Sync refactor — Part 1 (#1688)

* It's half-alive * Wakeups largely working * Other tweaks, typing works * Fix bugs, add receipt stream * Delete notifier, other tweaks * Dedupe a bit, add a template for the invite stream * Clean up, add templates for other streams * Don't leak channels * Bring forward some more PDU logic, clean up other places * Add some more wakeups * Use addRoomDeltaToResponse * Log tweaks, typing fixed? * Fix timed out syncs * Don't reset next batch position on timeout * Add account data stream/position * End of day * Fix complete sync for receipt, typing * Streams package * Clean up a bit * Complete sync send-to-device * Don't drop errors * More lightweight notifications * Fix typing positions * Don't advance position on remove again unless needed * Device list updates * Advance account data position * Use limit for incremental sync * Limit fixes, amongst other things * Remove some fmt.Println * Tweaks * Re-add notifier * Fix invite position * Fixes * Notify account data without advancing PDU position in notifier * Apply account data position * Get initial position for account data * Fix position update * Fix complete sync positions * Review comments @Kegsay * Room consumer parameters
2025-08-02 06:12:45 +00:00 · 2021-01-08 16:59:06 +00:00 · 2021-01-08 16:59:06 +00:00 · b5a8935042
commit b5a8935042
parent 56a7839aed
35 changed files with 1452 additions and 1116 deletions
--- a/syncapi/streams/stream_pdu.go
+++ b/syncapi/streams/stream_pdu.go
@ -0,0 +1,305 @@
+package streams
+
+import (
+	"context"
+
+	"github.com/matrix-org/dendrite/syncapi/types"
+	userapi "github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+type PDUStreamProvider struct {
+	StreamProvider
+}
+
+func (p *PDUStreamProvider) Setup() {
+	p.StreamProvider.Setup()
+
+	p.latestMutex.Lock()
+	defer p.latestMutex.Unlock()
+
+	id, err := p.DB.MaxStreamPositionForPDUs(context.Background())
+	if err != nil {
+		panic(err)
+	}
+	p.latest = id
+}
+
+func (p *PDUStreamProvider) CompleteSync(
+	ctx context.Context,
+	req *types.SyncRequest,
+) types.StreamPosition {
+	from := types.StreamPosition(0)
+	to := p.LatestPosition(ctx)
+
+	// Get the current sync position which we will base the sync response on.
+	// For complete syncs, we want to start at the most recent events and work
+	// backwards, so that we show the most recent events in the room.
+	r := types.Range{
+		From:      to,
+		To:        0,
+		Backwards: true,
+	}
+
+	// Extract room state and recent events for all rooms the user is joined to.
+	joinedRoomIDs, err := p.DB.RoomIDsWithMembership(ctx, req.Device.UserID, gomatrixserverlib.Join)
+	if err != nil {
+		req.Log.WithError(err).Error("p.DB.RoomIDsWithMembership failed")
+		return from
+	}
+
+	stateFilter := gomatrixserverlib.DefaultStateFilter() // TODO: use filter provided in request
+
+	// Build up a /sync response. Add joined rooms.
+	for _, roomID := range joinedRoomIDs {
+		var jr *types.JoinResponse
+		jr, err = p.getJoinResponseForCompleteSync(
+			ctx, roomID, r, &stateFilter, req.Limit, req.Device,
+		)
+		if err != nil {
+			req.Log.WithError(err).Error("p.getJoinResponseForCompleteSync failed")
+			return from
+		}
+		req.Response.Rooms.Join[roomID] = *jr
+		req.Rooms[roomID] = gomatrixserverlib.Join
+	}
+
+	// Add peeked rooms.
