Merge pull request #10836 from Luap99/diff

podman diff accept two images or containers

cmd/podman/containers/diff.go

@@ -1,10 +1,11 @@
 package containers
 
 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/cmd/podman/validate"
+	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/pkg/domain/entities"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
@@ -13,11 +14,11 @@ import (
 var (
 	// podman container _diff_
 	diffCmd = &cobra.Command{
-		Use:               "diff [options] CONTAINER",
+		Use:               "diff [options] CONTAINER [CONTAINER]",
-		Args:              validate.IDOrLatestArgs,
+		Args:              diff.ValidateContainerDiffArgs,
 		Short:             "Inspect changes to the container's file systems",
-		Long:              `Displays changes to the container filesystem's'.  The container will be compared to its parent layer.`,
+		Long:              `Displays changes to the container filesystem's'.  The container will be compared to its parent layer or the second argument when given.`,
-		RunE:              diff,
+		RunE:              diffRun,
 		ValidArgsFunction: common.AutocompleteContainers,
 		Example: `podman container diff myCtr
   podman container diff -l --format json myCtr`,
@@ -33,41 +34,22 @@ func init() {
 
 	diffOpts = &entities.DiffOptions{}
 	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 {
+func diffRun(cmd *cobra.Command, args []string) error {
 	if len(args) == 0 && !diffOpts.Latest {
 		return errors.New("container must be specified: podman container diff [options [...]] ID-NAME")
 	}
-
+	diffOpts.Type = define.DiffContainer
-	var id string
+	return diff.Diff(cmd, args, *diffOpts)
-	if len(args) > 0 {
-		id = args[0]
-	}
-	results, err := registry.ContainerEngine().ContainerDiff(registry.GetContext(), id, *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)
 }

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/diff"
-	"github.com/containers/podman/v3/cmd/podman/images"
 	"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}",
+		Use:               "diff [options] {CONTAINER|IMAGE} [{CONTAINER|IMAGE}]",
-		Args:              validate.IDOrLatestArgs,
+		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 {
+func diffRun(cmd *cobra.Command, args []string) error {
-	// Latest implies looking for a container
+	diffOpts.Type = define.DiffAll
-	if diffOpts.Latest {
+	return diff.Diff(cmd, args, diffOpts)
-		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])
 }

cmd/podman/diff/diff.go

@@ -0,0 +1,79 @@
+package diff
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/containers/common/pkg/report"
+	"github.com/containers/podman/v3/cmd/podman/registry"
+	"github.com/containers/podman/v3/pkg/domain/entities"
+	"github.com/docker/docker/pkg/archive"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+)
+
+func Diff(cmd *cobra.Command, args []string, options entities.DiffOptions) error {
+	results, err := registry.ContainerEngine().Diff(registry.GetContext(), args, options)
+	if err != nil {
+		return err
+	}
+
+	switch {
+	case report.IsJSON(options.Format):
+		return changesToJSON(results)
+	case options.Format == "":
+		return changesToTable(results)
+	default:
+		return errors.New("only supported value for '--format' is 'json'")
+	}
+}
+
+type ChangesReportJSON struct {
+	Changed []string `json:"changed,omitempty"`
+	Added   []string `json:"added,omitempty"`
+	Deleted []string `json:"deleted,omitempty"`
+}
+
+func changesToJSON(diffs *entities.DiffReport) error {
+	body := ChangesReportJSON{}
+	for _, row := range diffs.Changes {
+		switch row.Kind {
+		case archive.ChangeAdd:
+			body.Added = append(body.Added, row.Path)
+		case archive.ChangeDelete:
+			body.Deleted = append(body.Deleted, row.Path)
+		case archive.ChangeModify:
+			body.Changed = append(body.Changed, row.Path)
+		default:
+			return errors.Errorf("output kind %q not recognized", row.Kind)
+		}
+	}
+
+	// Pull in configured json library
+	enc := json.NewEncoder(os.Stdout)
+	enc.SetIndent("", "     ")
+	return enc.Encode(body)
+}
+
+func changesToTable(diffs *entities.DiffReport) error {
+	for _, row := range diffs.Changes {
+		fmt.Fprintln(os.Stdout, row.String())
+	}
+	return nil
+}
+
+// IDOrLatestArgs used to validate a nameOrId was provided or the "--latest" flag
+func ValidateContainerDiffArgs(cmd *cobra.Command, args []string) error {
+	given, _ := cmd.Flags().GetBool("latest")
+	if len(args) > 0 && !given {
+		return cobra.RangeArgs(1, 2)(cmd, args)
+	}
+	if len(args) > 0 && given {
+		return errors.New("--latest and containers cannot be used together")
+	}
+	if len(args) == 0 && !given {
+		return errors.Errorf("%q requires a name, id, or the \"--latest\" flag", cmd.CommandPath())
+	}
+	return nil
+}

