buildkit/util/pull/pull.go

481 lines
12 KiB
Go

package pull
import (
"context"
"sync"
"time"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/diff"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/platforms"
"github.com/containerd/containerd/reference"
"github.com/containerd/containerd/remotes"
"github.com/containerd/containerd/remotes/docker/schema1"
"github.com/containerd/containerd/rootfs"
ctdsnapshot "github.com/containerd/containerd/snapshots"
"github.com/moby/buildkit/snapshot"
"github.com/moby/buildkit/util/imageutil"
"github.com/moby/buildkit/util/progress"
digest "github.com/opencontainers/go-digest"
"github.com/opencontainers/image-spec/identity"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
type Puller struct {
Snapshotter snapshot.Snapshotter
ContentStore content.Store
Applier diff.Applier
Src reference.Spec
Platform *ocispec.Platform
// See NewResolver()
Resolver remotes.Resolver
resolveOnce sync.Once
desc ocispec.Descriptor
ref string
resolveErr error
}
type Pulled struct {
Ref string
Descriptor ocispec.Descriptor
ChainID digest.Digest
}
func (p *Puller) Resolve(ctx context.Context) (string, ocispec.Descriptor, error) {
p.resolveOnce.Do(func() {
resolveProgressDone := oneOffProgress(ctx, "resolve "+p.Src.String())
desc := ocispec.Descriptor{
Digest: p.Src.Digest(),
}
if desc.Digest != "" {
info, err := p.ContentStore.Info(ctx, desc.Digest)
if err == nil {
desc.Size = info.Size
p.ref = p.Src.String()
ra, err := p.ContentStore.ReaderAt(ctx, desc)
if err == nil {
mt, err := imageutil.DetectManifestMediaType(ra)
if err == nil {
desc.MediaType = mt
p.desc = desc
resolveProgressDone(nil)
return
}
}
}
}
ref, desc, err := p.Resolver.Resolve(ctx, p.Src.String())
if err != nil {
p.resolveErr = err
resolveProgressDone(err)
return
}
p.desc = desc
p.ref = ref
resolveProgressDone(nil)
})
return p.ref, p.desc, p.resolveErr
}
func (p *Puller) Pull(ctx context.Context) (*Pulled, error) {
if _, _, err := p.Resolve(ctx); err != nil {
return nil, err
}
var platform platforms.MatchComparer
if p.Platform != nil {
platform = platforms.Only(*p.Platform)
} else {
platform = platforms.Default()
}
ongoing := newJobs(p.ref)
pctx, stopProgress := context.WithCancel(ctx)
go showProgress(pctx, ongoing, p.ContentStore)
fetcher, err := p.Resolver.Fetcher(ctx, p.ref)
if err != nil {
stopProgress()
return nil, err
}
// TODO: need a wrapper snapshot interface that combines content
// and snapshots as 1) buildkit shouldn't have a dependency on contentstore
// or 2) cachemanager should manage the contentstore
handlers := []images.Handler{
images.HandlerFunc(func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
ongoing.add(desc)
return nil, nil
}),
}
var schema1Converter *schema1.Converter
if p.desc.MediaType == images.MediaTypeDockerSchema1Manifest {
schema1Converter = schema1.NewConverter(p.ContentStore, fetcher)
handlers = append(handlers, schema1Converter)
} else {
// Get all the children for a descriptor
childrenHandler := images.ChildrenHandler(p.ContentStore)
// Set any children labels for that content
childrenHandler = images.SetChildrenLabels(p.ContentStore, childrenHandler)
// Filter the children by the platform
childrenHandler = images.FilterPlatforms(childrenHandler, platform)
// Limit manifests pulled to the best match in an index
childrenHandler = images.LimitManifests(childrenHandler, platform, 1)
handlers = append(handlers,
remotes.FetchHandler(p.ContentStore, fetcher),
childrenHandler,
)
}
if err := images.Dispatch(ctx, images.Handlers(handlers...), p.desc); err != nil {
stopProgress()
return nil, err
}
stopProgress()
var usedBlobs, unusedBlobs []ocispec.Descriptor
if schema1Converter != nil {
ongoing.remove(p.desc) // Not left in the content store so this is sufficient.