+	peeks, err := p.DB.PeeksInRange(ctx, req.Device.UserID, req.Device.ID, r)
+	if err != nil {
+		req.Log.WithError(err).Error("p.DB.PeeksInRange failed")
+		return from
+	}
+	for _, peek := range peeks {
+		if !peek.Deleted {
+			var jr *types.JoinResponse
+			jr, err = p.getJoinResponseForCompleteSync(
+				ctx, peek.RoomID, r, &stateFilter, req.Limit, req.Device,
+			)
+			if err != nil {
+				req.Log.WithError(err).Error("p.getJoinResponseForCompleteSync failed")
+				return from
+			}
+			req.Response.Rooms.Peek[peek.RoomID] = *jr
+		}
+	}
+
+	return to
+}
+
+// nolint:gocyclo
+func (p *PDUStreamProvider) IncrementalSync(
+	ctx context.Context,
+	req *types.SyncRequest,
+	from, to types.StreamPosition,
+) (newPos types.StreamPosition) {
+	r := types.Range{
+		From:      from,
+		To:        to,
+		Backwards: from > to,
+	}
+	newPos = to
+
+	var err error
+	var stateDeltas []types.StateDelta
+	var joinedRooms []string
+
+	// TODO: use filter provided in request
+	stateFilter := gomatrixserverlib.DefaultStateFilter()
+
+	if req.WantFullState {
+		if stateDeltas, joinedRooms, err = p.DB.GetStateDeltasForFullStateSync(ctx, req.Device, r, req.Device.UserID, &stateFilter); err != nil {
+			req.Log.WithError(err).Error("p.DB.GetStateDeltasForFullStateSync failed")
+			return
+		}
+	} else {
+		if stateDeltas, joinedRooms, err = p.DB.GetStateDeltas(ctx, req.Device, r, req.Device.UserID, &stateFilter); err != nil {
+			req.Log.WithError(err).Error("p.DB.GetStateDeltas failed")
+			return
+		}
+	}
+
+	for _, roomID := range joinedRooms {
+		req.Rooms[roomID] = gomatrixserverlib.Join
+	}
+
+	for _, delta := range stateDeltas {
+		if err = p.addRoomDeltaToResponse(ctx, req.Device, r, delta, req.Limit, req.Response); err != nil {
+			req.Log.WithError(err).Error("d.addRoomDeltaToResponse failed")
+			return newPos
+		}
+	}
+
+	return r.To
+}
+
+func (p *PDUStreamProvider) addRoomDeltaToResponse(
+	ctx context.Context,
+	device *userapi.Device,
+	r types.Range,
+	delta types.StateDelta,
+	numRecentEventsPerRoom int,
+	res *types.Response,
+) error {
+	if delta.MembershipPos > 0 && delta.Membership == gomatrixserverlib.Leave {
+		// make sure we don't leak recent events after the leave event.
+		// TODO: History visibility makes this somewhat complex to handle correctly. For example:
+		// TODO: This doesn't work for join -> leave in a single /sync request (see events prior to join).
+		// TODO: This will fail on join -> leave -> sensitive msg -> join -> leave
+		//       in a single /sync request
+		// This is all "okay" assuming history_visibility == "shared" which it is by default.
+		r.To = delta.MembershipPos
+	}
+	recentStreamEvents, limited, err := p.DB.RecentEvents(
+		ctx, delta.RoomID, r,
+		numRecentEventsPerRoom, true, true,
+	)
+	if err != nil {
+		return err
+	}
+	recentEvents := p.DB.StreamEventsToEvents(device, recentStreamEvents)
+	delta.StateEvents = removeDuplicates(delta.StateEvents, recentEvents) // roll back
+	prevBatch, err := p.DB.GetBackwardTopologyPos(ctx, recentStreamEvents)
+	if err != nil {
+		return err
+	}
+
+	// XXX: should we ever get this far if we have no recent events or state in this room?
+	// in practice we do for peeks, but possibly not joins?
+	if len(recentEvents) == 0 && len(delta.StateEvents) == 0 {
+		return nil
+	}
+
+	switch delta.Membership {
+	case gomatrixserverlib.Join:
+		jr := types.NewJoinResponse()
+
+		jr.Timeline.PrevBatch = &prevBatch
+		jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
+		jr.Timeline.Limited = limited
+		jr.State.Events = gomatrixserverlib.HeaderedToClientEvents(delta.StateEvents, gomatrixserverlib.FormatSync)
+		res.Rooms.Join[delta.RoomID] = *jr
+	case gomatrixserverlib.Peek:
+		jr := types.NewJoinResponse()
+
+		jr.Timeline.PrevBatch = &prevBatch
+		jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
+		jr.Timeline.Limited = limited
+		jr.State.Events = gomatrixserverlib.HeaderedToClientEvents(delta.StateEvents, gomatrixserverlib.FormatSync)
+		res.Rooms.Peek[delta.RoomID] = *jr
+	case gomatrixserverlib.Leave:
+		fallthrough // transitions to leave are the same as ban
+	case gomatrixserverlib.Ban:
+		// TODO: recentEvents may contain events that this user is not allowed to see because they are
+		//       no longer in the room.