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",
+		Use:               "diff [options] IMAGE [IMAGE]",
-		Args:              cobra.ExactArgs(1),
+		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.`,
+		Long:              `Displays changes to the image's filesystem.  The image will be compared to its parent layer or the second argument when given.`,
-		RunE:              diff,
+		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 {
+func diffRun(cmd *cobra.Command, args []string) error {
-	if diffOpts.Latest {
+	diffOpts.Type = define.DiffImage
-		return errors.New("image diff does not support --latest")
+	return diff.Diff(cmd, args, *diffOpts)
-	}
-
-	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)
 }

docs/source/markdown/links/podman-container-diff.1

@@ -1 +0,0 @@
-.so man1/podman-diff.1

docs/source/markdown/podman-container-diff.1.md

@@ -0,0 +1,54 @@
+% podman-container-diff(1)
+
+## NAME
+podman\-container\-diff - Inspect changes on a container's filesystem
+
+## SYNOPSIS
+**podman container diff** [*options*] *container* [*container*]
+
+## DESCRIPTION
+Displays changes on a container's filesystem. The container will be compared to its parent layer or the second argument when given.
+
+The output is prefixed with the following symbols:
+
+| Symbol | Description |
+|--------|-------------|
+| A | A file or directory was added.   |
+| D | A file or directory was deleted. |
+| C | A file or directory was changed. |
+
+## OPTIONS
+
+#### **--format**
+
+Alter the output into a different format. The only valid format for **podman container diff** is `json`.
+
+#### **--latest**, **-l**
+
+Instead of providing the container name or ID, use the last created container. If you use methods other than Podman
+to run containers such as CRI-O, the last started container could be from either of those methods. (This option is not available with the remote Podman client)
+
+## EXAMPLE
+
+```
+# podman container diff container1
+C /usr
+C /usr/local
+C /usr/local/bin
+A /usr/local/bin/docker-entrypoint.sh
+```
+
+```
+$ podman container diff --format json container1 container2
+{
+     "added": [
+          "/test"
+     ]
+}
+```
+
+## SEE ALSO
+**[podman(1)](podman.1.md)**, **[podman-container(1)](podman-container.1.md)**
+
+## HISTORY
+July 2021, Originally compiled by Paul Holzinger <pholzing@redhat.com>

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

@@ -19,7 +19,7 @@ The container command allows you to manage containers
 | commit     | [podman-commit(1)](podman-commit.1.md)              | Create new image based on the changed container.                             |
 | cp         | [podman-cp(1)](podman-cp.1.md)                      | Copy files/folders between a container and the local filesystem.             |
 | create     | [podman-create(1)](podman-create.1.md)              | Create a new container.                                                      |
-| diff       | [podman-diff(1)](podman-diff.1.md)                  | Inspect changes on a container or image's filesystem.                        |
+| diff       | [podman-container-diff(1)](podman-container-diff.1.md) | Inspect changes on a container's filesystem                               |
 | exec       | [podman-exec(1)](podman-exec.1.md)                  | Execute a command in a running container.                                    |
 | exists     | [podman-container-exists(1)](podman-container-exists.1.md)  | Check if a container exists in local storage                         |
 | export     | [podman-export(1)](podman-export.1.md)              | Export a container's filesystem contents as a tar archive.                   |

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

@@ -4,18 +4,24 @@
 podman\-diff - Inspect changes on a container or image's filesystem
 
 ## SYNOPSIS
-**podman diff** [*options*] *name*
+**podman diff** [*options*] *container|image* [*container|image*]
-
-**podman container diff** [*options*] *name*
 
 ## DESCRIPTION
-Displays changes on a container or image's filesystem.  The container or image will be compared to its parent layer
+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.
+
+The output is prefixed with the following symbols:
+
+| Symbol | Description |
+|--------|-------------|
+| A | A file or directory was added.   |
+| D | A file or directory was deleted. |
+| C | A file or directory was changed. |
 
 ## OPTIONS
 
 #### **--format**
 
-Alter the output into a different format.  The only valid format for diff is `json`.
+Alter the output into a different format.  The only valid format for **podman diff** is `json`.
 
