Add more tests for Copy and some fixes.

integration/dockerfiles/Dockerfile_test_copy_symlink

@@ -1,14 +1,10 @@
 FROM busybox as t
-RUN echo "hello" > /tmp/target
-RUN ln -s /tmp/target /tmp/link
-
-## Relative link
-RUN cd tmp && ln -s target relative_link
-
+RUN mkdir temp
+RUN echo "hello" > temp/target
+RUN ln -s target temp/link
 ## Relative link with paths
-RUN mkdir workdir && cd workdir && ln -s ../tmp/target relative_dir_link
+RUN mkdir workdir && cd workdir && ln -s ../temp/target relative_link
 
 FROM scratch
-COPY --from=t /tmp/link /tmp/
-COPY --from=t /tmp/relative_link /tmp/
-COPY --from=t /workdir/relative_dir_link /workdir/
+COPY --from=t temp/ dest/
+COPY --from=t /workdir/relative_link /workdirAnother/

pkg/commands/add.go

@@ -21,6 +21,7 @@ import (
 
 	v1 "github.com/google/go-containerregistry/pkg/v1"
 	"github.com/moby/buildkit/frontend/dockerfile/instructions"
+	"github.com/pkg/errors"
 
 	"github.com/GoogleContainerTools/kaniko/pkg/dockerfile"
 
@@ -66,18 +67,18 @@ func (a *AddCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bui
 			}
 			logrus.Infof("Adding remote URL %s to %s", src, urlDest)
 			if err := util.DownloadFileToDest(src, urlDest); err != nil {
-				return err
+				return errors.Wrap(err, "downloading remote source file")
 			}
 			a.snapshotFiles = append(a.snapshotFiles, urlDest)
 		} else if util.IsFileLocalTarArchive(fullPath) {
 			tarDest, err := util.DestinationFilepath("", dest, config.WorkingDir)
 			if err != nil {
-				return err
+				return errors.Wrap(err, "determining dest for tar")
 			}
 			logrus.Infof("Unpacking local tar archive %s to %s", src, tarDest)
 			extractedFiles, err := util.UnpackLocalTarArchive(fullPath, tarDest)
 			if err != nil {
-				return err
+				return errors.Wrap(err, "unpacking local tar")
 			}
 			logrus.Debugf("Added %v from local tar archive %s", extractedFiles, src)
 			a.snapshotFiles = append(a.snapshotFiles, extractedFiles...)
@@ -98,7 +99,7 @@ func (a *AddCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bui
 	}
 
 	if err := copyCmd.ExecuteCommand(config, buildArgs); err != nil {
-		return err
+		return errors.Wrap(err, "executing copy command")
 	}
 	a.snapshotFiles = append(a.snapshotFiles, copyCmd.snapshotFiles...)
 	return nil

pkg/commands/copy.go

@@ -54,17 +54,18 @@ func (c *CopyCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bu
 
 	uid, gid, err := getUserGroup(c.cmd.Chown, replacementEnvs)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "getting user group from chowm")
 	}
 
 	srcs, dest, err := util.ResolveEnvAndWildcards(c.cmd.SourcesAndDest, c.buildcontext, replacementEnvs)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "resolving src")
 	}
 
 	// For each source, iterate through and copy it over
 	for _, src := range srcs {
 		fullPath := filepath.Join(c.buildcontext, src)
+
 		fi, err := os.Lstat(fullPath)
 		if err != nil {
 			return errors.Wrap(err, "could not copy source")
@@ -79,27 +80,27 @@ func (c *CopyCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bu
 
 		destPath, err := util.DestinationFilepath(fullPath, dest, cwd)
 		if err != nil {
-			return err
+			return errors.Wrap(err, "find destination path")
 		}
 
 		// If the destination dir is a symlink we need to resolve the path and use
 		// that instead of the symlink path
 		destPath, err = resolveIfSymlink(destPath)
 		if err != nil {
-			return err
+			return errors.Wrap(err, "resolving dest symlink")
 		}
 
 		if fi.IsDir() {
 			copiedFiles, err := util.CopyDir(fullPath, destPath, c.buildcontext, uid, gid)
 			if err != nil {
-				return err
+				return errors.Wrap(err, "copying dir")
 			}
 			c.snapshotFiles = append(c.snapshotFiles, copiedFiles...)
 		} else if util.IsSymlink(fi) {
 			// If file is a symlink, we want to copy the target file to destPath
-			exclude, err := util.CopySymlink(fullPath, destPath, c.buildcontext, uid, gid)
+			exclude, err := util.CopySymlink(fullPath, destPath, c.buildcontext)
 			if err != nil {
-				return err
+				return errors.Wrap(err, "copying symlink")
 			}
 			if exclude {
 				continue
@@ -109,7 +110,7 @@ func (c *CopyCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bu
 			// ... Else, we want to copy over a file
 			exclude, err := util.CopyFile(fullPath, destPath, c.buildcontext, uid, gid)
 			if err != nil {
-				return err
+				return errors.Wrap(err, "copying file")
 			}
 			if exclude {
 				continue