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pull.go
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pull.go
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package libimage
import (
"context"
"fmt"
"io"
"strings"
"time"
"github.com/containers/common/pkg/config"
registryTransport "github.com/containers/image/v5/docker"
dockerArchiveTransport "github.com/containers/image/v5/docker/archive"
"github.com/containers/image/v5/docker/reference"
ociArchiveTransport "github.com/containers/image/v5/oci/archive"
ociTransport "github.com/containers/image/v5/oci/layout"
"github.com/containers/image/v5/pkg/shortnames"
storageTransport "github.com/containers/image/v5/storage"
"github.com/containers/image/v5/transports/alltransports"
"github.com/containers/image/v5/types"
"github.com/containers/storage"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
// PullOptions allows for custommizing image pulls.
type PullOptions struct {
CopyOptions
// If true, all tags of the image will be pulled from the container
// registry. Only supported for the docker transport.
AllTags bool
}
// Pull pulls the specified name. Name may refer to any of the supported
// transports from github.com/containers/image. If no transport is encoded,
// name will be treated as a reference to a registry (i.e., docker transport).
//
// Note that pullPolicy is only used when pulling from a container registry but
// it *must* be different than the default value `config.PullPolicyUnsupported`. This
// way, callers are forced to decide on the pull behaviour. The reasoning
// behind is that some (commands of some) tools have different default pull
// policies (e.g., buildah-bud versus podman-build). Making the pull-policy
// choice explicit is an attempt to prevent silent regressions.
//
// The error is storage.ErrImageUnknown iff the pull policy is set to "never"
// and no local image has been found. This allows for an easier integration
// into some users of this package (e.g., Buildah).
func (r *Runtime) Pull(ctx context.Context, name string, pullPolicy config.PullPolicy, options *PullOptions) ([]*Image, error) {
logrus.Debugf("Pulling image %s (policy: %s)", name, pullPolicy)
if options == nil {
options = &PullOptions{}
}
var possiblyUnqualifiedName string // used for short-name resolution
ref, err := alltransports.ParseImageName(name)
if err != nil {
// If the image clearly refers to a local one, we can look it up directly.
// In fact, we need to since they are not parseable.
if strings.HasPrefix(name, "sha256:") || (len(name) == 64 && !strings.ContainsAny(name, "/.:@")) {
if pullPolicy == config.PullPolicyAlways {
return nil, errors.Errorf("pull policy is always but image has been referred to by ID (%s)", name)
}
local, _, err := r.LookupImage(name, nil)
if err != nil {
return nil, err
}
return []*Image{local}, err
}
// If the input does not include a transport assume it refers
// to a registry.
dockerRef, dockerErr := alltransports.ParseImageName("docker://" + name)
if dockerErr != nil {
return nil, err
}
ref = dockerRef
possiblyUnqualifiedName = name
} else if ref.Transport().Name() == registryTransport.Transport.Name() {
// Normalize the input if we're referring to the docker
// transport directly. That makes sure that a `docker://fedora`
// will resolve directly to `docker.io/library/fedora:latest`
// and not be subject to short-name resolution.
named := ref.DockerReference()
if named == nil {
return nil, errors.New("internal error: unexpected nil reference")
}
possiblyUnqualifiedName = named.String()
}
if options.AllTags && ref.Transport().Name() != registryTransport.Transport.Name() {
return nil, errors.Errorf("pulling all tags is not supported for %s transport", ref.Transport().Name())
}
if r.eventChannel != nil {
defer r.writeEvent(&Event{ID: "", Name: name, Time: time.Now(), Type: EventTypeImagePull})
}
// Some callers may set the platform via the system context at creation
// time of the runtime. We need this information to decide whether we
// need to enforce pulling from a registry (see
// containers/podman/issues/10682).
if options.Architecture == "" {
options.Architecture = r.systemContext.ArchitectureChoice
}
if options.OS == "" {
options.OS = r.systemContext.OSChoice
}
if options.Variant == "" {
options.Variant = r.systemContext.VariantChoice
}
var (
pulledImages []string
pullError error
)
// Dispatch the copy operation.
