split merge function

Signed-off-by: Naoki MATSUMOTO <[email protected]>

pkg/image/merge.go

@@ -7,13 +7,15 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"path/filepath"
 	"strconv"
 	"sync"
 	"time"
 
 	"github.com/klauspost/compress/zstd"
 	"github.com/naoki9911/fuse-diff-containerd/pkg/benchmark"
 	"github.com/naoki9911/fuse-diff-containerd/pkg/bsdiffx"
+	"github.com/naoki9911/fuse-diff-containerd/pkg/utils"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -903,3 +905,26 @@ func MergeCdimg(lowerCdimg, upperCdimg string, merged io.Writer, mc MergeConfig)
 	}
 	return &header, nil
 }
+
+func MergeDimgsWithLinear(dimgs []*DimgEntry, tmpDir string, mc MergeConfig) (*DimgEntry, error) {
+	lowerDimg := dimgs[len(dimgs)-1]
+	for idx := len(dimgs) - 2; idx >= 0; idx-- {
+		upperDimg := dimgs[idx]
+		mergedDimgPath := filepath.Join(tmpDir, utils.GetRandomId("merge")+".dimg")
+		mergedFile, err := os.Create(mergedDimgPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create temporary dimg %s: %v", mergedDimgPath, err)
+		}
+		defer mergedFile.Close()
+
+		logger.Infof("merge %s and %s", lowerDimg.Digest(), upperDimg.Digest())
+		header, err := MergeDimg(lowerDimg.Path, upperDimg.Path, mergedFile, mc)
+		if err != nil {
+			return nil, fmt.Errorf("failed to merge dimgs: %v", err)
+		}
+		lowerDimg.DimgHeader = *header
+		lowerDimg.Path = mergedDimgPath
+	}
+
+	return lowerDimg, nil
+}

pkg/server/server.go

@@ -191,29 +191,19 @@ func (ds *DiffServer) handleGetUpdateData(w http.ResponseWriter, r *http.Request
 	}
 	logger.Infof("Dimgs are sent to client %s", dimgsMsg)
 
-	lowerDimg := selectedDimgPaths[len(selectedDimgPaths)-1]
-	for idx := len(selectedDimgPaths) - 2; idx >= 0; idx-- {
-		upperDimg := selectedDimgPaths[idx]
-		mergedDimgPath := filepath.Join(imageStorePath, utils.GetRandomId("d4c-server")+".dimg")
-		mergedFile, err := os.Create(mergedDimgPath)
-		if err != nil {
-			logger.Errorf("failed to create temporarly dimg %s: %v", mergedDimgPath, err)
-			w.WriteHeader(http.StatusInternalServerError)
-			return
-		}
-		defer mergedFile.Close()
-
-		logger.Infof("merge %s and %s", lowerDimg.Digest(), upperDimg.Digest())
-		header, err := image.MergeDimg(lowerDimg.Path, upperDimg.Path, mergedFile, ds.mergeConfig)
-		if err != nil {
-			logger.Errorf("failed to merge dimgs: %v", err)
-			w.WriteHeader(http.StatusInternalServerError)
-			return
-		}
-		lowerDimg.DimgHeader = *header
-		lowerDimg.Path = mergedDimgPath
+	tmpDir := filepath.Join(imageStorePath, utils.GetRandomId("merge-tmp"))
+	err = os.Mkdir(tmpDir, 0755)
+	if err != nil {
+		logger.Errorf("failed to create temporary directory %s: %v", tmpDir, err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	resDimg, err := image.MergeDimgsWithLinear(selectedDimgPaths, tmpDir, ds.mergeConfig)
+	if err != nil {
+		logger.Errorf("failed to merge: %v", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
 	}
-	resDimg := lowerDimg
 
 	resDimgFile, err := image.OpenDimgFile(resDimg.Path)
 	if err != nil {