 #### **--latest**, **-l**
 
@@ -25,15 +31,12 @@ to run containers such as CRI-O, the last started container could be from either
 ## EXAMPLE
 
 ```
-# podman diff redis:alpine
+$ podman diff container1
-C /usr
+A /myscript.sh
-C /usr/local
-C /usr/local/bin
-A /usr/local/bin/docker-entrypoint.sh
 ```
 
 ```
-# podman diff --format json redis:alpine
+$ podman diff --format json myimage
 {
   "changed": [
     "/usr",
@@ -46,8 +49,13 @@ A /usr/local/bin/docker-entrypoint.sh
 }
 ```
 
+```
+$ podman diff container1 image1
+A /test
+```
+
 ## SEE ALSO
-podman(1)
+**[podman(1)](podman.1.md)**, **[podman-container-diff(1)](podman-container-diff.1.md)**, **[podman-image-diff(1)](podman-image-diff.1.md)**
 
 ## HISTORY
 August 2017, Originally compiled by Ryan Cole <rycole@redhat.com>

docs/source/markdown/podman-image-diff.1.md

@@ -4,21 +4,29 @@
 podman-image-diff - Inspect changes on an image's filesystem
 
 ## SYNOPSIS
-**podman image diff** [*options*] *name*
+**podman image diff** [*options*] *image* [*image*]
 
 ## DESCRIPTION
-Displays changes on a container or image's filesystem.  The container or image will be compared to its parent layer
+Displays changes on an image's filesystem.  The image will be compared to its parent layer or the second argument when given.
+
+The output is prefixed with the following symbols:
+
+| Symbol | Description |
+|--------|-------------|
+| A | A file or directory was added.   |
+| D | A file or directory was deleted. |
+| C | A file or directory was changed. |
 
 ## OPTIONS
 
 #### **--format**
 
-Alter the output into a different format.  The only valid format for diff is `json`.
+Alter the output into a different format.  The only valid format for **podman image diff** is `json`.
 
