6d832ae544
* Initial cut for backfilling The syncserver now asks the roomserver via QueryBackfill (which already existed to *handle* backfill requests) which then makes federation requests via gomatrixserverlib.RequestBackfill. Currently, tests fail on subsequent /messages requests because we don't know which servers are in the room, because we are unable to get state snapshots from a backfilled event because that code doesn't exist yet. * WIP backfill, doesn't work * Make initial backfill pass checks * Persist backfilled events with state snapshots * Remove debug lines * Linting * Review comments
420 lines
14 KiB
Go
420 lines
14 KiB
Go
// Copyright 2018 New Vector Ltd
|
|
//
|
|
// 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"
|
|
"fmt"
|
|
"net/http"
|
|
"sort"
|
|
"strconv"
|
|
|
|
"github.com/matrix-org/dendrite/clientapi/jsonerror"
|
|
"github.com/matrix-org/dendrite/common/config"
|
|
"github.com/matrix-org/dendrite/roomserver/api"
|
|
"github.com/matrix-org/dendrite/syncapi/storage"
|
|
"github.com/matrix-org/dendrite/syncapi/types"
|
|
"github.com/matrix-org/gomatrixserverlib"
|
|
"github.com/matrix-org/util"
|
|
"github.com/sirupsen/logrus"
|
|
)
|
|
|
|
type messagesReq struct {
|
|
ctx context.Context
|
|
db storage.Database
|
|
queryAPI api.RoomserverQueryAPI
|
|
federation *gomatrixserverlib.FederationClient
|
|
cfg *config.Dendrite
|
|
roomID string
|
|
from *types.PaginationToken
|
|
to *types.PaginationToken
|
|
wasToProvided bool
|
|
limit int
|
|
backwardOrdering bool
|
|
}
|
|
|
|
type messagesResp struct {
|
|
Start string `json:"start"`
|
|
End string `json:"end"`
|
|
Chunk []gomatrixserverlib.ClientEvent `json:"chunk"`
|
|
}
|
|
|
|
const defaultMessagesLimit = 10
|
|
|
|
// OnIncomingMessagesRequest implements the /messages endpoint from the
|
|
// client-server API.
|
|
// See: https://matrix.org/docs/spec/client_server/latest.html#get-matrix-client-r0-rooms-roomid-messages
|
|
func OnIncomingMessagesRequest(
|
|
req *http.Request, db storage.Database, roomID string,
|
|
federation *gomatrixserverlib.FederationClient,
|
|
queryAPI api.RoomserverQueryAPI,
|
|
cfg *config.Dendrite,
|
|
) util.JSONResponse {
|
|
var err error
|
|
|
|
// Extract parameters from the request's URL.
|
|
// Pagination tokens.
|
|
from, err := types.NewPaginationTokenFromString(req.URL.Query().Get("from"))
|
|
if err != nil {
|
|
return util.JSONResponse{
|
|
Code: http.StatusBadRequest,
|
|
JSON: jsonerror.InvalidArgumentValue("Invalid from parameter: " + err.Error()),
|
|
}
|
|
}
|
|
|
|
// Direction to return events from.
|
|
dir := req.URL.Query().Get("dir")
|
|
if dir != "b" && dir != "f" {
|
|
return util.JSONResponse{
|
|
Code: http.StatusBadRequest,
|
|
JSON: jsonerror.MissingArgument("Bad or missing dir query parameter (should be either 'b' or 'f')"),
|
|
}
|
|
}
|
|
// A boolean is easier to handle in this case, especially since dir is sure
|
|
// to have one of the two accepted values (so dir == "f" <=> !backwardOrdering).
|
|
backwardOrdering := (dir == "b")
|
|
|
|
// Pagination tokens. To is optional, and its default value depends on the
|
|
// direction ("b" or "f").
|
|
var to *types.PaginationToken
|
|
wasToProvided := true
|
|
if s := req.URL.Query().Get("to"); len(s) > 0 {
|
|
to, err = types.NewPaginationTokenFromString(s)
|
|
if err != nil {
|
|
return util.JSONResponse{
|
|
Code: http.StatusBadRequest,
|
|
JSON: jsonerror.InvalidArgumentValue("Invalid to parameter: " + err.Error()),
|
|
}
|
|
}
|
|
} else {
|
|
// If "to" isn't provided, it defaults to either the earliest stream
|
|
// position (if we're going backward) or to the latest one (if we're
|
|
// going forward).
