Add image prune --filter support

Signed-off-by: Austin Vazquez <macedonv@amazon.com>

cmd/nerdctl/image_prune.go

@@ -38,6 +38,7 @@ func newImagePruneCommand() *cobra.Command {
 	}
 
 	imagePruneCommand.Flags().BoolP("all", "a", false, "Remove all unused images, not just dangling ones")
+	imagePruneCommand.Flags().StringSlice("filter", []string{}, "Filter output based on conditions provided")
 	imagePruneCommand.Flags().BoolP("force", "f", false, "Do not prompt for confirmation")
 	return imagePruneCommand
 }
@@ -52,6 +53,14 @@ func processImagePruneOptions(cmd *cobra.Command) (types.ImagePruneOptions, erro
 		return types.ImagePruneOptions{}, err
 	}
 
+	var filters []string
+	if cmd.Flags().Changed("filter") {
+		filters, err = cmd.Flags().GetStringSlice("filter")
+		if err != nil {
+			return types.ImagePruneOptions{}, err
+		}
+	}
+
 	force, err := cmd.Flags().GetBool("force")
 	if err != nil {
 		return types.ImagePruneOptions{}, err
@@ -61,6 +70,7 @@ func processImagePruneOptions(cmd *cobra.Command) (types.ImagePruneOptions, erro
 		Stdout:   cmd.OutOrStdout(),
 		GOptions: globalOptions,
 		All:      all,
+		Filters:  filters,
 		Force:    force,
 	}, err
 }

cmd/nerdctl/image_prune_test.go

@@ -71,3 +71,53 @@ func TestImagePruneAll(t *testing.T) {
 	base.Cmd("image", "prune", "--force", "--all").AssertOutContains(imageName)
 	base.Cmd("images").AssertOutNotContains(imageName)
 }
+
+func TestImagePruneFilterLabel(t *testing.T) {
+	testutil.RequiresBuild(t)
+	testutil.RegisterBuildCacheCleanup(t)
+
+	base := testutil.NewBase(t)
+	imageName := testutil.Identifier(t)
+	t.Cleanup(func() { base.Cmd("rmi", "--force", imageName) })
+
+	dockerfile := fmt.Sprintf(`FROM %s
+CMD ["echo", "nerdctl-test-image-prune-filter-label"]
+LABEL foo=bar
+LABEL version=0.1`, testutil.CommonImage)
+
+	buildCtx := createBuildContext(t, dockerfile)
+
+	base.Cmd("build", "-t", imageName, buildCtx).AssertOK()
+	base.Cmd("images", "--all").AssertOutContains(imageName)
+
+	base.Cmd("image", "prune", "--force", "--all", "--filter", "label=foo=baz").AssertOK()
+	base.Cmd("images", "--all").AssertOutContains(imageName)
+
+	base.Cmd("image", "prune", "--force", "--all", "--filter", "label=foo=bar").AssertOK()
+	base.Cmd("images", "--all").AssertOutNotContains(imageName)
+}
+
+func TestImagePruneFilterUntil(t *testing.T) {
+	testutil.RequiresBuild(t)
+	testutil.RegisterBuildCacheCleanup(t)
+
+	base := testutil.NewBase(t)
+	imageName := testutil.Identifier(t)
+	t.Cleanup(func() { base.Cmd("rmi", "--force", imageName) })
+
+	dockerfile := fmt.Sprintf(`FROM %s
+CMD ["echo", "nerdctl-test-image-prune-filter-label"]
+LABEL foo=bar
+LABEL version=0.1`, testutil.CommonImage)
+
+	buildCtx := createBuildContext(t, dockerfile)
+
+	base.Cmd("build", "-t", imageName, buildCtx).AssertOK()
+	base.Cmd("images").AssertOutContains(imageName)
+
+	base.Cmd("image", "prune", "--force", "--all", "--filter", "until=12h").AssertOK()
+	base.Cmd("images", "--all").AssertOutContains(imageName)
+
+	base.Cmd("image", "prune", "--force", "--all", "--filter", "until=100ms").AssertOK()
+	base.Cmd("images", "--all").AssertOutNotContains(imageName)
+}

docs/command-reference.md

@@ -886,10 +886,11 @@ Usage: `nerdctl image prune [OPTIONS]`
 Flags:
 
 - :whale: `-a, --all`: Remove all unused images, not just dangling ones
+- :whale: `-f, --filter`: Filter the images.
+  - :whale: `--filter=until=<timestamp>`: Images created before given date formatted timestamps or Go duration strings. Currently does not support Unix timestamps.
+  - :whale: `--filter=label<key>=<value>`: Matches images based on the presence of a label alone or a label and a value
 - :whale: `-f, --force`: Do not prompt for confirmation
 
-Unimplemented `docker image prune` flags: `--filter`
-
 ### :nerd_face: nerdctl image convert
 
