Merge branch 'master' into add-receipts

build/docker/README.md

@@ -38,21 +38,38 @@ go run github.com/matrix-org/dendrite/cmd/generate-keys \
   --tls-key=server.key
 ```
 
-## Starting Dendrite
+## Starting Dendrite as a monolith deployment
 
-Once in place, start the dependencies:
+Create your config based on the `dendrite.yaml` configuration file in the `docker/config`
+folder in the [Dendrite repository](https://github.com/matrix-org/dendrite). Additionally,
+make the following changes to the configuration:
+
+- Enable Naffka: `use_naffka: true`
+
+Once in place, start the PostgreSQL dependency:
 
 ```
-docker-compose -f docker-compose.deps.yml up
+docker-compose -f docker-compose.deps.yml up postgres
 ```
 
-Wait a few seconds for Kafka and Postgres to finish starting up, and then start a monolith:
+Wait a few seconds for PostgreSQL to finish starting up, and then start a monolith:
 
 ```
 docker-compose -f docker-compose.monolith.yml up
 ```
 
-... or start the polylith components:
+## Starting Dendrite as a polylith deployment
+
+Create your config based on the `dendrite.yaml` configuration file in the `docker/config`
+folder in the [Dendrite repository](https://github.com/matrix-org/dendrite).
+
+Once in place, start all the dependencies:
+
+```
+docker-compose -f docker-compose.deps.yml up
+```
+
+Wait a few seconds for PostgreSQL and Kafka to finish starting up, and then start a polylith:
 
 ```
 docker-compose -f docker-compose.polylith.yml up

build/docker/config/dendrite-config.yaml

@@ -76,7 +76,7 @@ global:
 
     # Naffka database options. Not required when using Kafka.
     naffka_database:
-      connection_string: file:naffka.db
+      connection_string: postgresql://dendrite:itsasecret@postgres/dendrite_naffka?sslmode=disable
       max_open_conns: 100
       max_idle_conns: 2
       conn_max_lifetime: -1

build/docker/docker-compose.deps.yml

@@ -6,6 +6,9 @@ services:
     restart: always
     volumes:
       - ./postgres/create_db.sh:/docker-entrypoint-initdb.d/20-create_db.sh
+    # To persist your PostgreSQL databases outside of the Docker image, to 
+    # prevent data loss, you will need to add something like this:
+    #  - ./path/to/persistent/storage:/var/lib/postgresql/data
     environment:
       POSTGRES_PASSWORD: itsasecret
       POSTGRES_USER: dendrite

build/docker/postgres/create_db.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 for db in account device mediaapi syncapi roomserver signingkeyserver keyserver federationsender appservice e2ekey naffka; do
     createdb -U dendrite -O dendrite dendrite_$db

docs/systemd/monolith-example.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=Dendrite (Matrix Homeserver)
+After=syslog.target
+After=network.target
+After=postgresql.service
+
+[Service]
+RestartSec=2s
+Type=simple
+User=dendrite
+Group=dendrite
+WorkingDirectory=/opt/dendrite/
+ExecStart=/opt/dendrite/bin/dendrite-monolith-server
+Restart=always
+
+[Install]
+WantedBy=multi-user.target

federationapi/routing/send.go

@@ -183,7 +183,7 @@ func (t *txnReq) processTransaction(ctx context.Context) (*gomatrixserverlib.Res
 
 	// Process the events.
 	for _, e := range pdus {
-		if err := t.processEvent(ctx, e.Unwrap(), true); err != nil {
+		if err := t.processEvent(ctx, e.Unwrap()); err != nil {
 			// If the error is due to the event itself being bad then we skip
 			// it and move onto the next event. We report an error so that the
 			// sender knows that we have skipped processing it.
@@ -246,9 +246,6 @@ func isProcessingErrorFatal(err error) bool {
 type roomNotFoundError struct {
 	roomID string
 }
-type unmarshalError struct {
-	err error
-}
 type verifySigError struct {
 	eventID string
 	err     error
@@ -259,7 +256,6 @@ type missingPrevEventsError struct {
 }
 
 func (e roomNotFoundError) Error() string { return fmt.Sprintf("room %q not found", e.roomID) }
-func (e unmarshalError) Error() string    { return fmt.Sprintf("unable to parse event: %s", e.err) }
 func (e verifySigError) Error() string {
 	return fmt.Sprintf("unable to verify signature of event %q: %s", e.eventID, e.err)
 }
@@ -338,11 +334,28 @@ func (t *txnReq) processDeviceListUpdate(ctx context.Context, e gomatrixserverli
 	}
 }
 
