azurestore: Buffer upload data on disk instead of in-memory (#1070)

Closes #1031

pkg/azurestore/azurestore.go

@@ -1,13 +1,14 @@
 package azurestore
 
 import (
-	"bufio"
 	"bytes"
 	"context"
-	"encoding/binary"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
+	"io/fs"
+	"os"
 	"strings"
 
 	"github.com/tus/tusd/v2/internal/uid"
@@ -18,13 +19,20 @@ type AzureStore struct {
 	Service      AzService
 	ObjectPrefix string
 	Container    string
+
+	// TemporaryDirectory is the path where AzureStore will create temporary files
+	// on disk during the upload. An empty string ("", the default value) will
+	// cause AzureStore to use the operating system's default temporary directory.
+	TemporaryDirectory string
 }
 
 type AzUpload struct {
 	ID          string
 	InfoBlob    AzBlob
 	BlockBlob   AzBlob
 	InfoHandler *handler.FileInfo
+
+	tempDir string
 }
 
 func New(service AzService) *AzureStore {
@@ -73,6 +81,7 @@ func (store AzureStore) NewUpload(ctx context.Context, info handler.FileInfo) (h
 		InfoHandler: &info,
 		InfoBlob:    infoBlob,
 		BlockBlob:   blockBlob,
+		tempDir:     store.TemporaryDirectory,
 	}
 
 	err = azUpload.writeInfo(ctx)
@@ -128,6 +137,7 @@ func (store AzureStore) GetUpload(ctx context.Context, id string) (handler.Uploa
 		InfoHandler: &info,
 		InfoBlob:    infoBlob,
 		BlockBlob:   blockBlob,
+		tempDir:     store.TemporaryDirectory,
 	}, nil
 }
 
@@ -140,21 +150,38 @@ func (store AzureStore) AsLengthDeclarableUpload(upload handler.Upload) handler.
 }
 
 func (upload *AzUpload) WriteChunk(ctx context.Context, offset int64, src io.Reader) (int64, error) {
-	r := bufio.NewReader(src)
-	buf := new(bytes.Buffer)
-	n, err := r.WriteTo(buf)
+	// Create a temporary file for holding the uploaded data
+	file, err := os.CreateTemp(upload.tempDir, "tusd-az-tmp-")
+	if err != nil {
+		return 0, err
+	}
+	defer os.Remove(file.Name())
+
+	// Copy the entire request body into the file
+	n, err := io.Copy(file, src)
 	if err != nil {
+		file.Close()
 		return 0, err
 	}
 
-	chunkSize := int64(binary.Size(buf.Bytes()))
-	if chunkSize > MaxBlockBlobChunkSize {
-		return 0, fmt.Errorf("azurestore: Chunk of size %v too large. Max chunk size is %v", chunkSize, MaxBlockBlobChunkSize)
+	// Seek to the beginning
+	if _, err := file.Seek(0, 0); err != nil {
+		file.Close()
+		return 0, err
+	}
+
+	if n > MaxBlockBlobChunkSize {
+		file.Close()
+		return 0, fmt.Errorf("azurestore: Chunk of size %v too large. Max chunk size is %v", n, MaxBlockBlobChunkSize)
 	}
 
-	re := bytes.NewReader(buf.Bytes())
-	err = upload.BlockBlob.Upload(ctx, re)
+	err = upload.BlockBlob.Upload(ctx, file)
 	if err != nil {
+		file.Close()
+		return 0, err
+	}
+
+	if err := file.Close(); err != nil && !errors.Is(err, fs.ErrClosed) {
 		return 0, err
 	}
 

pkg/azurestore/azurestore_test.go

@@ -290,7 +290,12 @@ func TestWriteChunk(t *testing.T) {
 		infoBlob.EXPECT().Download(ctx).Return(newReadCloser(data), nil).Times(1),
 		service.EXPECT().NewBlob(ctx, mockID).Return(blockBlob, nil).Times(1),
 		blockBlob.EXPECT().GetOffset(ctx).Return(offset, nil).Times(1),
-		blockBlob.EXPECT().Upload(ctx, bytes.NewReader([]byte(mockReaderData))).Return(nil).Times(1),
+		blockBlob.EXPECT().Upload(ctx, gomock.Any()).DoAndReturn(func(_ context.Context, reader io.ReadSeeker) error {
+			actual, err := io.ReadAll(reader)
+			assert.Nil(err)
+			assert.Equal(mockReaderData, string(actual))
+			return nil
+		}).Times(1),
 	)
 
 	upload, err := store.GetUpload(ctx, mockID)