make prune to remove dangling images only

Signed-off-by: Han Xu <[email protected]>

Author: suyanhanx

cmd/nerdctl/image_prune.go

@@ -71,8 +71,15 @@ func imagePruneAction(cmd *cobra.Command, _ []string) error {
 	}
 
 	if !options.Force {
-		var confirm string
-		msg := "This will remove all images without at least one container associated to them."
+		var (
+			confirm string
+			msg     string
+		)
+		if !options.All {
+			msg = "This will remove all dangling images."
+		} else {
+			msg = "This will remove all images without at least one container associated to them."
+		}
 		msg += "\nAre you sure you want to continue? [y/N] "
 
 		fmt.Fprintf(cmd.OutOrStdout(), "WARNING! %s", msg)

cmd/nerdctl/image_prune_test.go

@@ -29,9 +29,9 @@ func TestImagePrune(t *testing.T) {
 	testutil.RequiresBuild(t)
 
 	base := testutil.NewBase(t)
-	defer base.Cmd("builder", "prune").Run()
+	defer base.Cmd("builder", "prune").AssertOK()
 	imageName := testutil.Identifier(t)
-	defer base.Cmd("rmi", imageName).Run()
+	defer base.Cmd("rmi", imageName).AssertOK()
 
 	dockerfile := fmt.Sprintf(`FROM %s
 	CMD ["echo", "nerdctl-test-image-prune"]`, testutil.CommonImage)
@@ -40,12 +40,36 @@ func TestImagePrune(t *testing.T) {
 	assert.NilError(t, err)
 	defer os.RemoveAll(buildCtx)
 
+	base.Cmd("build", buildCtx).AssertOK()
 	base.Cmd("build", "-t", imageName, buildCtx).AssertOK()
+	base.Cmd("images").AssertOutContainsAll(imageName, "<none>")
+
+	base.Cmd("image", "prune", "--force").AssertNoOut(imageName)
+	base.Cmd("images").AssertNoOut("<none>")
+	base.Cmd("images").AssertOutContains(imageName)
+}
+
+func TestImagePruneAll(t *testing.T) {
+	testutil.RequiresBuild(t)
+
+	base := testutil.NewBase(t)
+	defer base.Cmd("builder", "prune").AssertOK()
+	imageName := testutil.Identifier(t)
+
+	dockerfile := fmt.Sprintf(`FROM %s
+	CMD ["echo", "nerdctl-test-image-prune"]`, testutil.CommonImage)
+
+	buildCtx, err := createBuildContext(dockerfile)
+	assert.NilError(t, err)
+	defer os.RemoveAll(buildCtx)
+
+	base.Cmd("build", "-t", imageName, buildCtx).AssertOK()
+	// The following commands will clean up all images, so it should fail at this point.
+	defer base.Cmd("rmi", imageName).AssertFail()
 	base.Cmd("images").AssertOutContains(imageName)
 
 	tID := testutil.Identifier(t)
 	base.Cmd("run", "--name", tID, imageName).AssertOK()
-	defer base.Cmd("rm", "-f", tID).Run()
 	base.Cmd("image", "prune", "--force", "--all").AssertNoOut(imageName)
 	base.Cmd("images").AssertOutContains(imageName)
 

pkg/cmd/image/prune.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/images"
 	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/nerdctl/pkg/api/types"
+	"github.com/containerd/nerdctl/pkg/imgutil"
 	"github.com/opencontainers/go-digest"
 	"github.com/sirupsen/logrus"
 )
@@ -40,21 +41,33 @@ func Prune(ctx context.Context, client *containerd.Client, options types.ImagePr
 	if err != nil {
 		return err
 	}
-	containerList, err := containerStore.List(ctx)
-	if err != nil {
-		return err
-	}
-	usedImages := make(map[string]struct{})
-	for _, container := range containerList {
-		usedImages[container.Image] = struct{}{}
+
+	var filteredImages []images.Image
+
+	if options.All {
+		containerList, err := containerStore.List(ctx)
+		if err != nil {
+			return err
+		}
+		usedImages := make(map[string]struct{})
+		for _, container := range containerList {
+			usedImages[container.Image] = struct{}{}
+		}
+
+		for _, image := range imageList {
+			if _, ok := usedImages[image.Name]; ok {
+				continue
+			}
+
+			filteredImages = append(filteredImages, image)
+		}
+	} else {
+		filteredImages = imgutil.FilterDangling(imageList, true)
 	}
 
 	delOpts := []images.DeleteOpt{images.SynchronousDelete()}
 	removedImages := make(map[string][]digest.Digest)
-	for _, image := range imageList {
-		if _, ok := usedImages[image.Name]; ok {
-			continue
-		}
+	for _, image := range filteredImages {
 		digests, err := image.RootFS(ctx, contentStore, platforms.DefaultStrict())
 		if err != nil {
 			logrus.WithError(err).Warnf("failed to enumerate rootfs")