-func (t *txnReq) processEvent(ctx context.Context, e gomatrixserverlib.Event, isInboundTxn bool) error {
+func (t *txnReq) getServers(ctx context.Context, roomID string) []gomatrixserverlib.ServerName {
+	servers := []gomatrixserverlib.ServerName{t.Origin}
+	serverReq := &api.QueryServerJoinedToRoomRequest{
+		RoomID: roomID,
+	}
+	serverRes := &api.QueryServerJoinedToRoomResponse{}
+	if err := t.rsAPI.QueryServerJoinedToRoom(ctx, serverReq, serverRes); err == nil {
+		servers = append(servers, serverRes.ServerNames...)
+		util.GetLogger(ctx).Infof("Found %d server(s) to query for missing events in %q", len(servers), roomID)
+	}
+	return servers
+}
+
+func (t *txnReq) processEvent(ctx context.Context, e gomatrixserverlib.Event) error {
 	logger := util.GetLogger(ctx).WithField("event_id", e.EventID()).WithField("room_id", e.RoomID())
 
 	// Work out if the roomserver knows everything it needs to know to auth
-	// the event.
+	// the event. This includes the prev_events and auth_events.
+	// NOTE! This is going to include prev_events that have an empty state
+	// snapshot. This is because we will need to re-request the event, and
+	// it's /state_ids, in order for it to exist in the roomserver correctly
+	// before the roomserver tries to work out
 	stateReq := api.QueryMissingAuthPrevEventsRequest{
 		RoomID:       e.RoomID(),
 		AuthEventIDs: e.AuthEventIDs(),
@@ -350,7 +363,7 @@ func (t *txnReq) processEvent(ctx context.Context, e gomatrixserverlib.Event, is
 	}
 	var stateResp api.QueryMissingAuthPrevEventsResponse
 	if err := t.rsAPI.QueryMissingAuthPrevEvents(ctx, &stateReq, &stateResp); err != nil {
-		return err
+		return fmt.Errorf("t.rsAPI.QueryMissingAuthPrevEvents: %w", err)
 	}
 
 	if !stateResp.RoomExists {
@@ -365,52 +378,14 @@ func (t *txnReq) processEvent(ctx context.Context, e gomatrixserverlib.Event, is
 
 	if len(stateResp.MissingAuthEventIDs) > 0 {
 		logger.Infof("Event refers to %d unknown auth_events", len(stateResp.MissingAuthEventIDs))
-
-		servers := []gomatrixserverlib.ServerName{t.Origin}
-		serverReq := &api.QueryServerJoinedToRoomRequest{
-			RoomID: e.RoomID(),
-		}
-		serverRes := &api.QueryServerJoinedToRoomResponse{}
-		if err := t.rsAPI.QueryServerJoinedToRoom(ctx, serverReq, serverRes); err == nil {
-			servers = append(servers, serverRes.ServerNames...)
-			logger.Infof("Found %d server(s) to query for missing events", len(servers))
-		}
-
-	getAuthEvent:
-		for _, missingAuthEventID := range stateResp.MissingAuthEventIDs {
-			for _, server := range servers {
-				logger.Infof("Retrieving missing auth event %q from %q", missingAuthEventID, server)
-				tx, err := t.federation.GetEvent(ctx, server, missingAuthEventID)
-				if err != nil {
-					continue // try the next server
-				}
-				ev, err := gomatrixserverlib.NewEventFromUntrustedJSON(tx.PDUs[0], stateResp.RoomVersion)
-				if err != nil {
-					logger.WithError(err).Errorf("Failed to unmarshal auth event %q", missingAuthEventID)
-					continue // try the next server
-				}
-				if err = api.SendInputRoomEvents(
-					context.Background(),
-					t.rsAPI,
-					[]api.InputRoomEvent{
-						{
-							Kind:         api.KindOutlier,
-							Event:        ev.Headered(stateResp.RoomVersion),
-							AuthEventIDs: ev.AuthEventIDs(),
-							SendAsServer: api.DoNotSendToOtherServers,
-						},
-					},
-				); err != nil {
-					logger.WithError(err).Errorf("Failed to send auth event %q to roomserver", missingAuthEventID)
-					continue getAuthEvent // move onto the next event
-				}
-			}
+		if err := t.retrieveMissingAuthEvents(ctx, e, &stateResp); err != nil {
+			return fmt.Errorf("t.retrieveMissingAuthEvents: %w", err)
 		}
 	}
 