 ## EXAMPLE
 
 ```
-# podman diff redis:old redis:alpine
+$ podman diff redis:old
 C /usr
 C /usr/local
 C /usr/local/bin
@@ -26,7 +34,7 @@ A /usr/local/bin/docker-entrypoint.sh
 ```
 
 ```
-# podman diff --format json redis:old redis:alpine
+$ podman diff --format json redis:old redis:alpine
 {
   "changed": [
     "/usr",

libpod/container_internal_linux.go

@@ -923,7 +923,7 @@ func (c *Container) exportCheckpoint(options ContainerCheckpointOptions) error {
 	var addToTarFiles []string
 	if !options.IgnoreRootfs {
 		// To correctly track deleted files, let's go through the output of 'podman diff'
-		rootFsChanges, err := c.runtime.GetDiff("", c.ID())
+		rootFsChanges, err := c.runtime.GetDiff("", c.ID(), define.DiffContainer)
 		if err != nil {
 			return errors.Wrapf(err, "error exporting root file-system diff for %q", c.ID())
 		}

libpod/define/diff.go

@@ -0,0 +1,26 @@
+package define
+
+// extra type to use as enum
+type DiffType uint8
+
+const (
+	// only diff containers
+	DiffContainer DiffType = 1 << iota
+	// only diff images
+	DiffImage
+	// diff both containers and images
+	DiffAll DiffType = 0b11111111
+)
+
+func (d DiffType) String() string {
+	switch d {
+	case DiffAll:
+		return "all"
+	case DiffContainer:
+		return "container"
+	case DiffImage:
+		return "image"
+	default:
+		return "unknown"
+	}
+}

libpod/diff.go

@@ -2,6 +2,7 @@ package libpod
 
 import (
 	"github.com/containers/common/libimage"
+	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/libpod/layers"
 	"github.com/containers/storage/pkg/archive"
 	"github.com/pkg/errors"
@@ -21,14 +22,14 @@ var initInodes = map[string]bool{
 }
 
 // GetDiff returns the differences between the two images, layers, or containers
-func (r *Runtime) GetDiff(from, to string) ([]archive.Change, error) {
+func (r *Runtime) GetDiff(from, to string, diffType define.DiffType) ([]archive.Change, error) {
-	toLayer, err := r.getLayerID(to)
+	toLayer, err := r.getLayerID(to, diffType)
 	if err != nil {
 		return nil, err
 	}
 	fromLayer := ""
 	if from != "" {
-		fromLayer, err = r.getLayerID(from)
+		fromLayer, err = r.getLayerID(from, diffType)
 		if err != nil {
 			return nil, err
 		}
@@ -49,25 +50,30 @@ func (r *Runtime) GetDiff(from, to string) ([]archive.Change, error) {
 // GetLayerID gets a full layer id given a full or partial id
 // If the id matches a container or image, the id of the top layer is returned
 // If the id matches a layer, the top layer id is returned
-func (r *Runtime) getLayerID(id string) (string, error) {
+func (r *Runtime) getLayerID(id string, diffType define.DiffType) (string, error) {
-	var toLayer string
+	var lastErr error
-	toImage, _, err := r.libimageRuntime.LookupImage(id, &libimage.LookupImageOptions{IgnorePlatform: true})
+	if diffType&define.DiffImage == define.DiffImage {
-	if err == nil {
+		toImage, _, err := r.libimageRuntime.LookupImage(id, &libimage.LookupImageOptions{IgnorePlatform: true})
-		return toImage.TopLayer(), nil
+		if err == nil {
+			return toImage.TopLayer(), nil
+		}
+		lastErr = err
 	}
 
-	targetID, err := r.store.Lookup(id)
+	if diffType&define.DiffContainer == define.DiffContainer {
-	if err != nil {
+		toCtr, err := r.store.Container(id)
-		targetID = id
+		if err == nil {
-	}
+			return toCtr.LayerID, nil
-	toCtr, err := r.store.Container(targetID)
-	if err != nil {
-		toLayer, err = layers.FullID(r.store, targetID)
-		if err != nil {
-			return "", errors.Errorf("layer, image, or container %s does not exist", id)
 		}
-	} else {
+		lastErr = err
-		toLayer = toCtr.LayerID
 	}
-	return toLayer, nil
+
+	if diffType == define.DiffAll {
+		toLayer, err := layers.FullID(r.store, id)
+		if err == nil {
+			return toLayer, nil
+		}
+		lastErr = err
+	}
+	return "", errors.Wrapf(lastErr, "%s not found", id)
 }

pkg/api/handlers/compat/changes.go

@@ -4,14 +4,39 @@ import (
 	"net/http"
 
 	"github.com/containers/podman/v3/libpod"
+	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/pkg/api/handlers/utils"
+	"github.com/gorilla/schema"
+	"github.com/pkg/errors"
 )
 
 func Changes(w http.ResponseWriter, r *http.Request) {
+	decoder := r.Context().Value("decoder").(*schema.Decoder)
 	runtime := r.Context().Value("runtime").(*libpod.Runtime)
 
