dendrite/syncapi/routing/context.go
Till eb29a31550
Optimize /sync and history visibility (#2961)
Should fix the following issues or make a lot less worse when using
Postgres:

The main issue behind #2911: The client gives up after a certain time,
causing a cascade of context errors, because the response couldn't be
built up fast enough. This mostly happens on accounts with many rooms,
due to the inefficient way we're getting recent events and current state

For #2777: The queries for getting the membership events for history
visibility were being executed for each room (I think 185?), resulting
in a whooping 2k queries for membership events. (Getting the
statesnapshot -> block nids -> actual wanted membership event)

Both should now be better by:
- Using a LATERAL join to get all recent events for all joined rooms in
one go (TODO: maybe do the same for room summary and current state etc)
- If we're lazy loading on initial syncs, we're now not getting the
whole current state, just to drop the majority of it because we're lazy
loading members - we add a filter to exclude membership events on the
first call to `CurrentState`.
- Using an optimized query to get the membership events needed to
calculate history visibility

---------

Co-authored-by: kegsay <kegan@matrix.org>
2023-02-07 14:31:23 +01:00

324 lines
11 KiB
Go

// Copyright 2022 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package routing
import (
"context"
"database/sql"
"encoding/json"
"fmt"
"net/http"
"strconv"
"time"
"github.com/matrix-org/dendrite/clientapi/jsonerror"
"github.com/matrix-org/dendrite/internal/caching"
"github.com/matrix-org/dendrite/internal/sqlutil"
roomserver "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/matrix-org/util"
"github.com/sirupsen/logrus"
)
type ContextRespsonse struct {
End string `json:"end"`
Event *gomatrixserverlib.ClientEvent `json:"event,omitempty"`
EventsAfter []gomatrixserverlib.ClientEvent `json:"events_after,omitempty"`
EventsBefore []gomatrixserverlib.ClientEvent `json:"events_before,omitempty"`
Start string `json:"start"`
State []gomatrixserverlib.ClientEvent `json:"state,omitempty"`
}
func Context(
req *http.Request, device *userapi.Device,
rsAPI roomserver.SyncRoomserverAPI,
syncDB storage.Database,
roomID, eventID string,
lazyLoadCache caching.LazyLoadCache,
) util.JSONResponse {
snapshot, err := syncDB.NewDatabaseSnapshot(req.Context())
if err != nil {
return jsonerror.InternalServerError()
}
var succeeded bool
defer sqlutil.EndTransactionWithCheck(snapshot, &succeeded, &err)
filter, err := parseRoomEventFilter(req)
if err != nil {
errMsg := ""
switch err.(type) {
case *json.InvalidUnmarshalError:
errMsg = "unable to parse filter"
case *strconv.NumError:
errMsg = "unable to parse limit"
default:
errMsg = err.Error()
}
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.InvalidParam(errMsg),
Headers: nil,
}
}
if filter.Rooms != nil {
*filter.Rooms = append(*filter.Rooms, roomID)
}
ctx := req.Context()
membershipRes := roomserver.QueryMembershipForUserResponse{}
membershipReq := roomserver.QueryMembershipForUserRequest{UserID: device.UserID, RoomID: roomID}
if err = rsAPI.QueryMembershipForUser(ctx, &membershipReq, &membershipRes); err != nil {
logrus.WithError(err).Error("unable to query membership")
return jsonerror.InternalServerError()
}
if !membershipRes.RoomExists {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("room does not exist"),
}
}
stateFilter := gomatrixserverlib.StateFilter{
NotSenders: filter.NotSenders,
NotTypes: filter.NotTypes,
Senders: filter.Senders,
Types: filter.Types,
LazyLoadMembers: filter.LazyLoadMembers,