switch ref.Transport().Name() {
// DOCKER REGISTRY
case registryTransport.Transport.Name():
pulledImages, pullError = r.copyFromRegistry(ctx, ref, possiblyUnqualifiedName, pullPolicy, options)
// DOCKER ARCHIVE
case dockerArchiveTransport.Transport.Name():
pulledImages, pullError = r.copyFromDockerArchive(ctx, ref, &options.CopyOptions)
// ALL OTHER TRANSPORTS
default:
pulledImages, pullError = r.copyFromDefault(ctx, ref, &options.CopyOptions)
}
if pullError != nil {
return nil, pullError
}
localImages := []*Image{}
lookupOptions := &LookupImageOptions{IgnorePlatform: true}
for _, name := range pulledImages {
local, _, err := r.LookupImage(name, lookupOptions)
if err != nil {
return nil, errors.Wrapf(err, "error locating pulled image %q name in containers storage", name)
}
localImages = append(localImages, local)
}
return localImages, pullError
}
// copyFromDefault is the default copier for a number of transports. Other
// transports require some specific dancing, sometimes Yoga.
func (r *Runtime) copyFromDefault(ctx context.Context, ref types.ImageReference, options *CopyOptions) ([]string, error) {
c, err := r.newCopier(options)
if err != nil {
return nil, err
}
defer c.close()
// Figure out a name for the storage destination.
var storageName, imageName string
switch ref.Transport().Name() {
case ociTransport.Transport.Name():
split := strings.SplitN(ref.StringWithinTransport(), ":", 2)
storageName = toLocalImageName(split[0])
imageName = storageName
case ociArchiveTransport.Transport.Name():
manifest, err := ociArchiveTransport.LoadManifestDescriptor(ref)
if err != nil {
return nil, err
}
// if index.json has no reference name, compute the image digest instead
if manifest.Annotations == nil || manifest.Annotations["org.opencontainers.image.ref.name"] == "" {
storageName, err = getImageDigest(ctx, ref, nil)
if err != nil {
return nil, err
}
imageName = "sha256:" + storageName[1:]
} else {
storageName = manifest.Annotations["org.opencontainers.image.ref.name"]
named, err := NormalizeName(storageName)
if err != nil {
return nil, err
}
imageName = named.String()
storageName = imageName
}
case storageTransport.Transport.Name():
storageName = ref.StringWithinTransport()
named := ref.DockerReference()
if named == nil {
return nil, errors.Errorf("could not get an image name for storage reference %q", ref)
}
imageName = named.String()
default:
storageName = toLocalImageName(ref.StringWithinTransport())
imageName = storageName
}
// Create a storage reference.
destRef, err := storageTransport.Transport.ParseStoreReference(r.store, storageName)
if err != nil {
return nil, errors.Wrapf(err, "parsing %q", storageName)
}
_, err = c.copy(ctx, ref, destRef)
return []string{imageName}, err
}
// storageReferencesFromArchiveReader returns a slice of image references inside the
// archive reader. A docker archive may include more than one image and this
// method allows for extracting them into containers storage references which
// can later be used from copying.
func (r *Runtime) storageReferencesReferencesFromArchiveReader(ctx context.Context, readerRef types.ImageReference, reader *dockerArchiveTransport.Reader) ([]types.ImageReference, []string, error) {
destNames, err := reader.ManifestTagsForReference(readerRef)
if err != nil {
return nil, nil, err
}
var imageNames []string
if len(destNames) == 0 {
destName, err := getImageDigest(ctx, readerRef, &r.systemContext)
if err != nil {
return nil, nil, err
}
destNames = append(destNames, destName)
// Make sure the image can be loaded after the pull by
// replacing the @ with sha256:.
imageNames = append(imageNames, "sha256:"+destName[1:])
} else {
for i := range destNames {
ref, err := NormalizeName(destNames[i])
if err != nil {
return nil, nil, err
}
destNames[i] = ref.String()
}
imageNames = destNames
}
references := []types.ImageReference{}
for _, destName := range destNames {
destRef, err := storageTransport.Transport.ParseStoreReference(r.store, destName)
if err != nil {
return nil, nil, errors.Wrapf(err, "error parsing dest reference name %#v", destName)
}
references = append(references, destRef)
}
return references, imageNames, nil
}
// copyFromDockerArchive copies one image from the specified reference.
func (r *Runtime) copyFromDockerArchive(ctx context.Context, ref types.ImageReference, options *CopyOptions) ([]string, error) {
// There may be more than one image inside the docker archive, so we
// need a quick glimpse inside.
reader, readerRef, err := dockerArchiveTransport.NewReaderForReference(&r.systemContext, ref)
if err != nil {
return nil, err
}
return r.copyFromDockerArchiveReaderReference(ctx, reader, readerRef, options)
}
// copyFromDockerArchiveReaderReference copies the specified readerRef from reader.