 Convert an image format.

pkg/api/types/image_types.go

@@ -236,6 +236,8 @@ type ImagePruneOptions struct {
 	GOptions GlobalCommandOptions
 	// All Remove all unused images, not just dangling ones.
 	All bool
+	// Filters output based on conditions provided for the --filter argument
+	Filters []string
 	// Force will not prompt for confirmation.
 	Force bool
 }

pkg/cmd/image/prune.go

@@ -34,45 +34,43 @@ import (
 // Prune will remove all dangling images. If all is specified, will also remove all images not referenced by any container.
 func Prune(ctx context.Context, client *containerd.Client, options types.ImagePruneOptions) error {
 	var (
-		imageStore     = client.ImageService()
-		contentStore   = client.ContentStore()
-		containerStore = client.ContainerService()
+		imageStore   = client.ImageService()
+		contentStore = client.ContentStore()
 	)
 
-	imageList, err := imageStore.List(ctx)
-	if err != nil {
-		return err
-	}
-
-	var filteredImages []images.Image
+	var (
+		imagesToBeRemoved []images.Image
+		err               error
+	)
 
-	if options.All {
-		containerList, err := containerStore.List(ctx)
+	filters := []imgutil.Filter{}
+	if len(options.Filters) > 0 {
+		parsedFilters, err := imgutil.ParseFilters(options.Filters)
 		if err != nil {
 			return err
 		}
-		usedImages := make(map[string]struct{})
-		for _, container := range containerList {
-			usedImages[container.Image] = struct{}{}
+		if len(parsedFilters.Labels) > 0 {
+			filters = append(filters, imgutil.FilterByLabel(ctx, client, parsedFilters.Labels))
 		}
-
-		for _, image := range imageList {
-			if _, ok := usedImages[image.Name]; ok {
-				continue
-			}
-
-			filteredImages = append(filteredImages, image)
+		if len(parsedFilters.Until) > 0 {
+			filters = append(filters, imgutil.FilterUntil(parsedFilters.Until))
 		}
+	}
+
+	if options.All {
+		// Remove all unused images; not just dangling ones
+		imagesToBeRemoved, err = imgutil.GetUnusedImages(ctx, client, filters...)
 	} else {
-		filteredImages, err = imgutil.FilterDanglingImages()(imageList)
-		if err != nil {
-			return err
-		}
+		// Remove dangling images only
+		imagesToBeRemoved, err = imgutil.GetDanglingImages(ctx, client, filters...)
+	}
+	if err != nil {
+		return err
 	}
 
 	delOpts := []images.DeleteOpt{images.SynchronousDelete()}
 	removedImages := make(map[string][]digest.Digest)
-	for _, image := range filteredImages {
+	for _, image := range imagesToBeRemoved {
 		digests, err := image.RootFS(ctx, contentStore, platforms.DefaultStrict())
 		if err != nil {
 			log.G(ctx).WithError(err).Warnf("failed to enumerate rootfs")

pkg/imgutil/filtering.go

@@ -18,6 +18,7 @@ package imgutil
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"regexp"
 	"strings"
@@ -35,15 +36,23 @@ import (
 const (
 	FilterBeforeType    = "before"
 	FilterSinceType     = "since"
+	FilterUntilType     = "until"
 	FilterLabelType     = "label"
 	FilterReferenceType = "reference"
 	FilterDanglingType  = "dangling"
 )
 
+var (
+	errMultipleUntilFilters     = errors.New("more than one until filter provided")
+	errNoUntilTimestamp         = errors.New("no until timestamp provided")
+	errUnparsableUntilTimestamp = errors.New("unable to parse until timestamp")
+)
+
 // Filters contains all types of filters to filter images.
 type Filters struct {
 	Before    []string
 	Since     []string
+	Until     string
 	Labels    map[string]string
 	Reference []string
 	Dangling  *bool
@@ -85,6 +94,13 @@ func ParseFilters(filters []string) (*Filters, error) {
 				}
 				f.Since = append(f.Since, fmt.Sprintf("name==%s", canonicalRef.String()))
 				f.Since = append(f.Since, fmt.Sprintf("name==%s", tempFilterToken[1]))
+			} else if tempFilterToken[0] == FilterUntilType {
+				if len(tempFilterToken[0]) == 0 {
+					return nil, errNoUntilTimestamp
+				} else if len(f.Until) > 0 {
+					return nil, errMultipleUntilFilters
+				}
+				f.Until = tempFilterToken[1]
 			} else if tempFilterToken[0] == FilterLabelType {
 				// To support filtering labels by keys.
 				f.Labels[tempFilterToken[1]] = ""
@@ -161,6 +177,57 @@ func FilterByCreatedAt(ctx context.Context, client *containerd.Client, before []
 	}
 }
 
