daemon/images/image_delete.go
package images // import "github.com/docker/docker/daemon/images"
import (
"context"
"fmt"
"strings"
"time"
"github.com/distribution/reference"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/api/types/events"
imagetypes "github.com/docker/docker/api/types/image"
"github.com/docker/docker/container"
"github.com/docker/docker/errdefs"
"github.com/docker/docker/image"
"github.com/docker/docker/pkg/stringid"
"github.com/pkg/errors"
)
type conflictType int
const (
conflictDependentChild conflictType = 1 << iota
conflictRunningContainer
conflictActiveReference
conflictStoppedContainer
conflictHard = conflictDependentChild | conflictRunningContainer
conflictSoft = conflictActiveReference | conflictStoppedContainer
)
// ImageDelete deletes the image referenced by the given imageRef from this
// daemon. The given imageRef can be an image ID, ID prefix, or a repository
// reference (with an optional tag or digest, defaulting to the tag name
// "latest"). There is differing behavior depending on whether the given
// imageRef is a repository reference or not.
//
// If the given imageRef is a repository reference then that repository
// reference will be removed. However, if there exists any containers which
// were created using the same image reference then the repository reference
// cannot be removed unless either there are other repository references to the
// same image or force is true. Following removal of the repository reference,
// the referenced image itself will attempt to be deleted as described below
// but quietly, meaning any image delete conflicts will cause the image to not
// be deleted and the conflict will not be reported.
//
// There may be conflicts preventing deletion of an image and these conflicts
// are divided into two categories grouped by their severity:
//
// Hard Conflict:
// - a pull or build using the image.
// - any descendant image.
// - any running container using the image.
//
// Soft Conflict:
// - any stopped container using the image.
// - any repository tag or digest references to the image.
//
// The image cannot be removed if there are any hard conflicts and can be
// removed if there are soft conflicts only if force is true.
//
// If prune is true, ancestor images will each attempt to be deleted quietly,
// meaning any delete conflicts will cause the image to not be deleted and the
// conflict will not be reported.
func (i *ImageService) ImageDelete(ctx context.Context, imageRef string, force, prune bool) ([]imagetypes.DeleteResponse, error) {
start := time.Now()
records := []imagetypes.DeleteResponse{}
img, err := i.GetImage(ctx, imageRef, backend.GetImageOpts{})
if err != nil {
return nil, err
}
imgID := img.ID()
repoRefs := i.referenceStore.References(imgID.Digest())
using := func(c *container.Container) bool {
return c.ImageID == imgID
}
var removedRepositoryRef bool
if !isImageIDPrefix(imgID.String(), imageRef) {
// A repository reference was given and should be removed
// first. We can only remove this reference if either force is
// true, there are multiple repository references to this
// image, or there are no containers using the given reference.
if !force && isSingleReference(repoRefs) {
if ctr := i.containers.First(using); ctr != nil {
// If we removed the repository reference then
// this image would remain "dangling" and since
// we really want to avoid that the client must
// explicitly force its removal.
err := errors.Errorf("conflict: unable to remove repository reference %q (must force) - container %s is using its referenced image %s", imageRef, stringid.TruncateID(ctr.ID), stringid.TruncateID(imgID.String()))
return nil, errdefs.Conflict(err)
}
}
parsedRef, err := reference.ParseNormalizedNamed(imageRef)
if err != nil {
return nil, err
}
parsedRef, err = i.removeImageRef(parsedRef)
if err != nil {
return nil, err
}
untaggedRecord := imagetypes.DeleteResponse{Untagged: reference.FamiliarString(parsedRef)}
i.LogImageEvent(imgID.String(), imgID.String(), events.ActionUnTag)
records = append(records, untaggedRecord)
repoRefs = i.referenceStore.References(imgID.Digest())
// If a tag reference was removed and the only remaining
// references to the same repository are digest references,
// then clean up those digest references.
if _, isCanonical := parsedRef.(reference.Canonical); !isCanonical {
foundRepoTagRef := false
for _, repoRef := range repoRefs {
if _, repoRefIsCanonical := repoRef.(reference.Canonical); !repoRefIsCanonical && parsedRef.Name() == repoRef.Name() {
foundRepoTagRef = true
break
}
}
if !foundRepoTagRef {
// Remove canonical references from same repository
var remainingRefs []reference.Named
for _, repoRef := range repoRefs {
if _, repoRefIsCanonical := repoRef.(reference.Canonical); repoRefIsCanonical && parsedRef.Name() == repoRef.Name() {
if _, err := i.removeImageRef(repoRef); err != nil {
return records, err
}
records = append(records, imagetypes.DeleteResponse{Untagged: reference.FamiliarString(repoRef)})
} else {
remainingRefs = append(remainingRefs, repoRef)
}
}
repoRefs = remainingRefs
}
}
// If it has remaining references then the untag finished the remove
if len(repoRefs) > 0 {
return records, nil
}
removedRepositoryRef = true
} else {
// If an ID reference was given AND there is at most one tag
// reference to the image AND all references are within one
// repository, then remove all references.
