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dendrite/syncapi/streams/stream_pdu.go
Neil Alexander b05e028f7d
Tweak LoadMembershipAtEvent behaviour when state not known (#2716)
Previously `LoadMembershipAtEvent` would fail if the state before one of
the events was not known, i.e. because it was an outlier. This modifies
it so that it gracefully handles not knowing the state and returns no
memberships instead, so that history visibility doesn't freak out and
kill `/sync` requests dead.
2022-09-13 12:52:09 +01:00

654 lines
22 KiB
Go

package streams
import (
"context"
"database/sql"
"fmt"
"sort"
"sync"
"time"
"github.com/matrix-org/dendrite/internal/caching"
roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/syncapi/internal"
"github.com/matrix-org/dendrite/syncapi/storage"
"github.com/matrix-org/dendrite/syncapi/types"
userapi "github.com/matrix-org/dendrite/userapi/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/sirupsen/logrus"
"github.com/tidwall/gjson"
"go.uber.org/atomic"
"github.com/matrix-org/dendrite/syncapi/notifier"
)
// The max number of per-room goroutines to have running.
// Too high and this will consume lots of CPU, too low and complete
// sync responses will take longer to process.
const PDU_STREAM_WORKERS = 256
// The maximum number of tasks that can be queued in total before
// backpressure will build up and the rests will start to block.
const PDU_STREAM_QUEUESIZE = PDU_STREAM_WORKERS * 8
type PDUStreamProvider struct {
StreamProvider
tasks chan func()
workers atomic.Int32
// userID+deviceID -> lazy loading cache
lazyLoadCache caching.LazyLoadCache
rsAPI roomserverAPI.SyncRoomserverAPI
notifier *notifier.Notifier
}
func (p *PDUStreamProvider) worker() {
defer p.workers.Dec()
for {
select {
case f := <-p.tasks:
f()
case <-time.After(time.Second * 10):
return
}
}
}
func (p *PDUStreamProvider) queue(f func()) {
if p.workers.Load() < PDU_STREAM_WORKERS {
p.workers.Inc()
go p.worker()
}
p.tasks <- f
}
func (p *PDUStreamProvider) Setup() {
p.StreamProvider.Setup()
p.tasks = make(chan func(), PDU_STREAM_QUEUESIZE)
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 := req.Filter.Room.State
eventFilter := req.Filter.Room.Timeline
if err = p.addIgnoredUsersToFilter(ctx, req, &eventFilter); err != nil {
req.Log.WithError(err).Error("unable to update event filter with ignored users")
}
// Invalidate the lazyLoadCache, otherwise we end up with missing displaynames/avatars
// TODO: This might be inefficient, when joined to many and/or large rooms.
for _, roomID := range joinedRoomIDs {
joinedUsers := p.notifier.JoinedUsers(roomID)
for _, sharedUser := range joinedUsers {
p.lazyLoadCache.InvalidateLazyLoadedUser(req.Device, roomID, sharedUser)
}
}
// Build up a /sync response. Add joined rooms.
var reqMutex sync.Mutex
var reqWaitGroup sync.WaitGroup
reqWaitGroup.Add(len(joinedRoomIDs))
for _, room := range joinedRoomIDs {
roomID := room
p.queue(func() {
defer reqWaitGroup.Done()
jr, jerr := p.getJoinResponseForCompleteSync(
ctx, roomID, r, &stateFilter, &eventFilter, req.WantFullState, req.Device, false,
)
if jerr != nil {
req.Log.WithError(jerr).Error("p.getJoinResponseForCompleteSync failed")
return
}
reqMutex.Lock()
defer reqMutex.Unlock()
req.Response.Rooms.Join[roomID] = *jr
req.Rooms[roomID] = gomatrixserverlib.Join
})
}
reqWaitGroup.Wait()
// 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, &eventFilter, req.WantFullState, req.Device, true,
)
if err != nil {
req.Log.WithError(err).Error("p.getJoinResponseForCompleteSync failed")
return from
}
req.Response.Rooms.Peek[peek.RoomID] = *jr
}
}
return to
}
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,
}
var err error
var stateDeltas []types.StateDelta
var syncJoinedRooms []string
stateFilter := req.Filter.Room.State
eventFilter := req.Filter.Room.Timeline
if req.WantFullState {
if stateDeltas, syncJoinedRooms, 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, syncJoinedRooms, 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 syncJoinedRooms {
req.Rooms[roomID] = gomatrixserverlib.Join
}
if len(stateDeltas) == 0 {
return to
}
if err = p.addIgnoredUsersToFilter(ctx, req, &eventFilter); err != nil {
req.Log.WithError(err).Error("unable to update event filter with ignored users")
}
newPos = from
for _, delta := range stateDeltas {
newRange := r
// If this room was joined in this sync, try to fetch
// as much timeline events as allowed by the filter.
if delta.NewlyJoined {
// Reverse the range, so we get the most recent first.
