Add podman system check for checking storage consistency

Add a `podman system check` that performs consistency checks on local
storage, optionally removing damaged items so that they can be
recreated.

Signed-off-by: Nalin Dahyabhai <[email protected]>

cmd/podman/system/check.go

@@ -0,0 +1,138 @@
+package system
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/containers/common/pkg/completion"
+	"github.com/containers/podman/v5/cmd/podman/registry"
+	"github.com/containers/podman/v5/cmd/podman/validate"
+	"github.com/containers/podman/v5/pkg/domain/entities/types"
+	multierror "github.com/hashicorp/go-multierror"
+	"github.com/spf13/cobra"
+)
+
+var (
+	checkOptions     = types.SystemCheckOptions{}
+	checkDescription = `
+	podman system check
+
+        Check storage for consistency and remove anything that looks damaged
+`
+
+	checkCommand = &cobra.Command{
+		Use:               "check [options]",
+		Short:             "Check storage consistency",
+		Args:              validate.NoArgs,
+		Long:              checkDescription,
+		RunE:              check,
+		ValidArgsFunction: completion.AutocompleteNone,
+		Example:           `podman system check`,
+	}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: checkCommand,
+		Parent:  systemCmd,
+	})
+	flags := checkCommand.Flags()
+	flags.BoolVarP(&checkOptions.Quick, "quick", "q", false, "Skip time-consuming checks. The default is to include time-consuming checks")
+	flags.BoolVarP(&checkOptions.Repair, "repair", "r", false, "Remove inconsistent images")
+	flags.BoolVarP(&checkOptions.RepairLossy, "force", "f", false, "Remove inconsistent images and containers")
+	flags.DurationP("max", "m", 24*time.Hour, "Maximum allowed age of unreferenced layers")
+	_ = checkCommand.RegisterFlagCompletionFunc("max", completion.AutocompleteNone)
+}
+
+func check(cmd *cobra.Command, args []string) error {
+	flags := cmd.Flags()
+	if flags.Changed("max") {
+		maxAge, err := flags.GetDuration("max")
+		if err != nil {
+			return err
+		}
+		checkOptions.UnreferencedLayerMaximumAge = &maxAge
+	}
+	response, err := registry.ContainerEngine().SystemCheck(context.Background(), checkOptions)
+	if err != nil {
+		return err
+	}
+
+	if err = printSystemCheckResults(response); err != nil {
+		return err
+	}
+
+	if !checkOptions.Repair && !checkOptions.RepairLossy && response.Errors {
+		return errors.New("damage detected in local storage")
+	}
+
+	recheckOptions := checkOptions
+	recheckOptions.Repair = false
+	recheckOptions.RepairLossy = false
+	if response, err = registry.ContainerEngine().SystemCheck(context.Background(), recheckOptions); err != nil {
+		return err
+	}
+	if response.Errors {
+		return errors.New("damage in local storage still present after repair attempt")
+	}
+
+	return nil
+}
+
+func printSystemCheckResults(report *types.SystemCheckReport) error {
+	if !report.Errors {
+		return nil
+	}
+	errorSlice := func(strs []string) []error {
+		if strs == nil {
+			return nil
+		}
+		errs := make([]error, len(strs))
+		for i, s := range strs {
+			errs[i] = errors.New(s)
+		}
+		return errs
+	}
+	for damagedLayer, errorsSlice := range report.Layers {
+		merr := multierror.Append(nil, errorSlice(errorsSlice)...)
+		if err := merr.ErrorOrNil(); err != nil {
+			fmt.Printf("Damaged layer %s:\n%s", damagedLayer, err)
+		}
+	}
+	for _, removedLayer := range report.RemovedLayers {
+		fmt.Printf("Deleted damaged layer: %s\n", removedLayer)
+	}
+	for damagedROLayer, errorsSlice := range report.ROLayers {
+		merr := multierror.Append(nil, errorSlice(errorsSlice)...)
+		if err := merr.ErrorOrNil(); err != nil {
+			fmt.Printf("Damaged read-only layer %s:\n%s", damagedROLayer, err)
+		}
+	}
+	for damagedImage, errorsSlice := range report.Images {
+		merr := multierror.Append(nil, errorSlice(errorsSlice)...)
+		if err := merr.ErrorOrNil(); err != nil {
+			fmt.Printf("Damaged image %s:\n%s", damagedImage, err)
+		}
+	}
+	for removedImage := range report.RemovedImages {
+		fmt.Printf("Deleted damaged image: %s\n", removedImage)
+	}
+	for damagedROImage, errorsSlice := range report.ROImages {
+		merr := multierror.Append(nil, errorSlice(errorsSlice)...)
+		if err := merr.ErrorOrNil(); err != nil {
+			fmt.Printf("Damaged read-only image %s\n%s", damagedROImage, err)
+		}
+	}
+	for damagedContainer, errorsSlice := range report.Containers {
+		merr := multierror.Append(nil, errorSlice(errorsSlice)...)
+		if err := merr.ErrorOrNil(); err != nil {
+			fmt.Printf("Damaged container %s:\n%s", damagedContainer, err)
+		}
+	}
+	for removedContainer := range report.RemovedContainers {
+		fmt.Printf("Deleted damaged container: %s\n", removedContainer)
+	}
+	return nil
+}

