Change grid cache to LRU

- Change max size to max entries
- Use freelru

go.mod

@@ -10,7 +10,9 @@ require (
 	github.com/RyanCarrier/dijkstra/v2 v2.0.2
 	github.com/ansrivas/fiberprometheus/v2 v2.6.1
 	github.com/bamiaux/rez v0.0.0-20170731184118-29f4463c688b
+	github.com/cespare/xxhash/v2 v2.3.0
 	github.com/cockroachdb/pebble v1.1.1
+	github.com/elastic/go-freelru v0.13.0
 	github.com/gofiber/fiber/v2 v2.52.4
 	github.com/kelindar/binary v1.0.19
 	github.com/rs/zerolog v1.33.0
@@ -27,7 +29,6 @@ require (
 	github.com/andybalholm/brotli v1.1.0 // indirect
 	github.com/andybalholm/cascadia v1.3.2 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
-	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/cockroachdb/errors v1.11.3 // indirect
 	github.com/cockroachdb/fifo v0.0.0-20240616162244-4768e80dfb9a // indirect
 	github.com/cockroachdb/logtags v0.0.0-20230118201751-21c54148d20b // indirect

go.sum

@@ -36,6 +36,8 @@ github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSV
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/elastic/go-freelru v0.13.0 h1:TKKY6yCfNNNky7Pj9xZAOEpBcdNgZJfihEftOb55omg=
+github.com/elastic/go-freelru v0.13.0/go.mod h1:bSdWT4M0lW79K8QbX6XY2heQYSCqD7THoYf82pT/H3I=
 github.com/getsentry/sentry-go v0.28.1 h1:zzaSm/vHmGllRM6Tpx1492r0YDzauArdBfkJRtY6P5k=
 github.com/getsentry/sentry-go v0.28.1/go.mod h1:1fQZ+7l7eeJ3wYi82q5Hg8GqAPgefRq+FP/QhafYVgg=
 github.com/go-errors/errors v1.4.2 h1:J6MZopCL4uSllY1OfXM374weqZFFItUbrImctkmUxIA=

handlers/grid.go

@@ -131,7 +131,7 @@ func Grid() fiber.Handler {
 		gridFname := filepath.Join("static", postID+".jpeg")
 
 		// If already exists, return
-		if _, err := os.Stat(gridFname); err == nil {
+		if _, ok := scraper.LRU.Get(gridFname); ok {
 			return c.SendFile(gridFname)
 		}
 
@@ -197,6 +197,7 @@ func Grid() fiber.Handler {
 		if err := jpeg.Encode(f, grid, &jpeg.Options{Quality: 80}); err != nil {
 			return err
 		}
+		scraper.LRU.Add(gridFname, true)
 		return c.SendFile(gridFname)
 	}
 }

handlers/scraper/cache.go

@@ -1,10 +1,20 @@
 package handlers
 
 import (
+	"os"
+
+	"github.com/cespare/xxhash/v2"
 	"github.com/cockroachdb/pebble"
+	"github.com/elastic/go-freelru"
+	"github.com/rs/zerolog/log"
 )
 
 var DB *pebble.DB
+var LRU *freelru.SyncedLRU[string, bool]
+
+func hashStringXXHASH(s string) uint32 {
+	return uint32(xxhash.Sum64String(s))
+}
 
 func InitDB() {
 	db, err := pebble.Open("database", &pebble.Options{})
@@ -14,3 +24,28 @@ func InitDB() {
 	}
 	DB = db
 }
+
+func InitLRU(maxEntries int) {
+	// Initialize LRU for grid caching
+	lru, err := freelru.NewSynced[string, bool](uint32(maxEntries), hashStringXXHASH)
+	if err != nil {
+		panic(err)
+	}
+
+	lru.SetOnEvict(func(key string, value bool) {
+		os.Remove(key)
+	})
+
+	// Fill LRU with existing files
+	dir, err := os.ReadDir("static")
+	if err != nil {
+		log.Fatal().Err(err).Msg("Failed to read static folder")
+	}
+	for _, d := range dir {
+		if !d.IsDir() {
+			lru.Add("static/"+d.Name(), true)
+		}
+	}
+
+	LRU = lru
+}

main.go

@@ -7,9 +7,7 @@ import (
 	scraper "instafix/handlers/scraper"
 	"instafix/utils"
 	"instafix/views"
-	"io/fs"
 	"os"
-	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -24,32 +22,6 @@ import (
 	"github.com/valyala/bytebufferpool"
 )
 
