check file changed in loop

pkg/snapshot/layered_map.go

@@ -30,9 +30,10 @@ import (
 )
 
 type LayeredMap struct {
-	layers    []map[string]string
-	whiteouts []map[string]string
-	hasher    func(string) (string, error)
+	layers         []map[string]string
+	whiteouts      []map[string]string
+	layerHashCache map[string]string
+	hasher         func(string) (string, error)
 	// cacheHasher doesn't include mtime in it's hash so that filesystem cache keys are stable
 	cacheHasher func(string) (string, error)
 }
@@ -43,6 +44,7 @@ func NewLayeredMap(h func(string) (string, error), c func(string) (string, error
 		cacheHasher: c,
 	}
 	l.layers = []map[string]string{}
+	l.layerHashCache = map[string]string{}
 	return &l
 }
 
@@ -103,7 +105,14 @@ func (l *LayeredMap) MaybeAddWhiteout(s string) bool {
 // Add will add the specified file s to the layered map.
 func (l *LayeredMap) Add(s string) error {
 	// Use hash function and add to layers
-	newV, err := l.hasher(s)
+	newV, err := func(s string) (string, error) {
+		if v, ok := l.layerHashCache[s]; ok {
+			// clear it cache for next layer.
+			delete(l.layerHashCache, s)
+			return v, nil
+		}
+		return l.hasher(s)
+	}(s)
 	if err != nil {
 		return fmt.Errorf("error creating hash for %s: %v", s, err)
 	}
@@ -126,6 +135,7 @@ func (l *LayeredMap) CheckFileChange(s string) (bool, error) {
 		}
 		return false, err
 	}
+	l.layerHashCache[s] = newV
 	oldV, ok := l.Get(s)
 	if ok && newV == oldV {
 		return false, nil

pkg/snapshot/snapshot.go

@@ -135,61 +135,46 @@ func (s *Snapshotter) scanFullFilesystem() ([]string, []string, error) {
 
 	timer := timing.Start("Walking filesystem")
 
-	foundPaths := make([]string, 0)
+	changedPaths := make([]string, 0)
+
+	//   Get a list of all the files that existed before this layer
+	existingPaths := s.l.getFlattenedPathsForWhiteOut()
 
 	godirwalk.Walk(s.directory, &godirwalk.Options{
 		Callback: func(path string, ent *godirwalk.Dirent) error {
 			if util.IsInIgnoreList(path) {
 				if util.IsDestDir(path) {
 					logrus.Tracef("Skipping paths under %s, as it is a ignored directory", path)
-
 					return filepath.SkipDir
 				}
 
 				return nil
 			}
-
-			foundPaths = append(foundPaths, path)
-
+			if ok, err := s.l.CheckFileChange(path); err != nil {
+				return err
+			} else if ok {
+				changedPaths = append(changedPaths, path)
+			}
+			delete(existingPaths, path)
 			return nil
 		},
 		Unsorted: true,
 	},
 	)
 	timing.DefaultRun.Stop(timer)
 	timer = timing.Start("Resolving Paths")
-	// First handle whiteouts
-	//   Get a list of all the files that existed before this layer
-	existingPaths := s.l.getFlattenedPathsForWhiteOut()
 
 	filesToAdd := []string{}
-	resolvedMemFs := make(map[string]bool)
-
-	for _, path := range foundPaths {
-		delete(existingPaths, path)
-		resolvedFiles, err := filesystem.ResolvePaths([]string{path}, s.ignorelist)
-		if err != nil {
-			return nil, nil, err
-		}
-		for _, path := range resolvedFiles {
-			// Continue if this path is already processed
-			if _, ok := resolvedMemFs[path]; ok {
-				continue
-			}
-			if util.CheckIgnoreList(path) {
-				logrus.Tracef("Not adding %s to layer, as it's whitelisted", path)
-				continue
-			}
-			// Only add changed files.
-			fileChanged, err := s.l.CheckFileChange(path)
-			if err != nil {
-				return nil, nil, fmt.Errorf("could not check if file has changed %s %s", path, err)
-			}
-			if fileChanged {
-				logrus.Tracef("Adding file %s to layer, because it was changed.", path)
-				filesToAdd = append(filesToAdd, path)
-			}
+	resolvedFiles, err := filesystem.ResolvePaths(changedPaths, s.ignorelist)
+	if err != nil {
+		return nil, nil, err
+	}
+	for _, path := range resolvedFiles {
+		if util.CheckIgnoreList(path) {
+			logrus.Tracef("Not adding %s to layer, as it's whitelisted", path)
+			continue
 		}
+		filesToAdd = append(filesToAdd, path)
 	}
 
 	// The paths left here are the ones that have been deleted in this layer.

pkg/snapshot/snapshot_test.go

@@ -66,6 +66,7 @@ func TestSnapshotFSFileChange(t *testing.T) {
 	}
 	for _, path := range util.ParentDirectoriesWithoutLeadingSlash(batPath) {
 		if path == "/" {
+			snapshotFiles["/"] = ""
 			continue
 		}
 		snapshotFiles[path+"/"] = ""
@@ -164,6 +165,7 @@ func TestSnapshotFSChangePermissions(t *testing.T) {
 	}
 	for _, path := range util.ParentDirectoriesWithoutLeadingSlash(batPathWithoutLeadingSlash) {
 		if path == "/" {
+			snapshotFiles["/"] = ""
 			continue
 		}
 		snapshotFiles[path+"/"] = ""