+	query := struct {
+		Parent   string `schema:"parent"`
+		DiffType string `schema:"diffType"`
+	}{}
+	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
+		utils.Error(w, "Something went wrong.", http.StatusBadRequest, errors.Wrapf(err, "failed to parse parameters for %s", r.URL.String()))
+		return
+	}
+	var diffType define.DiffType
+	switch query.DiffType {
+	case "", "all":
+		diffType = define.DiffAll
+	case "container":
+		diffType = define.DiffContainer
+	case "image":
+		diffType = define.DiffImage
+	default:
+		utils.Error(w, "Something went wrong.", http.StatusBadRequest, errors.Errorf("invalid diffType value %q", query.DiffType))
+		return
+	}
+
 	id := utils.GetName(r)
-	changes, err := runtime.GetDiff("", id)
+	changes, err := runtime.GetDiff(query.Parent, id, diffType)
 	if err != nil {
 		utils.InternalServerError(w, err)
 		return

pkg/api/server/register_containers.go

@@ -1505,6 +1505,15 @@ func (s *APIServer) registerContainersHandlers(r *mux.Router) error {
 	//    type: string
 	//    required: true
 	//    description: the name or id of the container
+	//  - in: query
+	//    name: parent
+	//    type: string
+	//    description: specify a second layer which is used to compare against it instead of the parent layer
+	//  - in: query
+	//    name: diffType
+	//    type: string
+	//    enum: [all, container, image]
+	//    description: select what you want to match, default is all
 	// responses:
 	//   200:
 	//     description: Array of Changes

pkg/api/server/register_images.go

@@ -1286,7 +1286,16 @@ func (s *APIServer) registerImagesHandlers(r *mux.Router) error {
 	//    name: name
 	//    type: string
 	//    required: true
-	//    description: the name or id of the container
+	//    description: the name or id of the image
+	//  - in: query
+	//    name: parent
+	//    type: string
+	//    description: specify a second layer which is used to compare against it instead of the parent layer
+	//  - in: query
+	//    name: diffType
+	//    type: string
+	//    enum: [all, container, image]
+	//    description: select what you want to match, default is all
 	// responses:
 	//   200:
 	//     description: Array of Changes

pkg/bindings/containers/diff.go

@@ -13,13 +13,16 @@ func Diff(ctx context.Context, nameOrID string, options *DiffOptions) ([]archive
 	if options == nil {
 		options = new(DiffOptions)
 	}
-	_ = options
 	conn, err := bindings.GetClient(ctx)
 	if err != nil {
 		return nil, err
 	}
 
-	response, err := conn.DoRequest(nil, http.MethodGet, "/containers/%s/changes", nil, nil, nameOrID)
+	params, err := options.ToParams()
+	if err != nil {
+		return nil, err
+	}
+	response, err := conn.DoRequest(nil, http.MethodGet, "/containers/%s/changes", params, nil, nameOrID)
 	if err != nil {
 		return nil, err
 	}

pkg/bindings/containers/types.go

@@ -70,7 +70,12 @@ type CreateOptions struct{}
 
 //go:generate go run ../generator/generator.go DiffOptions
 // DiffOptions are optional options for creating containers
-type DiffOptions struct{}
+type DiffOptions struct {
+	// By the default diff will compare against the parent layer. Change the Parent if you want to compare against something else.
+	Parent *string
+	// Change the type the backend should match. This can be set to "all", "container" or "image".
+	DiffType *string
+}
 
 //go:generate go run ../generator/generator.go ExecInspectOptions
 // ExecInspectOptions are optional options for inspecting

pkg/bindings/containers/types_diff_options.go

@@ -19,3 +19,35 @@ func (o *DiffOptions) Changed(fieldName string) bool {
 func (o *DiffOptions) ToParams() (url.Values, error) {
 	return util.ToParams(o)
 }
+
+// WithParent
+func (o *DiffOptions) WithParent(value string) *DiffOptions {
+	v := &value
+	o.Parent = v
+	return o
+}
+
+// GetParent
+func (o *DiffOptions) GetParent() string {
+	var parent string
+	if o.Parent == nil {
+		return parent
+	}
+	return *o.Parent
+}
+
+// WithDiffType
+func (o *DiffOptions) WithDiffType(value string) *DiffOptions {
+	v := &value
+	o.DiffType = v
+	return o
+}
+
+// GetDiffType
+func (o *DiffOptions) GetDiffType() string {
+	var diffType string
+	if o.DiffType == nil {
+		return diffType
+	}
+	return *o.DiffType
+}

