buildkit/util/imageutil/schema1.go

88 lines
2.5 KiB
Go

package imageutil
import (
"context"
"encoding/json"
"io/ioutil"
"strings"
"time"
"github.com/containerd/containerd/remotes"
digest "github.com/opencontainers/go-digest"
specs "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
func readSchema1Config(ctx context.Context, ref string, desc specs.Descriptor, fetcher remotes.Fetcher, cache ContentCache) (digest.Digest, []byte, error) {
rc, err := fetcher.Fetch(ctx, desc)
if err != nil {
return "", nil, err
}
defer rc.Close()
dt, err := ioutil.ReadAll(rc)
if err != nil {
return "", nil, errors.Wrap(err, "failed to fetch schema1 manifest")
}
dt, err = convertSchema1ConfigMeta(dt)
if err != nil {
return "", nil, err
}
return desc.Digest, dt, nil
}
func convertSchema1ConfigMeta(in []byte) ([]byte, error) {
type history struct {
V1Compatibility string `json:"v1Compatibility"`
}
var m struct {
History []history `json:"history"`
}
if err := json.Unmarshal(in, &m); err != nil {
return nil, errors.Wrap(err, "failed to unmarshal schema1 manifest")
}
if len(m.History) == 0 {
return nil, errors.Errorf("invalid schema1 manifest")
}
var img specs.Image
if err := json.Unmarshal([]byte(m.History[0].V1Compatibility), &img); err != nil {
return nil, errors.Wrap(err, "failed to unmarshal image from schema 1 history")
}
img.RootFS = specs.RootFS{
Type: "layers", // filled in by exporter
}
img.History = make([]specs.History, len(m.History))
for i := range m.History {
var h v1History
if err := json.Unmarshal([]byte(m.History[i].V1Compatibility), &h); err != nil {
return nil, errors.Wrap(err, "failed to unmarshal history")
}
img.History[len(m.History)-i-1] = specs.History{
Author: h.Author,
Comment: h.Comment,
Created: &h.Created,
CreatedBy: strings.Join(h.ContainerConfig.Cmd, " "),
EmptyLayer: (h.ThrowAway != nil && *h.ThrowAway) || (h.Size != nil && *h.Size == 0),
}
}
dt, err := json.MarshalIndent(img, "", " ")
if err != nil {
return nil, errors.Wrap(err, "failed to marshal schema1 config")
}
return dt, nil
}
type v1History struct {
Author string `json:"author,omitempty"`
Created time.Time `json:"created"`
Comment string `json:"comment,omitempty"`
ThrowAway *bool `json:"throwaway,omitempty"`
Size *int `json:"Size,omitempty"` // used before ThrowAway field
ContainerConfig struct {
Cmd []string `json:"Cmd,omitempty"`
} `json:"container_config,omitempty"`
}