Roomserver/federation input refactor (#2104)

* Put federation client functions into their own file

* Look for missing auth events in RS input

* Remove retrieveMissingAuthEvents from federation API

* Logging

* Sorta transplanted the code over

* Use event origin failing all else

* Don't get stuck on mutexes:

* Add verifier

* Don't mark state events with zero snapshot NID as not existing

* Check missing state if not an outlier before storing the event

* Reject instead of soft-fail, don't copy roominfo so much

* Use synchronous contexts, limit time to fetch missing events

* Clean up some commented out bits

* Simplify `/send` endpoint significantly

* Submit async

* Report errors on sending to RS input

* Set max payload in NATS to 16MB

* Tweak metrics

* Add `workerForRoom` for tidiness

* Try skipping unmarshalling errors for RespMissingEvents

* Track missing prev events separately to avoid calculating state when not possible

* Tweak logic around checking missing state

* Care about state when checking missing prev events

* Don't check missing state for create events

* Try that again

* Handle create events better

* Send create room events as new

* Use given event kind when sending auth/state events

* Revert "Use given event kind when sending auth/state events"

This reverts commit 089d64d271.

* Only search for missing prev events or state for new events

* Tweaks

* We only have missing prev if we don't supply state

* Room version tweaks

* Allow async inputs again

* Apply backpressure to consumers/synchronous requests to hopefully stop things being overwhelmed

* Set timeouts on roomserver input tasks (need to decide what timeout makes sense)

* Use work queue policy, deliver all on restart

* Reduce chance of duplicates being sent by NATS

* Limit the number of servers we attempt to reduce backpressure

* Some review comment fixes

* Tidy up a couple things

* Don't limit servers, randomise order using map

* Some context refactoring

* Update gmsl

* Don't resend create events

* Set stateIDs length correctly or else the roomserver thinks there are missing events when there aren't

* Exclude our own servername

* Try backing off servers

* Make excluding self behaviour optional

* Exclude self from g_m_e

* Update sytest-whitelist

* Update consumers for the roomserver output stream

* Remember to send outliers for state returned from /gme

* Make full HTTP tests less upsetti

* Remove 'If a device list update goes missing, the server resyncs on the next one' from the sytest blacklist

* Remove debugging test

* Fix blacklist again, remove unnecessary duplicate context

* Clearer contexts, don't use background in case there's something happening there

* Don't queue up events more than once in memory

* Correctly identify create events when checking for state

* Fill in gaps again in /gme code

* Remove `AuthEventIDs` from `InputRoomEvent`

* Remove stray field

Co-authored-by: Kegan Dougal <kegan@matrix.org>

roomserver/api/input.go

@@ -54,12 +54,8 @@ type InputRoomEvent struct {
 	Kind Kind `json:"kind"`
 	// The event JSON for the event to add.
 	Event *gomatrixserverlib.HeaderedEvent `json:"event"`
-	// List of state event IDs that authenticate this event.
-	// These are likely derived from the "auth_events" JSON key of the event.
-	// But can be different because the "auth_events" key can be incomplete or wrong.
-	// For example many matrix events forget to reference the m.room.create event even though it is needed for auth.
-	// (since synapse allows this to happen we have to allow it as well.)
-	AuthEventIDs []string `json:"auth_event_ids"`
+	// Which server told us about this event.
+	Origin gomatrixserverlib.ServerName `json:"origin"`
 	// Whether the state is supplied as a list of event IDs or whether it
 	// should be derived from the state at the previous events.
 	HasState bool `json:"has_state"`

roomserver/api/wrapper.go

@@ -26,6 +26,7 @@ import (
 func SendEvents(
 	ctx context.Context, rsAPI RoomserverInternalAPI,
 	kind Kind, events []*gomatrixserverlib.HeaderedEvent,
+	origin gomatrixserverlib.ServerName,
 	sendAsServer gomatrixserverlib.ServerName, txnID *TransactionID,
 	async bool,
 ) error {
@@ -34,7 +35,7 @@ func SendEvents(
 		ires[i] = InputRoomEvent{
 			Kind:          kind,
 			Event:         event,
-			AuthEventIDs:  event.AuthEventIDs(),
+			Origin:        origin,
 			SendAsServer:  string(sendAsServer),
 			TransactionID: txnID,
 		}
@@ -48,7 +49,7 @@ func SendEvents(
 func SendEventWithState(
 	ctx context.Context, rsAPI RoomserverInternalAPI, kind Kind,
 	state *gomatrixserverlib.RespState, event *gomatrixserverlib.HeaderedEvent,
-	haveEventIDs map[string]bool, async bool,
+	origin gomatrixserverlib.ServerName, haveEventIDs map[string]bool, async bool,
 ) error {
 	outliers, err := state.Events()
 	if err != nil {
@@ -61,9 +62,9 @@ func SendEventWithState(
 			continue
 		}
 		ires = append(ires, InputRoomEvent{
-			Kind:         KindOutlier,
-			Event:        outlier.Headered(event.RoomVersion),
-			AuthEventIDs: outlier.AuthEventIDs(),
+			Kind:   KindOutlier,
+			Event:  outlier.Headered(event.RoomVersion),
+			Origin: origin,
 		})
 	}
 
@@ -75,7 +76,7 @@ func SendEventWithState(
 	ires = append(ires, InputRoomEvent{
 		Kind:          kind,
 		Event:         event,
-		AuthEventIDs:  event.AuthEventIDs(),
+		Origin:        origin,
 		HasState:      true,
 		StateEventIDs: stateEventIDs,
 	})