Added dry run option in removeImage

Signed-off-by: Mark Zvenigorodsky <mark.zvenigorodsky@gmail.com>

Author: zvenigorodsky

common/libimage/image.go

@@ -331,7 +331,7 @@ func (i *Image) Containers() ([]string, error) {
 
 // removeContainers removes all containers using the image.
 func (i *Image) removeContainers(options *RemoveImagesOptions) error {
-	if !options.Force && !options.ExternalContainers {
+	if (!options.Force && !options.ExternalContainers) || options.DryRun {
 		// Nothing to do.
 		return nil
 	}
@@ -487,13 +487,15 @@ func (i *Image) removeRecursive(ctx context.Context, rmMap map[string]*RemoveIma
 
 		// Only try to untag if we know it's not an ID or digest.
 		if !byID && !byDigest {
-			if err := i.Untag(referencedBy); handleError(err) != nil {
-				return processedIDs, err
+			if !options.DryRun {
+				if err := i.Untag(referencedBy); handleError(err) != nil {
+					return processedIDs, err
+				}
+				report.Untagged = append(report.Untagged, referencedBy)
+
+				// If there's still tags left, we cannot delete it.
+				skipRemove = len(i.Names()) > 0
 			}
-			report.Untagged = append(report.Untagged, referencedBy)
-
-			// If there's still tags left, we cannot delete it.
-			skipRemove = len(i.Names()) > 0
 		}
 	}
 
@@ -528,11 +530,13 @@ func (i *Image) removeRecursive(ctx context.Context, rmMap map[string]*RemoveIma
 		parent = nil
 	}
 
-	if _, err := i.runtime.store.DeleteImage(i.ID(), true); handleError(err) != nil {
-		if errors.Is(err, storage.ErrImageUsedByContainer) {
-			err = fmt.Errorf("%w: consider listing external containers and force-removing image", err)
+	if !options.DryRun {
+		if _, err := i.runtime.store.DeleteImage(i.ID(), true); handleError(err) != nil {
+			if errors.Is(err, storage.ErrImageUsedByContainer) {
+				err = fmt.Errorf("%w: consider listing external containers and force-removing image", err)
+			}
+			return processedIDs, err
 		}
-		return processedIDs, err
 	}
 
 	report.Untagged = append(report.Untagged, i.Names()...)

common/libimage/runtime.go

@@ -701,6 +701,9 @@ type RemoveImagesOptions struct {
 	WithSize bool
 	// NoPrune will not remove dangling images
 	NoPrune bool
+	// DryRun will not remove images but will display image id's
+	// that would have been removed
+	DryRun bool
 }
 
 // RemoveImages removes images specified by names.  If no names are specified,