p.desc, err = schema1Converter.Convert(ctx)
if err != nil {
return nil, err
}
ongoing.add(p.desc)
var mu sync.Mutex // images.Dispatch calls handlers in parallel
allBlobs := make(map[digest.Digest]ocispec.Descriptor)
for _, j := range ongoing.added {
allBlobs[j.Digest] = j.Descriptor
}
handlers := []images.Handler{
images.HandlerFunc(func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
mu.Lock()
defer mu.Unlock()
usedBlobs = append(usedBlobs, desc)
delete(allBlobs, desc.Digest)
return nil, nil
}),
images.FilterPlatforms(images.ChildrenHandler(p.ContentStore), platform),
}
if err := images.Dispatch(ctx, images.Handlers(handlers...), p.desc); err != nil {
return nil, err
}
for _, j := range allBlobs {
unusedBlobs = append(unusedBlobs, j)
}
} else {
for _, j := range ongoing.added {
usedBlobs = append(usedBlobs, j.Descriptor)
}
}
// split all pulled data to layers and rest. layers remain roots and are deleted with snapshots. rest will be linked to layers.
var notLayerBlobs []ocispec.Descriptor
var layerBlobs []ocispec.Descriptor
for _, j := range usedBlobs {
switch j.MediaType {
case ocispec.MediaTypeImageLayer, images.MediaTypeDockerSchema2Layer, ocispec.MediaTypeImageLayerGzip, images.MediaTypeDockerSchema2LayerGzip, images.MediaTypeDockerSchema2LayerForeign, images.MediaTypeDockerSchema2LayerForeignGzip:
layerBlobs = append(layerBlobs, j)
default:
notLayerBlobs = append(notLayerBlobs, j)
}
}
for _, l := range layerBlobs {
labels := map[string]string{}
var fields []string
for _, nl := range notLayerBlobs {
k := "containerd.io/gc.ref.content." + nl.Digest.Hex()[:12]
labels[k] = nl.Digest.String()
fields = append(fields, "labels."+k)
}
if _, err := p.ContentStore.Update(ctx, content.Info{
Digest: l.Digest,
Labels: labels,
}, fields...); err != nil {
return nil, err
}
}
for _, nl := range append(notLayerBlobs, unusedBlobs...) {
if err := p.ContentStore.Delete(ctx, nl.Digest); err != nil {
return nil, err
}
}
csh, release := snapshot.NewContainerdSnapshotter(p.Snapshotter)
defer release()
unpackProgressDone := oneOffProgress(ctx, "unpacking "+p.Src.String())
chainid, err := unpack(ctx, p.desc, p.ContentStore, csh, p.Snapshotter, p.Applier, platform)
if err != nil {
return nil, unpackProgressDone(err)
}
unpackProgressDone(nil)
return &Pulled{
Ref: p.ref,
Descriptor: p.desc,
ChainID: chainid,
}, nil
}
func unpack(ctx context.Context, desc ocispec.Descriptor, cs content.Store, csh ctdsnapshot.Snapshotter, s snapshot.Snapshotter, applier diff.Applier, platform platforms.MatchComparer) (digest.Digest, error) {
layers, err := getLayers(ctx, cs, desc, platform)
if err != nil {
return "", err
}
var chain []digest.Digest
for _, layer := range layers {
labels := map[string]string{
"containerd.io/gc.root": time.Now().UTC().Format(time.RFC3339Nano),
}
if _, err := rootfs.ApplyLayer(ctx, layer, chain, csh, applier, ctdsnapshot.WithLabels(labels)); err != nil {
return "", err
}
chain = append(chain, layer.Diff.Digest)
}
chainID := identity.ChainID(chain)
if err != nil {
return "", err
}
if err := fillBlobMapping(ctx, s, layers); err != nil {
return "", err
}
return chainID, nil
}
func fillBlobMapping(ctx context.Context, s snapshot.Snapshotter, layers []rootfs.Layer) error {
var chain []digest.Digest
for _, l := range layers {
chain = append(chain, l.Diff.Digest)
chainID := identity.ChainID(chain)
if err := s.SetBlob(ctx, string(chainID), l.Diff.Digest, l.Blob.Digest); err != nil {
return err
}
}
return nil
}
func getLayers(ctx context.Context, provider content.Provider, desc ocispec.Descriptor, platform platforms.MatchComparer) ([]rootfs.Layer, error) {
manifest, err := images.Manifest(ctx, provider, desc, platform)
if err != nil {
return nil, errors.WithStack(err)
}
