remote load: check if input is directory

The remote client does not support loading directories yet.  To prevent
confusing error messages and to make the behaviour more explicit, check
if the input points to a directory and throw an error if needed.

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

docs/source/markdown/podman-load.1.md

@@ -9,9 +9,11 @@ podman\-load - Load an image from a container image archive into container stora
 **podman image load** [*options*] [*name*[:*tag*]]
 
 ## DESCRIPTION
-**podman load** loads an image from either an **oci-archive** or **docker-archive** stored on the local machine into container storage. **podman load** reads from stdin by default or a file if the **input** option is set.
+**podman load** loads an image from either an **oci-archive** or a **docker-archive** stored on the local machine into container storage. **podman load** reads from stdin by default or a file if the **input** option is set.
 You can also specify a name for the image if the archive does not contain a named reference, of if you want an additional name for the local image.
 
+The local client further supports loading an **oci-dir** or a **docker-dir** as created with **podman save** (1).
+
 The **quiet** option suppresses the progress output when set.
 Note: `:` is a restricted character and cannot be part of the file name.
 

pkg/domain/infra/tunnel/images.go

@@ -199,6 +199,13 @@ func (ir *ImageEngine) Load(ctx context.Context, opts entities.ImageLoadOptions)
 		return nil, err
 	}
 	defer f.Close()
+	fInfo, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	if fInfo.IsDir() {
+		return nil, errors.Errorf("remote client supports archives only but %q is a directory", opts.Input)
+	}
 	ref := opts.Name
 	if len(opts.Tag) > 0 {
 		ref += ":" + opts.Tag

test/e2e/load_test.go

@@ -139,6 +139,22 @@ var _ = Describe("Podman load", func() {
 		Expect(result.ExitCode()).To(Equal(0))
 	})
 
+	It("podman-remote load directory", func() {
+		// Remote-only test looking for the specific remote error
+		// message when trying to load a directory.
+		if !IsRemote() {
+			Skip("Remote only test")
+		}
+
+		result := podmanTest.Podman([]string{"load", "-i", podmanTest.TempDir})
+		result.WaitWithDefaultTimeout()
+		Expect(result.ExitCode()).To(Equal(125))
+
+		errMsg := fmt.Sprintf("remote client supports archives only but %q is a directory", podmanTest.TempDir)
+		found, _ := result.ErrorGrepString(errMsg)
+		Expect(found).Should(BeTrue())
+	})
+
 	It("podman load bogus file", func() {
 		save := podmanTest.PodmanNoCache([]string{"load", "-i", "foobar.tar"})
 		save.WaitWithDefaultTimeout()