/federationapi.go

@@ -118,7 +118,7 @@ func NewInternalAPI(
 
 	stats := statistics.NewStatistics(federationDB, cfg.FederationMaxRetries+1)
 
-	js, _ := base.NATS.Prepare(base.ProcessContext, &cfg.Matrix.JetStream)
+	js, nats := base.NATS.Prepare(base.ProcessContext, &cfg.Matrix.JetStream)
 
 	queues := queue.NewOutgoingQueues(
 		federationDB, base.ProcessContext,
@@ -132,7 +132,7 @@ func NewInternalAPI(
 	)
 
 	rsConsumer := consumers.NewOutputRoomEventConsumer(
-		base.ProcessContext, cfg, js, queues,
+		base.ProcessContext, cfg, js, nats, queues,
 		federationDB, rsAPI,
 	)
 	if err = rsConsumer.Start(); err != nil {

roomserver/api/api.go

@@ -177,6 +177,7 @@ type FederationRoomserverAPI interface {
 	QueryBulkStateContentAPI
 	// QueryServerBannedFromRoom returns whether a server is banned from a room by server ACLs.
 	QueryServerBannedFromRoom(ctx context.Context, req *QueryServerBannedFromRoomRequest, res *QueryServerBannedFromRoomResponse) error
+	QueryMembershipsForRoom(ctx context.Context, req *QueryMembershipsForRoomRequest, res *QueryMembershipsForRoomResponse) error
 	QueryRoomVersionForRoom(ctx context.Context, req *QueryRoomVersionForRoomRequest, res *QueryRoomVersionForRoomResponse) error
 	GetRoomIDForAlias(ctx context.Context, req *GetRoomIDForAliasRequest, res *GetRoomIDForAliasResponse) error
 	QueryEventsByID(ctx context.Context, req *QueryEventsByIDRequest, res *QueryEventsByIDResponse) error