Track the total size of the of the torrents map

stats/stats.go

@@ -81,6 +81,7 @@ type Stats struct {
 	Announces uint64 `json:"Tracker.Announces"`
 	Scrapes   uint64 `json:"Tracker.Scrapes"`
 
+	TorrentsSize    uint64 `json:"Torrents.Size"`
 	TorrentsAdded   uint64 `json:"Torrents.Added"`
 	TorrentsRemoved uint64 `json:"Torrents.Removed"`
 	TorrentsReaped  uint64 `json:"Torrents.Reaped"`
@@ -192,12 +193,15 @@ func (s *Stats) handleEvent(event int) {
 
 	case NewTorrent:
 		s.TorrentsAdded++
+		s.TorrentsSize++
 
 	case DeletedTorrent:
 		s.TorrentsRemoved++
+		s.TorrentsSize--
 
 	case ReapedTorrent:
 		s.TorrentsReaped++
+		s.TorrentsSize--
 
 	case AcceptedConnection:
 		s.ConnectionsAccepted++

tracker/storage.go

@@ -44,6 +44,10 @@ func NewStorage(cfg *config.Config) *Storage {
 	return s
 }
 
+func (s *Storage) Len() int {
+	return int(atomic.LoadInt32(&s.size))
+}
+
 func (s *Storage) GetShardIndex(infohash string) uint32 {
 	idx := fnv.New32()
 	idx.Write([]byte(infohash))
@@ -198,7 +202,7 @@ func (s *Storage) PurgeInactivePeers(purgeEmptyTorrents bool, before time.Time)
 
 	// Build a list of keys to process.
 	index := 0
-	maxkeys := int(atomic.LoadInt32(&s.size))
+	maxkeys := s.Len()
 	keys := make([]string, maxkeys)
 	for i := range s.shards {
 		shard := &s.shards[i]