// This will be limited by the eventFilter.
newRange = types.Range{
From: r.To,
To: 0,
Backwards: true,
}
}
var pos types.StreamPosition
if pos, err = p.addRoomDeltaToResponse(ctx, req.Device, newRange, delta, &eventFilter, &stateFilter, req.Response); err != nil {
req.Log.WithError(err).Error("d.addRoomDeltaToResponse failed")
return to
}
// Reset the position, as it is only for the special case of newly joined rooms
if delta.NewlyJoined {
pos = newRange.From
}
switch {
case r.Backwards && pos < newPos:
fallthrough
case !r.Backwards && pos > newPos:
newPos = pos
}
}
return newPos
}
// nolint:gocyclo
func (p *PDUStreamProvider) addRoomDeltaToResponse(
ctx context.Context,
device *userapi.Device,
r types.Range,
delta types.StateDelta,
eventFilter *gomatrixserverlib.RoomEventFilter,
stateFilter *gomatrixserverlib.StateFilter,
res *types.Response,
) (types.StreamPosition, 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,
eventFilter, true, true,
)
if err != nil {
if err == sql.ErrNoRows {
return r.To, nil
}
return r.From, fmt.Errorf("p.DB.RecentEvents: %w", 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 r.From, fmt.Errorf("p.DB.GetBackwardTopologyPos: %w", err)
}
// If we didn't return any events at all then don't bother doing anything else.
if len(recentEvents) == 0 && len(delta.StateEvents) == 0 {
return r.To, nil
}
// Sort the events so that we can pick out the latest events from both sections.
recentEvents = gomatrixserverlib.HeaderedReverseTopologicalOrdering(recentEvents, gomatrixserverlib.TopologicalOrderByPrevEvents)
delta.StateEvents = gomatrixserverlib.HeaderedReverseTopologicalOrdering(delta.StateEvents, gomatrixserverlib.TopologicalOrderByAuthEvents)
// Work out what the highest stream position is for all of the events in this
// room that were returned.
latestPosition := r.To
updateLatestPosition := func(mostRecentEventID string) {
var pos types.StreamPosition
if _, pos, err = p.DB.PositionInTopology(ctx, mostRecentEventID); err == nil {
switch {
case r.Backwards && pos < latestPosition:
fallthrough
case !r.Backwards && pos > latestPosition:
latestPosition = pos
}
}
}
if stateFilter.LazyLoadMembers {
delta.StateEvents, err = p.lazyLoadMembers(
ctx, delta.RoomID, true, limited, stateFilter,
device, recentEvents, delta.StateEvents,
)
if err != nil && err != sql.ErrNoRows {
return r.From, fmt.Errorf("p.lazyLoadMembers: %w", err)
}
}
hasMembershipChange := false
for _, recentEvent := range recentStreamEvents {
if recentEvent.Type() == gomatrixserverlib.MRoomMember && recentEvent.StateKey() != nil {
hasMembershipChange = true
break
}
}
// Applies the history visibility rules
events, err := applyHistoryVisibilityFilter(ctx, p.DB, p.rsAPI, delta.RoomID, device.UserID, eventFilter.Limit, recentEvents)
if err != nil {
logrus.WithError(err).Error("unable to apply history visibility filter")
}
if len(delta.StateEvents) > 0 {
updateLatestPosition(delta.StateEvents[len(delta.StateEvents)-1].EventID())
}
if len(events) > 0 {
updateLatestPosition(events[len(events)-1].EventID())
}
switch delta.Membership {
case gomatrixserverlib.Join:
jr := types.NewJoinResponse()
if hasMembershipChange {
p.addRoomSummary(ctx, jr, delta.RoomID, device.UserID, latestPosition)
}
jr.Timeline.PrevBatch = &prevBatch
jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(events, gomatrixserverlib.FormatSync)
// If we are limited by the filter AND the history visibility filter
// didn't "remove" events, return that the response is limited.
jr.Timeline.Limited = limited && len(events) == len(recentEvents)
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
// TODO: Apply history visibility on peeked rooms
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:
lr := types.NewLeaveResponse()
lr.Timeline.PrevBatch = &prevBatch
lr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(events, gomatrixserverlib.FormatSync)
// If we are limited by the filter AND the history visibility filter
// didn't "remove" events, return that the response is limited.
lr.Timeline.Limited = limited && len(events) == len(recentEvents)
lr.State.Events = gomatrixserverlib.HeaderedToClientEvents(delta.StateEvents, gomatrixserverlib.FormatSync)
res.Rooms.Leave[delta.RoomID] = *lr
}
return latestPosition, nil
}
// applyHistoryVisibilityFilter gets the current room state and supplies it to ApplyHistoryVisibilityFilter, to make
// sure we always return the required events in the timeline.
func applyHistoryVisibilityFilter(
ctx context.Context,
db storage.Database,
rsAPI roomserverAPI.SyncRoomserverAPI,
roomID, userID string,
limit int,
recentEvents []*gomatrixserverlib.HeaderedEvent,
) ([]*gomatrixserverlib.HeaderedEvent, error) {
// We need to make sure we always include the latest states events, if they are in the timeline.
