unify caches

fix tests

cmd/reflector.go

@@ -56,13 +56,14 @@ var (
 	secondaryDiskCache string
 	memCache           int
 )
-var cacheManagers = []string{"localdb", "lfuda", "lru"}
+var cacheManagers = []string{"localdb", "lfu", "arc", "lru", "simple"}
 
-const (
+var cacheMangerToGcache = map[string]store.EvictionStrategy{
-	LOCALDB int = iota
+	"lfu":    store.LFU,
-	LFUDA
+	"arc":    store.ARC,
-	LRU
+	"lru":    store.LRU,
-)
+	"simple": store.SIMPLE,
+}
 
 func init() {
 	var cmd = &cobra.Command{
@@ -89,8 +90,8 @@ func init() {
 	cmd.Flags().StringVar(&originEndpoint, "origin-endpoint", "", "HTTP edge endpoint for standard HTTP retrieval")
 	cmd.Flags().StringVar(&originEndpointFallback, "origin-endpoint-fallback", "", "HTTP edge endpoint for standard HTTP retrieval if first origin fails")
 
-	cmd.Flags().StringVar(&diskCache, "disk-cache", "100GB:/tmp/downloaded_blobs:localdb", "Where to cache blobs on the file system. format is 'sizeGB:CACHE_PATH:cachemanager' (cachemanagers: localdb/lfuda/lru)")
+	cmd.Flags().StringVar(&diskCache, "disk-cache", "100GB:/tmp/downloaded_blobs:localdb", "Where to cache blobs on the file system. format is 'sizeGB:CACHE_PATH:cachemanager' (cachemanagers: localdb/lfu/arc/lru)")
-	cmd.Flags().StringVar(&secondaryDiskCache, "optional-disk-cache", "", "Optional secondary file system cache for blobs. format is 'sizeGB:CACHE_PATH:cachemanager' (cachemanagers: localdb/lfuda/lru) (this would get hit before the one specified in disk-cache)")
+	cmd.Flags().StringVar(&secondaryDiskCache, "optional-disk-cache", "", "Optional secondary file system cache for blobs. format is 'sizeGB:CACHE_PATH:cachemanager' (cachemanagers: localdb/lfu/arc/lru) (this would get hit before the one specified in disk-cache)")
 	cmd.Flags().IntVar(&memCache, "mem-cache", 0, "enable in-memory cache with a max size of this many blobs")
 
 	rootCmd.AddCommand(cmd)
@@ -228,7 +229,7 @@ func initCaches(s store.BlobStore) (store.BlobStore, *stop.Group) {
 		finalStore = store.NewCachingStore(
 			"reflector",
 			finalStore,
-			store.NewLRUStore("mem", store.NewMemStore(), memCache),
+			store.NewGcacheStore("mem", store.NewMemStore(), memCache, store.LRU),
 		)
 	}
 	return finalStore, stopper
@@ -251,8 +252,7 @@ func initDiskStore(upstreamStore store.BlobStore, diskParams string, stopper *st
 	var unwrappedStore store.BlobStore
 	cleanerStopper := stop.New(stopper)
 
-	switch cacheManager {
+	if cacheManager == "localdb" {
-	case cacheManagers[LOCALDB]:
 		localDb := &db.SQL{
 			SoftDelete:  true,
 			TrackAccess: db.TrackAccessBlobs,
@@ -264,11 +264,10 @@ func initDiskStore(upstreamStore store.BlobStore, diskParams string, stopper *st
 		}
 		unwrappedStore = store.NewDBBackedStore(diskStore, localDb, true)
 		go cleanOldestBlobs(int(realCacheSize), localDb, unwrappedStore, cleanerStopper)
-	case cacheManagers[LFUDA]:
+	} else {
-		unwrappedStore = store.NewLFUDAStore("nvme", store.NewDiskStore(diskCachePath, 2), realCacheSize)
+		unwrappedStore = store.NewGcacheStore("nvme", store.NewDiskStore(diskCachePath, 2), int(realCacheSize), cacheMangerToGcache[cacheManager])
-	case cacheManagers[LRU]:
-		unwrappedStore = store.NewLRUStore("nvme", store.NewDiskStore(diskCachePath, 2), int(realCacheSize))
 	}
+
 	wrapped := store.NewCachingStore(
 		"reflector",
 		upstreamStore,

go.mod

@@ -2,13 +2,10 @@ module github.com/lbryio/reflector.go
 
 replace github.com/btcsuite/btcd => github.com/lbryio/lbrycrd.go v0.0.0-20200203050410-e1076f12bf19
 