|
|
to, err = setToDefault(req.Context(), db, backwardOrdering, roomID)
|
|
if err != nil {
|
|
util.GetLogger(req.Context()).WithError(err).Error("setToDefault failed")
|
|
return jsonerror.InternalServerError()
|
|
}
|
|
wasToProvided = false
|
|
}
|
|
|
|
// Maximum number of events to return; defaults to 10.
|
|
limit := defaultMessagesLimit
|
|
if len(req.URL.Query().Get("limit")) > 0 {
|
|
limit, err = strconv.Atoi(req.URL.Query().Get("limit"))
|
|
|
|
if err != nil {
|
|
return util.JSONResponse{
|
|
Code: http.StatusBadRequest,
|
|
JSON: jsonerror.InvalidArgumentValue("limit could not be parsed into an integer: " + err.Error()),
|
|
}
|
|
}
|
|
}
|
|
// TODO: Implement filtering (#587)
|
|
|
|
// Check the room ID's format.
|
|
if _, _, err = gomatrixserverlib.SplitID('!', roomID); err != nil {
|
|
return util.JSONResponse{
|
|
Code: http.StatusBadRequest,
|
|
JSON: jsonerror.MissingArgument("Bad room ID: " + err.Error()),
|
|
}
|
|
}
|
|
|
|
mReq := messagesReq{
|
|
ctx: req.Context(),
|
|
db: db,
|
|
queryAPI: queryAPI,
|
|
federation: federation,
|
|
cfg: cfg,
|
|
roomID: roomID,
|
|
from: from,
|
|
to: to,
|
|
wasToProvided: wasToProvided,
|
|
limit: limit,
|
|
backwardOrdering: backwardOrdering,
|
|
}
|
|
|
|
clientEvents, start, end, err := mReq.retrieveEvents()
|
|
if err != nil {
|
|
util.GetLogger(req.Context()).WithError(err).Error("mreq.retrieveEvents failed")
|
|
return jsonerror.InternalServerError()
|
|
}
|
|
util.GetLogger(req.Context()).WithFields(logrus.Fields{
|
|
"from": from.String(),
|
|
"to": to.String(),
|
|
"limit": limit,
|
|
"backwards": backwardOrdering,
|
|
"return_start": start.String(),
|
|
"return_end": end.String(),
|
|
}).Info("Responding")
|
|
|
|
// Respond with the events.
|
|
return util.JSONResponse{
|
|
Code: http.StatusOK,
|
|
JSON: messagesResp{
|
|
Chunk: clientEvents,
|
|
Start: start.String(),
|
|
End: end.String(),
|
|
},
|
|
}
|
|
}
|
|
|
|
// retrieveEvents retrieve events from the local database for a request on
|
|
// /messages. If there's not enough events to retrieve, it asks another
|
|
// homeserver in the room for older events.
|
|
// Returns an error if there was an issue talking to the database or with the
|
|
// remote homeserver.
|
|
func (r *messagesReq) retrieveEvents() (
|
|
clientEvents []gomatrixserverlib.ClientEvent, start,
|
|
end *types.PaginationToken, err error,
|
|
) {
|
|
// Retrieve the events from the local database.
|
|
streamEvents, err := r.db.GetEventsInRange(
|
|
r.ctx, r.from, r.to, r.roomID, r.limit, r.backwardOrdering,
|
|
)
|
|
if err != nil {
|
|
err = fmt.Errorf("GetEventsInRange: %w", err)
|
|
return
|
|
}
|
|
|
|
var events []gomatrixserverlib.HeaderedEvent
|
|
|
|
// There can be two reasons for streamEvents to be empty: either we've
|
|
// reached the oldest event in the room (or the most recent one, depending
|
|
// on the ordering), or we've reached a backward extremity.
|
|
if len(streamEvents) == 0 {
|
|
if events, err = r.handleEmptyEventsSlice(); err != nil {
|
|
return
|
|
}
|
|
} else {
|
|
if events, err = r.handleNonEmptyEventsSlice(streamEvents); err != nil {
|
|
return
|
|
}
|
|
}
|
|
|
|
// If we didn't get any event, we don't need to proceed any further.
|
|
if len(events) == 0 {
|
|
return []gomatrixserverlib.ClientEvent{}, r.from, r.to, nil
|
|
}
|
|
|
|
// Sort the events to ensure we send them in the right order.