docs/source/markdown/podman-system-check.1.md

@@ -0,0 +1,59 @@
+% podman-system-check 1
+
+## NAME
+podman\-system\-check - Perform consistency checks on image and container storage
+
+## SYNOPSIS
+**podman system check** [*options*]
+
+## DESCRIPTION
+Perform consistency checks on image and container storage, reporting images and
+containers which have identified issues.
+
+## OPTIONS
+
+#### **--force**, **-f**
+
+When attempting to remove damaged images, also remove containers which depend
+on those images.  By default, damaged images which are being used by containers
+are left alone.
+
+Containers which depend on damaged images do so regardless of which engine
+created them, but because podman only "knows" how to shut down containers that
+it started, the effect on still-running containers which were started by other
+engines is difficult to predict.
+
+#### **--max**, **-m**=*duration*
+
+When considering layers which are not used by any images or containers, assume
+that any layers which are more than *duration* old are the results of canceled
+attempts to pull images, and should be treated as though they are damaged.
+
+#### **--quick**, **-q**
+
+Skip checks which are known to be time-consuming.  This will prevent some types
+of errors from being detected.
+
+#### **--repair**, **-r**
+
+Remove any images which are determined to have been damaged in some way, unless
+they are in use by containers.  Use **--force** to remove containers which
+depend on damaged images, and those damaged images, as well.
+
+## EXAMPLE
+
+A reasonably quick check:
+```
+podman system check --quick --repair --force
+```
+
+A more thorough check:
+```
+podman system check --repair --max=1h --force
+```
+
+## SEE ALSO
+**[podman(1)](podman.1.md)**, **[podman-system(1)](podman-system.1.md)**
+
+## HISTORY
+April 2024

docs/source/markdown/podman-system.1.md

@@ -13,6 +13,7 @@ The system command allows management of the podman systems
 
 | Command    | Man Page                                                     | Description                                                              |
 | -------    | ------------------------------------------------------------ | ------------------------------------------------------------------------ |
+| check      | [podman-system-check(1)](podman-system-check.1.md)           | Perform consistency checks on image and container storage.
 | connection | [podman-system-connection(1)](podman-system-connection.1.md) | Manage the destination(s) for Podman service(s)                          |
 | df         | [podman-system-df(1)](podman-system-df.1.md)                 | Show podman disk usage.                                                  |
 | events     | [podman-events(1)](podman-events.1.md)                       | Monitor Podman events                                                    |

libpod/runtime.go

@@ -31,6 +31,7 @@ import (
 	"github.com/containers/podman/v5/libpod/lock"
 	"github.com/containers/podman/v5/libpod/plugin"
 	"github.com/containers/podman/v5/libpod/shutdown"
+	"github.com/containers/podman/v5/pkg/domain/entities"
 	"github.com/containers/podman/v5/pkg/rootless"
 	"github.com/containers/podman/v5/pkg/systemd"
 	"github.com/containers/podman/v5/pkg/util"
@@ -39,9 +40,11 @@ import (
 	"github.com/containers/storage/pkg/lockfile"
 	"github.com/containers/storage/pkg/unshare"
 	"github.com/docker/docker/pkg/namesgenerator"
+	"github.com/hashicorp/go-multierror"
 	jsoniter "github.com/json-iterator/go"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/sirupsen/logrus"
+	"golang.org/x/exp/slices"
 )
 
