Prefer /state_ids when missing state across federation (#1008)

* Prefer /state_ids when missing state across federation

* Linting

* Better logging
This commit is contained in:
Kegsay 2020-05-05 15:48:37 +01:00 committed by GitHub
parent 9d15312ef6
commit 31d3b0d4a5
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3 changed files with 126 additions and 12 deletions

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@ -54,7 +54,7 @@ func (c *RoomserverProducer) SendEvents(
// SendEventWithState writes an event with KindNew to the roomserver input log
// with the state at the event as KindOutlier before it.
func (c *RoomserverProducer) SendEventWithState(
ctx context.Context, state gomatrixserverlib.RespState, event gomatrixserverlib.HeaderedEvent,
ctx context.Context, state *gomatrixserverlib.RespState, event gomatrixserverlib.HeaderedEvent,
) error {
outliers, err := state.Events()
if err != nil {

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@ -26,6 +26,7 @@ import (
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
"github.com/sirupsen/logrus"
)
// Send implements /_matrix/federation/v1/send/{txnID}
@ -297,22 +298,27 @@ func (t *txnReq) processEventWithMissingState(e gomatrixserverlib.Event, roomVer
// However not all version of synapse support /state_ids so you may
// need to fallback to /state.
// TODO: Attempt to fill in the gap using /get_missing_events
// TODO: Attempt to fetch the state using /state_ids and /events
state, err := t.federation.LookupState(t.context, t.Origin, e.RoomID(), e.EventID(), roomVersion)
// Attempt to fetch the missing state using /state_ids and /events
var respState *gomatrixserverlib.RespState
var err error
respState, err = t.lookupMissingStateViaStateIDs(e, roomVersion)
if err != nil {
return err
}
// Check that the returned state is valid.
if err := state.Check(t.context, t.keys); err != nil {
return err
// Fallback to /state
util.GetLogger(t.context).WithError(err).Warn("processEventWithMissingState failed to /state_ids, falling back to /state")
respState, err = t.lookupMissingStateViaState(e, roomVersion)
if err != nil {
return err
}
}
// Check that the event is allowed by the state.
retryAllowedState:
if err := checkAllowedByState(e, state.StateEvents); err != nil {
if err := checkAllowedByState(e, respState.StateEvents); err != nil {
switch missing := err.(type) {
case gomatrixserverlib.MissingAuthEventError:
// An auth event was missing so let's look up that event over federation
for _, s := range state.StateEvents {
for _, s := range respState.StateEvents {
if s.EventID() != missing.AuthEventID {
continue
}
@ -329,5 +335,113 @@ retryAllowedState:
}
// pass the event along with the state to the roomserver
return t.producer.SendEventWithState(t.context, state, e.Headered(roomVersion))
return t.producer.SendEventWithState(t.context, respState, e.Headered(roomVersion))
}
func (t *txnReq) lookupMissingStateViaState(e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion) (
respState *gomatrixserverlib.RespState, err error) {
state, err := t.federation.LookupState(t.context, t.Origin, e.RoomID(), e.EventID(), roomVersion)
if err != nil {
return nil, err
}
// Check that the returned state is valid.
if err := state.Check(t.context, t.keys); err != nil {
return nil, err
}
return &state, nil
}
func (t *txnReq) lookupMissingStateViaStateIDs(e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion) (
*gomatrixserverlib.RespState, error) {
// fetch all the state events we do know about: the current state
queryReq := api.QueryLatestEventsAndStateRequest{
RoomID: e.RoomID(),
StateToFetch: nil, // fetch all state
}
var queryRes api.QueryLatestEventsAndStateResponse
if err := t.rsAPI.QueryLatestEventsAndState(t.context, &queryReq, &queryRes); err != nil {
return nil, err
}
if !queryRes.RoomExists {
return nil, fmt.Errorf("room %s doesn't exist", e.RoomID())
}
// allow indexing of current state by event ID
haveEventMap := make(map[string]*gomatrixserverlib.HeaderedEvent, len(queryRes.StateEvents))
for i := range queryRes.StateEvents {
haveEventMap[queryRes.StateEvents[i].EventID()] = &queryRes.StateEvents[i]
}
// fetch the state event IDs at the time of the event
stateIDs, err := t.federation.LookupStateIDs(t.context, t.Origin, e.RoomID(), e.EventID())
if err != nil {
return nil, err
}
// work out which auth/state IDs are missing
wantIDs := append(stateIDs.StateEventIDs, stateIDs.AuthEventIDs...)
missing := make(map[string]bool)
for _, sid := range wantIDs {
if _, ok := haveEventMap[sid]; !ok {
missing[sid] = true
}
}
util.GetLogger(t.context).WithFields(logrus.Fields{
"missing": len(missing),
"event_id": e.EventID(),
"room_id": e.RoomID(),
"already_have": len(queryRes.StateEvents),
"total_state": len(stateIDs.StateEventIDs),
"total_auth_events": len(stateIDs.AuthEventIDs),
}).Info("Fetching missing state at event")
for missingEventID := range missing {
txn, err := t.federation.GetEvent(t.context, t.Origin, missingEventID)
if err != nil {
util.GetLogger(t.context).WithError(err).WithField("event_id", missingEventID).Warn("failed to get missing /event for event ID")
return nil, err
}
for _, pdu := range txn.PDUs {
event, err := gomatrixserverlib.NewEventFromUntrustedJSON(pdu, roomVersion)
if err != nil {
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Failed to parse event JSON of event %q", event.EventID())
return nil, unmarshalError{err}
}
if err := gomatrixserverlib.VerifyAllEventSignatures(t.context, []gomatrixserverlib.Event{event}, t.keys); err != nil {
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Couldn't validate signature of event %q", event.EventID())
return nil, verifySigError{event.EventID(), err}
}
h := event.Headered(roomVersion)
haveEventMap[event.EventID()] = &h
}
}
return t.createRespStateFromStateIDs(stateIDs, haveEventMap)
}
func (t *txnReq) createRespStateFromStateIDs(stateIDs gomatrixserverlib.RespStateIDs, haveEventMap map[string]*gomatrixserverlib.HeaderedEvent) (
*gomatrixserverlib.RespState, error) {
// 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)),
}
for i := range stateIDs.StateEventIDs {
ev, ok := haveEventMap[stateIDs.StateEventIDs[i]]
if !ok {
return nil, fmt.Errorf("missing state event %s", stateIDs.StateEventIDs[i])
}
respState.StateEvents[i] = ev.Unwrap()
}
for i := range stateIDs.AuthEventIDs {
ev, ok := haveEventMap[stateIDs.AuthEventIDs[i]]
if !ok {
return nil, fmt.Errorf("missing auth event %s", stateIDs.AuthEventIDs[i])
}
respState.AuthEvents[i] = ev.Unwrap()
}
// Check that the returned state is valid.
if err := respState.Check(t.context, t.keys); err != nil {
return nil, err
}
return &respState, nil
}

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@ -29,7 +29,7 @@ type QueryLatestEventsAndStateRequest struct {
// The room ID to query the latest events for.
RoomID string `json:"room_id"`
// The state key tuples to fetch from the room current state.
// If this list is empty or nil then no state events are returned.
// If this list is empty or nil then *ALL* current state events are returned.
StateToFetch []gomatrixserverlib.StateKeyTuple `json:"state_to_fetch"`
}