// We grep at least limit * 2 events, to ensure we really get the needed events.
stateEvents, err := db.CurrentState(ctx, roomID, &gomatrixserverlib.StateFilter{Limit: limit * 2}, nil)
if err != nil {
// Not a fatal error, we can continue without the stateEvents,
// they are only needed if there are state events in the timeline.
logrus.WithError(err).Warnf("Failed to get current room state for history visibility")
}
alwaysIncludeIDs := make(map[string]struct{}, len(stateEvents))
for _, ev := range stateEvents {
alwaysIncludeIDs[ev.EventID()] = struct{}{}
}
startTime := time.Now()
events, err := internal.ApplyHistoryVisibilityFilter(ctx, db, rsAPI, recentEvents, alwaysIncludeIDs, userID, "sync")
if err != nil {
return nil, err
}
logrus.WithFields(logrus.Fields{
"duration": time.Since(startTime),
"room_id": roomID,
"before": len(recentEvents),
"after": len(events),
}).Trace("Applied history visibility (sync)")
return events, nil
}
func (p *PDUStreamProvider) addRoomSummary(ctx context.Context, jr *types.JoinResponse, roomID, userID string, latestPosition types.StreamPosition) {
// Work out how many members are in the room.
joinedCount, _ := p.DB.MembershipCount(ctx, roomID, gomatrixserverlib.Join, latestPosition)
invitedCount, _ := p.DB.MembershipCount(ctx, roomID, gomatrixserverlib.Invite, latestPosition)
jr.Summary.JoinedMemberCount = &joinedCount
jr.Summary.InvitedMemberCount = &invitedCount
fetchStates := []gomatrixserverlib.StateKeyTuple{
{EventType: gomatrixserverlib.MRoomName},
{EventType: gomatrixserverlib.MRoomCanonicalAlias},
}
// Check if the room has a name or a canonical alias
latestState := &roomserverAPI.QueryLatestEventsAndStateResponse{}
err := p.rsAPI.QueryLatestEventsAndState(ctx, &roomserverAPI.QueryLatestEventsAndStateRequest{StateToFetch: fetchStates, RoomID: roomID}, latestState)
if err != nil {
return
}
// Check if the room has a name or canonical alias, if so, return.
for _, ev := range latestState.StateEvents {
switch ev.Type() {
case gomatrixserverlib.MRoomName:
if gjson.GetBytes(ev.Content(), "name").Str != "" {
return
}
case gomatrixserverlib.MRoomCanonicalAlias:
if gjson.GetBytes(ev.Content(), "alias").Str != "" {
return
}
}
}
heroes, err := p.DB.GetRoomHeroes(ctx, roomID, userID, []string{"join", "invite"})
if err != nil {
return
}
sort.Strings(heroes)
jr.Summary.Heroes = heroes
}
func (p *PDUStreamProvider) getJoinResponseForCompleteSync(
ctx context.Context,
roomID string,
r types.Range,
stateFilter *gomatrixserverlib.StateFilter,
eventFilter *gomatrixserverlib.RoomEventFilter,
wantFullState bool,
device *userapi.Device,
isPeek bool,
) (jr *types.JoinResponse, err error) {
jr = types.NewJoinResponse()
// 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
recentStreamEvents, limited, err := p.DB.RecentEvents(
ctx, roomID, r, eventFilter, true, true,
)
if err != nil {
if err == sql.ErrNoRows {
return jr, nil
}
return
}
// Work our way through the timeline events and pick out the event IDs
// of any state events that appear in the timeline. We'll specifically
// exclude them at the next step, so that we don't get duplicate state
// events in both `recentStreamEvents` and `stateEvents`.
