From c7dff7dca927ac370fcdbf49279d607bf8076071 Mon Sep 17 00:00:00 2001
From: tejal29 <tejal29@gmail.com>
Date: Wed, 21 Oct 2020 15:38:58 -0700
Subject: [PATCH] wip

---
 pkg/skaffold/docker/dependencies.go | 24 +++++++++++++++++++++++-
 pkg/skaffold/docker/parse.go        |  8 +++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/pkg/skaffold/docker/dependencies.go b/pkg/skaffold/docker/dependencies.go
index d9ff2009469..796d39740a2 100644
--- a/pkg/skaffold/docker/dependencies.go
+++ b/pkg/skaffold/docker/dependencies.go
@@ -28,6 +28,18 @@ import (
 	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/walk"
 )
 
+
+// dockerDependencies describes
+type dockerfileDependencies struct {
+	 files []string
+	 err error
+}
+
+// dependencyCache is a cache for dependencies for each dockerfile.
+var (
+	dependencyCache = map[string]dockerfileDependencies{}
+)
+
 // NormalizeDockerfilePath returns the absolute path to the dockerfile.
 func NormalizeDockerfilePath(context, dockerfile string) (string, error) {
 	// Expected case: should be found relative to the context directory.
@@ -50,6 +62,17 @@ func GetDependencies(ctx context.Context, workspace string, dockerfilePath strin
 		return nil, fmt.Errorf("normalizing dockerfile path: %w", err)
 	}
 
+	if _, ok := dependencyCache[absDockerfilePath]; !ok {
+		paths, err := getDependencies(workspace, dockerfilePath, absDockerfilePath, buildArgs, cfg)
+		dependencyCache[absDockerfilePath] = dockerfileDependencies{
+			files: paths,
+			err: err,
+		}
+	}
+	return dependencyCache[absDockerfilePath].files, dependencyCache[absDockerfilePath].err
+}
+
+func getDependencies(workspace string, dockerfilePath string, absDockerfilePath string, buildArgs map[string]*string, cfg Config) ([]string, error){
 	// If the Dockerfile doesn't exist, we can't compute the dependencies.
 	// But since we know the Dockerfile is a dependency, let's return a list
 	// with only that file. It makes errors down the line more actionable
@@ -93,7 +116,6 @@ func GetDependencies(ctx context.Context, workspace string, dockerfilePath strin
 		dependencies = append(dependencies, file)
 	}
 	sort.Strings(dependencies)
-
 	return dependencies, nil
 }
 
diff --git a/pkg/skaffold/docker/parse.go b/pkg/skaffold/docker/parse.go
index d70f63a924b..c99ee3dcd7f 100644
--- a/pkg/skaffold/docker/parse.go
+++ b/pkg/skaffold/docker/parse.go
@@ -62,9 +62,10 @@ type fromTo struct {
 var (
 	// RetrieveImage is overridden for unit testing
 	RetrieveImage = retrieveImage
-	onBuildRetrieveErr   = errors.New("error retrieving ONBUILD image")
+	unsupportedMediaTypeError   = errors.New("unsupported MediaType error")
 )
 
+
 func readCopyCmdsFromDockerfile(onlyLastImage bool, absDockerfilePath, workspace string, buildArgs map[string]*string, cfg Config) ([]fromTo, error) {
 	f, err := os.Open(absDockerfilePath)
 	if err != nil {
@@ -218,6 +219,7 @@ func extractCopyCommands(nodes []*parser.Node, onlyLastImage bool, cfg Config) (
 			if !stages[strings.ToLower(from.image)] {
 				img, err := RetrieveImage(from.image, cfg)
 				if err != nil {
+					if
 					return nil, err
 				}
 
@@ -320,7 +322,7 @@ func expandOnbuildInstructions(nodes []*parser.Node, cfg Config) ([]*parser.Node
 			} else if ons, err := parseOnbuild(from.image, cfg); err == nil {
 				onbuildNodes = ons
 			} else {
-				if errors.Is(err, onBuildRetrieveErr) {
+				if errors.Is(err, notSupportedManifestError) {
 					// TODO: [4895] collect warning codes for warnings seen during a dev iteration.
 					logrus.Warnf("could not retrieve ONBUILD image %s. Will ignore files dependencies for all ONBUILD triggers", from.image)
 					return []*parser.Node{}, nil
@@ -346,7 +348,7 @@ func parseOnbuild(image string, cfg Config) ([]*parser.Node, error) {
 	// Image names are case SENSITIVE
 	img, err := RetrieveImage(image, cfg)
 	if err != nil {
-		return nil, onBuildRetrieveErr
+		return nil,
 	}
 
 	if len(img.Config.OnBuild) == 0 {