pkg/bindings/images/types.go

@@ -16,6 +16,10 @@ type RemoveOptions struct {
 //go:generate go run ../generator/generator.go DiffOptions
 // DiffOptions are optional options image diffs
 type DiffOptions struct {
+	// By the default diff will compare against the parent layer. Change the Parent if you want to compare against something else.
+	Parent *string
+	// Change the type the backend should match. This can be set to "all", "container" or "image".
+	DiffType *string
 }
 
 //go:generate go run ../generator/generator.go ListOptions

pkg/bindings/images/types_diff_options.go

@@ -19,3 +19,35 @@ func (o *DiffOptions) Changed(fieldName string) bool {
 func (o *DiffOptions) ToParams() (url.Values, error) {
 	return util.ToParams(o)
 }
+
+// WithParent
+func (o *DiffOptions) WithParent(value string) *DiffOptions {
+	v := &value
+	o.Parent = v
+	return o
+}
+
+// GetParent
+func (o *DiffOptions) GetParent() string {
+	var parent string
+	if o.Parent == nil {
+		return parent
+	}
+	return *o.Parent
+}
+
+// WithDiffType
+func (o *DiffOptions) WithDiffType(value string) *DiffOptions {
+	v := &value
+	o.DiffType = v
+	return o
+}
+
+// GetDiffType
+func (o *DiffOptions) GetDiffType() string {
+	var diffType string
+	if o.DiffType == nil {
+		return diffType
+	}
+	return *o.DiffType
+}

pkg/domain/entities/engine_container.go

@@ -23,7 +23,6 @@ type ContainerEngine interface {
 	ContainerCopyFromArchive(ctx context.Context, nameOrID, path string, reader io.Reader, options CopyOptions) (ContainerCopyFunc, error)
 	ContainerCopyToArchive(ctx context.Context, nameOrID string, path string, writer io.Writer) (ContainerCopyFunc, error)
 	ContainerCreate(ctx context.Context, s *specgen.SpecGenerator) (*ContainerCreateReport, error)
-	ContainerDiff(ctx context.Context, nameOrID string, options DiffOptions) (*DiffReport, error)
 	ContainerExec(ctx context.Context, nameOrID string, options ExecOptions, streams define.AttachStreams) (int, error)
 	ContainerExecDetached(ctx context.Context, nameOrID string, options ExecOptions) (string, error)
 	ContainerExists(ctx context.Context, nameOrID string, options ContainerExistsOptions) (*BoolReport, error)
@@ -52,6 +51,7 @@ type ContainerEngine interface {
 	ContainerUnmount(ctx context.Context, nameOrIDs []string, options ContainerUnmountOptions) ([]*ContainerUnmountReport, error)
 	ContainerUnpause(ctx context.Context, namesOrIds []string, options PauseUnPauseOptions) ([]*PauseUnpauseReport, error)
 	ContainerWait(ctx context.Context, namesOrIds []string, options WaitOptions) ([]WaitReport, error)
+	Diff(ctx context.Context, namesOrIds []string, options DiffOptions) (*DiffReport, error)
 	Events(ctx context.Context, opts EventsOptions) error
 	GenerateSystemd(ctx context.Context, nameOrID string, opts GenerateSystemdOptions) (*GenerateSystemdReport, error)
 	GenerateKube(ctx context.Context, nameOrIDs []string, opts GenerateKubeOptions) (*GenerateKubeReport, error)

pkg/domain/entities/engine_image.go

@@ -10,7 +10,6 @@ import (
 type ImageEngine interface {
 	Build(ctx context.Context, containerFiles []string, opts BuildOptions) (*BuildReport, error)
 	Config(ctx context.Context) (*config.Config, error)
-	Diff(ctx context.Context, nameOrID string, options DiffOptions) (*DiffReport, error)
 	Exists(ctx context.Context, nameOrID string) (*BoolReport, error)
 	History(ctx context.Context, nameOrID string, opts ImageHistoryOptions) (*ImageHistoryReport, error)
 	Import(ctx context.Context, opts ImageImportOptions) (*ImageImportReport, error)

pkg/domain/entities/types.go

@@ -4,6 +4,7 @@ import (
 	"net"
 
 	buildahDefine "github.com/containers/buildah/define"
+	"github.com/containers/podman/v3/libpod/define"
 	"github.com/containers/podman/v3/libpod/events"
 	"github.com/containers/podman/v3/pkg/specgen"
 	"github.com/containers/storage/pkg/archive"
@@ -62,9 +63,10 @@ type InspectOptions struct {
 
 // All API and CLI diff commands and diff sub-commands use the same options
 type DiffOptions struct {
-	Format  string `json:",omitempty"` // CLI only
+	Format  string          `json:",omitempty"` // CLI only
-	Latest  bool   `json:",omitempty"` // API and CLI, only supported by containers
+	Latest  bool            `json:",omitempty"` // API and CLI, only supported by containers
