image prune skips images with child images.

While image build process, intermediate images are created.
These images are also used as cache images, used in rebuilding
same images. This fix the deletion of cache images.

Signed-off-by: Kunal Kushwaha <kunal.kushwaha@gmail.com>

1 files changed, 16 insertions, 6 deletions

diff --git a/libpod/image/prune.go b/libpod/image/prune.go
index 3afff22af..3b4ea74c4 100644
--- a/libpod/image/prune.go
+++ b/libpod/image/prune.go
@@ -57,7 +57,7 @@ func generatePruneFilterFuncs(filter, filterValue string) (ImageFilter, error) {
 }
 
 // GetPruneImages returns a slice of images that have no names/unused
-func (ir *Runtime) GetPruneImages(all bool, filterFuncs []ImageFilter) ([]*Image, error) {
+func (ir *Runtime) GetPruneImages(ctx context.Context, all bool, filterFuncs []ImageFilter) ([]*Image, error) {
 	var (
 		pruneImages []*Image
 	)
@@ -74,10 +74,6 @@ func (ir *Runtime) GetPruneImages(all bool, filterFuncs []ImageFilter) ([]*Image
 			}
 		}
 
-		if len(i.Names()) == 0 {
-			pruneImages = append(pruneImages, i)
-			continue
-		}
 		if all {
 			containers, err := i.Containers()
 			if err != nil {
@@ -85,8 +81,22 @@ func (ir *Runtime) GetPruneImages(all bool, filterFuncs []ImageFilter) ([]*Image
 			}
 			if len(containers) < 1 {
 				pruneImages = append(pruneImages, i)
+				continue
 			}
 		}
+
+		//skip the cache or intermediate images
+		intermediate, err := i.Intermediate(ctx)
+		if err != nil {
+			return nil, err
+		}
+		if intermediate {
+			continue
+		}
+
+		if i.Dangling() {
+			pruneImages = append(pruneImages, i)
+		}
 	}
 	return pruneImages, nil
 }
@@ -111,7 +121,7 @@ func (ir *Runtime) PruneImages(ctx context.Context, all bool, filter []string) (
 		filterFuncs = append(filterFuncs, generatedFunc)
 	}
 
-	pruneImages, err := ir.GetPruneImages(all, filterFuncs)
+	pruneImages, err := ir.GetPruneImages(ctx, all, filterFuncs)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to get images to prune")
 	}