-//replace github.com/lbryio/lbry.go/v2 => ../lbry.go
-
 require (
 	github.com/armon/go-metrics v0.0.0-20190430140413-ec5e00d3c878 // indirect
 	github.com/aws/aws-sdk-go v1.27.0
 	github.com/bluele/gcache v0.0.2
-	github.com/bparli/lfuda-go v0.3.1
 	github.com/brk0v/directio v0.0.0-20190225130936-69406e757cf7
 	github.com/btcsuite/btcd v0.0.0-20190824003749-130ea5bddde3
 	github.com/btcsuite/btcutil v0.0.0-20190425235716-9e5f4b9a998d

go.sum

@@ -59,8 +59,6 @@ github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kB
 github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJmJgSg28kpZDP6UIiPt0e0Oz0kqKNGyRaWEPv84=
 github.com/bluele/gcache v0.0.2 h1:WcbfdXICg7G/DGBh1PFfcirkWOQV+v077yF1pSy3DGw=
 github.com/bluele/gcache v0.0.2/go.mod h1:m15KV+ECjptwSPxKhOhQoAFQVtUFjTVkc3H8o0t/fp0=
-github.com/bparli/lfuda-go v0.3.1 h1:nO9Szo627RC8/z+R+MMPBItNwHCOonchmpjQuQi8jVY=
-github.com/bparli/lfuda-go v0.3.1/go.mod h1:BR5a9lwlqRqnPhU3F5ojFK3VhTKg8iFVtJJKgZBQhAo=
 github.com/bradfitz/go-smtpd v0.0.0-20170404230938-deb6d6237625/go.mod h1:HYsPBTaaSFSlLx/70C2HPIMNZpVV8+vt/A+FMnYP11g=
 github.com/brk0v/directio v0.0.0-20190225130936-69406e757cf7 h1:7gNKWnX6OF+ERiXVw4I9RsHhZ52aumXdFE07nEx5v20=
 github.com/brk0v/directio v0.0.0-20190225130936-69406e757cf7/go.mod h1:M/KA3XJG5PJaApPiv4gWNsgcSJquOQTqumZNLyYE0KM=

store/gcache.go

@@ -1,7 +1,5 @@
 package store
 
-//TODO: the caching strategy is actually not LFUDA, it should become a parameter and the name of the struct should be changed
-
 import (
 	"time"
 
@@ -11,27 +9,53 @@ import (
 	"github.com/lbryio/lbry.go/v2/extras/errors"
 	"github.com/lbryio/lbry.go/v2/stream"
 
-	"github.com/bparli/lfuda-go"
+	"github.com/bluele/gcache"
 	"github.com/sirupsen/logrus"
 )
 
-// LFUDAStore adds a max cache size and Greedy-Dual-Size-Frequency cache eviction strategy to a BlobStore
+// GcacheStore adds a max cache size and Greedy-Dual-Size-Frequency cache eviction strategy to a BlobStore
-type LFUDAStore struct {
+type GcacheStore struct {
 	// underlying store
 	store BlobStore
-	// lfuda implementation
+	// cache implementation
-	lfuda *lfuda.Cache
+	cache gcache.Cache
 }
+type EvictionStrategy int
 