-	Archive bool   `json:",omitempty"` // CLI only
+	Archive bool            `json:",omitempty"` // CLI only
+	Type    define.DiffType // Type which should be compared
 }
 
 // DiffReport provides changes for object

pkg/domain/infra/abi/containers.go

@@ -858,16 +858,26 @@ func (ic *ContainerEngine) ContainerListExternal(ctx context.Context) ([]entitie
 	return ps.GetExternalContainerLists(ic.Libpod)
 }
 
-// ContainerDiff provides changes to given container
+// Diff provides changes to given container
-func (ic *ContainerEngine) ContainerDiff(ctx context.Context, nameOrID string, opts entities.DiffOptions) (*entities.DiffReport, error) {
+func (ic *ContainerEngine) Diff(ctx context.Context, namesOrIDs []string, opts entities.DiffOptions) (*entities.DiffReport, error) {
+	var (
+		base   string
+		parent string
+	)
 	if opts.Latest {
 		ctnr, err := ic.Libpod.GetLatestContainer()
 		if err != nil {
 			return nil, errors.Wrap(err, "unable to get latest container")
 		}
-		nameOrID = ctnr.ID()
+		base = ctnr.ID()
 	}
-	changes, err := ic.Libpod.GetDiff("", nameOrID)
+	if len(namesOrIDs) > 0 {
+		base = namesOrIDs[0]
+		if len(namesOrIDs) > 1 {
+			parent = namesOrIDs[1]
+		}
+	}
+	changes, err := ic.Libpod.GetDiff(parent, base, opts.Type)
 	return &entities.DiffReport{Changes: changes}, err
 }
 

pkg/domain/infra/abi/images.go

@@ -403,14 +403,6 @@ func (ir *ImageEngine) Import(ctx context.Context, options entities.ImageImportO
 	return &entities.ImageImportReport{Id: imageID}, nil
 }
 
-func (ir *ImageEngine) Diff(_ context.Context, nameOrID string, _ entities.DiffOptions) (*entities.DiffReport, error) {
-	changes, err := ir.Libpod.GetDiff("", nameOrID)
-	if err != nil {
-		return nil, err
-	}
-	return &entities.DiffReport{Changes: changes}, nil
-}
-
 func (ir *ImageEngine) Search(ctx context.Context, term string, opts entities.ImageSearchOptions) ([]entities.ImageSearchReport, error) {
 	filter, err := libimage.ParseSearchFilter(opts.Filters)
 	if err != nil {

pkg/domain/infra/tunnel/containers.go

@@ -765,8 +765,18 @@ func (ic *ContainerEngine) ContainerRun(ctx context.Context, opts entities.Conta
 	return &report, err
 }
 
-func (ic *ContainerEngine) ContainerDiff(ctx context.Context, nameOrID string, _ entities.DiffOptions) (*entities.DiffReport, error) {
+func (ic *ContainerEngine) Diff(ctx context.Context, namesOrIDs []string, opts entities.DiffOptions) (*entities.DiffReport, error) {
-	changes, err := containers.Diff(ic.ClientCtx, nameOrID, nil)
+	var base string
+	options := new(containers.DiffOptions).WithDiffType(opts.Type.String())
+	if len(namesOrIDs) > 0 {
+		base = namesOrIDs[0]
+		if len(namesOrIDs) > 1 {
+			options.WithParent(namesOrIDs[1])
+		}
+	} else {
+		return nil, errors.New("no arguments for diff")
+	}
+	changes, err := containers.Diff(ic.ClientCtx, base, options)
 	return &entities.DiffReport{Changes: changes}, err
 }
 

pkg/domain/infra/tunnel/images.go

@@ -299,16 +299,6 @@ func (ir *ImageEngine) Save(ctx context.Context, nameOrID string, tags []string,
 	return utils2.UntarToFileSystem(opts.Output, f, nil)
 }
 
-// Diff reports the changes to the given image
-func (ir *ImageEngine) Diff(ctx context.Context, nameOrID string, _ entities.DiffOptions) (*entities.DiffReport, error) {
-	options := new(images.DiffOptions)
-	changes, err := images.Diff(ir.ClientCtx, nameOrID, options)
-	if err != nil {
-		return nil, err
-	}
-	return &entities.DiffReport{Changes: changes}, nil
-}
-
 func (ir *ImageEngine) Search(ctx context.Context, term string, opts entities.ImageSearchOptions) ([]entities.ImageSearchReport, error) {
 	mappedFilters := make(map[string][]string)
 	filters, err := libimage.ParseSearchFilter(opts.Filters)

test/e2e/diff_test.go

@@ -1,10 +1,12 @@
 package integration
 
 import (
+	"fmt"
 	"os"
 	"sort"
 
 	. "github.com/containers/podman/v3/test/utils"
+	"github.com/containers/storage/pkg/stringid"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 )
@@ -40,13 +42,6 @@ var _ = Describe("Podman diff", func() {
 		Expect(len(session.OutputToStringArray())).To(BeNumerically(">", 0))
 	})
 
-	It("podman container diff of image", func() {
-		session := podmanTest.Podman([]string{"container", "diff", ALPINE})
