podman diff accept two images or containers

First, make podman diff accept optionally a second argument. This allows
the user to specify a second image/container to compare the first with.
If it is not set the parent layer will be used as before.

Second, podman container diff should only use containers and podman
image diff should only use images. Previously, podman container diff
would use the image when both an image and container with this name
exists.

To make this work two new parameters have been added to the api. If they
are not used the previous behaviour is used. The same applies to the
bindings.

Fixes #10649

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

1 files changed, 11 insertions, 31 deletions

diff --git a/cmd/podman/diff.go b/cmd/podman/diff.go
index e2a3cd727..c592b6a22 100644
--- a/cmd/podman/diff.go
+++ b/cmd/podman/diff.go
@@ -1,13 +1,11 @@
 package main
 
 import (
-	"fmt"
-
 	"github.com/containers/podman/v3/cmd/podman/common"
-	"github.com/containers/podman/v3/cmd/podman/containers"
-	"github.com/containers/podman/v3/cmd/podman/images"
+	"github.com/containers/podman/v3/cmd/podman/diff"
 	"github.com/containers/podman/v3/cmd/podman/registry"
 	"github.com/containers/podman/v3/cmd/podman/validate"
+	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/pkg/domain/entities"
 	"github.com/spf13/cobra"
 )
@@ -16,13 +14,13 @@ import (
 
 var (
 	// Command: podman _diff_ Object_ID
-	diffDescription = `Displays changes on a container or image's filesystem.  The container or image will be compared to its parent layer.`
+	diffDescription = `Displays changes on a container or image's filesystem.  The container or image will be compared to its parent layer or the second argument when given.`
 	diffCmd         = &cobra.Command{
-		Use:               "diff [options] {CONTAINER|IMAGE}",
-		Args:              validate.IDOrLatestArgs,
+		Use:               "diff [options] {CONTAINER|IMAGE} [{CONTAINER|IMAGE}]",
+		Args:              diff.ValidateContainerDiffArgs,
 		Short:             "Display the changes to the object's file system",
 		Long:              diffDescription,
-		RunE:              diff,
+		RunE:              diffRun,
 		ValidArgsFunction: common.AutocompleteContainersAndImages,
 		Example: `podman diff imageID
   podman diff ctrID
@@ -37,36 +35,18 @@ func init() {
 		Command: diffCmd,
 	})
 	flags := diffCmd.Flags()
+	// FIXME: Why does this exists? It is not used anywhere.
 	flags.BoolVar(&diffOpts.Archive, "archive", true, "Save the diff as a tar archive")
 	_ = flags.MarkHidden("archive")
 
 	formatFlagName := "format"
-	flags.StringVar(&diffOpts.Format, formatFlagName, "", "Change the output format")
+	flags.StringVar(&diffOpts.Format, formatFlagName, "", "Change the output format (json)")
 	_ = diffCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 
 	validate.AddLatestFlag(diffCmd, &diffOpts.Latest)
 }
 
-func diff(cmd *cobra.Command, args []string) error {
-	// Latest implies looking for a container
-	if diffOpts.Latest {
-		return containers.Diff(cmd, args, diffOpts)
-	}
-
-	options := entities.ContainerExistsOptions{
-		External: true,
-	}
-	if found, err := registry.ContainerEngine().ContainerExists(registry.GetContext(), args[0], options); err != nil {
-		return err
-	} else if found.Value {
-		return containers.Diff(cmd, args, diffOpts)
-	}
-
-	if found, err := registry.ImageEngine().Exists(registry.GetContext(), args[0]); err != nil {
-		return err
-	} else if found.Value {
-		return images.Diff(cmd, args, diffOpts)
-	}
-
-	return fmt.Errorf("%s not found on system", args[0])
+func diffRun(cmd *cobra.Command, args []string) error {
+	diffOpts.Type = define.DiffAll
+	return diff.Diff(cmd, args, diffOpts)
 }