buildkit/cache/remotecache/export.go

143 lines
4.0 KiB
Go

package remotecache
import (
"bytes"
"context"
"encoding/json"
"fmt"
"time"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/images"
v1 "github.com/moby/buildkit/cache/remotecache/v1"
"github.com/moby/buildkit/solver"
"github.com/moby/buildkit/util/contentutil"
"github.com/moby/buildkit/util/progress"
digest "github.com/opencontainers/go-digest"
specs "github.com/opencontainers/image-spec/specs-go"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
type ResolveCacheExporterFunc func(ctx context.Context, attrs map[string]string) (Exporter, error)
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 {
now := time.Now()
st.Completed = &now
pw.Write(id, st)
pw.Close()
return err
}
}
type Exporter interface {
solver.CacheExporterTarget
// Finalize finalizes and return metadata that are returned to the client
// e.g. ExporterResponseManifestDesc
Finalize(ctx context.Context) (map[string]string, error)
}
const (
// ExportResponseManifestDesc is a key for the map returned from Exporter.Finalize.
// The map value is a JSON string of an OCI desciptor of a manifest.
ExporterResponseManifestDesc = "cache.manifest"
)
type contentCacheExporter struct {
solver.CacheExporterTarget
chains *v1.CacheChains
ingester content.Ingester
}
func NewExporter(ingester content.Ingester) Exporter {
cc := v1.NewCacheChains()
return &contentCacheExporter{CacheExporterTarget: cc, chains: cc, ingester: ingester}
}
func (ce *contentCacheExporter) Finalize(ctx context.Context) (map[string]string, error) {
return export(ctx, ce.ingester, ce.chains)
}
func export(ctx context.Context, ingester content.Ingester, cc *v1.CacheChains) (map[string]string, error) {
res := make(map[string]string)
config, descs, err := cc.Marshal()
if err != nil {
return nil, err
}
// own type because oci type can't be pushed and docker type doesn't have annotations
type manifestList struct {
specs.Versioned
MediaType string `json:"mediaType,omitempty"`
// Manifests references platform specific manifests.
Manifests []ocispec.Descriptor `json:"manifests"`
}
var mfst manifestList
mfst.SchemaVersion = 2
mfst.MediaType = images.MediaTypeDockerSchema2ManifestList
for _, l := range config.Layers {
dgstPair, ok := descs[l.Blob]
if !ok {
return nil, errors.Errorf("missing blob %s", l.Blob)
}
layerDone := oneOffProgress(ctx, fmt.Sprintf("writing layer %s", l.Blob))
if err := contentutil.Copy(ctx, ingester, dgstPair.Provider, dgstPair.Descriptor); err != nil {
return nil, layerDone(errors.Wrap(err, "error writing layer blob"))
}
layerDone(nil)
mfst.Manifests = append(mfst.Manifests, dgstPair.Descriptor)
}
dt, err := json.Marshal(config)
if err != nil {
return nil, err
}
dgst := digest.FromBytes(dt)
desc := ocispec.Descriptor{
Digest: dgst,
Size: int64(len(dt)),
MediaType: v1.CacheConfigMediaTypeV0,
}
configDone := oneOffProgress(ctx, fmt.Sprintf("writing config %s", dgst))
if err := content.WriteBlob(ctx, ingester, dgst.String(), bytes.NewReader(dt), desc); err != nil {
return nil, configDone(errors.Wrap(err, "error writing config blob"))
}
configDone(nil)
mfst.Manifests = append(mfst.Manifests, desc)
dt, err = json.Marshal(mfst)
if err != nil {
return nil, errors.Wrap(err, "failed to marshal manifest")
}
dgst = digest.FromBytes(dt)
desc = ocispec.Descriptor{
Digest: dgst,
Size: int64(len(dt)),
MediaType: mfst.MediaType,
}
mfstDone := oneOffProgress(ctx, fmt.Sprintf("writing manifest %s", dgst))
if err := content.WriteBlob(ctx, ingester, dgst.String(), bytes.NewReader(dt), desc); err != nil {
return nil, mfstDone(errors.Wrap(err, "error writing manifest blob"))
}
descJSON, err := json.Marshal(desc)
if err != nil {
return nil, err
}
res[ExporterResponseManifestDesc] = string(descJSON)
mfstDone(nil)
return res, nil
}