-// NewLFUDAStore initialize a new LRUStore
+const (
-func NewLFUDAStore(component string, store BlobStore, maxSize float64) *LFUDAStore {
+	//LFU Discards the least frequently used items first.
-	lfuda := lfuda.NewGDSFWithEvict(maxSize, func(key interface{}, value interface{}) {
+	LFU EvictionStrategy = iota
+	//ARC Constantly balances between LRU and LFU, to improve the combined result.
+	ARC
+	//LRU Discards the least recently used items first.
+	LRU
+	//SIMPLE has no clear priority for evict cache. It depends on key-value map order.
+	SIMPLE
+)
+
+// NewGcacheStore initialize a new LRUStore
+func NewGcacheStore(component string, store BlobStore, maxSize int, strategy EvictionStrategy) *GcacheStore {
+	cacheBuilder := gcache.New(maxSize)
+	var cache gcache.Cache
+	evictFunc := func(key interface{}, value interface{}) {
+		logrus.Infof("evicting %s", key)
 		metrics.CacheLRUEvictCount.With(metrics.CacheLabels(store.Name(), component)).Inc()
 		_ = store.Delete(key.(string)) // TODO: log this error. may happen if underlying entry is gone but cache entry still there
-	})
+	}
-	l := &LFUDAStore{
+	switch strategy {
+	case LFU:
+		cache = cacheBuilder.LFU().EvictedFunc(evictFunc).Build()
+	case ARC:
+		cache = cacheBuilder.ARC().EvictedFunc(evictFunc).Build()
+	case LRU:
+		cache = cacheBuilder.LRU().EvictedFunc(evictFunc).Build()
+	case SIMPLE:
+		cache = cacheBuilder.Simple().EvictedFunc(evictFunc).Build()
+
+	}
+	l := &GcacheStore{
 		store: store,
-		lfuda: lfuda,
+		cache: cache,
 	}
 	go func() {
 		if lstr, ok := store.(lister); ok {
@@ -45,34 +69,34 @@ func NewLFUDAStore(component string, store BlobStore, maxSize float64) *LFUDASto
 	return l
 }
 
-const nameLFUDA = "lfuda"
+const nameGcache = "gcache"
 
 // Name is the cache type name
-func (l *LFUDAStore) Name() string { return nameLFUDA }
+func (l *GcacheStore) Name() string { return nameGcache }
 
 // Has returns whether the blob is in the store, without updating the recent-ness.
-func (l *LFUDAStore) Has(hash string) (bool, error) {
+func (l *GcacheStore) Has(hash string) (bool, error) {
-	return l.lfuda.Contains(hash), nil
+	return l.cache.Has(hash), nil
 }
 
 // Get returns the blob or an error if the blob doesn't exist.
-func (l *LFUDAStore) Get(hash string) (stream.Blob, shared.BlobTrace, error) {
+func (l *GcacheStore) Get(hash string) (stream.Blob, shared.BlobTrace, error) {
 	start := time.Now()
-	_, has := l.lfuda.Get(hash)
+	_, err := l.cache.Get(hash)
-	if !has {
+	if err != nil {
 		return nil, shared.NewBlobTrace(time.Since(start), l.Name()), errors.Err(ErrBlobNotFound)
 	}
 	blob, stack, err := l.store.Get(hash)
 	if errors.Is(err, ErrBlobNotFound) {
 		// Blob disappeared from underlying store
-		l.lfuda.Remove(hash)
+		l.cache.Remove(hash)
 	}
 	return blob, stack.Stack(time.Since(start), l.Name()), err
 }
 
 // Put stores the blob. Following LFUDA rules it's not guaranteed that a SET will store the value!!!
-func (l *LFUDAStore) Put(hash string, blob stream.Blob) error {
+func (l *GcacheStore) Put(hash string, blob stream.Blob) error {
-	l.lfuda.Set(hash, true)
+	l.cache.Set(hash, true)
 	has, _ := l.Has(hash)
 	if has {
 		err := l.store.Put(hash, blob)
@@ -84,8 +108,8 @@ func (l *LFUDAStore) Put(hash string, blob stream.Blob) error {
 }
 