|
|
events = gomatrixserverlib.HeaderedReverseTopologicalOrdering(
|
|
events,
|
|
gomatrixserverlib.TopologicalOrderByPrevEvents,
|
|
)
|
|
if r.backwardOrdering {
|
|
// This reverses the array from old->new to new->old
|
|
sort.SliceStable(events, func(i, j int) bool {
|
|
return true
|
|
})
|
|
}
|
|
|
|
// Convert all of the events into client events.
|
|
clientEvents = gomatrixserverlib.HeaderedToClientEvents(events, gomatrixserverlib.FormatAll)
|
|
// Get the position of the first and the last event in the room's topology.
|
|
// This position is currently determined by the event's depth, so we could
|
|
// also use it instead of retrieving from the database. However, if we ever
|
|
// change the way topological positions are defined (as depth isn't the most
|
|
// reliable way to define it), it would be easier and less troublesome to
|
|
// only have to change it in one place, i.e. the database.
|
|
startPos, err := r.db.EventPositionInTopology(
|
|
r.ctx, events[0].EventID(),
|
|
)
|
|
if err != nil {
|
|
err = fmt.Errorf("EventPositionInTopology: for start event %s: %w", events[0].EventID(), err)
|
|
return
|
|
}
|
|
endPos, err := r.db.EventPositionInTopology(
|
|
r.ctx, events[len(events)-1].EventID(),
|
|
)
|
|
if err != nil {
|
|
err = fmt.Errorf("EventPositionInTopology: for end event %s: %w", events[len(events)-1].EventID(), err)
|
|
return
|
|
}
|
|
// Generate pagination tokens to send to the client using the positions
|
|
// retrieved previously.
|
|
start = types.NewPaginationTokenFromTypeAndPosition(
|
|
types.PaginationTokenTypeTopology, startPos, 0,
|
|
)
|
|
end = types.NewPaginationTokenFromTypeAndPosition(
|
|
types.PaginationTokenTypeTopology, endPos, 0,
|
|
)
|
|
|
|
if r.backwardOrdering {
|
|
// A stream/topological position is a cursor located between two events.
|
|
// While they are identified in the code by the event on their right (if
|
|
// we consider a left to right chronological order), tokens need to refer
|
|
// to them by the event on their left, therefore we need to decrement the
|
|
// end position we send in the response if we're going backward.
|
|
end.PDUPosition--
|
|
}
|
|
|
|
// The lowest token value is 1, therefore we need to manually set it to that
|
|
// value if we're below it.
|
|
if end.PDUPosition < types.StreamPosition(1) {
|
|
end.PDUPosition = types.StreamPosition(1)
|
|
}
|
|
|
|
return clientEvents, start, end, err
|
|
}
|
|
|
|
// handleEmptyEventsSlice handles the case where the initial request to the
|
|
// database returned an empty slice of events. It does so by checking whether
|
|
// the set is empty because we've reached a backward extremity, and if that is
|
|
// the case, by retrieving as much events as requested by backfilling from
|
|
// another homeserver.
|
|
// Returns an error if there was an issue talking with the database or
|
|
// backfilling.
|
|
func (r *messagesReq) handleEmptyEventsSlice() (
|
|
events []gomatrixserverlib.HeaderedEvent, err error,
|
|
) {
|
|
backwardExtremities, err := r.db.BackwardExtremitiesForRoom(r.ctx, r.roomID)
|
|
|
|
// Check if we have backward extremities for this room.
|
|
if len(backwardExtremities) > 0 {
|
|
// If so, retrieve as much events as needed through backfilling.
|
|
events, err = r.backfill(r.roomID, backwardExtremities, r.limit)
|
|
if err != nil {
|
|
return
|
|
}
|
|
} else {
|
|
// If not, it means the slice was empty because we reached the room's
|
|
// creation, so return an empty slice.
|
|
events = []gomatrixserverlib.HeaderedEvent{}
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// handleNonEmptyEventsSlice handles the case where the initial request to the
|
|
// database returned a non-empty slice of events. It does so by checking whether
|
|
// events are missing from the expected result, and retrieve missing events
|
|
// through backfilling if needed.
|
|
// Returns an error if there was an issue while backfilling.
|
|
func (r *messagesReq) handleNonEmptyEventsSlice(streamEvents []types.StreamEvent) (
|
|
events []gomatrixserverlib.HeaderedEvent, err error,
|
|
) {
|
|
// Check if we have enough events.
|
|
isSetLargeEnough := len(streamEvents) >= r.limit
|
|
if !isSetLargeEnough {
|
|
// it might be fine we don't have up to 'limit' events, let's find out
|
|
if r.backwardOrdering {
|
|
if r.wasToProvided {
|
|
// The condition in the SQL query is a strict "greater than" so
|
|
// we need to check against to-1.