func (r *Runtime) copyFromDockerArchiveReaderReference(ctx context.Context, reader *dockerArchiveTransport.Reader, readerRef types.ImageReference, options *CopyOptions) ([]string, error) {
c, err := r.newCopier(options)
if err != nil {
return nil, err
}
defer c.close()
// Get a slice of storage references we can copy.
references, destNames, err := r.storageReferencesReferencesFromArchiveReader(ctx, readerRef, reader)
if err != nil {
return nil, err
}
// Now copy all of the images. Use readerRef for performance.
for _, destRef := range references {
if _, err := c.copy(ctx, readerRef, destRef); err != nil {
return nil, err
}
}
return destNames, nil
}
// copyFromRegistry pulls the specified, possibly unqualified, name from a
// registry. On successful pull it returns the used fully-qualified name that
// can later be used to look up the image in the local containers storage.
//
// If options.All is set, all tags from the specified registry will be pulled.
func (r *Runtime) copyFromRegistry(ctx context.Context, ref types.ImageReference, inputName string, pullPolicy config.PullPolicy, options *PullOptions) ([]string, error) {
// Sanity check.
if err := pullPolicy.Validate(); err != nil {
return nil, err
}
if !options.AllTags {
return r.copySingleImageFromRegistry(ctx, inputName, pullPolicy, options)
}
named := reference.TrimNamed(ref.DockerReference())
tags, err := registryTransport.GetRepositoryTags(ctx, &r.systemContext, ref)
if err != nil {
return nil, err
}
pulledTags := []string{}
for _, tag := range tags {
select { // Let's be gentle with Podman remote.
case <-ctx.Done():
return nil, errors.Errorf("pulling cancelled")
default:
// We can continue.
}
tagged, err := reference.WithTag(named, tag)
if err != nil {
return nil, errors.Wrapf(err, "error creating tagged reference (name %s, tag %s)", named.String(), tag)
}
pulled, err := r.copySingleImageFromRegistry(ctx, tagged.String(), pullPolicy, options)
if err != nil {
return nil, err
}
pulledTags = append(pulledTags, pulled...)
}
return pulledTags, nil
}
// copySingleImageFromRegistry pulls the specified, possibly unqualified, name
// from a registry. On successful pull it returns the used fully-qualified
// name that can later be used to look up the image in the local containers
// storage.
func (r *Runtime) copySingleImageFromRegistry(ctx context.Context, imageName string, pullPolicy config.PullPolicy, options *PullOptions) ([]string, error) { //nolint:gocyclo
// Sanity check.
if err := pullPolicy.Validate(); err != nil {
return nil, err
}
var (
localImage *Image
resolvedImageName string
err error
)
// Always check if there's a local image. If, we should use it's
// resolved name for pulling. Assume we're doing a `pull foo`.
// If there's already a local image "localhost/foo", then we should
// attempt pulling that instead of doing the full short-name dance.
lookupOptions := &LookupImageOptions{
// NOTE: we must ignore the platform of a local image when
// doing lookups. Some images set an incorrect or even invalid
// platform (see containers/podman/issues/10682). Doing the
// lookup while ignoring the platform checks prevents
// redundantly downloading the same image.
IgnorePlatform: true,
}
localImage, resolvedImageName, err = r.LookupImage(imageName, lookupOptions)
if err != nil && errors.Cause(err) != storage.ErrImageUnknown {
logrus.Errorf("Looking up %s in local storage: %v", imageName, err)
}
// If the local image is corrupted, we need to repull it.
if localImage != nil {
if err := localImage.isCorrupted(imageName); err != nil {
logrus.Error(err)
localImage = nil
}
}
customPlatform := false
if len(options.Architecture)+len(options.OS)+len(options.Variant) > 0 {
customPlatform = true
// Unless the pull policy is "always", we must pessimistically assume
// that the local image has an invalid architecture (see
// containers/podman/issues/10682). Hence, whenever the user requests
// a custom platform, set the pull policy to "always" to make sure
// we're pulling down the image.