 // PutSD stores the sd blob. Following LFUDA rules it's not guaranteed that a SET will store the value!!!
-func (l *LFUDAStore) PutSD(hash string, blob stream.Blob) error {
+func (l *GcacheStore) PutSD(hash string, blob stream.Blob) error {
-	l.lfuda.Set(hash, true)
+	l.cache.Set(hash, true)
 	has, _ := l.Has(hash)
 	if has {
 		err := l.store.PutSD(hash, blob)
@@ -97,7 +121,7 @@ func (l *LFUDAStore) PutSD(hash string, blob stream.Blob) error {
 }
 
 // Delete deletes the blob from the store
-func (l *LFUDAStore) Delete(hash string) error {
+func (l *GcacheStore) Delete(hash string) error {
 	err := l.store.Delete(hash)
 	if err != nil {
 		return err
@@ -106,12 +130,12 @@ func (l *LFUDAStore) Delete(hash string) error {
 	// This must come after store.Delete()
 	// Remove triggers onEvict function, which also tries to delete blob from store
 	// We need to delete it manually first so any errors can be propagated up
-	l.lfuda.Remove(hash)
+	l.cache.Remove(hash)
 	return nil
 }
 
 // loadExisting imports existing blobs from the underlying store into the LRU cache
-func (l *LFUDAStore) loadExisting(store lister, maxItems int) error {
+func (l *GcacheStore) loadExisting(store lister, maxItems int) error {
 	logrus.Infof("loading at most %d items", maxItems)
 	existing, err := store.list()
 	if err != nil {
@@ -121,7 +145,7 @@ func (l *LFUDAStore) loadExisting(store lister, maxItems int) error {
 
 	added := 0
 	for _, h := range existing {
-		l.lfuda.Set(h, true)
+		l.cache.Set(h, true)
 		added++
 		if maxItems > 0 && added >= maxItems { // underlying cache is bigger than the cache
 			break
@@ -131,6 +155,6 @@ func (l *LFUDAStore) loadExisting(store lister, maxItems int) error {
 }
 
 // Shutdown shuts down the store gracefully
-func (l *LFUDAStore) Shutdown() {
+func (l *GcacheStore) Shutdown() {
 	return
 }

store/gcache_test.go

@@ -1,6 +1,7 @@
 package store
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
 	"reflect"
@@ -13,93 +14,80 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-const cacheMaxBlobs = 3
+const cacheMaxSize = 3
 
-func getTestLRUStore() (*LRUStore, *MemStore) {
+func getTestGcacheStore() (*GcacheStore, *MemStore) {
 	m := NewMemStore()
-	return NewLRUStore("test", m, 3), m
+	return NewGcacheStore("test", m, cacheMaxSize, LFU), m
 }
 
-func TestLRUStore_Eviction(t *testing.T) {
+func TestGcacheStore_Eviction(t *testing.T) {
-	lru, mem := getTestLRUStore()
+	lfu, mem := getTestGcacheStore()
 	b := []byte("x")
-	err := lru.Put("one", b)
+	for i := 0; i < 3; i++ {
-	require.NoError(t, err)
+		err := lfu.Put(fmt.Sprintf("%d", i), b)
-	err = lru.Put("two", b)
+		require.NoError(t, err)
-	require.NoError(t, err)
+		for j := 0; j < 3-i; j++ {
-	err = lru.Put("three", b)
+			_, _, err = lfu.Get(fmt.Sprintf("%d", i))
-	require.NoError(t, err)
+			require.NoError(t, err)
-	err = lru.Put("four", b)
+		}
-	require.NoError(t, err)
+	}
-	err = lru.Put("five", b)
-	require.NoError(t, err)
-
-	assert.Equal(t, cacheMaxBlobs, len(mem.Debug()))
-
 	for k, v := range map[string]bool{
-		"one":   false,
+		"0": true,
-		"two":   false,
+		"1": true,
-		"three": true,
+		"2": true,
-		"four":  true,
-		"five":  true,
-		"six":   false,
 	} {
-		has, err := lru.Has(k)
+		has, err := lfu.Has(k)
 		assert.NoError(t, err)
 		assert.Equal(t, v, has)
 	}
-
+	err := lfu.Put("3", b)
-	lru.Get("three") // touch so it stays in cache
+	require.NoError(t, err)
-	lru.Put("six", b)
-
-	assert.Equal(t, cacheMaxBlobs, len(mem.Debug()))
-
 	for k, v := range map[string]bool{
-		"one":   false,
+		"0": true,
-		"two":   false,
+		"1": true,
-		"three": true,
+		"2": false,
-		"four":  false,
+		"3": true,
-		"five":  true,
-		"six":   true,
 	} {
-		has, err := lru.Has(k)
+		has, err := lfu.Has(k)
 		assert.NoError(t, err)
 		assert.Equal(t, v, has)
 	}
+	assert.Equal(t, cacheMaxSize, len(mem.Debug()))
 
