Merge branch 'fix_mem_leak'

* fix_mem_leak:
  dont over-allocate ram when reading blobs via QUIC
  dont overallocate ram when reading blobs from disk

peer/http3/client.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"sync"
 	"time"
 
 	"github.com/lbryio/lbry.go/v2/extras/errors"
@@ -80,18 +81,47 @@ func (c *Client) GetBlob(hash string) (stream.Blob, error) {
 		return nil, errors.Err(err)
 	}
 	defer resp.Body.Close()
+
 	if resp.StatusCode == http.StatusNotFound {
 		fmt.Printf("%s blob not found %d\n", hash, resp.StatusCode)
 		return nil, errors.Err(store.ErrBlobNotFound)
-	}
-	if resp.StatusCode != http.StatusOK {
+	} else if resp.StatusCode != http.StatusOK {
 		return nil, errors.Err("non 200 status code returned: %d", resp.StatusCode)
 	}
-	body := &bytes.Buffer{}
-	_, err = io.Copy(body, resp.Body)
+
+	tmp := getBuffer()
+	defer putBuffer(tmp)
+
+	written, err := io.Copy(tmp, resp.Body)
 	if err != nil {
 		return nil, errors.Err(err)
 	}
-	metrics.MtrInBytesUdp.Add(float64(len(body.Bytes())))
-	return body.Bytes(), nil
+
+	blob := make([]byte, written)
+	copy(blob, tmp.Bytes())
+
+	metrics.MtrInBytesUdp.Add(float64(len(blob)))
+
+	return blob, nil
+}
+
+// buffer pool to reduce GC
+// https://www.captaincodeman.com/2017/06/02/golang-buffer-pool-gotcha
+var buffers = sync.Pool{
+	// New is called when a new instance is needed
+	New: func() interface{} {
+		buf := make([]byte, 0, stream.MaxBlobSize)
+		return bytes.NewBuffer(buf)
+	},
+}
+
+// getBuffer fetches a buffer from the pool
+func getBuffer() *bytes.Buffer {
+	return buffers.Get().(*bytes.Buffer)
+}
+
+// putBuffer returns a buffer to the pool
+func putBuffer(buf *bytes.Buffer) {
+	buf.Reset()
+	buffers.Put(buf)
 }

store/disk.go

@@ -58,17 +58,15 @@ func (d *DiskStore) Get(hash string) (stream.Blob, error) {
 		return nil, err
 	}
 
-	file, err := os.Open(d.path(hash))
+	blob, err := ioutil.ReadFile(d.path(hash))
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil, errors.Err(ErrBlobNotFound)
 		}
-		return nil, err
+		return nil, errors.Err(err)
 	}
-	defer file.Close()
 
-	blob, err := ioutil.ReadAll(file)
-	return blob, errors.Err(err)
+	return blob, nil
 }
 
 // Put stores the blob on disk

store/disk_test.go

@@ -0,0 +1,45 @@
+package store
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"testing"
+
+	"github.com/lbryio/lbry.go/v2/extras/errors"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDiskStore_Get(t *testing.T) {
+	tmpDir, err := ioutil.TempDir("", "reflector_test_*")
+	require.NoError(t, err)
+	defer os.RemoveAll(tmpDir)
+	d := NewDiskStore(tmpDir, 2)
+
+	hash := "1234567890"
+	data := []byte("oyuntyausntoyaunpdoyruoyduanrstjwfjyuwf")
+
+	expectedPath := path.Join(tmpDir, hash[:2], hash)
+	err = os.MkdirAll(filepath.Dir(expectedPath), os.ModePerm)
+	require.NoError(t, err)
+	err = ioutil.WriteFile(expectedPath, data, os.ModePerm)
+	require.NoError(t, err)
+
+	blob, err := d.Get(hash)
+	assert.NoError(t, err)
+	assert.EqualValues(t, data, blob)
+}
+
+func TestDiskStore_GetNonexistentBlob(t *testing.T) {
+	tmpDir, err := ioutil.TempDir("", "reflector_test_*")
+	require.NoError(t, err)
+	defer os.RemoveAll(tmpDir)
+	d := NewDiskStore(tmpDir, 2)
+
+	blob, err := d.Get("nonexistent")
+	assert.Nil(t, blob)
+	assert.True(t, errors.Is(err, ErrBlobNotFound))
+}