IncludeRedundantMembers: filter.IncludeRedundantMembers,
NotRooms: filter.NotRooms,
Rooms: filter.Rooms,
ContainsURL: filter.ContainsURL,
}
id, requestedEvent, err := snapshot.SelectContextEvent(ctx, roomID, eventID)
if err != nil {
if err == sql.ErrNoRows {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound(fmt.Sprintf("Event %s not found", eventID)),
}
}
logrus.WithError(err).WithField("eventID", eventID).Error("unable to find requested event")
return jsonerror.InternalServerError()
}
// verify the user is allowed to see the context for this room/event
startTime := time.Now()
filteredEvents, err := internal.ApplyHistoryVisibilityFilter(ctx, snapshot, rsAPI, []*gomatrixserverlib.HeaderedEvent{&requestedEvent}, nil, device.UserID, "context")
if err != nil {
logrus.WithError(err).Error("unable to apply history visibility filter")
return jsonerror.InternalServerError()
}
logrus.WithFields(logrus.Fields{
"duration": time.Since(startTime),
"room_id": roomID,
}).Debug("applied history visibility (context)")
if len(filteredEvents) == 0 {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("User is not allowed to query context"),
}
}
eventsBefore, err := snapshot.SelectContextBeforeEvent(ctx, id, roomID, filter)
if err != nil && err != sql.ErrNoRows {
logrus.WithError(err).Error("unable to fetch before events")
return jsonerror.InternalServerError()
}
_, eventsAfter, err := snapshot.SelectContextAfterEvent(ctx, id, roomID, filter)
if err != nil && err != sql.ErrNoRows {
logrus.WithError(err).Error("unable to fetch after events")
return jsonerror.InternalServerError()
}
startTime = time.Now()
eventsBeforeFiltered, eventsAfterFiltered, err := applyHistoryVisibilityOnContextEvents(ctx, snapshot, rsAPI, eventsBefore, eventsAfter, device.UserID)
if err != nil {
logrus.WithError(err).Error("unable to apply history visibility filter")
return jsonerror.InternalServerError()
}
logrus.WithFields(logrus.Fields{
"duration": time.Since(startTime),
"room_id": roomID,
}).Debug("applied history visibility (context eventsBefore/eventsAfter)")
// TODO: Get the actual state at the last event returned by SelectContextAfterEvent
state, err := snapshot.CurrentState(ctx, roomID, &stateFilter, nil)
if err != nil {
logrus.WithError(err).Error("unable to fetch current room state")
return jsonerror.InternalServerError()
}
eventsBeforeClient := gomatrixserverlib.HeaderedToClientEvents(eventsBeforeFiltered, gomatrixserverlib.FormatAll)
eventsAfterClient := gomatrixserverlib.HeaderedToClientEvents(eventsAfterFiltered, gomatrixserverlib.FormatAll)
newState := state
if filter.LazyLoadMembers {
allEvents := append(eventsBeforeFiltered, eventsAfterFiltered...)
allEvents = append(allEvents, &requestedEvent)
evs := gomatrixserverlib.HeaderedToClientEvents(allEvents, gomatrixserverlib.FormatAll)
newState, err = applyLazyLoadMembers(ctx, device, snapshot, roomID, evs, lazyLoadCache)
if err != nil {
logrus.WithError(err).Error("unable to load membership events")
return jsonerror.InternalServerError()
}
}
ev := gomatrixserverlib.HeaderedToClientEvent(&requestedEvent, gomatrixserverlib.FormatAll)
response := ContextRespsonse{
Event: &ev,
EventsAfter: eventsAfterClient,
EventsBefore: eventsBeforeClient,
State: gomatrixserverlib.HeaderedToClientEvents(newState, gomatrixserverlib.FormatAll),
}
if len(response.State) > filter.Limit {
response.State = response.State[len(response.State)-filter.Limit:]
}
start, end, err := getStartEnd(ctx, snapshot, eventsBefore, eventsAfter)
if err == nil {
response.End = end.String()
response.Start = start.String()
}
succeeded = true
