podman image prune -- implement all flag

we now, by default, only prune dangling images.  if --all is passed, we
prune dangling images AND images that do not have an associated containers.

also went ahead and enabled the podman-remote image prune side of things.

Fixes: #2192

Signed-off-by: baude <bbaude@redhat.com>

1 files changed, 30 insertions, 9 deletions

diff --git a/libpod/image/prune.go b/libpod/image/prune.go
index 6a1f160d5..8602c222c 100644
--- a/libpod/image/prune.go
+++ b/libpod/image/prune.go
@@ -1,9 +1,11 @@
 package image
 
+import "github.com/pkg/errors"
+
 // GetPruneImages returns a slice of images that have no names/unused
-func (ir *Runtime) GetPruneImages() ([]*Image, error) {
+func (ir *Runtime) GetPruneImages(all bool) ([]*Image, error) {
 	var (
-		unamedImages []*Image
+		pruneImages []*Image
 	)
 	allImages, err := ir.GetImages()
 	if err != nil {
@@ -11,16 +13,35 @@ func (ir *Runtime) GetPruneImages() ([]*Image, error) {
 	}
 	for _, i := range allImages {
 		if len(i.Names()) == 0 {
-			unamedImages = append(unamedImages, i)
+			pruneImages = append(pruneImages, i)
 			continue
 		}
-		containers, err := i.Containers()
-		if err != nil {
-			return nil, err
+		if all {
+			containers, err := i.Containers()
+			if err != nil {
+				return nil, err
+			}
+			if len(containers) < 1 {
+				pruneImages = append(pruneImages, i)
+			}
 		}
-		if len(containers) < 1 {
-			unamedImages = append(unamedImages, i)
+	}
+	return pruneImages, nil
+}
+
+// PruneImages prunes dangling and optionally all unused images from the local
+// image store
+func (ir *Runtime) PruneImages(all bool) ([]string, error) {
+	var prunedCids []string
+	pruneImages, err := ir.GetPruneImages(all)
+	if err != nil {
+		return nil, errors.Wrap(err, "unable to get images to prune")
+	}
+	for _, p := range pruneImages {
+		if err := p.Remove(true); err != nil {
+			return nil, errors.Wrap(err, "failed to prune image")
 		}
+		prunedCids = append(prunedCids, p.ID())
 	}
-	return unamedImages, nil
+	return prunedCids, nil
 }