45a8f68026
Generalize content addressable and reference storage
404 lines
14 KiB
Go
404 lines
14 KiB
Go
package daemon
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import (
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"fmt"
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"strings"
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"github.com/docker/docker/api/errors"
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"github.com/docker/docker/api/types"
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"github.com/docker/docker/container"
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"github.com/docker/docker/image"
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"github.com/docker/docker/pkg/stringid"
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"github.com/docker/docker/reference"
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)
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type conflictType int
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const (
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conflictDependentChild conflictType = (1 << iota)
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conflictRunningContainer
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conflictActiveReference
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conflictStoppedContainer
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conflictHard = conflictDependentChild | conflictRunningContainer
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conflictSoft = conflictActiveReference | conflictStoppedContainer
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)
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// ImageDelete deletes the image referenced by the given imageRef from this
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// daemon. The given imageRef can be an image ID, ID prefix, or a repository
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// reference (with an optional tag or digest, defaulting to the tag name
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// "latest"). There is differing behavior depending on whether the given
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// imageRef is a repository reference or not.
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//
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// If the given imageRef is a repository reference then that repository
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// reference will be removed. However, if there exists any containers which
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// were created using the same image reference then the repository reference
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// cannot be removed unless either there are other repository references to the
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// same image or force is true. Following removal of the repository reference,
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// the referenced image itself will attempt to be deleted as described below
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// but quietly, meaning any image delete conflicts will cause the image to not
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// be deleted and the conflict will not be reported.
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//
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// There may be conflicts preventing deletion of an image and these conflicts
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// are divided into two categories grouped by their severity:
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//
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// Hard Conflict:
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// - a pull or build using the image.
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// - any descendant image.
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// - any running container using the image.
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//
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// Soft Conflict:
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// - any stopped container using the image.
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// - any repository tag or digest references to the image.
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//
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// The image cannot be removed if there are any hard conflicts and can be
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// removed if there are soft conflicts only if force is true.
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//
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// If prune is true, ancestor images will each attempt to be deleted quietly,
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// meaning any delete conflicts will cause the image to not be deleted and the
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// conflict will not be reported.
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//
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// FIXME: remove ImageDelete's dependency on Daemon, then move to the graph
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// package. This would require that we no longer need the daemon to determine
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// whether images are being used by a stopped or running container.
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func (daemon *Daemon) ImageDelete(imageRef string, force, prune bool) ([]types.ImageDelete, error) {
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records := []types.ImageDelete{}
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imgID, err := daemon.GetImageID(imageRef)
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if err != nil {
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return nil, daemon.imageNotExistToErrcode(err)
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}
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repoRefs := daemon.referenceStore.References(imgID.Digest())
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var removedRepositoryRef bool
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if !isImageIDPrefix(imgID.String(), imageRef) {
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// A repository reference was given and should be removed
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// first. We can only remove this reference if either force is
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// true, there are multiple repository references to this
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// image, or there are no containers using the given reference.
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if !force && isSingleReference(repoRefs) {
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if container := daemon.getContainerUsingImage(imgID); container != nil {
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// If we removed the repository reference then
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// this image would remain "dangling" and since
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// we really want to avoid that the client must
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// explicitly force its removal.
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err := fmt.Errorf("conflict: unable to remove repository reference %q (must force) - container %s is using its referenced image %s", imageRef, stringid.TruncateID(container.ID), stringid.TruncateID(imgID.String()))
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return nil, errors.NewRequestConflictError(err)
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}
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}
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parsedRef, err := reference.ParseNamed(imageRef)
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if err != nil {
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return nil, err
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}
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parsedRef, err = daemon.removeImageRef(parsedRef)
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if err != nil {
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return nil, err
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}
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untaggedRecord := types.ImageDelete{Untagged: parsedRef.String()}
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daemon.LogImageEvent(imgID.String(), imgID.String(), "untag")
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records = append(records, untaggedRecord)
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repoRefs = daemon.referenceStore.References(imgID.Digest())
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// If a tag reference was removed and the only remaining
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// references to the same repository are digest references,
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// then clean up those digest references.
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if _, isCanonical := parsedRef.(reference.Canonical); !isCanonical {
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foundRepoTagRef := false
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for _, repoRef := range repoRefs {
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if _, repoRefIsCanonical := repoRef.(reference.Canonical); !repoRefIsCanonical && parsedRef.Name() == repoRef.Name() {
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foundRepoTagRef = true
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break
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}
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}
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if !foundRepoTagRef {
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// Remove canonical references from same repository
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remainingRefs := []reference.Named{}
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for _, repoRef := range repoRefs {
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if _, repoRefIsCanonical := repoRef.(reference.Canonical); repoRefIsCanonical && parsedRef.Name() == repoRef.Name() {
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if _, err := daemon.removeImageRef(repoRef); err != nil {
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return records, err
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}
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untaggedRecord := types.ImageDelete{Untagged: repoRef.String()}
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records = append(records, untaggedRecord)
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} else {
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remainingRefs = append(remainingRefs, repoRef)
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}
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}
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repoRefs = remainingRefs
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}
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}
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// If it has remaining references then the untag finished the remove
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if len(repoRefs) > 0 {
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return records, nil
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}
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removedRepositoryRef = true
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} else {
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// If an ID reference was given AND there is at most one tag
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// reference to the image AND all references are within one
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// repository, then remove all references.