return util.JSONResponse{
Code: http.StatusOK,
JSON: response,
}
}
// applyHistoryVisibilityOnContextEvents is a helper function to avoid roundtrips to the roomserver
// by combining the events before and after the context event. Returns the filtered events,
// and an error, if any.
func applyHistoryVisibilityOnContextEvents(
ctx context.Context, snapshot storage.DatabaseTransaction, rsAPI roomserver.SyncRoomserverAPI,
eventsBefore, eventsAfter []*gomatrixserverlib.HeaderedEvent,
userID string,
) (filteredBefore, filteredAfter []*gomatrixserverlib.HeaderedEvent, err error) {
eventIDsBefore := make(map[string]struct{}, len(eventsBefore))
eventIDsAfter := make(map[string]struct{}, len(eventsAfter))
// Remember before/after eventIDs, so we can restore them
// after applying history visibility checks
for _, ev := range eventsBefore {
eventIDsBefore[ev.EventID()] = struct{}{}
}
for _, ev := range eventsAfter {
eventIDsAfter[ev.EventID()] = struct{}{}
}
allEvents := append(eventsBefore, eventsAfter...)
filteredEvents, err := internal.ApplyHistoryVisibilityFilter(ctx, snapshot, rsAPI, allEvents, nil, userID, "context")
if err != nil {
return nil, nil, err
}
// "Restore" events in the correct context
for _, ev := range filteredEvents {
if _, ok := eventIDsBefore[ev.EventID()]; ok {
filteredBefore = append(filteredBefore, ev)
}
if _, ok := eventIDsAfter[ev.EventID()]; ok {
filteredAfter = append(filteredAfter, ev)
}
}
return filteredBefore, filteredAfter, nil
}
func getStartEnd(ctx context.Context, snapshot storage.DatabaseTransaction, startEvents, endEvents []*gomatrixserverlib.HeaderedEvent) (start, end types.TopologyToken, err error) {
if len(startEvents) > 0 {
start, err = snapshot.EventPositionInTopology(ctx, startEvents[0].EventID())
if err != nil {
return
}
}
if len(endEvents) > 0 {
end, err = snapshot.EventPositionInTopology(ctx, endEvents[0].EventID())
}
return
}
func applyLazyLoadMembers(
ctx context.Context,
device *userapi.Device,
snapshot storage.DatabaseTransaction,
roomID string,
events []gomatrixserverlib.ClientEvent,
lazyLoadCache caching.LazyLoadCache,
) ([]*gomatrixserverlib.HeaderedEvent, error) {
eventSenders := make(map[string]struct{})
// get members who actually send an event
for _, e := range events {
// Don't add membership events the client should already know about
if _, cached := lazyLoadCache.IsLazyLoadedUserCached(device, e.RoomID, e.Sender); cached {
continue
}
eventSenders[e.Sender] = struct{}{}
}
wantUsers := make([]string, 0, len(eventSenders))
for userID := range eventSenders {
wantUsers = append(wantUsers, userID)
}
// Query missing membership events
filter := gomatrixserverlib.DefaultStateFilter()
filter.Senders = &wantUsers
filter.Types = &[]string{gomatrixserverlib.MRoomMember}
memberships, err := snapshot.GetStateEventsForRoom(ctx, roomID, &filter)
if err != nil {
return nil, err
}
// cache the membership events
for _, membership := range memberships {
lazyLoadCache.StoreLazyLoadedUser(device, roomID, *membership.StateKey(), membership.EventID())
}
return memberships, nil
}
func parseRoomEventFilter(req *http.Request) (*gomatrixserverlib.RoomEventFilter, error) {
// Default room filter
filter := &gomatrixserverlib.RoomEventFilter{Limit: 10}
l := req.URL.Query().Get("limit")
f := req.URL.Query().Get("filter")
if l != "" {
limit, err := strconv.Atoi(l)
if err != nil {
return nil, err
}
// NOTSPEC: feels like a good idea to have an upper bound limit
if limit > 100 {
limit = 100
}
filter.Limit = limit
}
if f != "" {
if err := json.Unmarshal([]byte(f), &filter); err != nil {
return nil, err
}
}
return filter, nil
}