//
// NOTE that this is will even override --pull={false,never}. This is
// very likely a bug but a consistent one in Podman/Buildah and should
// be addressed at a later point.
if pullPolicy != config.PullPolicyAlways {
logrus.Debugf("Enforcing pull policy to %q to support custom platform (arch: %q, os: %q, variant: %q)", "always", options.Architecture, options.OS, options.Variant)
pullPolicy = config.PullPolicyAlways
}
}
if pullPolicy == config.PullPolicyNever {
if localImage != nil {
logrus.Debugf("Pull policy %q but no local image has been found for %s", pullPolicy, imageName)
return []string{resolvedImageName}, nil
}
logrus.Debugf("Pull policy %q and %s resolved to local image %s", pullPolicy, imageName, resolvedImageName)
return nil, errors.Wrap(storage.ErrImageUnknown, imageName)
}
if pullPolicy == config.PullPolicyMissing && localImage != nil {
return []string{resolvedImageName}, nil
}
// If we looked up the image by ID, we cannot really pull from anywhere.
if localImage != nil && strings.HasPrefix(localImage.ID(), imageName) {
switch pullPolicy {
case config.PullPolicyAlways:
return nil, errors.Errorf("pull policy is always but image has been referred to by ID (%s)", imageName)
default:
return []string{resolvedImageName}, nil
}
}
// If we found a local image, we should use it's locally resolved name
// (see containers/buildah/issues/2904). An exception is if a custom
// platform is specified (e.g., `--arch=arm64`). In that case, we need
// to pessimistically pull the image since some images declare wrong
// platforms making platform checks absolutely unreliable (see
// containers/podman/issues/10682).
//
// In other words: multi-arch support can only be as good as the images
// in the wild.
if localImage != nil && !customPlatform {
if imageName != resolvedImageName {
logrus.Debugf("Image %s resolved to local image %s which will be used for pulling", imageName, resolvedImageName)
}
imageName = resolvedImageName
}
sys := r.systemContextCopy()
resolved, err := shortnames.Resolve(sys, imageName)
if err != nil {
return nil, err
}
// NOTE: Below we print the description from the short-name resolution.
// In theory we could print it here. In practice, however, this is
// causing a hard time for Buildah uses who are doing a `buildah from
// image` and expect just the container name to be printed if the image
// is present locally.
// The pragmatic solution is to only print the description when we found
// a _newer_ image that we're about to pull.
wroteDesc := false
writeDesc := func() error {
if wroteDesc {
return nil
}
wroteDesc = true
if desc := resolved.Description(); len(desc) > 0 {
logrus.Debug(desc)
if options.Writer != nil {
if _, err := options.Writer.Write([]byte(desc + "\n")); err != nil {
return err
}
}
}
return nil
}
c, err := r.newCopier(&options.CopyOptions)
if err != nil {
return nil, err
}
defer c.close()
var pullErrors []error
for _, candidate := range resolved.PullCandidates {
candidateString := candidate.Value.String()
logrus.Debugf("Attempting to pull candidate %s for %s", candidateString, imageName)
srcRef, err := registryTransport.NewReference(candidate.Value)
if err != nil {
return nil, err
}
if pullPolicy == config.PullPolicyNewer && localImage != nil {
isNewer, err := localImage.HasDifferentDigest(ctx, srcRef)
if err != nil {
pullErrors = append(pullErrors, err)
continue
}
if !isNewer {
logrus.Debugf("Skipping pull candidate %s as the image is not newer (pull policy %s)", candidateString, pullPolicy)
continue
}
}
destRef, err := storageTransport.Transport.ParseStoreReference(r.store, candidate.Value.String())
if err != nil {
return nil, err
}
if err := writeDesc(); err != nil {
return nil, err
}
if options.Writer != nil {
if _, err := io.WriteString(options.Writer, fmt.Sprintf("Trying to pull %s...\n", candidateString)); err != nil {
return nil, err
}
}
if _, err := c.copy(ctx, srcRef, destRef); err != nil {
logrus.Debugf("Error pulling candidate %s: %v", candidateString, err)
pullErrors = append(pullErrors, err)
continue
}
if err := candidate.Record(); err != nil {
// Only log the recording errors. Podman has seen
// reports where users set most of the system to
// read-only which can cause issues.
logrus.Errorf("Error recording short-name alias %q: %v", candidateString, err)
}
logrus.Debugf("Pulled candidate %s successfully", candidateString)
return []string{candidate.Value.String()}, nil
}
if localImage != nil && pullPolicy == config.PullPolicyNewer {
return []string{resolvedImageName}, nil
}
if len(pullErrors) == 0 {
return nil, errors.Errorf("internal error: no image pulled (pull policy %s)", pullPolicy)
}
return nil, resolved.FormatPullErrors(pullErrors)
}