From 6011ddc0a89a28409e3703b1e3e62fa249e04c97 Mon Sep 17 00:00:00 2001
From: Till Faelligen <2353100+S7evinK@users.noreply.github.com>
Date: Fri, 14 Jul 2023 08:28:30 +0200
Subject: [PATCH] Discard "illegal base64 data at input byte 0" errors in the
 SyncAPI

---
 syncapi/consumers/roomserver.go | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/syncapi/consumers/roomserver.go b/syncapi/consumers/roomserver.go
index 8c83e688..1e87aee9 100644
--- a/syncapi/consumers/roomserver.go
+++ b/syncapi/consumers/roomserver.go
@@ -17,16 +17,12 @@ package consumers
 import (
 	"context"
 	"database/sql"
+	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 
 	"github.com/getsentry/sentry-go"
-	"github.com/matrix-org/gomatrixserverlib/spec"
-	"github.com/nats-io/nats.go"
-	"github.com/sirupsen/logrus"
-	log "github.com/sirupsen/logrus"
-	"github.com/tidwall/gjson"
-
 	"github.com/matrix-org/dendrite/internal/fulltext"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/roomserver/api"
@@ -38,6 +34,11 @@ import (
 	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/streams"
 	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib/spec"
+	"github.com/nats-io/nats.go"
+	"github.com/sirupsen/logrus"
+	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
 )
 
 // OutputRoomEventConsumer consumes events that originated in the room server.
@@ -141,7 +142,14 @@ func (s *OutputRoomEventConsumer) onMessage(ctx context.Context, msgs []*nats.Ms
 		)
 	}
 	if err != nil {
-		log.WithError(err).Error("roomserver output log: failed to process event")
+		if errors.As(err, new(base64.CorruptInputError)) {
+			// no matter how often we retry this event, we will always get this error, discard the event
+			return true
+		}
+		log.WithFields(log.Fields{
+			"type": output.Type,
+		}).WithError(err).Error("roomserver output log: failed to process event")
+		sentry.CaptureException(err)
 		return false
 	}
 
@@ -237,21 +245,18 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 
 	ev, err := s.updateStateEvent(ev)
 	if err != nil {
-		sentry.CaptureException(err)
 		return err
 	}
 
 	for i := range addsStateEvents {
 		addsStateEvents[i], err = s.updateStateEvent(addsStateEvents[i])
 		if err != nil {
-			sentry.CaptureException(err)
 			return err
 		}
 	}
 
 	if msg.RewritesState {
 		if err = s.db.PurgeRoomState(ctx, ev.RoomID()); err != nil {
-			sentry.CaptureException(err)
 			return fmt.Errorf("s.db.PurgeRoom: %w", err)
 		}
 	}
@@ -289,7 +294,6 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 
 	if pduPos, err = s.notifyJoinedPeeks(ctx, ev, pduPos); err != nil {
 		log.WithError(err).Errorf("Failed to notifyJoinedPeeks for PDU pos %d", pduPos)
-		sentry.CaptureException(err)
 		return err
 	}
 
@@ -430,7 +434,6 @@ func (s *OutputRoomEventConsumer) onNewInviteEvent(
 
 	pduPos, err := s.db.AddInviteEvent(ctx, msg.Event)
 	if err != nil {
-		sentry.CaptureException(err)
 		// panic rather than continue with an inconsistent database
 		log.WithFields(log.Fields{
 			"event_id":   msg.Event.EventID(),
@@ -452,7 +455,6 @@ func (s *OutputRoomEventConsumer) onRetireInviteEvent(
 	// It's possible we just haven't heard of this invite yet, so
 	// we should not panic if we try to retire it.
 	if err != nil && err != sql.ErrNoRows {
-		sentry.CaptureException(err)
 		// panic rather than continue with an inconsistent database
 		log.WithFields(log.Fields{
 			"event_id":   msg.EventID,
@@ -496,7 +498,6 @@ func (s *OutputRoomEventConsumer) onNewPeek(
 ) {
 	sp, err := s.db.AddPeek(ctx, msg.RoomID, msg.UserID, msg.DeviceID)
 	if err != nil {
-		sentry.CaptureException(err)
 		// panic rather than continue with an inconsistent database
 		log.WithFields(log.Fields{
 			log.ErrorKey: err,