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, 10 insertions, 30 deletions

diff --git a/cmd/podman/images/diff.go b/cmd/podman/images/diff.go
index 2e883d7ae..825aab362 100644
--- a/cmd/podman/images/diff.go
+++ b/cmd/podman/images/diff.go
@@ -1,11 +1,11 @@
 package images
 
 import (
-	"github.com/containers/common/pkg/report"
 	"github.com/containers/podman/v3/cmd/podman/common"
+	"github.com/containers/podman/v3/cmd/podman/diff"
 	"github.com/containers/podman/v3/cmd/podman/registry"
+	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/pkg/domain/entities"
-	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
@@ -13,11 +13,11 @@ import (
 var (
 	// podman container _inspect_
 	diffCmd = &cobra.Command{
-		Use:               "diff [options] IMAGE",
-		Args:              cobra.ExactArgs(1),
+		Use:               "diff [options] IMAGE [IMAGE]",
+		Args:              cobra.RangeArgs(1, 2),
 		Short:             "Inspect changes to the image's file systems",
-		Long:              `Displays changes to the image's filesystem.  The image will be compared to its parent layer.`,
-		RunE:              diff,
+		Long:              `Displays changes to the image's filesystem.  The image will be compared to its parent layer or the second argument when given.`,
+		RunE:              diffRun,
 		ValidArgsFunction: common.AutocompleteImages,
 		Example: `podman image diff myImage
   podman image diff --format json redis:alpine`,
@@ -39,31 +39,11 @@ func diffFlags(flags *pflag.FlagSet) {
 	_ = flags.MarkDeprecated("archive", "Provided for backwards compatibility, has no impact on output.")
 
 	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))
 }
 
-func diff(cmd *cobra.Command, args []string) error {
-	if diffOpts.Latest {
-		return errors.New("image diff does not support --latest")
-	}
-
-	results, err := registry.ImageEngine().Diff(registry.GetContext(), args[0], *diffOpts)
-	if err != nil {
-		return err
-	}
-
-	switch {
-	case report.IsJSON(diffOpts.Format):
-		return common.ChangesToJSON(results)
-	case diffOpts.Format == "":
-		return common.ChangesToTable(results)
-	default:
-		return errors.New("only supported value for '--format' is 'json'")
-	}
-}
-
-func Diff(cmd *cobra.Command, args []string, options entities.DiffOptions) error {
-	diffOpts = &options
-	return diff(cmd, args)
+func diffRun(cmd *cobra.Command, args []string) error {
+	diffOpts.Type = define.DiffImage
+	return diff.Diff(cmd, args, *diffOpts)
 }