go.mod

@@ -5,6 +5,7 @@ replace github.com/btcsuite/btcd => github.com/lbryio/lbrycrd.go v0.0.0-20200203
 require (
 	github.com/armon/go-metrics v0.0.0-20190430140413-ec5e00d3c878 // indirect
 	github.com/aws/aws-sdk-go v1.16.11
+	github.com/bparli/lfuda-go v0.3.0
 	github.com/btcsuite/btcd v0.0.0-20190824003749-130ea5bddde3
 	github.com/btcsuite/btcutil v0.0.0-20190425235716-9e5f4b9a998d
 	github.com/davecgh/go-spew v1.1.1
@@ -25,7 +26,7 @@ require (
 	github.com/lbryio/lbry.go v1.1.2 // indirect
 	github.com/lbryio/lbry.go/v2 v2.6.1-0.20200901175808-73382bb02128
 	github.com/lbryio/types v0.0.0-20191228214437-05a22073b4ec
-	github.com/lucas-clemente/quic-go v0.19.1
+	github.com/lucas-clemente/quic-go v0.19.2
 	github.com/phayes/freeport v0.0.0-20171002185219-e27662a4a9d6
 	github.com/prometheus/client_golang v0.9.2
 	github.com/sirupsen/logrus v1.4.2

go.sum

@@ -25,6 +25,8 @@ github.com/aws/aws-sdk-go v1.16.11/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpi
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 h1:xJ4a3vCFaGF/jqvzLMYoU8P317H5OQ+Via4RmuPwCS0=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kBD4zp0CCIs=
+github.com/bparli/lfuda-go v0.3.0 h1:b6qPjEb0BN006oQnj2nuGfz94yY3iYo0bmuFM079tQg=
+github.com/bparli/lfuda-go v0.3.0/go.mod h1:BR5a9lwlqRqnPhU3F5ojFK3VhTKg8iFVtJJKgZBQhAo=
 github.com/bradfitz/go-smtpd v0.0.0-20170404230938-deb6d6237625/go.mod h1:HYsPBTaaSFSlLx/70C2HPIMNZpVV8+vt/A+FMnYP11g=
 github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f h1:bAs4lUbRJpnnkd9VhRV3jjAVU7DJVjMaK+IsvSeZvFo=
 github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f/go.mod h1:TdznJufoqS23FtqVCzL0ZqgP5MqXbb4fg/WgDys70nA=
@@ -223,6 +225,8 @@ github.com/lbryio/types v0.0.0-20191228214437-05a22073b4ec/go.mod h1:CG3wsDv5BiV
 github.com/lib/pq v1.1.1/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lucas-clemente/quic-go v0.19.1 h1:J9TkQJGJVOR3UmGhd4zdVYwKSA0EoXbLRf15uQJ6gT4=
 github.com/lucas-clemente/quic-go v0.19.1/go.mod h1:ZUygOqIoai0ASXXLJ92LTnKdbqh9MHCLTX6Nr1jUrK0=
+github.com/lucas-clemente/quic-go v0.19.2 h1:w8BBYUx5Z+kNpeaOeQW/KzcNsKWhh4O6PeQhb0nURPg=
+github.com/lucas-clemente/quic-go v0.19.2/go.mod h1:ZUygOqIoai0ASXXLJ92LTnKdbqh9MHCLTX6Nr1jUrK0=
 github.com/lunixbochs/vtclean v1.0.0/go.mod h1:pHhQNgMf3btfWnGBVipUOjRYhoOsdGqdm/+2c2E2WMI=
 github.com/lusis/go-slackbot v0.0.0-20180109053408-401027ccfef5/go.mod h1:c2mYKRyMb1BPkO5St0c/ps62L4S0W2NAkaTXj9qEI+0=
 github.com/lusis/slack-test v0.0.0-20180109053238-3c758769bfa6/go.mod h1:sFlOUpQL1YcjhFVXhg1CG8ZASEs/Mf1oVb6H75JL/zg=