if isSingleReference(repoRefs) {
c := conflictHard
if !force {
c |= conflictSoft &^ conflictActiveReference
}
if conflict := i.checkImageDeleteConflict(imgID, c); conflict != nil {
return nil, conflict
}
for _, repoRef := range repoRefs {
parsedRef, err := i.removeImageRef(repoRef)
if err != nil {
return nil, err
}
i.LogImageEvent(imgID.String(), imgID.String(), events.ActionUnTag)
records = append(records, imagetypes.DeleteResponse{Untagged: reference.FamiliarString(parsedRef)})
}
}
}
if err := i.imageDeleteHelper(imgID, &records, force, prune, removedRepositoryRef); err != nil {
return nil, err
}
ImageActions.WithValues("delete").UpdateSince(start)
return records, nil
}
// isSingleReference returns true when all references are from one repository
// and there is at most one tag. Returns false for empty input.
func isSingleReference(repoRefs []reference.Named) bool {
if len(repoRefs) <= 1 {
return len(repoRefs) == 1
}
var singleRef reference.Named
canonicalRefs := map[string]struct{}{}
for _, repoRef := range repoRefs {
if _, isCanonical := repoRef.(reference.Canonical); isCanonical {
canonicalRefs[repoRef.Name()] = struct{}{}
} else if singleRef == nil {
singleRef = repoRef
} else {
return false
}
}
if singleRef == nil {
// Just use first canonical ref
singleRef = repoRefs[0]
}
_, ok := canonicalRefs[singleRef.Name()]
return len(canonicalRefs) == 1 && ok
}
// isImageIDPrefix returns whether the given possiblePrefix is a prefix of the
// given imageID.
func isImageIDPrefix(imageID, possiblePrefix string) bool {
if strings.HasPrefix(imageID, possiblePrefix) {
return true
}
if i := strings.IndexRune(imageID, ':'); i >= 0 {
return strings.HasPrefix(imageID[i+1:], possiblePrefix)
}
return false
}
// removeImageRef attempts to parse and remove the given image reference from
// this daemon's store of repository tag/digest references. The given
// repositoryRef must not be an image ID but a repository name followed by an
// optional tag or digest reference. If tag or digest is omitted, the default
// tag is used. Returns the resolved image reference and an error.
func (i *ImageService) removeImageRef(ref reference.Named) (reference.Named, error) {
ref = reference.TagNameOnly(ref)
// Ignore the boolean value returned, as far as we're concerned, this
// is an idempotent operation and it's okay if the reference didn't
// exist in the first place.
_, err := i.referenceStore.Delete(ref)
return ref, err
}
// removeAllReferencesToImageID attempts to remove every reference to the given
// imgID from this daemon's store of repository tag/digest references. Returns
// on the first encountered error. Removed references are logged to this
// daemon's event service. An "Untagged" types.ImageDeleteResponseItem is added to the
// given list of records.
func (i *ImageService) removeAllReferencesToImageID(imgID image.ID, records *[]imagetypes.DeleteResponse) error {
for _, imageRef := range i.referenceStore.References(imgID.Digest()) {
parsedRef, err := i.removeImageRef(imageRef)
if err != nil {
return err
}
i.LogImageEvent(imgID.String(), imgID.String(), events.ActionUnTag)
*records = append(*records, imagetypes.DeleteResponse{
Untagged: reference.FamiliarString(parsedRef),
})
}
return nil
}
// ImageDeleteConflict holds a soft or hard conflict and an associated error.
