fix add command bug when adding remote URLs (#277)

deploy/Dockerfile_debug

@@ -30,7 +30,7 @@ RUN make -C /go/src/github.com/awslabs/amazon-ecr-credential-helper linux-amd64
 FROM gcr.io/cloud-builders/bazel:latest
 RUN git clone https://github.com/GoogleContainerTools/distroless.git
 WORKDIR /distroless
-RUN bazel build //experimental/busybox:busybox.tar
+RUN bazel build //experimental/busybox:busybox_tar
 RUN tar -C /distroless/bazel-genfiles/experimental/busybox/ -xf /distroless/bazel-genfiles/experimental/busybox/busybox.tar
 
 FROM scratch

integration/dockerfiles/Dockerfile_test_add

@@ -20,3 +20,4 @@ COPY $file /arg
 
 # Finally, test adding a remote URL, concurrently with a normal file
 ADD https://github.com/GoogleCloudPlatform/docker-credential-gcr/releases/download/v1.4.3/docker-credential-gcr_linux_386-1.4.3.tar.gz context/foo /test/all/
+ADD https://github.com/GoogleCloudPlatform/docker-credential-gcr/releases/download/v1.4.3-static/docker-credential-gcr_linux_amd64-1.4.3.tar.gz /destination

integration/integration_test.go

@@ -197,7 +197,7 @@ func TestRun(t *testing.T) {
 
 func TestLayers(t *testing.T) {
 	offset := map[string]int{
-		"Dockerfile_test_add":     9,
+		"Dockerfile_test_add":     10,
 		"Dockerfile_test_scratch": 3,
 		// the Docker built image combined some of the dirs defined by separate VOLUME commands into one layer
 		// which is why this offset exists

pkg/constants/constants.go

@@ -57,7 +57,11 @@ const (
 )
 
 // KanikoBuildFiles is the list of files required to build kaniko
-var KanikoBuildFiles = []string{"/kaniko/executor", "/kaniko/ssl/certs/ca-certificates.crt"}
+var KanikoBuildFiles = []string{"/kaniko/executor",
+	"/kaniko/ssl/certs/ca-certificates.crt",
+	"/kaniko/docker-credential-gcr",
+	"/kaniko/docker-credential-ecr-login",
+	"/kaniko/.docker/config.json"}
 
 // ScratchEnvVars are the default environment variables needed for a scratch image.
 var ScratchEnvVars = []string{"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"}

pkg/snapshot/snapshot.go

@@ -24,6 +24,7 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/GoogleContainerTools/kaniko/pkg/constants"
 	"github.com/GoogleContainerTools/kaniko/pkg/util"
 	"github.com/sirupsen/logrus"
 )
@@ -94,8 +95,8 @@ func (s *Snapshotter) snapshotFiles(f io.Writer, files []string) (bool, error) {
 		if val, ok := snapshottedFiles[file]; ok && val {
 			continue
 		}
-		if util.CheckWhitelist(file) {
-			logrus.Debugf("Not adding %s to layer, as it's whitelisted", file)
+		if util.CheckWhitelist(file) && !isBuildFile(file) {
+			logrus.Infof("Not adding %s to layer, as it's whitelisted", file)
 			continue
 		}
 		snapshottedFiles[file] = true
@@ -118,6 +119,15 @@ func (s *Snapshotter) snapshotFiles(f io.Writer, files []string) (bool, error) {
 	return filesAdded, nil
 }
 
+func isBuildFile(file string) bool {
+	for _, buildFile := range constants.KanikoBuildFiles {
+		if file == buildFile {
+			return true
+		}
+	}
+	return false
+}
+
 func (s *Snapshotter) snapShotFS(f io.Writer) (bool, error) {
 	logrus.Info("Taking snapshot of full filesystem...")
 	s.hardlinks = map[uint64]string{}

pkg/util/command_util.go

@@ -180,7 +180,11 @@ func IsSrcsValid(srcsAndDest instructions.SourcesAndDest, resolvedSources []stri
 		}
 	}
 
+	// If there is only one source and it's a directory, docker assumes the dest is a directory
 	if len(resolvedSources) == 1 {
+		if IsSrcRemoteFileURL(resolvedSources[0]) {
+			return nil
+		}
 		fi, err := os.Lstat(filepath.Join(root, resolvedSources[0]))
 		if err != nil {
 			return err

pkg/util/command_util_test.go

@@ -339,6 +339,16 @@ var isSrcValidTests = []struct {
 		},
 		shouldErr: false,
 	},
+	{
+		srcsAndDest: []string{
+			testUrl,
+			"dest",
+		},
+		resolvedSources: []string{
+			testUrl,
+		},
+		shouldErr: false,
+	},
 }
 
 func Test_IsSrcsValid(t *testing.T) {