 	if len(stateResp.MissingPrevEventIDs) > 0 {
 		logger.Infof("Event refers to %d unknown prev_events", len(stateResp.MissingPrevEventIDs))
-		return t.processEventWithMissingState(ctx, e, stateResp.RoomVersion, isInboundTxn)
+		return t.processEventWithMissingState(ctx, e, stateResp.RoomVersion)
 	}
 
 	// pass the event to the roomserver which will do auth checks
@@ -427,6 +402,60 @@ func (t *txnReq) processEvent(ctx context.Context, e gomatrixserverlib.Event, is
 	)
 }
 
+func (t *txnReq) retrieveMissingAuthEvents(
+	ctx context.Context, e gomatrixserverlib.Event, stateResp *api.QueryMissingAuthPrevEventsResponse,
+) error {
+	logger := util.GetLogger(ctx).WithField("event_id", e.EventID()).WithField("room_id", e.RoomID())
+
+	missingAuthEvents := make(map[string]struct{})
+	for _, missingAuthEventID := range stateResp.MissingAuthEventIDs {
+		missingAuthEvents[missingAuthEventID] = struct{}{}
+	}
+
+	servers := t.getServers(ctx, e.RoomID())
+	if len(servers) > 5 {
+		servers = servers[:5]
+	}
+withNextEvent:
+	for missingAuthEventID := range missingAuthEvents {
+	withNextServer:
+		for _, server := range servers {
+			logger.Infof("Retrieving missing auth event %q from %q", missingAuthEventID, server)
+			tx, err := t.federation.GetEvent(ctx, server, missingAuthEventID)
+			if err != nil {
+				logger.WithError(err).Warnf("Failed to retrieve auth event %q", missingAuthEventID)
+				continue withNextServer
+			}
+			ev, err := gomatrixserverlib.NewEventFromUntrustedJSON(tx.PDUs[0], stateResp.RoomVersion)
+			if err != nil {
+				logger.WithError(err).Warnf("Failed to unmarshal auth event %q", missingAuthEventID)
+				continue withNextServer
+			}
+			if err = api.SendInputRoomEvents(
+				context.Background(),
+				t.rsAPI,
+				[]api.InputRoomEvent{
+					{
+						Kind:         api.KindOutlier,
+						Event:        ev.Headered(stateResp.RoomVersion),
+						AuthEventIDs: ev.AuthEventIDs(),
+						SendAsServer: api.DoNotSendToOtherServers,
+					},
+				},
+			); err != nil {
+				return fmt.Errorf("api.SendEvents: %w", err)
+			}
+			delete(missingAuthEvents, missingAuthEventID)
+			continue withNextEvent
+		}
+	}
+
+	if missing := len(missingAuthEvents); missing > 0 {
+		return fmt.Errorf("Event refers to %d auth_events which we failed to fetch", missing)
+	}
+	return nil
+}
+
 func checkAllowedByState(e gomatrixserverlib.Event, stateEvents []gomatrixserverlib.Event) error {
 	authUsingState := gomatrixserverlib.NewAuthEvents(nil)
 	for i := range stateEvents {
@@ -438,7 +467,7 @@ func checkAllowedByState(e gomatrixserverlib.Event, stateEvents []gomatrixserver
 	return gomatrixserverlib.Allowed(e, &authUsingState)
 }
 
