buildkit/cache/remotecache/import.go

99 lines
2.7 KiB
Go

package remotecache
import (
"context"
"encoding/json"
"io"
"github.com/containerd/containerd/content"
v1 "github.com/moby/buildkit/cache/remotecache/v1"
"github.com/moby/buildkit/solver"
"github.com/moby/buildkit/worker"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
// ResolveCacheImporterFunc returns importer and descriptor.
// Currently typ needs to be an empty string.
type ResolveCacheImporterFunc func(ctx context.Context, typ, ref string) (Importer, ocispec.Descriptor, error)
type Importer interface {
Resolve(ctx context.Context, desc ocispec.Descriptor, id string, w worker.Worker) (solver.CacheManager, error)
}
func NewImporter(provider content.Provider) Importer {
return &contentCacheImporter{provider: provider}
}
type contentCacheImporter struct {
provider content.Provider
}
func (ci *contentCacheImporter) Resolve(ctx context.Context, desc ocispec.Descriptor, id string, w worker.Worker) (solver.CacheManager, error) {
dt, err := readBlob(ctx, ci.provider, desc)
if err != nil {
return nil, err
}
var mfst ocispec.Index
if err := json.Unmarshal(dt, &mfst); err != nil {
return nil, err
}
allLayers := v1.DescriptorProvider{}
var configDesc ocispec.Descriptor
for _, m := range mfst.Manifests {
if m.MediaType == v1.CacheConfigMediaTypeV0 {
configDesc = m
continue
}
allLayers[m.Digest] = v1.DescriptorProviderPair{
Descriptor: m,
Provider: ci.provider,
}
}
if configDesc.Digest == "" {
return nil, errors.Errorf("invalid build cache from %+v", desc)
}
dt, err = readBlob(ctx, ci.provider, configDesc)
if err != nil {
return nil, err
}
cc := v1.NewCacheChains()
if err := v1.Parse(dt, allLayers, cc); err != nil {
return nil, err
}
keysStorage, resultStorage, err := v1.NewCacheKeyStorage(cc, w)
if err != nil {
return nil, err
}
return solver.NewCacheManager(id, keysStorage, resultStorage), nil
}
func readBlob(ctx context.Context, provider content.Provider, desc ocispec.Descriptor) ([]byte, error) {
maxBlobSize := int64(1 << 20)
if desc.Size > maxBlobSize {
return nil, errors.Errorf("blob %s is too large (%d > %d)", desc.Digest, desc.Size, maxBlobSize)
}
dt, err := content.ReadBlob(ctx, provider, desc)
if err != nil {
// NOTE: even if err == EOF, we might have got expected dt here.
// For instance, http.Response.Body is known to return non-zero bytes with EOF.
if err == io.EOF {
if dtDigest := desc.Digest.Algorithm().FromBytes(dt); dtDigest != desc.Digest {
err = errors.Wrapf(err, "got EOF, expected %s (%d bytes), got %s (%d bytes)",
desc.Digest, desc.Size, dtDigest, len(dt))
} else {
err = nil
}
}
}
return dt, err
}