support multi-image (docker) archives

Support loading and saving tarballs with more than one image.
Add a new `/libpod/images/export` endpoint to the rest API to
allow for exporting/saving multiple images into an archive.

Note that a non-release version of containers/image is vendored.
A release version must be vendored before cutting a new Podman
release.  We force the containers/image version via a replace in
the go.mod file; this way go won't try to match the versions.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

test/e2e/load_test.go

@@ -269,4 +269,12 @@ var _ = Describe("Podman load", func() {
 		result.WaitWithDefaultTimeout()
 		Expect(result.ExitCode()).To(Equal(0))
 	})
+
+	It("podman load multi-image archive", func() {
+		result := podmanTest.PodmanNoCache([]string{"load", "-i", "./testdata/image/docker-two-images.tar.xz"})
+		result.WaitWithDefaultTimeout()
+		Expect(result.ExitCode()).To(Equal(0))
+		Expect(result.LineInOutputContains("example.com/empty:latest")).To(BeTrue())
+		Expect(result.LineInOutputContains("example.com/empty/but:different")).To(BeTrue())
+	})
 })

test/e2e/pull_test.go

@@ -251,6 +251,49 @@ var _ = Describe("Podman pull", func() {
 		session = podmanTest.PodmanNoCache([]string{"rmi", "alpine"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
+
+		// Pulling a multi-image archive without further specifying
+		// which image _must_ error out. Pulling is restricted to one
+		// image.
+		session = podmanTest.PodmanNoCache([]string{"pull", fmt.Sprintf("docker-archive:./testdata/image/docker-two-images.tar.xz")})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+		expectedError := "Unexpected tar manifest.json: expected 1 item, got 2"
+		found, _ := session.ErrorGrepString(expectedError)
+		Expect(found).To(Equal(true))
+
+		// Now pull _one_ image from a multi-image archive via the name
+		// and index syntax.
+		session = podmanTest.PodmanNoCache([]string{"pull", fmt.Sprintf("docker-archive:./testdata/image/docker-two-images.tar.xz:@0")})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		session = podmanTest.PodmanNoCache([]string{"pull", fmt.Sprintf("docker-archive:./testdata/image/docker-two-images.tar.xz:example.com/empty:latest")})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		session = podmanTest.PodmanNoCache([]string{"pull", fmt.Sprintf("docker-archive:./testdata/image/docker-two-images.tar.xz:@1")})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		session = podmanTest.PodmanNoCache([]string{"pull", fmt.Sprintf("docker-archive:./testdata/image/docker-two-images.tar.xz:example.com/empty/but:different")})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		// Now check for some errors.
+		session = podmanTest.PodmanNoCache([]string{"pull", fmt.Sprintf("docker-archive:./testdata/image/docker-two-images.tar.xz:foo.com/does/not/exist:latest")})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+		expectedError = "Tag \"foo.com/does/not/exist:latest\" not found"
+		found, _ = session.ErrorGrepString(expectedError)
+		Expect(found).To(Equal(true))
+
+		session = podmanTest.PodmanNoCache([]string{"pull", fmt.Sprintf("docker-archive:./testdata/image/docker-two-images.tar.xz:@2")})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+		expectedError = "Invalid source index @2, only 2 manifest items available"
+		found, _ = session.ErrorGrepString(expectedError)
+		Expect(found).To(Equal(true))
 	})
 
 	It("podman pull from oci-archive", func() {

test/e2e/save_test.go

@@ -128,4 +128,51 @@ var _ = Describe("Podman save", func() {
 		save.WaitWithDefaultTimeout()
 		Expect(save.ExitCode()).To(Equal(0))
 	})
+
+	It("podman save --multi-image-archive (tagged images)", func() {
+		multiImageSave(podmanTest, RESTORE_IMAGES)
+	})
+
+	It("podman save --multi-image-archive (untagged images)", func() {
+		// Refer to images via ID instead of tag.
+		session := podmanTest.PodmanNoCache([]string{"images", "--format", "{{.ID}}"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		ids := session.OutputToStringArray()
+
+		Expect(len(RESTORE_IMAGES), len(ids))
+		multiImageSave(podmanTest, ids)
+	})
 })
+
+// Create a multi-image archive, remove all images, load it and
+// make sure that all images are (again) present.
+func multiImageSave(podmanTest *PodmanTestIntegration, images []string) {
+	// Create the archive.
+	outfile := filepath.Join(podmanTest.TempDir, "temp.tar")
+	session := podmanTest.PodmanNoCache(append([]string{"save", "-o", outfile, "--multi-image-archive"}, images...))
+	session.WaitWithDefaultTimeout()
+	Expect(session.ExitCode()).To(Equal(0))
+
+	// Remove all images.
+	session = podmanTest.PodmanNoCache([]string{"rmi", "-af"})
+	session.WaitWithDefaultTimeout()
+	Expect(session.ExitCode()).To(Equal(0))
+
+	// Now load the archive.
+	session = podmanTest.PodmanNoCache([]string{"load", "-i", outfile})
+	session.WaitWithDefaultTimeout()
+	Expect(session.ExitCode()).To(Equal(0))
+	// Grep for each image in the `podman load` output.
+	for _, image := range images {
+		found, _ := session.GrepString(image)
+		Expect(found).Should(BeTrue())
+	}
+
+	// Make sure that each image has really been loaded.
+	for _, image := range images {
+		session = podmanTest.PodmanNoCache([]string{"image", "exists", image})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+	}
+}

test/e2e/testdata/image

@@ -0,0 +1 @@
+../../../libpod/image/testdata/