+// FilterUntil filters images created before the provided timestamp.
+func FilterUntil(until string) Filter {
+	return func(imageList []images.Image) ([]images.Image, error) {
+		if len(until) == 0 {
+			return []images.Image{}, errNoUntilTimestamp
+		}
+
+		var (
+			parsedTime time.Time
+			err        error
+		)
+
+		type parseUntilFunc func(string) (time.Time, error)
+		parsingFuncs := []parseUntilFunc{
+			func(until string) (time.Time, error) {
+				return time.Parse(time.RFC3339, until)
+			},
+			func(until string) (time.Time, error) {
+				return time.Parse(time.RFC3339Nano, until)
+			},
+			func(until string) (time.Time, error) {
+				return time.Parse(time.DateOnly, until)
+			},
+			func(until string) (time.Time, error) {
+				// Go duration strings
+				d, err := time.ParseDuration(until)
+				if err != nil {
+					return time.Time{}, err
+				}
+				return time.Now().Add(-d), nil
+			},
+		}
+
+		for _, parse := range parsingFuncs {
+			parsedTime, err = parse(until)
+			if err != nil {
+				continue
+			}
+			break
+		}
+
+		if err != nil {
+			return []images.Image{}, errUnparsableUntilTimestamp
+		}
+
+		return filter(imageList, func(i images.Image) (bool, error) {
+			return imageCreatedBefore(i, parsedTime), nil
+		})
+	}
+}
+
 // FilterByLabel filters an image list based on labels applied to the image's config specification for the platform.
 // Any matching label will include the image in the list.
 func FilterByLabel(ctx context.Context, client *containerd.Client, labels map[string]string) Filter {
@@ -221,6 +288,10 @@ func imageCreatedBetween(image images.Image, min time.Time, max time.Time) bool
 	return image.CreatedAt.After(min) && image.CreatedAt.Before(max)
 }
 
+func imageCreatedBefore(image images.Image, max time.Time) bool {
+	return image.CreatedAt.Before(max)
+}
+
 func matchesAllLabels(imageCfgLabels map[string]string, filterLabels map[string]string) bool {
 	var matches int
 	for lk, lv := range filterLabels {

pkg/imgutil/filtering_test.go

@@ -108,6 +108,23 @@ func TestApplyFilters(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "ReturnErrorAndEmptyListOnFilterError",
+			images: []images.Image{
+				{
+					Name: "<none>:<none>",
+				},
+				{
+					Name: "docker.io/library/hello-world:latest",
+				},
+			},
+			filters: []Filter{
+				FilterDanglingImages(),
+				FilterUntil(""),
+			},
+			expectedImages: []images.Image{},
+			expectedErr:    errNoUntilTimestamp,
+		},
 	}
 
 	for _, test := range tests {
@@ -124,6 +141,74 @@ func TestApplyFilters(t *testing.T) {
 	}
 }
 
+func TestFilterUntil(t *testing.T) {
+	now := time.Now().UTC()
+
+	tests := []struct {
+		name           string
+		until          string
+		images         []images.Image
+		expectedImages []images.Image
+		expectedErr    error
+	}{
+		{
+			name:           "EmptyTimestampReturnsError",
+			until:          "",
+			images:         []images.Image{},
+			expectedImages: []images.Image{},
+			expectedErr:    errNoUntilTimestamp,
+		},
+		{
+			name:           "UnparseableTimestampReturnsError",
+			until:          "-2006-01-02T15:04:05Z07:00",
+			images:         []images.Image{},
+			expectedImages: []images.Image{},
+			expectedErr:    errUnparsableUntilTimestamp,
+		},
+		{
+			name:  "ImagesOlderThan3Hours(Go duration)",
+			until: "3h",
+			images: []images.Image{
+				{
+					Name:      "image:yesterday",
+					CreatedAt: now.Add(-24 * time.Hour),
+				},
+				{
+					Name:      "image:today",
+					CreatedAt: now.Add(-12 * time.Hour),
+				},
+				{
+					Name:      "image:latest",
+					CreatedAt: now,
+				},
+			},
+			expectedImages: []images.Image{
+				{
+					Name:      "image:yesterday",
+					CreatedAt: now.Add(-24 * time.Hour),
+				},
+				{
+					Name:      "image:today",
+					CreatedAt: now.Add(-12 * time.Hour),
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			actualImages, err := FilterUntil(test.until)(test.images)
+			if test.expectedErr == nil {
+				assert.NilError(t, err)
+			} else {
+				assert.ErrorIs(t, err, test.expectedErr)
+			}
+			assert.Equal(t, len(actualImages), len(test.expectedImages))
+			assert.DeepEqual(t, actualImages, test.expectedImages)
+		})
+	}
+}
+
 func TestFilterByReference(t *testing.T) {
 	tests := []struct {
 		name              string