Ensure thumbnail readers are cleaned up/read upon error (#585)

* Ensure thumbnail readers are cleaned up/read upon error

* Changelog

CHANGELOG.md

@@ -22,6 +22,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 * Purging old media has been fixed to actually identify old media.
 * JPEG thumbnails will now use sensible extensions.
 * Fixed directory permissions when exporting MMR to Synapse.
+* In some rare cases, memory usage may have leaked due to thumbnail error handling. This has been fixed.
+
 
 ## [1.3.4] - February 9, 2024
 

cmd/homeserver_offline_exporters/import_to_synapse/main.go

@@ -119,6 +119,12 @@ func main() {
 
 				thumb, err := thumbnailing.GenerateThumbnail(src, record.ContentType, s.width, s.height, s.method, false, ctx)
 				if err != nil {
+					if thumb.Reader != nil {
+						err2 := thumb.Reader.Close()
+						if err2 != nil {
+							ctx.Log.Warn("Non-fatal error cleaning up thumbnail stream: ", err2)
+						}
+					}
 					ctx.Log.Debug("Error generating thumbnail (you can probably ignore this). ", s, err)
 					return
 				}

pipelines/_steps/thumbnails/generate.go

@@ -46,6 +46,12 @@ func Generate(ctx rcontext.RequestContext, mediaRecord *database.DbMedia, width
 
 		i, err := thumbnailing.GenerateThumbnail(mediaStream, fixedContentType, width, height, method, animated, ctx)
 		if err != nil {
+			if i.Reader != nil {
+				err2 := i.Reader.Close()
+				if err2 != nil {
+					ctx.Log.Warn("Non-fatal error cleaning up thumbnail stream: ", err2)
+				}
+			}
 			if errors.Is(err, common.ErrMediaDimensionsTooSmall) {
 				metric.Inc()
 			}