implement cp reads tar file from stdin/stdout

enables podman cp uses - to stream a tar archive from STDIN or to STDOUT.

Signed-off-by: Qi Wang <qiwan@redhat.com>

cmd/podman/cp.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"archive/tar"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -142,7 +144,11 @@ func copyBetweenHostAndContainer(runtime *libpod.Runtime, src string, dest strin
 
 	var lastError error
 	for _, src := range glob {
-		err := copy(src, destPath, dest, idMappingOpts, &containerOwner, extract)
+		if src == "-" {
+			src = os.Stdin.Name()
+			extract = true
+		}
+		err := copy(src, destPath, dest, idMappingOpts, &containerOwner, extract, isFromHostToCtr)
 		if lastError != nil {
 			logrus.Error(lastError)
 		}
@@ -195,7 +201,7 @@ func getPathInfo(path string) (string, os.FileInfo, error) {
 	return path, srcfi, nil
 }
 
-func copy(src, destPath, dest string, idMappingOpts storage.IDMappingOptions, chownOpts *idtools.IDPair, extract bool) error {
+func copy(src, destPath, dest string, idMappingOpts storage.IDMappingOptions, chownOpts *idtools.IDPair, extract, isFromHostToCtr bool) error {
 	srcPath, err := filepath.EvalSymlinks(src)
 	if err != nil {
 		return errors.Wrapf(err, "error evaluating symlinks %q", srcPath)
@@ -205,6 +211,16 @@ func copy(src, destPath, dest string, idMappingOpts storage.IDMappingOptions, ch
 	if err != nil {
 		return err
 	}
+
+	filename := filepath.Base(destPath)
+	if filename == "-" && !isFromHostToCtr {
+		err := streamFileToStdout(srcPath, srcfi)
+		if err != nil {
+			return errors.Wrapf(err, "error streaming source file %s to Stdout", srcPath)
+		}
+		return nil
+	}
+
 	destdir := destPath
 	if !srcfi.IsDir() && !strings.HasSuffix(dest, string(os.PathSeparator)) {
 		destdir = filepath.Dir(destPath)
@@ -224,7 +240,6 @@ func copy(src, destPath, dest string, idMappingOpts storage.IDMappingOptions, ch
 	untarPath := chrootarchive.UntarPathAndChown(chownOpts, digest.Canonical.Digester().Hash(), idMappingOpts.UIDMap, idMappingOpts.GIDMap)
 
 	if srcfi.IsDir() {
-
 		logrus.Debugf("copying %q to %q", srcPath+string(os.PathSeparator)+"*", dest+string(os.PathSeparator)+"*")
 		if destDirIsExist && !strings.HasSuffix(src, fmt.Sprintf("%s.", string(os.PathSeparator))) {
 			destPath = filepath.Join(destPath, filepath.Base(srcPath))
@@ -276,3 +291,62 @@ func convertIDMap(idMaps []idtools.IDMap) (convertedIDMap []specs.LinuxIDMapping
 	}
 	return convertedIDMap
 }
+
+func streamFileToStdout(srcPath string, srcfi os.FileInfo) error {
+	if srcfi.IsDir() {
+		tw := tar.NewWriter(os.Stdout)
+		err := filepath.Walk(srcPath, func(path string, info os.FileInfo, err error) error {
+			if err != nil || !info.Mode().IsRegular() || path == srcPath {
+				return err
+			}
+			hdr, err := tar.FileInfoHeader(info, "")
+			if err != nil {
+				return err
+			}
+
+			if err = tw.WriteHeader(hdr); err != nil {
+				return err
+			}
+			fh, err := os.Open(path)
+			if err != nil {
+				return err
+			}
+			defer fh.Close()
+
+			_, err = io.Copy(tw, fh)
+			return err
+		})
+		if err != nil {
+			return errors.Wrapf(err, "error streaming directory %s to Stdout", srcPath)
+		}
+		return nil
+	}
+
+	file, err := os.Open(srcPath)
+	if err != nil {
+		return errors.Wrapf(err, "error opening file %s", srcPath)
+	}
+	defer file.Close()
+	if !archive.IsArchivePath(srcPath) {
+		tw := tar.NewWriter(os.Stdout)
+		hdr, err := tar.FileInfoHeader(srcfi, "")
+		if err != nil {
+			return err
+		}
+		err = tw.WriteHeader(hdr)
+		if err != nil {
+			return err
+		}
+		_, err = io.Copy(tw, file)
+		if err != nil {
+			return errors.Wrapf(err, "error streaming archive %s to Stdout", srcPath)
+		}
+		return nil
+	}
+
+	_, err = io.Copy(os.Stdout, file)
+	if err != nil {
+		return errors.Wrapf(err, "error streaming file to Stdout")
+	}
+	return nil
+}

docs/podman-cp.1.md

@@ -8,6 +8,7 @@ podman\-cp - Copy files/folders between a container and the local filesystem
 
 ## DESCRIPTION
 Copies the contents of **src_path** to the **dest_path**. You can copy from the containers's filesystem to the local machine or the reverse, from the local filesystem to the container.
+If - is specified for either the SRC_PATH or DEST_PATH, you can also stream a tar archive from STDIN or to STDOUT.
 