-func byteSizeStrToInt(n string) (int64, error) {
-	sizeStr := strings.ToLower(n)
-	sizeStr = strings.TrimSpace(sizeStr)
-
-	units := map[string]int64{
-		"kb": 1024,
-		"mb": 1024 * 1024,
-		"gb": 1024 * 1024 * 1024,
-		"tb": 1024 * 1024 * 1024 * 1024,
-	}
-
-	for unit, multiplier := range units {
-		if strings.HasSuffix(sizeStr, unit) {
-			sizeStr = strings.TrimSuffix(sizeStr, unit)
-			sizeStr = strings.TrimSpace(sizeStr)
-
-			size, err := strconv.ParseInt(sizeStr, 10, 64)
-			if err != nil {
-				return -1, err
-			}
-			return size * multiplier, nil
-		}
-	}
-	return -1, nil
-}
-
 func init() {
 	scraper.InitDB()
 
@@ -59,7 +31,7 @@ func init() {
 
 func main() {
 	listenAddr := flag.String("listen", "0.0.0.0:3000", "Address to listen on")
-	gridCacheSize := flag.String("grid-cache-size", "25GB", "Grid cache size")
+	gridCacheMaxFlag := flag.String("grid-cache-entries", "1024", "Maximum number of grid images to cache")
 	remoteScraperAddr := flag.String("remote-scraper", "", "Remote scraper address")
 	flag.Parse()
 
@@ -90,18 +62,18 @@ func main() {
 	zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
 	zerolog.SetGlobalLevel(zerolog.InfoLevel)
 
-	// Parse grid-cache-size
-	gridCacheSizeParsed, err := byteSizeStrToInt(*gridCacheSize)
-	if err != nil {
-		log.Fatal().Err(err).Msg("Failed to parse grid-cache-size")
+	// Initialize LRU
+	gridCacheMax, err := strconv.Atoi(*gridCacheMaxFlag)
+	if err != nil || gridCacheMax <= 0 {
+		log.Fatal().Err(err).Msg("Failed to parse grid-cache-entries or invalid value")
 	}
+	scraper.InitLRU(gridCacheMax)
 
 	// Evict cache every minute
 	go func() {
 		for {
-			time.Sleep(5 * time.Minute)
-			evictStatic(gridCacheSizeParsed)
 			evictCache()
+			time.Sleep(5 * time.Minute)
 		}
 	}()
 
@@ -113,8 +85,6 @@ func main() {
 		return c.Send(viewsBuf.Bytes())
 	})
 
-	// GET /p/Cw8X2wXPjiM
-	// GET /stories/fatfatpankocat/3226148677671954631/
 	app.Get("/p/:postID/", handlers.Embed())
 	app.Get("/tv/:postID", handlers.Embed())
 	app.Get("/reel/:postID", handlers.Embed())
@@ -135,29 +105,6 @@ func main() {
 	}
 }
 
-// Remove file in static folder until below threshold
-func evictStatic(threshold int64) {
-	var dirSize int64 = 0
-	readSize := func(path string, d fs.DirEntry, err error) error {
-		if err != nil {
-			return err
-		}
-		if !d.IsDir() {
-			if dirSize > threshold {
-				err := os.Remove(path)
-				return err
-			}
-			info, err := d.Info()
-			if err != nil {
-				return err
-			}
-			dirSize += info.Size()
-		}
-		return nil
-	}
-	filepath.WalkDir("static", readSize)
-}
-
 // Remove cache from Pebble if already expired
 func evictCache() {
 	iter, err := scraper.DB.NewIter(&pebble.IterOptions{LowerBound: []byte("exp-")})