image := images.Image{Target: desc}
diffIDs, err := image.RootFS(ctx, provider, platform)
if err != nil {
return nil, errors.Wrap(err, "failed to resolve rootfs")
}
if len(diffIDs) != len(manifest.Layers) {
return nil, errors.Errorf("mismatched image rootfs and manifest layers %+v %+v", diffIDs, manifest.Layers)
}
layers := make([]rootfs.Layer, len(diffIDs))
for i := range diffIDs {
layers[i].Diff = ocispec.Descriptor{
// TODO: derive media type from compressed type
MediaType: ocispec.MediaTypeImageLayer,
Digest: diffIDs[i],
}
layers[i].Blob = manifest.Layers[i]
}
return layers, nil
}
func showProgress(ctx context.Context, ongoing *jobs, cs content.Store) {
var (
ticker = time.NewTicker(150 * time.Millisecond)
statuses = map[string]statusInfo{}
done bool
)
defer ticker.Stop()
pw, _, ctx := progress.FromContext(ctx)
defer pw.Close()
for {
select {
case <-ticker.C:
case <-ctx.Done():
done = true
}
resolved := "resolved"
if !ongoing.isResolved() {
resolved = "resolving"
}
statuses[ongoing.name] = statusInfo{
Ref: ongoing.name,
Status: resolved,
}
actives := make(map[string]statusInfo)
if !done {
active, err := cs.ListStatuses(ctx, "")
if err != nil {
// log.G(ctx).WithError(err).Error("active check failed")
continue
}
// update status of active entries!
for _, active := range active {
actives[active.Ref] = statusInfo{
Ref: active.Ref,
Status: "downloading",
Offset: active.Offset,
Total: active.Total,
StartedAt: active.StartedAt,
UpdatedAt: active.UpdatedAt,
}
}
}
// now, update the items in jobs that are not in active
for _, j := range ongoing.jobs() {
refKey := remotes.MakeRefKey(ctx, j.Descriptor)
if a, ok := actives[refKey]; ok {
started := j.started
pw.Write(j.Digest.String(), progress.Status{
Action: a.Status,
Total: int(a.Total),
Current: int(a.Offset),
Started: &started,
})
continue
}
if !j.done {
info, err := cs.Info(context.TODO(), j.Digest)
if err != nil {
if errdefs.IsNotFound(err) {
pw.Write(j.Digest.String(), progress.Status{
Action: "waiting",
})
continue
}
} else {
j.done = true
}
if done || j.done {
started := j.started
createdAt := info.CreatedAt
pw.Write(j.Digest.String(), progress.Status{
Action: "done",
Current: int(info.Size),
Total: int(info.Size),
Completed: &createdAt,
Started: &started,
})
}
}
}
if done {
return
}
}
}
// jobs provides a way of identifying the download keys for a particular task
// encountering during the pull walk.
//
// This is very minimal and will probably be replaced with something more
// featured.
type jobs struct {
name string
added map[digest.Digest]*job
mu sync.Mutex
resolved bool
}
type job struct {
ocispec.Descriptor
done bool
started time.Time
}
func newJobs(name string) *jobs {
return &jobs{
name: name,
added: make(map[digest.Digest]*job),
}
}
func (j *jobs) add(desc ocispec.Descriptor) {
j.mu.Lock()
defer j.mu.Unlock()
if _, ok := j.added[desc.Digest]; ok {
return
}
j.added[desc.Digest] = &job{
Descriptor: desc,
started: time.Now(),
}
}
func (j *jobs) remove(desc ocispec.Descriptor) {
j.mu.Lock()
defer j.mu.Unlock()
delete(j.added, desc.Digest)
}
func (j *jobs) jobs() []*job {
j.mu.Lock()
defer j.mu.Unlock()
descs := make([]*job, 0, len(j.added))
for _, j := range j.added {
descs = append(descs, j)
}
return descs
}
func (j *jobs) isResolved() bool {
j.mu.Lock()
defer j.mu.Unlock()
return j.resolved
}
type statusInfo struct {
Ref string
Status string
Offset int64
Total int64
StartedAt time.Time
UpdatedAt time.Time
}
func oneOffProgress(ctx context.Context, id string) func(err error) error {
pw, _, _ := progress.FromContext(ctx)
now := time.Now()
st := progress.Status{
Started: &now,
}
pw.Write(id, st)
return func(err error) error {
// TODO: set error on status
now := time.Now()
st.Completed = &now
pw.Write(id, st)
pw.Close()
return err
}
}