-func (t *txnReq) processEventWithMissingState(ctx context.Context, e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion, isInboundTxn bool) error {
+func (t *txnReq) processEventWithMissingState(ctx context.Context, e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion) error {
 	// Do this with a fresh context, so that we keep working even if the
 	// original request times out. With any luck, by the time the remote
 	// side retries, we'll have fetched the missing state.
@@ -464,39 +493,82 @@ func (t *txnReq) processEventWithMissingState(ctx context.Context, e gomatrixser
 	// - fill in the gap completely then process event `e` returning no backwards extremity
 	// - fail to fill in the gap and tell us to terminate the transaction err=not nil
 	// - fail to fill in the gap and tell us to fetch state at the new backwards extremity, and to not terminate the transaction
-	backwardsExtremity, err := t.getMissingEvents(gmectx, e, roomVersion, isInboundTxn)
+	newEvents, err := t.getMissingEvents(gmectx, e, roomVersion)
 	if err != nil {
 		return err
 	}
-	if backwardsExtremity == nil {
-		// we filled in the gap!
+	if len(newEvents) == 0 {
 		return nil
 	}
 
+	backwardsExtremity := &newEvents[0]
+	newEvents = newEvents[1:]
+
 	// at this point we know we're going to have a gap: we need to work out the room state at the new backwards extremity.
-	// security: we have to do state resolution on the new backwards extremity (TODO: WHY)
 	// Therefore, we cannot just query /state_ids with this event to get the state before. Instead, we need to query
 	// the state AFTER all the prev_events for this event, then apply state resolution to that to get the state before the event.
 	var states []*gomatrixserverlib.RespState
 	needed := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{*backwardsExtremity}).Tuples()
 	for _, prevEventID := range backwardsExtremity.PrevEventIDs() {
+		// Look up what the state is after the backward extremity. This will either
+		// come from the roomserver, if we know all the required events, or it will
+		// come from a remote server via /state_ids if not.
 		var prevState *gomatrixserverlib.RespState
 		prevState, err = t.lookupStateAfterEvent(gmectx, roomVersion, backwardsExtremity.RoomID(), prevEventID, needed)
 		if err != nil {
 			util.GetLogger(ctx).WithError(err).Errorf("Failed to lookup state after prev_event: %s", prevEventID)
 			return err
 		}
+		// Append the state onto the collected state. We'll run this through the
+		// state resolution next.
 		states = append(states, prevState)
 	}
+
+	// Now that we have collected all of the state from the prev_events, we'll
+	// run the state through the appropriate state resolution algorithm for the
+	// room. This does a couple of things:
+	// 1. Ensures that the state is deduplicated fully for each state-key tuple
+	// 2. Ensures that we pick the latest events from both sets, in the case that
+	//    one of the prev_events is quite a bit older than the others
 	resolvedState, err := t.resolveStatesAndCheck(gmectx, roomVersion, states, backwardsExtremity)
 	if err != nil {
 		util.GetLogger(ctx).WithError(err).Errorf("Failed to resolve state conflicts for event %s", backwardsExtremity.EventID())
 		return err
 	}
 
-	// pass the event along with the state to the roomserver using a background context so we don't
-	// needlessly expire
-	return api.SendEventWithState(context.Background(), t.rsAPI, resolvedState, e.Headered(roomVersion), t.haveEventIDs())
+	// First of all, send the backward extremity into the roomserver with the
+	// newly resolved state. This marks the "oldest" point in the backfill and
+	// sets the baseline state for any new events after this.
+	err = api.SendEventWithState(
+		context.Background(),
+		t.rsAPI,
+		resolvedState,
+		backwardsExtremity.Headered(roomVersion),
+		t.haveEventIDs(),
+	)
+	if err != nil {
+		return fmt.Errorf("api.SendEventWithState: %w", err)
+	}
+
+	// Then send all of the newer backfilled events, of which will all be newer
+	// than the backward extremity, into the roomserver without state. This way
+	// they will automatically fast-forward based on the room state at the
+	// extremity in the last step.
+	headeredNewEvents := make([]gomatrixserverlib.HeaderedEvent, len(newEvents))
+	for i, newEvent := range newEvents {
+		headeredNewEvents[i] = newEvent.Headered(roomVersion)
+	}
+	if err = api.SendEvents(
+		context.Background(),
+		t.rsAPI,
+		append(headeredNewEvents, e.Headered(roomVersion)),
+		api.DoNotSendToOtherServers,
+		nil,
+	); err != nil {
+		return fmt.Errorf("api.SendEvents: %w", err)
+	}
+
+	return nil
 }
 
