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

federationapi/routing/send.go

@@ -164,7 +164,7 @@ func Send(
 
 	util.GetLogger(httpReq.Context()).Infof("Received transaction %q from %q containing %d PDUs, %d EDUs", txnID, request.Origin(), len(t.PDUs), len(t.EDUs))
 
-	resp, jsonErr := t.processTransaction(context.Background())
+	resp, jsonErr := t.processTransaction(httpReq.Context())
 	if jsonErr != nil {
 		util.GetLogger(httpReq.Context()).WithField("jsonErr", jsonErr).Error("t.processTransaction failed")
 		return *jsonErr
@@ -276,7 +276,7 @@ func (t *txnReq) processTransaction(ctx context.Context) (*gomatrixserverlib.Res
 		// If the event fail auth checks, gmsl.NotAllowed error will be returned which we be silently
 		// discarded by the caller of this function
 		if err = api.SendEvents(
-			context.Background(),
+			ctx,
 			t.rsAPI,
 			api.KindNew,
 			[]*gomatrixserverlib.HeaderedEvent{

roomserver/internal/input/input_events.go

@@ -65,24 +65,25 @@ var processRoomEventDuration = prometheus.NewHistogramVec(
 // TODO: Break up function - we should probably do transaction ID checks before calling this.
 // nolint:gocyclo
 func (r *Inputer) processRoomEvent(
-	ctx context.Context,
+	inctx context.Context,
 	input *api.InputRoomEvent,
 ) (err error) {
 	select {
-	case <-ctx.Done():
+	case <-inctx.Done():
 		// Before we do anything, make sure the context hasn't expired for this pending task.
 		// If it has then we'll give up straight away — it's probably a synchronous input
 		// request and the caller has already given up, but the inbox task was still queued.
 		return context.DeadlineExceeded
 	default:
-		// Otherwise we're going to wrap the context with a time limit. We'll allow no more
-		// than MaximumProcessingTime for everything that we need to do for this event, or
-		// it's possible that we could end up wedging the roomserver for a very long time.
-		var cancel context.CancelFunc
-		ctx, cancel = context.WithTimeout(ctx, MaximumProcessingTime)
-		defer cancel()
 	}
 
+	// Wrap the context with a time limit. We'll allow no more than MaximumProcessingTime for
+	// everything that we need to do for this event, or it's possible that we could end up wedging
+	// the roomserver for a very long time.
+	var cancel context.CancelFunc
+	ctx, cancel := context.WithTimeout(inctx, MaximumProcessingTime)
+	defer cancel()
+
 	// Measure how long it takes to process this event.
 	started := time.Now()
 	defer func() {

roomserver/internal/input/input_missing.go

@@ -394,9 +394,7 @@ func (t *missingStateReq) getMissingEvents(ctx context.Context, e *gomatrixserve
 	var missingResp *gomatrixserverlib.RespMissingEvents
 	for server := range t.servers {
 		var m gomatrixserverlib.RespMissingEvents
-		reqctx, cancel := context.WithTimeout(ctx, time.Second*30)
-		defer cancel()
-		if m, err = t.federation.LookupMissingEvents(reqctx, server, e.RoomID(), gomatrixserverlib.MissingEvents{
+		if m, err = t.federation.LookupMissingEvents(ctx, server, e.RoomID(), gomatrixserverlib.MissingEvents{
 			Limit: 20,
 			// The latest event IDs that the sender already has. These are skipped when retrieving the previous events of latest_events.
 			EarliestEvents: latestEvents,
@@ -409,10 +407,10 @@ func (t *missingStateReq) getMissingEvents(ctx context.Context, e *gomatrixserve
 			logger.WithError(err).Errorf("%s pushed us an event but %q did not respond to /get_missing_events", t.origin, server)
 			if errors.Is(err, context.DeadlineExceeded) {
 				select {
-				case <-reqctx.Done(): // this server took too long
-					continue
-				case <-ctx.Done(): // the input request timed out
+				case <-ctx.Done(): // the parent request context timed out
 					return nil, context.DeadlineExceeded
+				default: // this request exceed its own timeout
+					continue
 				}
 			}
 		}