func (s *TagStore) CmdPull(job *engine.Job) error {
if n := len(job.Args); n != 1 && n != 2 {
return fmt.Errorf("Usage: %s IMAGE [TAG|DIGEST]", job.Name)
}
var (
localName = job.Args[0]
tag string
sf = utils.NewStreamFormatter(job.GetenvBool("json"))
authConfig = ®istry.AuthConfig{}
metaHeaders map[string][]string
)
// Resolve the Repository name from fqn to RepositoryInfo
repoInfo, err := registry.ResolveRepositoryInfo(job, localName)
if err != nil {
return err
}
if len(job.Args) > 1 {
tag = job.Args[1]
}
job.GetenvJson("authConfig", authConfig)
job.GetenvJson("metaHeaders", &metaHeaders)
c, err := s.poolAdd("pull", utils.ImageReference(repoInfo.LocalName, tag))
if err != nil {
if c != nil {
// Another pull of the same repository is already taking place; just wait for it to finish
job.Stdout.Write(sf.FormatStatus("", "Repository %s already being pulled by another client. Waiting.", repoInfo.LocalName))
<-c
return nil
}
return err
}
defer s.poolRemove("pull", utils.ImageReference(repoInfo.LocalName, tag))
log.Debugf("pulling image from host %q with remote name %q", repoInfo.Index.Name, repoInfo.RemoteName)
endpoint, err := repoInfo.GetEndpoint()
if err != nil {
return err
}
r, err := registry.NewSession(authConfig, registry.HTTPRequestFactory(metaHeaders), endpoint, true)
if err != nil {
return err
}
logName := repoInfo.LocalName
if tag != "" {
logName = utils.ImageReference(logName, tag)
}
if len(repoInfo.Index.Mirrors) == 0 && (repoInfo.Index.Official || endpoint.Version == registry.APIVersion2) {
if repoInfo.Official {
j := job.Eng.Job("trust_update_base")
if err = j.Run(); err != nil {
log.Errorf("error updating trust base graph: %s", err)
}
}
log.Debugf("pulling v2 repository with local name %q", repoInfo.LocalName)
if err := s.pullV2Repository(job.Eng, r, job.Stdout, repoInfo, tag, sf, job.GetenvBool("parallel")); err == nil {
if err = job.Eng.Job("log", "pull", logName, "").Run(); err != nil {
log.Errorf("Error logging event 'pull' for %s: %s", logName, err)
}
return nil
} else if err != registry.ErrDoesNotExist && err != ErrV2RegistryUnavailable {
log.Errorf("Error from V2 registry: %s", err)
}
log.Debug("image does not exist on v2 registry, falling back to v1")
}
log.Debugf("pulling v1 repository with local name %q", repoInfo.LocalName)
if err = s.pullRepository(r, job.Stdout, repoInfo, tag, sf, job.GetenvBool("parallel")); err != nil {
return err
}
if err = job.Eng.Job("log", "pull", logName, "").Run(); err != nil {
log.Errorf("Error logging event 'pull' for %s: %s", logName, err)
}
return nil
}
// attemptIDReuse does a best attempt to match verified compatibilityIDs
// already in the graph with the computed strongIDs so we can keep using them.
// This process will never fail but may just return the strongIDs if none of
// the compatibilityIDs exists or can be verified. If the strongIDs themselves
// fail verification, we deterministically generate alternate IDs to use until
// we find one that's available or already exists with the correct data.
func (p *v2Puller) attemptIDReuse(imgs []contentAddressableDescriptor) {
// This function needs to be protected with a global lock, because it
// locks multiple IDs at once, and there's no good way to make sure
// the locking happens a deterministic order.
p.graph.imagesMutex.Lock()
defer p.graph.imagesMutex.Unlock()
idMap := make(map[string]struct{})
for _, img := range imgs {
idMap[img.id] = struct{}{}
idMap[img.compatibilityID] = struct{}{}
if p.graph.Exists(img.compatibilityID) {
if _, err := p.graph.GenerateV1CompatibilityChain(img.compatibilityID); err != nil {
logrus.Debugf("Migration v1Compatibility generation error: %v", err)
return
}
}
}
for id := range idMap {
p.graph.imageMutex.Lock(id)
defer p.graph.imageMutex.Unlock(id)
}
// continueReuse controls whether the function will try to find
// existing layers on disk under the old v1 IDs, to avoid repulling
// them. The hashes are checked to ensure these layers are okay to
// use. continueReuse starts out as true, but is set to false if
// the code encounters something that doesn't match the expected hash.
continueReuse := true
for i := len(imgs) - 1; i >= 0; i-- {
if p.graph.Exists(imgs[i].id) {
// Found an image in the graph under the strongID. Validate the
// image before using it.
if err := p.validateImageInGraph(imgs[i].id, imgs, i); err != nil {
continueReuse = false
logrus.Debugf("not using existing strongID: %v", err)
// The strong ID existed in the graph but didn't
// validate successfully. We can't use the strong ID
// because it didn't validate successfully. Treat the
// graph like a hash table with probing... compute
// SHA256(id) until we find an ID that either doesn't
// already exist in the graph, or has existing content
// that validates successfully.
for {
if err := p.tryNextID(imgs, i, idMap); err != nil {
logrus.Debug(err.Error())
} else {
break
}
}
}
continue
}
if continueReuse {
compatibilityID := imgs[i].compatibilityID
if err := p.validateImageInGraph(compatibilityID, imgs, i); err != nil {
logrus.Debugf("stopping ID reuse: %v", err)
continueReuse = false
} else {
// The compatibility ID exists in the graph and was
// validated. Use it.
imgs[i].id = compatibilityID
}
}
}
// fix up the parents of the images
for i := 0; i < len(imgs); i++ {
if i == len(imgs)-1 { // Base layer
imgs[i].parent = ""
} else {
imgs[i].parent = imgs[i+1].id
}
}
}