 // lookupStateAfterEvent returns the room state after `eventID`, which is the state before eventID with the state of `eventID` (if it's a state event)
@@ -510,18 +582,23 @@ func (t *txnReq) lookupStateAfterEvent(ctx context.Context, roomVersion gomatrix
 
 	respState, err := t.lookupStateBeforeEvent(ctx, roomVersion, roomID, eventID)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("t.lookupStateBeforeEvent: %w", err)
+	}
+
+	servers := t.getServers(ctx, roomID)
+	if len(servers) > 5 {
+		servers = servers[:5]
 	}
 
 	// fetch the event we're missing and add it to the pile
-	h, err := t.lookupEvent(ctx, roomVersion, eventID, false)
+	h, err := t.lookupEvent(ctx, roomVersion, eventID, false, servers)
 	switch err.(type) {
 	case verifySigError:
 		return respState, nil
 	case nil:
 		// do nothing
 	default:
-		return nil, err
+		return nil, fmt.Errorf("t.lookupEvent: %w", err)
 	}
 	t.haveEvents[h.EventID()] = h
 	if h.StateKey() != nil {
@@ -622,7 +699,11 @@ retryAllowedState:
 	if err = checkAllowedByState(*backwardsExtremity, resolvedStateEvents); err != nil {
 		switch missing := err.(type) {
 		case gomatrixserverlib.MissingAuthEventError:
-			h, err2 := t.lookupEvent(ctx, roomVersion, missing.AuthEventID, true)
+			servers := t.getServers(ctx, backwardsExtremity.RoomID())
+			if len(servers) > 5 {
+				servers = servers[:5]
+			}
+			h, err2 := t.lookupEvent(ctx, roomVersion, missing.AuthEventID, true, servers)
 			switch err2.(type) {
 			case verifySigError:
 				return &gomatrixserverlib.RespState{
@@ -652,11 +733,7 @@ retryAllowedState:
 // This function recursively calls txnReq.processEvent with the missing events, which will be processed before this function returns.
 // This means that we may recursively call this function, as we spider back up prev_events.
 // nolint:gocyclo
-func (t *txnReq) getMissingEvents(ctx context.Context, e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion, isInboundTxn bool) (backwardsExtremity *gomatrixserverlib.Event, err error) {
-	if !isInboundTxn {
-		// we've recursed here, so just take a state snapshot please!
-		return &e, nil
-	}
+func (t *txnReq) getMissingEvents(ctx context.Context, e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion) (newEvents []gomatrixserverlib.Event, err error) {
 	logger := util.GetLogger(ctx).WithField("event_id", e.EventID()).WithField("room_id", e.RoomID())
 	needed := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{e})
 	// query latest events (our trusted forward extremities)
@@ -667,7 +744,7 @@ func (t *txnReq) getMissingEvents(ctx context.Context, e gomatrixserverlib.Event
 	var res api.QueryLatestEventsAndStateResponse
 	if err = t.rsAPI.QueryLatestEventsAndState(ctx, &req, &res); err != nil {
 		logger.WithError(err).Warn("Failed to query latest events")
-		return &e, nil
+		return nil, err
 	}
 	latestEvents := make([]string, len(res.LatestEvents))
 	for i := range res.LatestEvents {
@@ -726,7 +803,7 @@ func (t *txnReq) getMissingEvents(ctx context.Context, e gomatrixserverlib.Event
 	logger.Infof("get_missing_events returned %d events", len(missingResp.Events))
 
 	// topologically sort and sanity check that we are making forward progress
-	newEvents := gomatrixserverlib.ReverseTopologicalOrdering(missingResp.Events, gomatrixserverlib.TopologicalOrderByPrevEvents)
+	newEvents = gomatrixserverlib.ReverseTopologicalOrdering(missingResp.Events, gomatrixserverlib.TopologicalOrderByPrevEvents)
 	shouldHaveSomeEventIDs := e.PrevEventIDs()
 	hasPrevEvent := false
 Event:
@@ -749,16 +826,9 @@ Event:
 			err:     err,
 		}
 	}
-	// process the missing events then the event which started this whole thing
-	for _, ev := range append(newEvents, e) {
-		err := t.processEvent(ctx, ev, false)
-		if err != nil {
-			return nil, err
-		}
-	}
 