-		session.WaitWithDefaultTimeout()
-		Expect(session.ExitCode()).To(Equal(0))
-		Expect(len(session.OutputToStringArray())).To(BeNumerically(">", 0))
-	})
-
 	It("podman diff bogus image", func() {
 		session := podmanTest.Podman([]string{"diff", "1234"})
 		session.WaitWithDefaultTimeout()
@@ -84,7 +79,11 @@ var _ = Describe("Podman diff", func() {
 		session := podmanTest.Podman([]string{"run", "--name", "diff-test", ALPINE, "touch", "/tmp/diff-test"})
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
-		session = podmanTest.Podman([]string{"diff", "diff-test"})
+		if !IsRemote() {
+			session = podmanTest.Podman([]string{"diff", "-l"})
+		} else {
+			session = podmanTest.Podman([]string{"diff", "diff-test"})
+		}
 		session.WaitWithDefaultTimeout()
 		containerDiff := session.OutputToStringArray()
 		sort.Strings(containerDiff)
@@ -92,4 +91,101 @@ var _ = Describe("Podman diff", func() {
 		Expect(session.LineInOutputContains("A /tmp/diff-test")).To(BeTrue())
 		Expect(session.ExitCode()).To(Equal(0))
 	})
+
+	It("podman image diff", func() {
+		file1 := "/" + stringid.GenerateNonCryptoID()
+		file2 := "/" + stringid.GenerateNonCryptoID()
+		file3 := "/" + stringid.GenerateNonCryptoID()
+
+		// Create container image with the files
+		containerfile := fmt.Sprintf(`
+FROM  %s
+RUN touch %s
+RUN touch %s
+RUN touch %s`, ALPINE, file1, file2, file3)
+
+		image := "podman-diff-test"
+		podmanTest.BuildImage(containerfile, image, "true")
+
+		// build a second image which used as base to compare against
+		// using ALPINE does not work in CI, most likely due the extra vfs.imagestore
+		containerfile = fmt.Sprintf(`
+FROM  %s
+RUN echo test
+`, ALPINE)
+		baseImage := "base-image"
+		podmanTest.BuildImage(containerfile, baseImage, "true")
+
+		session := podmanTest.Podman([]string{"image", "diff", image})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(BeNumerically("==", 1))
+		Expect(session.OutputToString()).To(Equal("A " + file3))
+
+		session = podmanTest.Podman([]string{"image", "diff", image, baseImage})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(BeNumerically("==", 4))
+		Expect(session.LineInOutputContains("A " + file1)).To(BeTrue())
+		Expect(session.LineInOutputContains("A " + file2)).To(BeTrue())
+		Expect(session.LineInOutputContains("A " + file3)).To(BeTrue())
+	})
+
+	It("podman image diff of single image", func() {
+		session := podmanTest.Podman([]string{"image", "diff", BB})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(BeNumerically(">", 0))
+	})
+
+	It("podman image diff bogus image", func() {
+		session := podmanTest.Podman([]string{"image", "diff", "1234", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+	})
+
+	It("podman image diff of the same image", func() {
+		session := podmanTest.Podman([]string{"image", "diff", ALPINE, ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(BeNumerically("==", 0))
+	})
+
+	It("podman diff container and image with same name", func() {
+		imagefile := "/" + stringid.GenerateNonCryptoID()
+		confile := "/" + stringid.GenerateNonCryptoID()
+
+		// Create container image with the files
+		containerfile := fmt.Sprintf(`
+FROM  %s
+RUN touch %s`, ALPINE, imagefile)
+
+		name := "podman-diff-test"
+		podmanTest.BuildImage(containerfile, name, "false")
+
+		session := podmanTest.Podman([]string{"run", "--name", name, ALPINE, "touch", confile})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		// podman diff prefers image over container when they have the same name
+		session = podmanTest.Podman([]string{"diff", name})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(BeNumerically("==", 2))
+		Expect(session.OutputToString()).To(ContainSubstring(imagefile))
+
+		session = podmanTest.Podman([]string{"image", "diff", name})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(BeNumerically("==", 2))
+		Expect(session.OutputToString()).To(ContainSubstring(imagefile))
+
+		// container diff has to show the container
+		session = podmanTest.Podman([]string{"container", "diff", name})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(BeNumerically("==", 2))
+		Expect(session.OutputToString()).To(ContainSubstring(confile))
+	})
+
 })