store/caching_test.go

@@ -58,6 +58,7 @@ func TestCachingStore_CacheMiss(t *testing.T) {
 	if !bytes.Equal(b, res) {
 		t.Errorf("expected Get() to return %s, got %s", string(b), string(res))
 	}
+	time.Sleep(10 * time.Millisecond) //storing to cache is done async so let's give it some time
 
 	has, err := cache.Has(hash)
 	if err != nil {

store/lfuda.go

@@ -0,0 +1,118 @@
+package store
+
+import (
+	"github.com/bparli/lfuda-go"
+	"github.com/lbryio/lbry.go/v2/extras/errors"
+	"github.com/lbryio/lbry.go/v2/stream"
+	"github.com/lbryio/reflector.go/internal/metrics"
+)
+
+// LRUStore adds a max cache size and LRU eviction to a BlobStore
+type LFUDAStore struct {
+	// underlying store
+	store BlobStore
+	// lfuda implementation
+	lfuda *lfuda.Cache
+}
+
+// NewLRUStore initialize a new LRUStore
+func NewLFUDAStore(component string, store BlobStore, maxSize float64) *LFUDAStore {
+	lfuda := lfuda.NewGDSFWithEvict(maxSize, func(key interface{}, value interface{}) {
+		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
+	})
+	lfuda.Age()
+	l := &LFUDAStore{
+		store: store,
+		lfuda: lfuda,
+	}
+	go func() {
+		if lstr, ok := store.(lister); ok {
+			err := l.loadExisting(lstr, int(maxSize/2000000.0))
+			if err != nil {
+				panic(err) // TODO: what should happen here? panic? return nil? just keep going?
+			}
+		}
+	}()
+
+	return l
+}
+
+const nameLFUDA = "lfuda"
+
+var fakeTrue = []byte{'t'}
+
+// Name is the cache type name
+func (l *LFUDAStore) Name() string { return nameLFUDA }
+
+// Has returns whether the blob is in the store, without updating the recent-ness.
+func (l *LFUDAStore) Has(hash string) (bool, error) {
+	return l.lfuda.Contains(hash), nil
+}
+
+// Get returns the blob or an error if the blob doesn't exist.
+func (l *LFUDAStore) Get(hash string) (stream.Blob, error) {
+	_, has := l.lfuda.Get(hash)
+	if !has {
+		return nil, errors.Err(ErrBlobNotFound)
+	}
+	blob, err := l.store.Get(hash)
+	if errors.Is(err, ErrBlobNotFound) {
+		// Blob disappeared from underlying store
+		l.lfuda.Remove(hash)
+	}
+	return blob, 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 {
+	err := l.store.Put(hash, blob)
+	if err != nil {
+		return err
+	}
+	l.lfuda.Set(hash, fakeTrue)
+	return nil
+}
+
+// PutSD stores the sd blob
+func (l *LFUDAStore) PutSD(hash string, blob stream.Blob) error {
+	err := l.store.PutSD(hash, blob)
+	if err != nil {
+		return err
+	}
+
+	l.lfuda.Set(hash, fakeTrue)
+	return nil
+}
+
+// Delete deletes the blob from the store
+func (l *LFUDAStore) 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.lfuda.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 {
+	existing, err := store.list()
+	if err != nil {
+		return err
+	}
+
+	added := 0
+	for _, h := range existing {
+		l.lfuda.Set(h, fakeTrue)
+		added++
+		if maxItems > 0 && added >= maxItems { // underlying cache is bigger than LRU cache
+			break
+		}
+	}
+	return nil
+}

store/lfuda_test.go

@@ -0,0 +1,139 @@
+package store
+
+import (
+	"io/ioutil"
+	"os"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/lbryio/lbry.go/v2/extras/errors"
+	log "github.com/sirupsen/logrus"
+
+	"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()))
+
+	keys := lfuda.lfuda.Keys()
+	log.Infof("%+v", keys)
+	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_test.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/lbryio/lbry.go/v2/extras/errors"
 
@@ -115,6 +116,7 @@ func TestLRUStore_loadExisting(t *testing.T) {
 	assert.Equal(t, hash, existing[0])
 
 	lru := NewLRUStore("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 := lru.Has(hash)
 	require.NoError(t, err)
 	assert.True(t, has, "hash should be loaded from disk store but it's not")