 	// we processed everything!
-	return nil, nil
+	return newEvents, nil
 }
 
 func (t *txnReq) lookupMissingStateViaState(ctx context.Context, roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
@@ -838,6 +908,12 @@ func (t *txnReq) lookupMissingStateViaStateIDs(ctx context.Context, roomID, even
 		"concurrent_requests": concurrentRequests,
 	}).Info("Fetching missing state at event")
 
+	// Get a list of servers to fetch from.
+	servers := t.getServers(ctx, roomID)
+	if len(servers) > 5 {
+		servers = servers[:5]
+	}
+
 	// Create a queue containing all of the missing event IDs that we want
 	// to retrieve.
 	pending := make(chan string, missingCount)
@@ -863,7 +939,7 @@ func (t *txnReq) lookupMissingStateViaStateIDs(ctx context.Context, roomID, even
 	// Define what we'll do in order to fetch the missing event ID.
 	fetch := func(missingEventID string) {
 		var h *gomatrixserverlib.HeaderedEvent
-		h, err = t.lookupEvent(ctx, roomVersion, missingEventID, false)
+		h, err = t.lookupEvent(ctx, roomVersion, missingEventID, false, servers)
 		switch err.(type) {
 		case verifySigError:
 			return
@@ -901,26 +977,25 @@ func (t *txnReq) lookupMissingStateViaStateIDs(ctx context.Context, roomID, even
 }
 
 func (t *txnReq) createRespStateFromStateIDs(stateIDs gomatrixserverlib.RespStateIDs) (
-	*gomatrixserverlib.RespState, error) {
+	*gomatrixserverlib.RespState, error) { // nolint:unparam
 	// create a RespState response using the response to /state_ids as a guide
-	respState := gomatrixserverlib.RespState{
-		AuthEvents:  make([]gomatrixserverlib.Event, len(stateIDs.AuthEventIDs)),
-		StateEvents: make([]gomatrixserverlib.Event, len(stateIDs.StateEventIDs)),
-	}
+	respState := gomatrixserverlib.RespState{}
 
 	for i := range stateIDs.StateEventIDs {
 		ev, ok := t.haveEvents[stateIDs.StateEventIDs[i]]
 		if !ok {
-			return nil, fmt.Errorf("missing state event %s", stateIDs.StateEventIDs[i])
+			logrus.Warnf("Missing state event in createRespStateFromStateIDs: %s", stateIDs.StateEventIDs[i])
+			continue
 		}
-		respState.StateEvents[i] = ev.Unwrap()
+		respState.StateEvents = append(respState.StateEvents, ev.Unwrap())
 	}
 	for i := range stateIDs.AuthEventIDs {
 		ev, ok := t.haveEvents[stateIDs.AuthEventIDs[i]]
 		if !ok {
-			return nil, fmt.Errorf("missing auth event %s", stateIDs.AuthEventIDs[i])
+			logrus.Warnf("Missing auth event in createRespStateFromStateIDs: %s", stateIDs.AuthEventIDs[i])
+			continue
 		}
-		respState.AuthEvents[i] = ev.Unwrap()
+		respState.AuthEvents = append(respState.AuthEvents, ev.Unwrap())
 	}
 	// We purposefully do not do auth checks on the returned events, as they will still
 	// be processed in the exact same way, just as a 'rejected' event
@@ -928,7 +1003,7 @@ func (t *txnReq) createRespStateFromStateIDs(stateIDs gomatrixserverlib.RespStat
 	return &respState, nil
 }
 