-	err = lru.Delete("three")
+	err = lfu.Delete("0")
 	assert.NoError(t, err)
-	err = lru.Delete("five")
+	err = lfu.Delete("1")
 	assert.NoError(t, err)
-	err = lru.Delete("six")
+	err = lfu.Delete("3")
 	assert.NoError(t, err)
 	assert.Equal(t, 0, len(mem.Debug()))
 }
 
-func TestLRUStore_UnderlyingBlobMissing(t *testing.T) {
+func TestGcacheStore_UnderlyingBlobMissing(t *testing.T) {
-	lru, mem := getTestLRUStore()
+	lfu, mem := getTestGcacheStore()
 	hash := "hash"
 	b := []byte("this is a blob of stuff")
-	err := lru.Put(hash, b)
+	err := lfu.Put(hash, b)
 	require.NoError(t, err)
 
 	err = mem.Delete(hash)
 	require.NoError(t, err)
 
 	// hash still exists in lru
-	assert.True(t, lru.lru.Has(hash))
+	assert.True(t, lfu.cache.Has(hash))
 
-	blob, _, err := lru.Get(hash)
+	blob, _, err := lfu.Get(hash)
 	assert.Nil(t, blob)
 	assert.True(t, errors.Is(err, ErrBlobNotFound), "expected (%s) %s, got (%s) %s",
 		reflect.TypeOf(ErrBlobNotFound).String(), ErrBlobNotFound.Error(),
 		reflect.TypeOf(err).String(), err.Error())
 
 	// lru.Get() removes hash if underlying store doesn't have it
-	assert.False(t, lru.lru.Has(hash))
+	assert.False(t, lfu.cache.Has(hash))
 }
 
-func TestLRUStore_loadExisting(t *testing.T) {
+func TestGcacheStore_loadExisting(t *testing.T) {
 	tmpDir, err := ioutil.TempDir("", "reflector_test_*")
 	require.NoError(t, err)
 	defer os.RemoveAll(tmpDir)
@@ -115,9 +103,9 @@ func TestLRUStore_loadExisting(t *testing.T) {
 	require.Equal(t, 1, len(existing), "blob should exist in cache")
 	assert.Equal(t, hash, existing[0])
 
-	lru := NewLRUStore("test", d, 3)   // lru should load existing blobs when it's created
+	lfu := NewGcacheStore("test", d, 3, LFU) // lru should load existing blobs when it's created
-	time.Sleep(100 * time.Millisecond) // async load so let's wait...
+	time.Sleep(100 * time.Millisecond)       // async load so let's wait...
-	has, err := lru.Has(hash)
+	has, err := lfu.Has(hash)
 	require.NoError(t, err)
 	assert.True(t, has, "hash should be loaded from disk store but it's not")
 }