// Implements the error interface.
type imageDeleteConflict struct {
hard bool
used bool
imgID image.ID
message string
}
func (idc *imageDeleteConflict) Error() string {
var forceMsg string
if idc.hard {
forceMsg = "cannot be forced"
} else {
forceMsg = "must be forced"
}
return fmt.Sprintf("conflict: unable to delete %s (%s) - %s", stringid.TruncateID(idc.imgID.String()), forceMsg, idc.message)
}
func (idc *imageDeleteConflict) Conflict() {}
// imageDeleteHelper attempts to delete the given image from this daemon. If
// the image has any hard delete conflicts (child images or running containers
// using the image) then it cannot be deleted. If the image has any soft delete
// conflicts (any tags/digests referencing the image or any stopped container
// using the image) then it can only be deleted if force is true. If the delete
// succeeds and prune is true, the parent images are also deleted if they do
// not have any soft or hard delete conflicts themselves. Any deleted images
// and untagged references are appended to the given records. If any error or
// conflict is encountered, it will be returned immediately without deleting
// the image. If quiet is true, any encountered conflicts will be ignored and
// the function will return nil immediately without deleting the image.
func (i *ImageService) imageDeleteHelper(imgID image.ID, records *[]imagetypes.DeleteResponse, force, prune, quiet bool) error {
// First, determine if this image has any conflicts. Ignore soft conflicts
// if force is true.
c := conflictHard
if !force {
c |= conflictSoft
}
if conflict := i.checkImageDeleteConflict(imgID, c); conflict != nil {
if quiet && (!i.imageIsDangling(imgID) || conflict.used) {
// Ignore conflicts UNLESS the image is "dangling" or not being used in
// which case we want the user to know.
return nil
}
// There was a conflict and it's either a hard conflict OR we are not
// forcing deletion on soft conflicts.
return conflict
}
parent, err := i.imageStore.GetParent(imgID)
if err != nil {
// There may be no parent
parent = ""
}
// Delete all repository tag/digest references to this image.
if err := i.removeAllReferencesToImageID(imgID, records); err != nil {
return err
}
removedLayers, err := i.imageStore.Delete(imgID)
if err != nil {
return err
}
i.LogImageEvent(imgID.String(), imgID.String(), events.ActionDelete)
*records = append(*records, imagetypes.DeleteResponse{Deleted: imgID.String()})
for _, removedLayer := range removedLayers {
*records = append(*records, imagetypes.DeleteResponse{Deleted: removedLayer.ChainID.String()})
}
if !prune || parent == "" {
return nil
}
// We need to prune the parent image. This means delete it if there are
// no tags/digests referencing it and there are no containers using it (
// either running or stopped).
// Do not force prunings, but do so quietly (stopping on any encountered
// conflicts).
return i.imageDeleteHelper(parent, records, false, true, true)
}
// checkImageDeleteConflict determines whether there are any conflicts
// preventing deletion of the given image from this daemon. A hard conflict is
// any image which has the given image as a parent or any running container
// using the image. A soft conflict is any tags/digest referencing the given
// image or any stopped container using the image. If ignoreSoftConflicts is
// true, this function will not check for soft conflict conditions.
func (i *ImageService) checkImageDeleteConflict(imgID image.ID, mask conflictType) *imageDeleteConflict {
// Check if the image has any descendant images.
if mask&conflictDependentChild != 0 && len(i.imageStore.Children(imgID)) > 0 {
return &imageDeleteConflict{
hard: true,
imgID: imgID,
message: "image has dependent child images",
}
}
if mask&conflictRunningContainer != 0 {
// Check if any running container is using the image.
running := func(c *container.Container) bool {
return c.ImageID == imgID && c.IsRunning()
}
if ctr := i.containers.First(running); ctr != nil {
return &imageDeleteConflict{
imgID: imgID,
hard: true,
used: true,
message: fmt.Sprintf("image is being used by running container %s", stringid.TruncateID(ctr.ID)),
}
}
}
// Check if any repository tags/digest reference this image.
if mask&conflictActiveReference != 0 && len(i.referenceStore.References(imgID.Digest())) > 0 {
return &imageDeleteConflict{
imgID: imgID,
message: "image is referenced in multiple repositories",
}
}
if mask&conflictStoppedContainer != 0 {
// Check if any stopped containers reference this image.
stopped := func(c *container.Container) bool {
return !c.IsRunning() && c.ImageID == imgID
}
if ctr := i.containers.First(stopped); ctr != nil {
return &imageDeleteConflict{
imgID: imgID,
used: true,
message: fmt.Sprintf("image is being used by stopped container %s", stringid.TruncateID(ctr.ID)),
}
}
}
return nil
}
// imageIsDangling returns whether the given image is "dangling" which means
// that there are no repository references to the given image and it has no
// child images.
func (i *ImageService) imageIsDangling(imgID image.ID) bool {
return !(len(i.referenceStore.References(imgID.Digest())) > 0 || len(i.imageStore.Children(imgID)) > 0)
}