-func (t *txnReq) lookupEvent(ctx context.Context, roomVersion gomatrixserverlib.RoomVersion, missingEventID string, localFirst bool) (*gomatrixserverlib.HeaderedEvent, error) {
+func (t *txnReq) lookupEvent(ctx context.Context, roomVersion gomatrixserverlib.RoomVersion, missingEventID string, localFirst bool, servers []gomatrixserverlib.ServerName) (*gomatrixserverlib.HeaderedEvent, error) {
 	if localFirst {
 		// fetch from the roomserver
 		queryReq := api.QueryEventsByIDRequest{
@@ -941,19 +1016,27 @@ func (t *txnReq) lookupEvent(ctx context.Context, roomVersion gomatrixserverlib.
 			return &queryRes.Events[0], nil
 		}
 	}
-	txn, err := t.federation.GetEvent(ctx, t.Origin, missingEventID)
-	if err != nil || len(txn.PDUs) == 0 {
-		util.GetLogger(ctx).WithError(err).WithField("event_id", missingEventID).Warn("failed to get missing /event for event ID")
-		return nil, err
-	}
-	pdu := txn.PDUs[0]
 	var event gomatrixserverlib.Event
-	event, err = gomatrixserverlib.NewEventFromUntrustedJSON(pdu, roomVersion)
-	if err != nil {
-		util.GetLogger(ctx).WithError(err).Warnf("Transaction: Failed to parse event JSON of event %q", event.EventID())
-		return nil, unmarshalError{err}
+	found := false
+	for _, serverName := range servers {
+		txn, err := t.federation.GetEvent(ctx, serverName, missingEventID)
+		if err != nil || len(txn.PDUs) == 0 {
+			util.GetLogger(ctx).WithError(err).WithField("event_id", missingEventID).Warn("Failed to get missing /event for event ID")
+			continue
+		}
+		event, err = gomatrixserverlib.NewEventFromUntrustedJSON(txn.PDUs[0], roomVersion)
+		if err != nil {
+			util.GetLogger(ctx).WithError(err).WithField("event_id", missingEventID).Warnf("Transaction: Failed to parse event JSON of event")
+			continue
+		}
+		found = true
+		break
 	}
-	if err = gomatrixserverlib.VerifyAllEventSignatures(ctx, []gomatrixserverlib.Event{event}, t.keys); err != nil {
+	if !found {
+		util.GetLogger(ctx).WithField("event_id", missingEventID).Warnf("Failed to get missing /event for event ID from %d server(s)", len(servers))
+		return nil, fmt.Errorf("wasn't able to find event via %d server(s)", len(servers))
+	}
+	if err := gomatrixserverlib.VerifyAllEventSignatures(ctx, []gomatrixserverlib.Event{event}, t.keys); err != nil {
 		util.GetLogger(ctx).WithError(err).Warnf("Transaction: Couldn't validate signature of event %q", event.EventID())
 		return nil, verifySigError{event.EventID(), err}
 	}

federationapi/routing/send_test.go

@@ -491,7 +491,7 @@ func TestTransactionFailAuthChecks(t *testing.T) {
 		queryMissingAuthPrevEvents: func(req *api.QueryMissingAuthPrevEventsRequest) api.QueryMissingAuthPrevEventsResponse {
 			return api.QueryMissingAuthPrevEventsResponse{
 				RoomExists:          true,
-				MissingAuthEventIDs: []string{"create_event"},
+				MissingAuthEventIDs: []string{},
 				MissingPrevEventIDs: []string{},
 			}
 		},
@@ -516,6 +516,23 @@ func TestTransactionFetchMissingPrevEvents(t *testing.T) {
 
 	var rsAPI *testRoomserverAPI // ref here so we can refer to inputRoomEvents inside these functions
 	rsAPI = &testRoomserverAPI{
+		queryEventsByID: func(req *api.QueryEventsByIDRequest) api.QueryEventsByIDResponse {
+			res := api.QueryEventsByIDResponse{}
+			for _, ev := range testEvents {
+				for _, id := range req.EventIDs {
+					if ev.EventID() == id {
+						res.Events = append(res.Events, ev)
+					}
+				}
+			}
+			return res
+		},
+		queryStateAfterEvents: func(req *api.QueryStateAfterEventsRequest) api.QueryStateAfterEventsResponse {
+			return api.QueryStateAfterEventsResponse{
+				PrevEventsExist: true,
+				StateEvents:     testEvents[:5],
+			}
+		},
 		queryMissingAuthPrevEvents: func(req *api.QueryMissingAuthPrevEventsRequest) api.QueryMissingAuthPrevEventsResponse {
 			missingPrevEvent := []string{"missing_prev_event"}
 			if len(req.PrevEventIDs) == 1 {

federationsender/internal/perform.go

@@ -196,6 +196,11 @@ func (r *FederationSenderInternalAPI) performJoinUsingServer(
 		return fmt.Errorf("respMakeJoin.JoinEvent.Build: %w", err)
 	}
 