+		lr := types.NewLeaveResponse()
+		lr.Timeline.PrevBatch = &prevBatch
+		lr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
+		lr.Timeline.Limited = false // TODO: if len(events) >= numRecents + 1 and then set limited:true
+		lr.State.Events = gomatrixserverlib.HeaderedToClientEvents(delta.StateEvents, gomatrixserverlib.FormatSync)
+		res.Rooms.Leave[delta.RoomID] = *lr
+	}
+
+	return nil
+}
+
+func (p *PDUStreamProvider) getJoinResponseForCompleteSync(
+	ctx context.Context,
+	roomID string,
+	r types.Range,
+	stateFilter *gomatrixserverlib.StateFilter,
+	numRecentEventsPerRoom int, device *userapi.Device,
+) (jr *types.JoinResponse, err error) {
+	var stateEvents []*gomatrixserverlib.HeaderedEvent
+	stateEvents, err = p.DB.CurrentState(ctx, roomID, stateFilter)
+	if err != nil {
+		return
+	}
+	// TODO: When filters are added, we may need to call this multiple times to get enough events.
+	//       See: https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L316
+	var recentStreamEvents []types.StreamEvent
+	var limited bool
+	recentStreamEvents, limited, err = p.DB.RecentEvents(
+		ctx, roomID, r, numRecentEventsPerRoom, true, true,
+	)
+	if err != nil {
+		return
+	}
+
+	// TODO FIXME: We don't fully implement history visibility yet. To avoid leaking events which the
+	// user shouldn't see, we check the recent events and remove any prior to the join event of the user
+	// which is equiv to history_visibility: joined
+	joinEventIndex := -1
+	for i := len(recentStreamEvents) - 1; i >= 0; i-- {
+		ev := recentStreamEvents[i]
+		if ev.Type() == gomatrixserverlib.MRoomMember && ev.StateKeyEquals(device.UserID) {
+			membership, _ := ev.Membership()
+			if membership == "join" {
+				joinEventIndex = i
+				if i > 0 {
+					// the create event happens before the first join, so we should cut it at that point instead
+					if recentStreamEvents[i-1].Type() == gomatrixserverlib.MRoomCreate && recentStreamEvents[i-1].StateKeyEquals("") {
+						joinEventIndex = i - 1
+						break
+					}
+				}
+				break
+			}
+		}
+	}
+	if joinEventIndex != -1 {
+		// cut all events earlier than the join (but not the join itself)
+		recentStreamEvents = recentStreamEvents[joinEventIndex:]
+		limited = false // so clients know not to try to backpaginate
+	}
+
+	// Retrieve the backward topology position, i.e. the position of the
+	// oldest event in the room's topology.
+	var prevBatch *types.TopologyToken
+	if len(recentStreamEvents) > 0 {
+		var backwardTopologyPos, backwardStreamPos types.StreamPosition
+		backwardTopologyPos, backwardStreamPos, err = p.DB.PositionInTopology(ctx, recentStreamEvents[0].EventID())
+		if err != nil {
+			return
+		}
+		prevBatch = &types.TopologyToken{
+			Depth:       backwardTopologyPos,
+			PDUPosition: backwardStreamPos,
+		}
+		prevBatch.Decrement()
+	}
+
+	// We don't include a device here as we don't need to send down
+	// transaction IDs for complete syncs, but we do it anyway because Sytest demands it for:
+	// "Can sync a room with a message with a transaction id" - which does a complete sync to check.
+	recentEvents := p.DB.StreamEventsToEvents(device, recentStreamEvents)
+	stateEvents = removeDuplicates(stateEvents, recentEvents)
+	jr = types.NewJoinResponse()
+	jr.Timeline.PrevBatch = prevBatch
+	jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
+	jr.Timeline.Limited = limited
+	jr.State.Events = gomatrixserverlib.HeaderedToClientEvents(stateEvents, gomatrixserverlib.FormatSync)
+	return jr, nil
+}
+
+func removeDuplicates(stateEvents, recentEvents []*gomatrixserverlib.HeaderedEvent) []*gomatrixserverlib.HeaderedEvent {
+	for _, recentEv := range recentEvents {
+		if recentEv.StateKey() == nil {
+			continue // not a state event
+		}
+		// TODO: This is a linear scan over all the current state events in this room. This will
+		//       be slow for big rooms. We should instead sort the state events by event ID  (ORDER BY)
+		//       then do a binary search to find matching events, similar to what roomserver does.
+		for j := 0; j < len(stateEvents); j++ {
+			if stateEvents[j].EventID() == recentEv.EventID() {
+				// overwrite the element to remove with the last element then pop the last element.
+				// This is orders of magnitude faster than re-slicing, but doesn't preserve ordering
+				// (we don't care about the order of stateEvents)
+				stateEvents[j] = stateEvents[len(stateEvents)-1]
+				stateEvents = stateEvents[:len(stateEvents)-1]
+				break // there shouldn't be multiple events with the same event ID
+			}
+		}
+	}
+	return stateEvents
+}