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moby--moby/image/v1/imagev1.go

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package v1
import (
"encoding/json"
"reflect"
"strings"
"github.com/docker/docker/api/types/versions"
"github.com/docker/docker/image"
"github.com/docker/docker/layer"
"github.com/docker/docker/pkg/stringid"
"github.com/opencontainers/go-digest"
"github.com/sirupsen/logrus"
)
// noFallbackMinVersion is the minimum version for which v1compatibility
// information will not be marshaled through the Image struct to remove
// blank fields.
var noFallbackMinVersion = "1.8.3"
// HistoryFromConfig creates a History struct from v1 configuration JSON
func HistoryFromConfig(imageJSON []byte, emptyLayer bool) (image.History, error) {
h := image.History{}
var v1Image image.V1Image
if err := json.Unmarshal(imageJSON, &v1Image); err != nil {
return h, err
}
return image.History{
Author: v1Image.Author,
Created: v1Image.Created,
CreatedBy: strings.Join(v1Image.ContainerConfig.Cmd, " "),
Comment: v1Image.Comment,
EmptyLayer: emptyLayer,
}, nil
}
// CreateID creates an ID from v1 image, layerID and parent ID.
// Used for backwards compatibility with old clients.
func CreateID(v1Image image.V1Image, layerID layer.ChainID, parent digest.Digest) (digest.Digest, error) {
v1Image.ID = ""
v1JSON, err := json.Marshal(v1Image)
if err != nil {
return "", err
}
var config map[string]*json.RawMessage
if err := json.Unmarshal(v1JSON, &config); err != nil {
return "", err
}
// FIXME: note that this is slightly incompatible with RootFS logic
config["layer_id"] = rawJSON(layerID)
if parent != "" {
config["parent"] = rawJSON(parent)
}
configJSON, err := json.Marshal(config)
if err != nil {
return "", err
}
logrus.Debugf("CreateV1ID %s", configJSON)
return digest.FromBytes(configJSON), nil
}
// MakeConfigFromV1Config creates an image config from the legacy V1 config format.
func MakeConfigFromV1Config(imageJSON []byte, rootfs *image.RootFS, history []image.History) ([]byte, error) {
var dver struct {
DockerVersion string `json:"docker_version"`
}
if err := json.Unmarshal(imageJSON, &dver); err != nil {
return nil, err
}
useFallback := versions.LessThan(dver.DockerVersion, noFallbackMinVersion)
if useFallback {
var v1Image image.V1Image
err := json.Unmarshal(imageJSON, &v1Image)
if err != nil {
return nil, err
}
imageJSON, err = json.Marshal(v1Image)
if err != nil {
return nil, err
}
}
var c map[string]*json.RawMessage
if err := json.Unmarshal(imageJSON, &c); err != nil {
return nil, err
}
delete(c, "id")
delete(c, "parent")
delete(c, "Size") // Size is calculated from data on disk and is inconsistent
delete(c, "parent_id")
delete(c, "layer_id")
delete(c, "throwaway")
c["rootfs"] = rawJSON(rootfs)
c["history"] = rawJSON(history)
return json.Marshal(c)
}
// MakeV1ConfigFromConfig creates a legacy V1 image config from an Image struct
func MakeV1ConfigFromConfig(img *image.Image, v1ID, parentV1ID string, throwaway bool) ([]byte, error) {
// Top-level v1compatibility string should be a modified version of the
// image config.
var configAsMap map[string]*json.RawMessage
if err := json.Unmarshal(img.RawJSON(), &configAsMap); err != nil {
return nil, err
}
// Delete fields that didn't exist in old manifest
imageType := reflect.TypeOf(img).Elem()
for i := 0; i < imageType.NumField(); i++ {
f := imageType.Field(i)
jsonName := strings.Split(f.Tag.Get("json"), ",")[0]
// Parent is handled specially below.
if jsonName != "" && jsonName != "parent" {
delete(configAsMap, jsonName)
}
}
configAsMap["id"] = rawJSON(v1ID)
if parentV1ID != "" {
configAsMap["parent"] = rawJSON(parentV1ID)
}
if throwaway {
configAsMap["throwaway"] = rawJSON(true)
}
return json.Marshal(configAsMap)
}
func rawJSON(value interface{}) *json.RawMessage {
jsonval, err := json.Marshal(value)
if err != nil {
return nil
}
return (*json.RawMessage)(&jsonval)
}
// ValidateID checks whether an ID string is a valid image ID.
func ValidateID(id string) error {
return stringid.ValidateID(id)
}