Don't recreate cached layers

GoogleContainerTools · Jul 16, 2019 · b64f234 · b64f234
1 parent baba32c
commit b64f234
Show file tree

Hide file tree

Showing 4 changed files with 41 additions and 2 deletions.
diff --git a/pkg/commands/base_command.go b/pkg/commands/base_command.go
@@ -44,6 +44,10 @@ func (b *BaseCommand) RequiresUnpackedFS() bool {
 	return false
 }
 
+func (b *BaseCommand) CacheImage() v1.Image {
+	return nil
+}
+
 func (b *BaseCommand) ShouldCacheOutput() bool {
 	return false
 }
diff --git a/pkg/commands/commands.go b/pkg/commands/commands.go
@@ -40,6 +40,9 @@ type DockerCommand interface {
 	// Return a cache-aware implementation of this command, if it exists.
 	CacheCommand(v1.Image) DockerCommand
 
+	// Return an image with cached layer for this command, if it exists
+	CacheImage() v1.Image
+
 	// Return true if this command depends on the build context.
 	FilesUsedFromContext(*v1.Config, *dockerfile.BuildArgs) ([]string, error)
 

diff --git a/pkg/commands/run.go b/pkg/commands/run.go
@@ -190,6 +190,10 @@ func (cr *CachingRunCommand) ExecuteCommand(config *v1.Config, buildArgs *docker
 	return nil
 }
 
+func (cr *CachingRunCommand) CacheImage() v1.Image {
+	return cr.img
+}
+
 func (cr *CachingRunCommand) FilesToSnapshot() []string {
 	return cr.extractedFiles
 }

diff --git a/pkg/executor/build.go b/pkg/executor/build.go
@@ -222,6 +222,7 @@ func (s *stageBuilder) build() error {
 	if err := util.DetectFilesystemWhitelist(constants.WhitelistPath); err != nil {
 		return err
 	}
+
 	// Take initial snapshot
 	t := timing.Start("Initial FS snapshot")
 	if err := s.snapshotter.Init(); err != nil {
@@ -253,9 +254,20 @@ func (s *stageBuilder) build() error {
 		if err := command.ExecuteCommand(&s.cf.Config, s.args); err != nil {
 			return err
 		}
-		files = command.FilesToSnapshot()
 		timing.DefaultRun.Stop(t)
 
+		cache_img := command.CacheImage()
+		if cache_img != nil {
+			layers, err := cache_img.Layers()
+			if err != nil {
+				logrus.Debugf("Failed to retrieve layer from cache image: %s", err)
+				continue
+			}
+			s.addLayerToImage(command.String(), layers[0])
+			continue
+		}
+
+		files = command.FilesToSnapshot()
 		if !s.shouldTakeSnapshot(index, files) {
 			continue
 		}
@@ -269,6 +281,7 @@ func (s *stageBuilder) build() error {
 		if err != nil {
 			return err
 		}
+
 		// Push layer to cache (in parallel) now along with new config file
 		if s.opts.Cache && command.ShouldCacheOutput() {
 			cacheGroup.Go(func() error {
@@ -326,6 +339,21 @@ func (s *stageBuilder) shouldTakeSnapshot(index int, files []string) bool {
 	return true
 }
 
+func (s *stageBuilder) addLayerToImage(createdBy string, layer v1.Layer) error {
+	logrus.Infof("Adding cached layer for command %s to the image", createdBy)
+	var err error
+	s.image, err = mutate.Append(s.image,
+		mutate.Addendum{
+			Layer: layer,
+			History: v1.History{
+				Author:    constants.Author,
+				CreatedBy: createdBy,
+			},
+		},
+	)
+	return err
+}
+
 func (s *stageBuilder) saveSnapshotToImage(createdBy string, tarPath string) error {
 	if tarPath == "" {
 		return nil
@@ -343,6 +371,7 @@ func (s *stageBuilder) saveSnapshotToImage(createdBy string, tarPath string) err
 	if err != nil {
 		return err
 	}
+
 	s.image, err = mutate.Append(s.image,
 		mutate.Addendum{
 			Layer: layer,
@@ -353,7 +382,6 @@ func (s *stageBuilder) saveSnapshotToImage(createdBy string, tarPath string) err
 		},
 	)
 	return err
-
 }
 
 func CalculateDependencies(opts *config.KanikoOptions) (map[int][]string, error) {