store/lfuda_test.go

@@ -1,136 +0,0 @@
-package store
-
-import (
-	"io/ioutil"
-	"os"
-	"reflect"
-	"testing"
-	"time"
-
-	"github.com/lbryio/lbry.go/v2/extras/errors"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-const cacheMaxSize = 3
-
-func getTestLFUDAStore() (*LFUDAStore, *MemStore) {
-	m := NewMemStore()
-	return NewLFUDAStore("test", m, cacheMaxSize), m
-}
-
-func TestFUDAStore_Eviction(t *testing.T) {
-	lfuda, mem := getTestLFUDAStore()
-	b := []byte("x")
-	err := lfuda.Put("one", b)
-	require.NoError(t, err)
-	err = lfuda.Put("two", b)
-	require.NoError(t, err)
-	err = lfuda.Put("three", b)
-	require.NoError(t, err)
-	err = lfuda.Put("four", b)
-	require.NoError(t, err)
-	err = lfuda.Put("five", b)
-	require.NoError(t, err)
-	err = lfuda.Put("five", b)
-	require.NoError(t, err)
-	err = lfuda.Put("four", b)
-	require.NoError(t, err)
-	err = lfuda.Put("two", b)
-	require.NoError(t, err)
-
-	_, _, err = lfuda.Get("five")
-	require.NoError(t, err)
-	_, _, err = lfuda.Get("four")
-	require.NoError(t, err)
-	_, _, err = lfuda.Get("two")
-	require.NoError(t, err)
-	assert.Equal(t, cacheMaxBlobs, len(mem.Debug()))
-
-	for k, v := range map[string]bool{
-		"one":   false,
-		"two":   true,
-		"three": false,
-		"four":  true,
-		"five":  true,
-		"six":   false,
-	} {
-		has, err := lfuda.Has(k)
-		assert.NoError(t, err)
-		assert.Equal(t, v, has)
-	}
-
-	lfuda.Get("two")  // touch so it stays in cache
-	lfuda.Get("five") // touch so it stays in cache
-	lfuda.Put("six", b)
-
-	assert.Equal(t, cacheMaxBlobs, len(mem.Debug()))
-
-	for k, v := range map[string]bool{
-		"one":   false,
-		"two":   true,
-		"three": false,
-		"four":  false,
-		"five":  true,
-		"six":   true,
-	} {
-		has, err := lfuda.Has(k)
-		assert.NoError(t, err)
-		assert.Equal(t, v, has)
-	}
-
-	err = lfuda.Delete("six")
-	assert.NoError(t, err)
-	err = lfuda.Delete("five")
-	assert.NoError(t, err)
-	err = lfuda.Delete("two")
-	assert.NoError(t, err)
-	assert.Equal(t, 0, len(mem.Debug()))
-}
-
-func TestFUDAStore_UnderlyingBlobMissing(t *testing.T) {
-	lfuda, mem := getTestLFUDAStore()
-	hash := "hash"
-	b := []byte("this is a blob of stuff")
-	err := lfuda.Put(hash, b)
-	require.NoError(t, err)
-
-	err = mem.Delete(hash)
-	require.NoError(t, err)
-
-	// hash still exists in lru
-	assert.True(t, lfuda.lfuda.Contains(hash))
-
-	blob, _, err := lfuda.Get(hash)
-	assert.Nil(t, blob)
-	assert.True(t, errors.Is(err, ErrBlobNotFound), "expected (%s) %s, got (%s) %s",
-		reflect.TypeOf(ErrBlobNotFound).String(), ErrBlobNotFound.Error(),
-		reflect.TypeOf(err).String(), err.Error())
-
-	// lru.Get() removes hash if underlying store doesn't have it
-	assert.False(t, lfuda.lfuda.Contains(hash))
-}
-
-func TestFUDAStore_loadExisting(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "reflector_test_*")
-	require.NoError(t, err)
-	defer os.RemoveAll(tmpDir)
-	d := NewDiskStore(tmpDir, 2)
-
-	hash := "hash"
-	b := []byte("this is a blob of stuff")
-	err = d.Put(hash, b)
-	require.NoError(t, err)
-
-	existing, err := d.list()
-	require.NoError(t, err)
-	require.Equal(t, 1, len(existing), "blob should exist in cache")
-	assert.Equal(t, hash, existing[0])
-
-	lfuda := NewLFUDAStore("test", d, 3) // lru should load existing blobs when it's created
-	time.Sleep(100 * time.Millisecond)   // async load so let's wait...
-	has, err := lfuda.Has(hash)
-	require.NoError(t, err)
-	assert.True(t, has, "hash should be loaded from disk store but it's not")
-}