+	// No longer reuse the request context from this point forward.
+	// We don't want the client timing out to interrupt the join.
+	var cancel context.CancelFunc
+	ctx, cancel = context.WithCancel(context.Background())
+
 	// Try to perform a send_join using the newly built event.
 	respSendJoin, err := r.federation.SendJoin(
 		ctx,
@@ -205,11 +210,16 @@ func (r *FederationSenderInternalAPI) performJoinUsingServer(
 	)
 	if err != nil {
 		r.statistics.ForServer(serverName).Failure()
+		cancel()
 		return fmt.Errorf("r.federation.SendJoin: %w", err)
 	}
 	r.statistics.ForServer(serverName).Success()
+
+	// Sanity-check the join response to ensure that it has a create
+	// event, that the room version is known, etc.
 	if err := sanityCheckSendJoinResponse(respSendJoin); err != nil {
-		return err
+		cancel()
+		return fmt.Errorf("sanityCheckSendJoinResponse: %w", err)
 	}
 
 	// Process the join response in a goroutine. The idea here is
@@ -217,8 +227,6 @@ func (r *FederationSenderInternalAPI) performJoinUsingServer(
 	// to complete, but if the client does give up waiting, we'll
 	// still continue to process the join anyway so that we don't
 	// waste the effort.
-	var cancel context.CancelFunc
-	ctx, cancel = context.WithCancel(context.Background())
 	go func() {
 		defer cancel()
 

internal/sqlutil/trace.go

@@ -93,7 +93,7 @@ func trackGoID(query string) {
 	if strings.HasPrefix(q, "SELECT") {
 		return // SELECTs can go on other goroutines
 	}
-	logrus.Warnf("unsafe goid: SQL executed not on an ExclusiveWriter: %s", q)
+	logrus.Warnf("unsafe goid %d: SQL executed not on an ExclusiveWriter: %s", thisGoID, q)
 }
 
 // Open opens a database specified by its database driver name and a driver-specific data source name,

roomserver/internal/query/query.go

@@ -122,7 +122,7 @@ func (r *Queryer) QueryMissingAuthPrevEvents(
 	}
 
 	for _, prevEventID := range request.PrevEventIDs {
-		if nids, err := r.DB.EventNIDs(ctx, []string{prevEventID}); err != nil || len(nids) == 0 {
+		if state, err := r.DB.StateAtEventIDs(ctx, []string{prevEventID}); err != nil || len(state) == 0 {
 			response.MissingPrevEventIDs = append(response.MissingPrevEventIDs, prevEventID)
 		}
 	}

roomserver/storage/shared/membership_updater.go

@@ -22,12 +22,21 @@ func NewMembershipUpdater(
 	ctx context.Context, d *Database, txn *sql.Tx, roomID, targetUserID string,
 	targetLocal bool, roomVersion gomatrixserverlib.RoomVersion,
 ) (*MembershipUpdater, error) {
-	roomNID, err := d.assignRoomNID(ctx, txn, roomID, roomVersion)
-	if err != nil {
-		return nil, err
-	}
+	var roomNID types.RoomNID
+	var targetUserNID types.EventStateKeyNID
+	var err error
+	err = d.Writer.Do(d.DB, txn, func(txn *sql.Tx) error {
+		roomNID, err = d.assignRoomNID(ctx, txn, roomID, roomVersion)
+		if err != nil {
+			return err
+		}
 
-	targetUserNID, err := d.assignStateKeyNID(ctx, txn, targetUserID)
+		targetUserNID, err = d.assignStateKeyNID(ctx, txn, targetUserID)
+		if err != nil {
+			return err
+		}
+		return nil
+	})
 	if err != nil {
 		return nil, err
 	}

signingkeyserver/internal/api.go

@@ -224,10 +224,6 @@ func (s *ServerKeyAPI) handleFetcherKeys(
 
 	// Now let's look at the results that we got from this fetcher.
 	for req, res := range fetcherResults {
-		if req.ServerName == s.ServerName {
-			continue
-		}
-
 		if prev, ok := results[req]; ok {
 			// We've already got a previous entry for this request
 			// so let's see if the newly retrieved one contains a more