 The CONTAINER can be a running or stopped container. The **src_path** or **dest_path** can be a file or directory.
 
@@ -107,5 +108,7 @@ podman cp containerID:/home/myuser/. /home/myuser/
 
 podman cp --extract /home/myuser/myfiles.tar.gz containerID:/myfiles
 
+podman cp - containerID:/myfiles.tar.gz < myfiles.tar.gz
+
 ## SEE ALSO
 podman(1), podman-mount(1), podman-umount(1)

test/e2e/cp_test.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
 
 	. "github.com/containers/libpod/test/utils"
 	. "github.com/onsi/ginkgo"
@@ -58,21 +59,12 @@ var _ = Describe("Podman cp", func() {
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
 
-		session = podmanTest.Podman([]string{"start", "-a", name})
-		session.WaitWithDefaultTimeout()
-
-		Expect(session.ExitCode()).To(Equal(0))
-		Expect(session.OutputToString()).To(Equal("copy from host to container"))
-
 		session = podmanTest.Podman([]string{"cp", name + ":foo", filepath.Join(path, "cp_from_container")})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		c := exec.Command("cat", filepath.Join(path, "cp_from_container"))
-		output, err := c.Output()
-		if err != nil {
-			os.Exit(1)
-		}
-		Expect(string(output)).To(Equal("copy from host to container"))
+
+		os.Remove("cp_from_container")
+		os.Remove("cp_test.txt")
 	})
 
 	It("podman cp file to dir", func() {
@@ -89,28 +81,18 @@ var _ = Describe("Podman cp", func() {
 		session := podmanTest.Podman([]string{"create", ALPINE, "ls", "foodir/"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		session = podmanTest.Podman([]string{"ps", "-a", "-q"})
-		session.WaitWithDefaultTimeout()
-		Expect(session.ExitCode()).To(Equal(0))
 		name := session.OutputToString()
 
 		session = podmanTest.Podman([]string{"cp", filepath.Join(path, "cp_test.txt"), name + ":foodir/"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		session = podmanTest.Podman([]string{"start", "-a", name})
-		session.WaitWithDefaultTimeout()
-		Expect(session.ExitCode()).To(Equal(0))
-		Expect(session.OutputToString()).To(Equal("cp_test.txt"))
 
 		session = podmanTest.Podman([]string{"cp", name + ":foodir/cp_test.txt", path + "/receive/"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		c := exec.Command("cat", filepath.Join(path, "receive", "cp_test.txt"))
-		output, err := c.Output()
-		if err != nil {
-			os.Exit(1)
-		}
-		Expect(string(output)).To(Equal("copy from host to container directory"))
+
+		os.Remove("cp_test.txt")
+		os.RemoveAll("receive")
 	})
 
 	It("podman cp dir to dir", func() {
@@ -132,17 +114,50 @@ var _ = Describe("Podman cp", func() {
 		session = podmanTest.Podman([]string{"cp", testDirPath, name + ":/foodir"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		session = podmanTest.Podman([]string{"start", "-a", name})
-		session.WaitWithDefaultTimeout()
-		Expect(session.ExitCode()).To(Equal(0))
-		Expect(len(session.OutputToStringArray())).To(Equal(0))
 
 		session = podmanTest.Podman([]string{"cp", testDirPath, name + ":/foodir"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		session = podmanTest.Podman([]string{"start", "-a", name})
+
+		os.RemoveAll(testDirPath)
+	})
+
+	It("podman cp stdin/stdout", func() {
+		path, err := os.Getwd()
+		if err != nil {
+			os.Exit(1)
+		}
+		testDirPath := filepath.Join(path, "TestDir")
+		err = os.Mkdir(testDirPath, 0777)
+		if err != nil {
+			os.Exit(1)
+		}
+		cmd := exec.Command("tar", "-zcvf", "file.tar.gz", testDirPath)
+		_, err = cmd.Output()
+		if err != nil {
+			os.Exit(1)
+		}
+
+		session := podmanTest.Podman([]string{"create", ALPINE, "ls", "foo"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		Expect(session.OutputToString()).To(Equal("TestDir"))
+		name := session.OutputToString()
+
+		data, err := ioutil.ReadFile("foo.tar.gz")
+		reader := strings.NewReader(string(data))
+		cmd.Stdin = reader
+		session = podmanTest.Podman([]string{"cp", "-", name + ":/foo"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		session = podmanTest.Podman([]string{"cp", "file.tar.gz", name + ":/foo.tar.gz"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		session = podmanTest.Podman([]string{"cp", name + ":/foo.tar.gz", "-"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		os.Remove("file.tar.gz")
+		os.RemoveAll(testDirPath)
 	})
 })