Merge pull request #10363 from vrothberg/fix-10350

image prune: remove unused images only with `--all`

cmd/podman/images/prune.go

@@ -15,10 +15,8 @@ import (
 )
 
 var (
-	pruneDescription = `Removes all unnamed images from local storage.
-
-  If an image is not being used by a container, it will be removed from the system.`
-	pruneCmd = &cobra.Command{
+	pruneDescription = `Removes dangling or unused images from local storage.`
+	pruneCmd         = &cobra.Command{
 		Use:               "prune [options]",
 		Args:              validate.NoArgs,
 		Short:             "Remove unused images",
@@ -41,7 +39,7 @@ func init() {
 	})
 
 	flags := pruneCmd.Flags()
-	flags.BoolVarP(&pruneOpts.All, "all", "a", false, "Remove all unused images, not just dangling ones")
+	flags.BoolVarP(&pruneOpts.All, "all", "a", false, "Remove all images not in use by containers, not just dangling ones")
 	flags.BoolVarP(&force, "force", "f", false, "Do not prompt for confirmation")
 
 	filterFlagName := "filter"

docs/source/markdown/podman-image-prune.1.md

@@ -8,8 +8,7 @@ podman-image-prune - Remove all unused images from the local store
 
 ## DESCRIPTION
 **podman image prune** removes all dangling images from local storage. With the `all` option,
-you can delete all unused images.  Unused images are dangling images as well as any image that
-does not have any containers based on it.
+you can delete all unused images (i.e., images not in use by any container).
 
 The image prune command does not prune cache images that only use layers that are necessary for other images.
 

pkg/domain/infra/abi/images.go

@@ -40,50 +40,34 @@ func (ir *ImageEngine) Exists(_ context.Context, nameOrID string) (*entities.Boo
 }
 
 func (ir *ImageEngine) Prune(ctx context.Context, opts entities.ImagePruneOptions) ([]*reports.PruneReport, error) {
-	// NOTE: the terms "dangling" and "intermediate" are not used
-	// consistently across our code base.  In libimage, "dangling" means
-	// that an image has no tags.  "intermediate" means that an image is
-	// dangling and that no other image depends on it (i.e., has no
-	// children).
-	//
-	// While pruning usually refers to "dangling" images, it has always
-	// removed "intermediate" ones.
-	defaultOptions := &libimage.RemoveImagesOptions{
-		Filters:  append(opts.Filter, "intermediate=true", "containers=false", "readonly=false"),
+	pruneOptions := &libimage.RemoveImagesOptions{
+		Filters:  append(opts.Filter, "containers=false", "readonly=false"),
 		WithSize: true,
 	}
 
-	// `image prune --all` means to *also* remove images which are not in
-	// use by any container.  Since image filters are chained, we need to
-	// do two look ups since the default ones are a subset of all.
-	unusedOptions := &libimage.RemoveImagesOptions{
-		Filters:  append(opts.Filter, "containers=false", "readonly=false"),
-		WithSize: true,
+	if !opts.All {
+		pruneOptions.Filters = append(pruneOptions.Filters, "dangling=true")
 	}
 
 	var pruneReports []*reports.PruneReport
 
 	// Now prune all images until we converge.
 	numPreviouslyRemovedImages := 1
 	for {
-		removedDefault, rmErrors := ir.Libpod.LibimageRuntime().RemoveImages(ctx, nil, defaultOptions)
-		if rmErrors != nil {
-			return nil, errorhandling.JoinErrors(rmErrors)
-		}
-		removedUnused, rmErrors := ir.Libpod.LibimageRuntime().RemoveImages(ctx, nil, unusedOptions)
+		removedImages, rmErrors := ir.Libpod.LibimageRuntime().RemoveImages(ctx, nil, pruneOptions)
 		if rmErrors != nil {
 			return nil, errorhandling.JoinErrors(rmErrors)
 		}
 
-		for _, rmReport := range append(removedDefault, removedUnused...) {
+		for _, rmReport := range removedImages {
 			r := *rmReport
 			pruneReports = append(pruneReports, &reports.PruneReport{
 				Id:   r.ID,
 				Size: uint64(r.Size),
 			})
 		}
 
-		numRemovedImages := len(removedDefault) + len(removedUnused)
+		numRemovedImages := len(removedImages)
 		if numRemovedImages+numPreviouslyRemovedImages == 0 {
 			break
 		}

test/e2e/prune_test.go

@@ -88,6 +88,53 @@ var _ = Describe("Podman prune", func() {
 		Expect(podmanTest.NumberOfContainers()).To(Equal(0))
 	})
 
+	It("podman image prune - remove only dangling images", func() {
+		session := podmanTest.Podman([]string{"images", "-a"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		hasNone, _ := session.GrepString("<none>")
+		Expect(hasNone).To(BeFalse())
+		numImages := len(session.OutputToStringArray())
+
+		// Since there's no dangling image, none should be removed.
+		session = podmanTest.Podman([]string{"image", "prune", "-f"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(Equal(0))
+
+		// Let's be extra sure that the same number of images is
+		// reported.
+		session = podmanTest.Podman([]string{"images", "-a"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(Equal(numImages))
+
+		// Now build a new image with dangling intermediate images.
+		podmanTest.BuildImage(pruneImage, "alpine_bash:latest", "true")
+
+		session = podmanTest.Podman([]string{"images", "-a"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		hasNone, _ = session.GrepString("<none>")
+		Expect(hasNone).To(BeTrue()) // ! we have dangling ones
+		numImages = len(session.OutputToStringArray())
+
+		// Since there's at least one dangling image, prune should
+		// remove them.
+		session = podmanTest.Podman([]string{"image", "prune", "-f"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		numPrunedImages := len(session.OutputToStringArray())
+		Expect(numPrunedImages >= 1).To(BeTrue())
+
+		// Now make sure that exactly the number of pruned images has
+		// been removed.
+		session = podmanTest.Podman([]string{"images", "-a"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(len(session.OutputToStringArray())).To(Equal(numImages - numPrunedImages))
+	})
+
 	It("podman image prune skip cache images", func() {
 		podmanTest.BuildImage(pruneImage, "alpine_bash:latest", "true")