buildkit/source/containerimage/pull.go

462 lines
11 KiB
Go

package containerimage
import (
gocontext "context"
"fmt"
"net/http"
"sync"
"time"
"github.com/BurntSushi/locker"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/platforms"
"github.com/containerd/containerd/remotes"
"github.com/containerd/containerd/remotes/docker"
"github.com/containerd/containerd/rootfs"
"github.com/containerd/containerd/snapshot"
"github.com/moby/buildkit/cache"
"github.com/moby/buildkit/source"
"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"
"golang.org/x/net/context"
)
// TODO: break apart containerd specifics like contentstore so the resolver
// code can be used with any implementation
type SourceOpt struct {
Snapshotter snapshot.Snapshotter
ContentStore content.Store
Applier rootfs.Applier
CacheAccessor cache.Accessor
}
type blobmapper interface {
GetBlob(ctx gocontext.Context, key string) (digest.Digest, error)
SetBlob(ctx gocontext.Context, key string, blob digest.Digest) error
}
type resolveRecord struct {
desc ocispec.Descriptor
ts time.Time
}
type imageSource struct {
SourceOpt
resolver remotes.Resolver
lru map[string]resolveRecord
}
func NewSource(opt SourceOpt) (source.Source, error) {
is := &imageSource{
SourceOpt: opt,
lru: map[string]resolveRecord{},
resolver: newCachedResolver(docker.NewResolver(docker.ResolverOptions{
Client: http.DefaultClient,
}), 5*time.Second),
}
if _, ok := opt.Snapshotter.(blobmapper); !ok {
return nil, errors.Errorf("imagesource requires snapshotter with blobs mapping support")
}
return is, nil
}
func (is *imageSource) ID() string {
return source.DockerImageScheme
}
func (is *imageSource) ResolveImageConfig(ctx context.Context, ref string) (digest.Digest, []byte, error) {
return imageutil.Config(ctx, ref, is.resolver, is.ContentStore)
}
func (is *imageSource) Resolve(ctx context.Context, id source.Identifier) (source.SourceInstance, error) {
imageIdentifier, ok := id.(*source.ImageIdentifier)
if !ok {
return nil, errors.Errorf("invalid image identifier %v", id)
}
p := &puller{
src: imageIdentifier,
is: is,
}
return p, nil
}
type puller struct {
is *imageSource
resolveOnce sync.Once
src *source.ImageIdentifier
desc ocispec.Descriptor
ref string
resolveErr error
}
func (p *puller) resolve(ctx context.Context) error {
p.resolveOnce.Do(func() {
resolveProgressDone := oneOffProgress(ctx, "resolve "+p.src.Reference.String())
dgst := p.src.Reference.Digest()
if dgst != "" {
info, err := p.is.ContentStore.Info(ctx, dgst)
if err == nil {
p.ref = p.src.Reference.String()
ra, err := p.is.ContentStore.ReaderAt(ctx, dgst)
if err == nil {
mt, err := imageutil.DetectManifestMediaType(ra)
if err == nil {
p.desc = ocispec.Descriptor{
Size: info.Size,
Digest: dgst,
MediaType: mt,
}
resolveProgressDone(nil)
return
}
}
}
}
ref, desc, err := p.is.resolver.Resolve(ctx, p.src.Reference.String())
if err != nil {
p.resolveErr = err
resolveProgressDone(err)
return
}
p.desc = desc
p.ref = ref
resolveProgressDone(nil)
})
return p.resolveErr
}
func (p *puller) CacheKey(ctx context.Context) (string, error) {
if err := p.resolve(ctx); err != nil {
return "", err
}
return p.desc.Digest.String(), nil
}
func (p *puller) Snapshot(ctx context.Context) (cache.ImmutableRef, error) {
if err := p.resolve(ctx); err != nil {
return nil, err
}
ongoing := newJobs(p.ref)
pctx, stopProgress := context.WithCancel(ctx)
go showProgress(pctx, ongoing, p.is.ContentStore)
fetcher, err := p.is.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 gocontext.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
ongoing.add(desc)
return nil, nil
}),
remotes.FetchHandler(p.is.ContentStore, fetcher),
images.ChildrenHandler(p.is.ContentStore),
}
if err := images.Dispatch(ctx, images.Handlers(handlers...), p.desc); err != nil {
stopProgress()
return nil, err
}
stopProgress()
unpackProgressDone := oneOffProgress(ctx, "unpacking "+p.src.Reference.String())
chainid, err := p.is.unpack(ctx, p.desc)
if err != nil {
return nil, unpackProgressDone(err)
}
unpackProgressDone(nil)
return p.is.CacheAccessor.Get(ctx, chainid, cache.WithDescription(fmt.Sprintf("pulled from %s", p.ref)))
}
func (is *imageSource) unpack(ctx context.Context, desc ocispec.Descriptor) (string, error) {
layers, err := getLayers(ctx, is.ContentStore, desc)
if err != nil {
return "", err
}
chainID, err := rootfs.ApplyLayers(ctx, layers, is.Snapshotter, is.Applier)
if err != nil {
return "", err
}
if err := is.fillBlobMapping(ctx, layers); err != nil {
return "", err
}
return string(chainID), nil
}
func (is *imageSource) fillBlobMapping(ctx context.Context, layers []rootfs.Layer) error {
var chain []digest.Digest
for _, l := range layers {
chain = append(chain, l.Diff.Digest)
chainID := identity.ChainID(chain)
if err := is.SourceOpt.Snapshotter.(blobmapper).SetBlob(ctx, string(chainID), l.Blob.Digest); err != nil {
return err
}
}
return nil
}
func getLayers(ctx context.Context, provider content.Provider, desc ocispec.Descriptor) ([]rootfs.Layer, error) {
manifest, err := images.Manifest(ctx, provider, desc, platforms.Format(platforms.Default()))
if err != nil {
return nil, errors.WithStack(err)
}
image := images.Image{Target: desc}
diffIDs, err := image.RootFS(ctx, provider, platforms.Format(platforms.Default()))
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(100 * 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) 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
}
}
func newCachedResolver(r remotes.Resolver, timeout time.Duration) remotes.Resolver {
return &cachedResolver{
Resolver: r,
cache: map[string]cachedResult{},
timeout: timeout,
locker: locker.NewLocker(),
}
}
type cachedResolver struct {
remotes.Resolver
cache map[string]cachedResult
timeout time.Duration
locker *locker.Locker
}
func (cr *cachedResolver) Resolve(ctx gocontext.Context, ref string) (name string, desc ocispec.Descriptor, err error) {
cr.locker.Lock(ref)
defer cr.locker.Unlock(ref)
r, ok := cr.cache[ref]
if ok && time.Since(r.ts) < cr.timeout {
return r.name, r.desc, nil
}
delete(cr.cache, ref)
n, d, err := cr.Resolver.Resolve(ctx, ref)
if err != nil {
return "", d, err
}
cr.cache[ref] = cachedResult{
name: n,
desc: d,
ts: time.Now(),
}
return n, d, nil
}
type cachedResult struct {
name string
desc ocispec.Descriptor
ts time.Time
}