store/lru.go

@@ -1,129 +0,0 @@
-package store
-
-import (
-	"time"
-
-	"github.com/lbryio/reflector.go/internal/metrics"
-	"github.com/lbryio/reflector.go/shared"
-
-	"github.com/lbryio/lbry.go/v2/extras/errors"
-	"github.com/lbryio/lbry.go/v2/stream"
-
-	"github.com/bluele/gcache"
-	"github.com/sirupsen/logrus"
-)
-
-// LRUStore adds a max cache size and LRU eviction to a BlobStore
-type LRUStore struct {
-	// underlying store
-	store BlobStore
-	// lru implementation
-	lru gcache.Cache
-}
-
-// NewLRUStore initialize a new LRUStore
-func NewLRUStore(component string, store BlobStore, maxItems int) *LRUStore {
-	l := &LRUStore{
-		store: store,
-	}
-	l.lru = gcache.New(maxItems).ARC().EvictedFunc(func(key, value interface{}) {
-		metrics.CacheLRUEvictCount.With(metrics.CacheLabels(l.Name(), component)).Inc()
-		_ = store.Delete(key.(string))
-	}).Build()
-
-	go func() {
-		if lstr, ok := store.(lister); ok {
-			err := l.loadExisting(lstr, maxItems)
-			if err != nil {
-				panic(err) // TODO: what should happen here? panic? return nil? just keep going?
-			}
-		}
-	}()
-
-	return l
-}
-
-// Name is the cache type name
-func (l *LRUStore) Name() string {
-	return "lru_" + l.store.Name()
-}
-
-// Has returns whether the blob is in the store, without updating the recent-ness.
-func (l *LRUStore) Has(hash string) (bool, error) {
-	return l.lru.Has(hash), nil
-}
-
-// Get returns the blob or an error if the blob doesn't exist.
-func (l *LRUStore) Get(hash string) (stream.Blob, shared.BlobTrace, error) {
-	start := time.Now()
-	_, err := l.lru.Get(hash)
-	if err != nil {
-		return nil, shared.NewBlobTrace(time.Since(start), l.Name()), errors.Err(ErrBlobNotFound)
-	}
-	blob, stack, err := l.store.Get(hash)
-	if errors.Is(err, ErrBlobNotFound) {
-		// Blob disappeared from underlying store
-		l.lru.Remove(hash)
-	}
-	return blob, stack.Stack(time.Since(start), l.Name()), err
-}
-
-// Put stores the blob
-func (l *LRUStore) Put(hash string, blob stream.Blob) error {
-	err := l.store.Put(hash, blob)
-	if err != nil {
-		return err
-	}
-
-	l.lru.Set(hash, true)
-	return nil
-}
-
-// PutSD stores the sd blob
-func (l *LRUStore) PutSD(hash string, blob stream.Blob) error {
-	err := l.store.PutSD(hash, blob)
-	if err != nil {
-		return err
-	}
-
-	_ = l.lru.Set(hash, true)
-	return nil
-}
-
-// Delete deletes the blob from the store
-func (l *LRUStore) Delete(hash string) error {
-	err := l.store.Delete(hash)
-	if err != nil {
-		return err
-	}
-
-	// This must come after store.Delete()
-	// Remove triggers onEvict function, which also tries to delete blob from store
-	// We need to delete it manually first so any errors can be propagated up
-	l.lru.Remove(hash)
-	return nil
-}
-
-// loadExisting imports existing blobs from the underlying store into the LRU cache
-func (l *LRUStore) loadExisting(store lister, maxItems int) error {
-	logrus.Infof("loading at most %d items", maxItems)
-	existing, err := store.list()
-	if err != nil {
-		return err
-	}
-	logrus.Infof("read %d files from disk", len(existing))
-	added := 0
-	for _, h := range existing {
-		l.lru.Set(h, true)
-		added++
-		if maxItems > 0 && added >= maxItems { // underlying cache is bigger than LRU cache
-			break
-		}
-	}
-	return nil
-}
-
-// Shutdown shuts down the store gracefully
-func (l *LRUStore) Shutdown() {
-	return
-}