|
|
streamPos := types.StreamPosition(streamEvents[len(streamEvents)-1].StreamPosition)
|
|
isSetLargeEnough = (r.to.PDUPosition-1 == streamPos)
|
|
}
|
|
} else {
|
|
streamPos := types.StreamPosition(streamEvents[0].StreamPosition)
|
|
isSetLargeEnough = (r.from.PDUPosition-1 == streamPos)
|
|
}
|
|
}
|
|
|
|
// Check if the slice contains a backward extremity.
|
|
backwardExtremities, err := r.db.BackwardExtremitiesForRoom(r.ctx, r.roomID)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
// Backfill is needed if we've reached a backward extremity and need more
|
|
// events. It's only needed if the direction is backward.
|
|
if len(backwardExtremities) > 0 && !isSetLargeEnough && r.backwardOrdering {
|
|
var pdus []gomatrixserverlib.HeaderedEvent
|
|
// Only ask the remote server for enough events to reach the limit.
|
|
pdus, err = r.backfill(r.roomID, backwardExtremities, r.limit-len(streamEvents))
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
// Append the PDUs to the list to send back to the client.
|
|
events = append(events, pdus...)
|
|
}
|
|
|
|
// Append the events ve previously retrieved locally.
|
|
events = append(events, r.db.StreamEventsToEvents(nil, streamEvents)...)
|
|
|
|
return
|
|
}
|
|
|
|
// backfill performs a backfill request over the federation on another
|
|
// homeserver in the room.
|
|
// See: https://matrix.org/docs/spec/server_server/latest#get-matrix-federation-v1-backfill-roomid
|
|
// It also stores the PDUs retrieved from the remote homeserver's response to
|
|
// the database.
|
|
// Returns with an empty string if the remote homeserver didn't return with any
|
|
// event, or if there is no remote homeserver to contact.
|
|
// Returns an error if there was an issue with retrieving the list of servers in
|
|
// the room or sending the request.
|
|
func (r *messagesReq) backfill(roomID string, fromEventIDs []string, limit int) ([]gomatrixserverlib.HeaderedEvent, error) {
|
|
var res api.QueryBackfillResponse
|
|
err := r.queryAPI.QueryBackfill(context.Background(), &api.QueryBackfillRequest{
|
|
RoomID: roomID,
|
|
EarliestEventsIDs: fromEventIDs,
|
|
Limit: limit,
|
|
ServerName: r.cfg.Matrix.ServerName,
|
|
}, &res)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("QueryBackfill failed: %w", err)
|
|
}
|
|
util.GetLogger(r.ctx).WithField("new_events", len(res.Events)).Info("Storing new events from backfill")
|
|
|
|
// TODO: we should only be inserting events into the database from the roomserver's kafka output stream.
|
|
// Currently, this can race with live events for the room and cause problems. It's also just a bit unclear
|
|
// when you have multiple entry points to write events.
|
|
|
|
// Store the events in the database, while marking them as unfit to show
|
|
// up in responses to sync requests.
|
|
for i := range res.Events {
|
|
if _, err = r.db.WriteEvent(
|
|
r.ctx,
|
|
&res.Events[i],
|
|
[]gomatrixserverlib.HeaderedEvent{},
|
|
[]string{},
|
|
[]string{},
|
|
nil, true,
|
|
); err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
return res.Events, nil
|
|
}
|
|
|
|
// setToDefault returns the default value for the "to" query parameter of a
|
|
// request to /messages if not provided. It defaults to either the earliest
|
|
// topological position (if we're going backward) or to the latest one (if we're
|
|
// going forward).
|
|
// Returns an error if there was an issue with retrieving the latest position
|
|
// from the database
|
|
func setToDefault(
|
|
ctx context.Context, db storage.Database, backwardOrdering bool,
|
|
roomID string,
|
|
) (to *types.PaginationToken, err error) {
|
|
if backwardOrdering {
|
|
// go 1 earlier than the first event so we correctly fetch the earliest event
|
|
to = types.NewPaginationTokenFromTypeAndPosition(types.PaginationTokenTypeTopology, 0, 0)
|
|
} else {
|
|
var pos types.StreamPosition
|
|
pos, err = db.MaxTopologicalPosition(ctx, roomID)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
to = types.NewPaginationTokenFromTypeAndPosition(types.PaginationTokenTypeTopology, pos, 0)
|
|
}
|
|
|
|
return
|
|
}
|