Merge pull request #10836 from Luap99/diff

podman diff accept two images or containers

3 files changed, 52 insertions, 20 deletions

diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 25db3cff0..850af235f 100644
--- a/libpod/container_internal_linux.go
+++ b/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())
 		}
diff --git a/libpod/define/diff.go b/libpod/define/diff.go
new file mode 100644
index 000000000..ee492eb3a
--- /dev/null
+++ b/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"
+	}
+}
diff --git a/libpod/diff.go b/libpod/diff.go
index c5a53478b..5bd162e7b 100644
--- a/libpod/diff.go
+++ b/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) {
-	toLayer, err := r.getLayerID(to)
+func (r *Runtime) GetDiff(from, to string, diffType define.DiffType) ([]archive.Change, error) {
+	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) {
-	var toLayer string
-	toImage, _, err := r.libimageRuntime.LookupImage(id, &libimage.LookupImageOptions{IgnorePlatform: true})
-	if err == nil {
-		return toImage.TopLayer(), nil
+func (r *Runtime) getLayerID(id string, diffType define.DiffType) (string, error) {
+	var lastErr error
+	if diffType&define.DiffImage == define.DiffImage {
+		toImage, _, err := r.libimageRuntime.LookupImage(id, &libimage.LookupImageOptions{IgnorePlatform: true})
+		if err == nil {
+			return toImage.TopLayer(), nil
+		}
+		lastErr = err
 	}
 
-	targetID, err := r.store.Lookup(id)
-	if err != nil {
-		targetID = id
+	if diffType&define.DiffContainer == define.DiffContainer {
+		toCtr, err := r.store.Container(id)
+		if err == nil {
+			return toCtr.LayerID, nil
+		}
+		lastErr = err
 	}
-	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)
+
+	if diffType == define.DiffAll {
+		toLayer, err := layers.FullID(r.store, id)
+		if err == nil {
+			return toLayer, nil
 		}
-	} else {
-		toLayer = toCtr.LayerID
+		lastErr = err
 	}
-	return toLayer, nil
+	return "", errors.Wrapf(lastErr, "%s not found", id)
 }