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moby--moby/daemon/image_delete.go
Antonio Murdaca f9e81b40f4 daemon: faster image cache miss detection
Lookup the graph parent reference to detect a builder cache miss before
looping the whole graph image index to build a parent-children tree.

Signed-off-by: Antonio Murdaca <runcom@redhat.com>
2015-10-21 17:13:45 +02:00

341 lines
12 KiB
Go

package daemon
import (
"fmt"
"strings"
"github.com/docker/docker/api/types"
derr "github.com/docker/docker/errors"
"github.com/docker/docker/graph/tags"
"github.com/docker/docker/image"
"github.com/docker/docker/pkg/parsers"
"github.com/docker/docker/pkg/stringid"
"github.com/docker/docker/utils"
)
// 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 descendent 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.
//
// FIXME: remove ImageDelete's dependency on Daemon, then move to the graph
// package. This would require that we no longer need the daemon to determine
// whether images are being used by a stopped or running container.
func (daemon *Daemon) ImageDelete(imageRef string, force, prune bool) ([]types.ImageDelete, error) {
records := []types.ImageDelete{}
img, err := daemon.repositories.LookupImage(imageRef)
if err != nil {
return nil, err
}
var removedRepositoryRef bool
if !isImageIDPrefix(img.ID, 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 || daemon.imageHasMultipleRepositoryReferences(img.ID)) {
if container := daemon.getContainerUsingImage(img.ID); container != 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.
return nil, derr.ErrorCodeImgDelUsed.WithArgs(imageRef, stringid.TruncateID(container.ID), stringid.TruncateID(img.ID))
}
}
parsedRef, err := daemon.removeImageRef(imageRef)
if err != nil {
return nil, err
}
untaggedRecord := types.ImageDelete{Untagged: parsedRef}
daemon.EventsService.Log("untag", img.ID, "")
records = append(records, untaggedRecord)
removedRepositoryRef = true
} else {
// If an ID reference was given AND there is exactly one
// repository reference to the image then we will want to
// remove that reference.
// FIXME: Is this the behavior we want?
repoRefs := daemon.repositories.ByID()[img.ID]
if len(repoRefs) == 1 {
parsedRef, err := daemon.removeImageRef(repoRefs[0])
if err != nil {
return nil, err
}
untaggedRecord := types.ImageDelete{Untagged: parsedRef}
daemon.EventsService.Log("untag", img.ID, "")
records = append(records, untaggedRecord)
}
}
return records, daemon.imageDeleteHelper(img, &records, force, prune, removedRepositoryRef)
}
// isImageIDPrefix returns whether the given possiblePrefix is a prefix of the
// given imageID.
func isImageIDPrefix(imageID, possiblePrefix string) bool {
return strings.HasPrefix(imageID, possiblePrefix)
}
// imageHasMultipleRepositoryReferences returns whether there are multiple
// repository references to the given imageID.
func (daemon *Daemon) imageHasMultipleRepositoryReferences(imageID string) bool {
return len(daemon.repositories.ByID()[imageID]) > 1
}
// getContainerUsingImage returns a container that was created using the given
// imageID. Returns nil if there is no such container.
func (daemon *Daemon) getContainerUsingImage(imageID string) *Container {
for _, container := range daemon.List() {
if container.ImageID == imageID {
return container
}
}
return nil
}
// 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 (daemon *Daemon) removeImageRef(repositoryRef string) (string, error) {
repository, ref := parsers.ParseRepositoryTag(repositoryRef)
if ref == "" {
ref = tags.DefaultTag
}
// 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 := daemon.repositories.Delete(repository, ref)
return utils.ImageReference(repository, 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.ImageDelete is added to the
// given list of records.
func (daemon *Daemon) removeAllReferencesToImageID(imgID string, records *[]types.ImageDelete) error {
imageRefs := daemon.repositories.ByID()[imgID]
for _, imageRef := range imageRefs {
parsedRef, err := daemon.removeImageRef(imageRef)
if err != nil {
return err
}
untaggedRecord := types.ImageDelete{Untagged: parsedRef}
daemon.EventsService.Log("untag", imgID, "")
*records = append(*records, untaggedRecord)
}
return nil
}
// ImageDeleteConflict holds a soft or hard conflict and an associated error.
// Implements the error interface.
type imageDeleteConflict struct {
hard bool
imgID string
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), forceMsg, idc.message)
}
// 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 (daemon *Daemon) imageDeleteHelper(img *image.Image, records *[]types.ImageDelete, force, prune, quiet bool) error {
// First, determine if this image has any conflicts. Ignore soft conflicts
// if force is true.
if conflict := daemon.checkImageDeleteConflict(img, force); conflict != nil {
if quiet && !daemon.imageIsDangling(img) {
// Ignore conflicts UNLESS the image is "dangling" 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
}
// Delete all repository tag/digest references to this image.
if err := daemon.removeAllReferencesToImageID(img.ID, records); err != nil {
return err
}
if err := daemon.Graph().Delete(img.ID); err != nil {
return err
}
daemon.EventsService.Log("delete", img.ID, "")
*records = append(*records, types.ImageDelete{Deleted: img.ID})
if !prune || img.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).
parentImg, err := daemon.Graph().Get(img.Parent)
if err != nil {
return derr.ErrorCodeImgNoParent.WithArgs(err)
}
// Do not force prunings, but do so quietly (stopping on any encountered
// conflicts).
return daemon.imageDeleteHelper(parentImg, 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 (daemon *Daemon) checkImageDeleteConflict(img *image.Image, ignoreSoftConflicts bool) *imageDeleteConflict {
// Check for hard conflicts first.
if conflict := daemon.checkImageDeleteHardConflict(img); conflict != nil {
return conflict
}
// Then check for soft conflicts.
if ignoreSoftConflicts {
// Don't bother checking for soft conflicts.
return nil
}
return daemon.checkImageDeleteSoftConflict(img)
}
func (daemon *Daemon) checkImageDeleteHardConflict(img *image.Image) *imageDeleteConflict {
// Check if the image ID is being used by a pull or build.
if daemon.Graph().IsHeld(img.ID) {
return &imageDeleteConflict{
hard: true,
imgID: img.ID,
message: "image is held by an ongoing pull or build",
}
}
// Check if the image has any descendent images.
if daemon.Graph().HasChildren(img.ID) {
return &imageDeleteConflict{
hard: true,
imgID: img.ID,
message: "image has dependent child images",
}
}
// Check if any running container is using the image.
for _, container := range daemon.List() {
if !container.IsRunning() {
// Skip this until we check for soft conflicts later.
continue
}
if container.ImageID == img.ID {
return &imageDeleteConflict{
imgID: img.ID,
hard: true,
message: fmt.Sprintf("image is being used by running container %s", stringid.TruncateID(container.ID)),
}
}
}
return nil
}
func (daemon *Daemon) checkImageDeleteSoftConflict(img *image.Image) *imageDeleteConflict {
// Check if any repository tags/digest reference this image.
if daemon.repositories.HasReferences(img) {
return &imageDeleteConflict{
imgID: img.ID,
message: "image is referenced in one or more repositories",
}
}
// Check if any stopped containers reference this image.
for _, container := range daemon.List() {
if container.IsRunning() {
// Skip this as it was checked above in hard conflict conditions.
continue
}
if container.ImageID == img.ID {
return &imageDeleteConflict{
imgID: img.ID,
message: fmt.Sprintf("image is being used by stopped container %s", stringid.TruncateID(container.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 (daemon *Daemon) imageIsDangling(img *image.Image) bool {
return !(daemon.repositories.HasReferences(img) || daemon.Graph().HasChildren(img.ID))
}