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if isSingleReference(repoRefs) {
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c := conflictHard
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if !force {
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c |= conflictSoft &^ conflictActiveReference
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}
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if conflict := daemon.checkImageDeleteConflict(imgID, c); conflict != nil {
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return nil, conflict
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}
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for _, repoRef := range repoRefs {
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parsedRef, err := daemon.removeImageRef(repoRef)
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if err != nil {
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return nil, err
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}
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untaggedRecord := types.ImageDelete{Untagged: parsedRef.String()}
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daemon.LogImageEvent(imgID.String(), imgID.String(), "untag")
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records = append(records, untaggedRecord)
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}
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}
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}
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return records, daemon.imageDeleteHelper(imgID, &records, force, prune, removedRepositoryRef)
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}
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// isSingleReference returns true when all references are from one repository
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// and there is at most one tag. Returns false for empty input.
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func isSingleReference(repoRefs []reference.Named) bool {
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if len(repoRefs) <= 1 {
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return len(repoRefs) == 1
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}
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var singleRef reference.Named
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canonicalRefs := map[string]struct{}{}
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for _, repoRef := range repoRefs {
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if _, isCanonical := repoRef.(reference.Canonical); isCanonical {
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canonicalRefs[repoRef.Name()] = struct{}{}
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} else if singleRef == nil {
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singleRef = repoRef
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} else {
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return false
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}
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}
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if singleRef == nil {
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// Just use first canonical ref
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singleRef = repoRefs[0]
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}
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_, ok := canonicalRefs[singleRef.Name()]
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return len(canonicalRefs) == 1 && ok
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}
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// isImageIDPrefix returns whether the given possiblePrefix is a prefix of the
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// given imageID.
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func isImageIDPrefix(imageID, possiblePrefix string) bool {
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if strings.HasPrefix(imageID, possiblePrefix) {
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return true
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}
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if i := strings.IndexRune(imageID, ':'); i >= 0 {
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return strings.HasPrefix(imageID[i+1:], possiblePrefix)
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}
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return false
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}
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// getContainerUsingImage returns a container that was created using the given
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// imageID. Returns nil if there is no such container.
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func (daemon *Daemon) getContainerUsingImage(imageID image.ID) *container.Container {
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return daemon.containers.First(func(c *container.Container) bool {
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return c.ImageID == imageID
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})
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}
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// removeImageRef attempts to parse and remove the given image reference from
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// this daemon's store of repository tag/digest references. The given
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// repositoryRef must not be an image ID but a repository name followed by an
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// optional tag or digest reference. If tag or digest is omitted, the default
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// tag is used. Returns the resolved image reference and an error.
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func (daemon *Daemon) removeImageRef(ref reference.Named) (reference.Named, error) {
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ref = reference.WithDefaultTag(ref)
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// Ignore the boolean value returned, as far as we're concerned, this
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// is an idempotent operation and it's okay if the reference didn't
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// exist in the first place.
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_, err := daemon.referenceStore.Delete(ref)
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return ref, err
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}
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// removeAllReferencesToImageID attempts to remove every reference to the given
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// imgID from this daemon's store of repository tag/digest references. Returns
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// on the first encountered error. Removed references are logged to this
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// daemon's event service. An "Untagged" types.ImageDelete is added to the
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// given list of records.
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func (daemon *Daemon) removeAllReferencesToImageID(imgID image.ID, records *[]types.ImageDelete) error {
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imageRefs := daemon.referenceStore.References(imgID.Digest())
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for _, imageRef := range imageRefs {
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parsedRef, err := daemon.removeImageRef(imageRef)
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if err != nil {
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return err
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}
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untaggedRecord := types.ImageDelete{Untagged: parsedRef.String()}
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daemon.LogImageEvent(imgID.String(), imgID.String(), "untag")
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*records = append(*records, untaggedRecord)
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}
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return nil
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}
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// ImageDeleteConflict holds a soft or hard conflict and an associated error.
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// Implements the error interface.