var excludingEventIDs []string
if !wantFullState {
excludingEventIDs = make([]string, 0, len(recentStreamEvents))
for _, event := range recentStreamEvents {
if event.StateKey() != nil {
excludingEventIDs = append(excludingEventIDs, event.EventID())
}
}
}
stateEvents, err := p.DB.CurrentState(ctx, roomID, stateFilter, excludingEventIDs)
if err != nil {
return
}
// 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()
}
p.addRoomSummary(ctx, jr, roomID, device.UserID, r.From)
// 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)
events := recentEvents
// Only apply history visibility checks if the response is for joined rooms
if !isPeek {
events, err = applyHistoryVisibilityFilter(ctx, p.DB, p.rsAPI, roomID, device.UserID, eventFilter.Limit, recentEvents)
if err != nil {
logrus.WithError(err).Error("unable to apply history visibility filter")
}
}
// If we are limited by the filter AND the history visibility filter
// didn't "remove" events, return that the response is limited.
limited = limited && len(events) == len(recentEvents)
if stateFilter.LazyLoadMembers {
if err != nil {
return nil, err
}
stateEvents, err = p.lazyLoadMembers(ctx, roomID,
false, limited, stateFilter,
device, recentEvents, stateEvents,
)
if err != nil && err != sql.ErrNoRows {
return nil, err
}
}
jr.Timeline.PrevBatch = prevBatch
jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(events, gomatrixserverlib.FormatSync)
// If we are limited by the filter AND the history visibility filter
// didn't "remove" events, return that the response is limited.
jr.Timeline.Limited = limited && len(events) == len(recentEvents)
jr.State.Events = gomatrixserverlib.HeaderedToClientEvents(stateEvents, gomatrixserverlib.FormatSync)
return jr, nil
}
func (p *PDUStreamProvider) lazyLoadMembers(
ctx context.Context, roomID string,
incremental, limited bool, stateFilter *gomatrixserverlib.StateFilter,
device *userapi.Device,
timelineEvents, stateEvents []*gomatrixserverlib.HeaderedEvent,
) ([]*gomatrixserverlib.HeaderedEvent, error) {
if len(timelineEvents) == 0 {
return stateEvents, nil
}
// Work out which memberships to include
timelineUsers := make(map[string]struct{})
if !incremental {
timelineUsers[device.UserID] = struct{}{}
}
// Add all users the client doesn't know about yet to a list
for _, event := range timelineEvents {
// Membership is not yet cached, add it to the list
if _, ok := p.lazyLoadCache.IsLazyLoadedUserCached(device, roomID, event.Sender()); !ok {
timelineUsers[event.Sender()] = struct{}{}
}
}
// Preallocate with the same amount, even if it will end up with fewer values
newStateEvents := make([]*gomatrixserverlib.HeaderedEvent, 0, len(stateEvents))
// Remove existing membership events we don't care about, e.g. users not in the timeline.events
for _, event := range stateEvents {
if event.Type() == gomatrixserverlib.MRoomMember && event.StateKey() != nil {
// If this is a gapped incremental sync, we still want this membership
isGappedIncremental := limited && incremental
// We want this users membership event, keep it in the list
stateKey := *event.StateKey()
if _, ok := timelineUsers[stateKey]; ok || isGappedIncremental {
newStateEvents = append(newStateEvents, event)
if !stateFilter.IncludeRedundantMembers {
p.lazyLoadCache.StoreLazyLoadedUser(device, roomID, stateKey, event.EventID())
}
delete(timelineUsers, stateKey)
}
} else {
newStateEvents = append(newStateEvents, event)
}
}
wantUsers := make([]string, 0, len(timelineUsers))
for userID := range timelineUsers {
wantUsers = append(wantUsers, userID)
}
// Query missing membership events
filter := gomatrixserverlib.DefaultStateFilter()
filter.Limit = stateFilter.Limit
filter.Senders = &wantUsers
filter.Types = &[]string{gomatrixserverlib.MRoomMember}
memberships, err := p.DB.GetStateEventsForRoom(ctx, roomID, &filter)
if err != nil {
return stateEvents, err
}
// cache the membership events
for _, membership := range memberships {
p.lazyLoadCache.StoreLazyLoadedUser(device, roomID, *membership.StateKey(), membership.EventID())
}
stateEvents = append(newStateEvents, memberships...)
return stateEvents, nil
}
// addIgnoredUsersToFilter adds ignored users to the eventfilter and
// the syncreq itself for further use in streams.
func (p *PDUStreamProvider) addIgnoredUsersToFilter(ctx context.Context, req *types.SyncRequest, eventFilter *gomatrixserverlib.RoomEventFilter) error {
ignores, err := p.DB.IgnoresForUser(ctx, req.Device.UserID)
if err != nil {
if err == sql.ErrNoRows {
return nil
}
return err
}
req.IgnoredUsers = *ignores
userList := make([]string, 0, len(ignores.List))
for userID := range ignores.List {
userList = append(userList, userID)
}
if len(userList) > 0 {
eventFilter.NotSenders = &userList
}
return 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
}