make prune to remove dangling images only

Signed-off-by: suyanhanx <[email protected]>

cmd/nerdctl/image_prune.go

@@ -19,6 +19,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"github.com/containerd/nerdctl/pkg/imgutil"
 	"strings"
 
 	"github.com/containerd/containerd"
@@ -55,20 +56,21 @@ func imagePruneAction(cmd *cobra.Command, _ []string) error {
 		return err
 	}
 
-	if !all {
-		logrus.Warn("Currently, `nerdctl image prune` requires --all to be specified. Skip pruning.")
-		// NOP
-		return nil
-	}
-
 	force, err := cmd.Flags().GetBool("force")
 	if err != nil {
 		return err
 	}
 
 	if !force {
-		var confirm string
-		msg := "This will remove all images without at least one container associated to them."
+		var (
+			confirm string
+			msg     string
+		)
+		if !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)
@@ -84,10 +86,10 @@ func imagePruneAction(cmd *cobra.Command, _ []string) error {
 	}
 	defer cancel()
 
-	return imagePrune(ctx, cmd, client)
+	return imagePrune(ctx, cmd, client, all)
 }
 
-func imagePrune(ctx context.Context, cmd *cobra.Command, client *containerd.Client) error {
+func imagePrune(ctx context.Context, cmd *cobra.Command, client *containerd.Client, all bool) error {
 	var (
 		imageStore     = client.ImageService()
 		contentStore   = client.ContentStore()
@@ -97,22 +99,39 @@ func imagePrune(ctx context.Context, cmd *cobra.Command, client *containerd.Clie
 	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{}{}
-	}
 
 	delOpts := []images.DeleteOpt{images.SynchronousDelete()}
 	removedImages := make(map[string][]digest.Digest)
-	for _, image := range imageList {
-		if _, ok := usedImages[image.Name]; ok {
-			continue
+	var filteredImages []images.Image
+
+	if 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 {
+		for _, image := range imageList {
+			_, tag := imgutil.ParseRepoTag(image.Name)
+
+			if tag == "" {
+				filteredImages = append(filteredImages, image)
+			}
+		}
+	}
 
+	for _, image := range filteredImages {
 		digests, err := image.RootFS(ctx, contentStore, platforms.DefaultStrict())
 		if err != nil {
 			logrus.WithError(err).Warnf("failed to enumerate rootfs")

cmd/nerdctl/system_prune.go

@@ -121,7 +121,7 @@ func systemPruneAction(cmd *cobra.Command, args []string) error {
 			return err
 		}
 	}
-	if err := imagePrune(ctx, cmd, client); err != nil {
+	if err := imagePrune(ctx, cmd, client, true); err != nil {
 		return nil
 	}
 	prunedObjects, err := buildCachePrune(ctx, cmd, all, globalOptions.Namespace)