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type imageDeleteConflict struct {
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hard bool
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used bool
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imgID image.ID
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message string
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}
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func (idc *imageDeleteConflict) Error() string {
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var forceMsg string
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if idc.hard {
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forceMsg = "cannot be forced"
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} else {
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forceMsg = "must be forced"
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}
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return fmt.Sprintf("conflict: unable to delete %s (%s) - %s", stringid.TruncateID(idc.imgID.String()), forceMsg, idc.message)
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}
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// imageDeleteHelper attempts to delete the given image from this daemon. If
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// the image has any hard delete conflicts (child images or running containers
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// using the image) then it cannot be deleted. If the image has any soft delete
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// conflicts (any tags/digests referencing the image or any stopped container
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// using the image) then it can only be deleted if force is true. If the delete
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// succeeds and prune is true, the parent images are also deleted if they do
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// not have any soft or hard delete conflicts themselves. Any deleted images
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// and untagged references are appended to the given records. If any error or
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// conflict is encountered, it will be returned immediately without deleting
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// the image. If quiet is true, any encountered conflicts will be ignored and
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// the function will return nil immediately without deleting the image.
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func (daemon *Daemon) imageDeleteHelper(imgID image.ID, records *[]types.ImageDelete, force, prune, quiet bool) error {
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// First, determine if this image has any conflicts. Ignore soft conflicts
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// if force is true.
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c := conflictHard
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if !force {
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c |= conflictSoft
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}
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if conflict := daemon.checkImageDeleteConflict(imgID, c); conflict != nil {
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if quiet && (!daemon.imageIsDangling(imgID) || conflict.used) {
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// Ignore conflicts UNLESS the image is "dangling" or not being used in
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// which case we want the user to know.
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return nil
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}
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// There was a conflict and it's either a hard conflict OR we are not
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// forcing deletion on soft conflicts.
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return conflict
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}
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parent, err := daemon.imageStore.GetParent(imgID)
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if err != nil {
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// There may be no parent
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parent = ""
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}
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// Delete all repository tag/digest references to this image.
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if err := daemon.removeAllReferencesToImageID(imgID, records); err != nil {
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return err
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}
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removedLayers, err := daemon.imageStore.Delete(imgID)
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if err != nil {
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return err
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}
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daemon.LogImageEvent(imgID.String(), imgID.String(), "delete")
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*records = append(*records, types.ImageDelete{Deleted: imgID.String()})
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for _, removedLayer := range removedLayers {
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*records = append(*records, types.ImageDelete{Deleted: removedLayer.ChainID.String()})
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}
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if !prune || parent == "" {
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return nil
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}
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// We need to prune the parent image. This means delete it if there are
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// no tags/digests referencing it and there are no containers using it (
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// either running or stopped).
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// Do not force prunings, but do so quietly (stopping on any encountered
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// conflicts).
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return daemon.imageDeleteHelper(parent, records, false, true, true)
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}
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// checkImageDeleteConflict determines whether there are any conflicts
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// preventing deletion of the given image from this daemon. A hard conflict is
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// any image which has the given image as a parent or any running container
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// using the image. A soft conflict is any tags/digest referencing the given
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// image or any stopped container using the image. If ignoreSoftConflicts is
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// true, this function will not check for soft conflict conditions.
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func (daemon *Daemon) checkImageDeleteConflict(imgID image.ID, mask conflictType) *imageDeleteConflict {
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// Check if the image has any descendant images.
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if mask&conflictDependentChild != 0 && len(daemon.imageStore.Children(imgID)) > 0 {
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return &imageDeleteConflict{
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hard: true,
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imgID: imgID,
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message: "image has dependent child images",
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}
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}
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if mask&conflictRunningContainer != 0 {
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// Check if any running container is using the image.
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running := func(c *container.Container) bool {
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return c.IsRunning() && c.ImageID == imgID
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}
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if container := daemon.containers.First(running); container != nil {
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return &imageDeleteConflict{
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imgID: imgID,
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hard: true,
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used: true,
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message: fmt.Sprintf("image is being used by running container %s", stringid.TruncateID(container.ID)),
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}
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}
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}
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// Check if any repository tags/digest reference this image.
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if mask&conflictActiveReference != 0 && len(daemon.referenceStore.References(imgID.Digest())) > 0 {
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return &imageDeleteConflict{
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imgID: imgID,
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message: "image is referenced in multiple repositories",
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}
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}
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if mask&conflictStoppedContainer != 0 {
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// Check if any stopped containers reference this image.
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stopped := func(c *container.Container) bool {
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return !c.IsRunning() && c.ImageID == imgID
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}
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if container := daemon.containers.First(stopped); container != nil {
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return &imageDeleteConflict{
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imgID: imgID,
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used: true,
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message: fmt.Sprintf("image is being used by stopped container %s", stringid.TruncateID(container.ID)),
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}
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}
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}
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return nil
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}
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// imageIsDangling returns whether the given image is "dangling" which means
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// that there are no repository references to the given image and it has no
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// child images.
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func (daemon *Daemon) imageIsDangling(imgID image.ID) bool {
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return !(len(daemon.referenceStore.References(imgID.Digest())) > 0 || len(daemon.imageStore.Children(imgID)) > 0)
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}
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