 // Set up the JSON library for all of Libpod
@@ -1249,3 +1252,133 @@ func (r *Runtime) LockConflicts() (map[uint32][]string, []uint32, error) {
 
 	return toReturn, locksHeld, nil
 }
+
+// SystemCheck checks our storage for consistency, and depending on the options
+// specified, will attempt to remove anything which fails consistency checks.
+func (r *Runtime) SystemCheck(ctx context.Context, options entities.SystemCheckOptions) (entities.SystemCheckReport, error) {
+	what := storage.CheckEverything()
+	if options.Quick {
+		what = storage.CheckMost()
+	}
+	if options.UnreferencedLayerMaximumAge != nil {
+		tmp := *options.UnreferencedLayerMaximumAge
+		what.LayerUnreferencedMaximumAge = &tmp
+	}
+	storageReport, err := r.store.Check(what)
+	if err != nil {
+		return entities.SystemCheckReport{}, err
+	}
+	if len(storageReport.Containers) == 0 &&
+		len(storageReport.Layers) == 0 &&
+		len(storageReport.ROLayers) == 0 &&
+		len(storageReport.Images) == 0 &&
+		len(storageReport.ROImages) == 0 {
+		// no errors detected
+		return entities.SystemCheckReport{}, nil
+	}
+	mapErrorSlicesToStringSlices := func(m map[string][]error) map[string][]string {
+		if len(m) == 0 {
+			return nil
+		}
+		mapped := make(map[string][]string, len(m))
+		for k, errs := range m {
+			strs := make([]string, len(errs))
+			for i, e := range errs {
+				strs[i] = e.Error()
+			}
+			mapped[k] = strs
+		}
+		return mapped
+	}
+
+	report := entities.SystemCheckReport{
+		Errors:     true,
+		Layers:     mapErrorSlicesToStringSlices(storageReport.Layers),
+		ROLayers:   mapErrorSlicesToStringSlices(storageReport.ROLayers),
+		Images:     mapErrorSlicesToStringSlices(storageReport.Images),
+		ROImages:   mapErrorSlicesToStringSlices(storageReport.ROImages),
+		Containers: mapErrorSlicesToStringSlices(storageReport.Containers),
+	}
+	if !options.Repair && report.Errors {
+		// errors detected, no corrective measures to be taken
+		return report, err
+	}
+
+	// get a list of images that we knew of before we tried to clean up any
+	// that were damaged
+	imagesBefore, err := r.store.Images()
+	if err != nil {
+		return report, fmt.Errorf("getting a list of images before attempting repairs: %w", err)
+	}
+
+	repairOptions := storage.RepairOptions{
+		RemoveContainers: options.RepairLossy,
+	}
+	var containers []*Container
+	if repairOptions.RemoveContainers {
+		// build a list of the containers that we claim as ours that we
+		// expect to be removing in a bit
+		for containerID := range storageReport.Containers {
+			ctr, lookupErr := r.state.LookupContainer(containerID)
+			if lookupErr != nil {
+				// we're about to remove it, so it's okay that
+				// it isn't even one of ours
+				continue
+			}
+			containers = append(containers, ctr)
+		}
+	}
+
+	// run the cleanup
+	merr := multierror.Append(nil, r.store.Repair(storageReport, &repairOptions)...)
+
+	if repairOptions.RemoveContainers {
+		// get the list of containers that storage will still admit to knowing about
+		containersAfter, err := r.store.Containers()
+		if err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("getting a list of containers after attempting repairs: %w", err))
+		}
+		for _, ctr := range containers {
+			// if one of our containers that we tried to remove is
+			// still on disk, report an error
+			if slices.IndexFunc(containersAfter, func(containerAfter storage.Container) bool {
+				return containerAfter.ID == ctr.ID()
+			}) != -1 {
+				merr = multierror.Append(merr, fmt.Errorf("clearing storage for container %s: %w", ctr.ID(), err))
+				continue
+			}
+			// remove the container from our database
+			if removeErr := r.state.RemoveContainer(ctr); removeErr != nil {
+				merr = multierror.Append(merr, fmt.Errorf("updating state database to reflect removal of container %s: %w", ctr.ID(), removeErr))
+				continue
+			}
+			if report.RemovedContainers == nil {
+				report.RemovedContainers = make(map[string]string)
+			}
+			report.RemovedContainers[ctr.ID()] = ctr.config.Name
+		}
+	}
+
+	// get a list of images that are still around after we clean up any
+	// that were damaged
+	imagesAfter, err := r.store.Images()
+	if err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("getting a list of images after attempting repairs: %w", err))
+	}
+	for _, imageBefore := range imagesBefore {
+		if slices.IndexFunc(imagesAfter, func(imageAfter storage.Image) bool {
+			return imageAfter.ID == imageBefore.ID
+		}) == -1 {
+			if report.RemovedImages == nil {
+				report.RemovedImages = make(map[string][]string)
+			}
+			report.RemovedImages[imageBefore.ID] = slices.Clone(imageBefore.Names)
+		}
+	}
+
+	if merr != nil {
+		err = merr.ErrorOrNil()
+	}
+
+	return report, err
+}