1
0
Fork 0
mirror of https://github.com/moby/moby.git synced 2022-11-09 12:21:53 -05:00
moby--moby/daemon/image_delete.go
David Calavera 27c76522de Define a context per request.
Avoid creating a global context object that will be used while the daemon is running.

Not only this object won't ever be garbage collected, but it won't ever be used for anything else than creating other contexts in each request. I think it's a bad practive to have something like this sprawling aroud the code.

This change removes that global object and initializes a context in the cases we don't have already one, like shutting down the server.
This also removes a bunch of context arguments from functions that did nothing with it.

Signed-off-by: David Calavera <david.calavera@gmail.com>
2015-09-24 18:44:53 -04:00

342 lines
12 KiB
Go

package daemon
import (
"fmt"
"strings"
"github.com/docker/docker/api/types"
"github.com/docker/docker/context"
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(ctx context.Context, 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(ctx, 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(ctx, imageRef)
if err != nil {
return nil, err
}
untaggedRecord := types.ImageDelete{Untagged: parsedRef}
daemon.EventsService.Log(ctx, "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(ctx, repoRefs[0])
if err != nil {
return nil, err
}
untaggedRecord := types.ImageDelete{Untagged: parsedRef}
daemon.EventsService.Log(ctx, "untag", img.ID, "")
records = append(records, untaggedRecord)
}
}
return records, daemon.imageDeleteHelper(ctx, 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(ctx context.Context, 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(ctx context.Context, 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(ctx context.Context, imgID string, records *[]types.ImageDelete) error {
imageRefs := daemon.Repositories().ByID()[imgID]
for _, imageRef := range imageRefs {
parsedRef, err := daemon.removeImageRef(ctx, imageRef)
if err != nil {
return err
}
untaggedRecord := types.ImageDelete{Untagged: parsedRef}
daemon.EventsService.Log(ctx, "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(ctx context.Context, 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(ctx, img, force); conflict != nil {
if quiet && !daemon.imageIsDangling(ctx, 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(ctx, img.ID, records); err != nil {
return err
}
if err := daemon.Graph().Delete(img.ID); err != nil {
return err
}
daemon.EventsService.Log(ctx, "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(ctx, 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(ctx context.Context, img *image.Image, ignoreSoftConflicts bool) *imageDeleteConflict {
// Check for hard conflicts first.
if conflict := daemon.checkImageDeleteHardConflict(ctx, img); conflict != nil {
return conflict
}
// Then check for soft conflicts.
if ignoreSoftConflicts {
// Don't bother checking for soft conflicts.
return nil
}
return daemon.checkImageDeleteSoftConflict(ctx, img)
}
func (daemon *Daemon) checkImageDeleteHardConflict(ctx context.Context, 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) {
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(ctx context.Context, 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(ctx context.Context, img *image.Image) bool {
return !(daemon.Repositories().HasReferences(img) || daemon.Graph().HasChildren(img))
}