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package daemon
import (
"io"
"runtime"
"github.com/docker/distribution/reference"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/builder"
"github.com/docker/docker/image"
"github.com/docker/docker/layer"
"github.com/docker/docker/pkg/containerfs"
"github.com/docker/docker/pkg/idtools"
"github.com/docker/docker/pkg/stringid"
"github.com/docker/docker/registry"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"golang.org/x/net/context"
)
type releaseableLayer struct {
released bool
layerStore layer.Store
roLayer layer.Layer
rwLayer layer.RWLayer
}
func (rl *releaseableLayer) Mount() (containerfs.ContainerFS, error) {
var err error
var mountPath containerfs.ContainerFS
var chainID layer.ChainID
if rl.roLayer != nil {
chainID = rl.roLayer.ChainID()
}
mountID := stringid.GenerateRandomID()
rl.rwLayer, err = rl.layerStore.CreateRWLayer(mountID, chainID, nil)
if err != nil {
return nil, errors.Wrap(err, "failed to create rwlayer")
}
mountPath, err = rl.rwLayer.Mount("")
if err != nil {
// Clean up the layer if we fail to mount it here.
metadata, err := rl.layerStore.ReleaseRWLayer(rl.rwLayer)
layer.LogReleaseMetadata(metadata)
if err != nil {
logrus.Errorf("Failed to release RWLayer: %s", err)
}
rl.rwLayer = nil
return nil, err
}
return mountPath, nil
}
func (rl *releaseableLayer) Commit(os string) (builder.ReleaseableLayer, error) {
var chainID layer.ChainID
if rl.roLayer != nil {
chainID = rl.roLayer.ChainID()
}
stream, err := rl.rwLayer.TarStream()
if err != nil {
return nil, err
}
defer stream.Close()
newLayer, err := rl.layerStore.Register(stream, chainID, layer.OS(os))
if err != nil {
return nil, err
}
// TODO: An optimization would be to handle empty layers before returning
return &releaseableLayer{layerStore: rl.layerStore, roLayer: newLayer}, nil
}
func (rl *releaseableLayer) DiffID() layer.DiffID {
if rl.roLayer == nil {
return layer.DigestSHA256EmptyTar
}
return rl.roLayer.DiffID()
}
func (rl *releaseableLayer) Release() error {
if rl.released {
return nil
}
if err := rl.releaseRWLayer(); err != nil {
// Best effort attempt at releasing read-only layer before returning original error.
rl.releaseROLayer()
return err
}
if err := rl.releaseROLayer(); err != nil {
return err
}
rl.released = true
return nil
}
func (rl *releaseableLayer) releaseRWLayer() error {
if rl.rwLayer == nil {
return nil
}
if err := rl.rwLayer.Unmount(); err != nil {
logrus.Errorf("Failed to unmount RWLayer: %s", err)
return err
}
metadata, err := rl.layerStore.ReleaseRWLayer(rl.rwLayer)
layer.LogReleaseMetadata(metadata)
if err != nil {
logrus.Errorf("Failed to release RWLayer: %s", err)
}
rl.rwLayer = nil
return err
}
func (rl *releaseableLayer) releaseROLayer() error {
if rl.roLayer == nil {
return nil
}
metadata, err := rl.layerStore.Release(rl.roLayer)
layer.LogReleaseMetadata(metadata)
if err != nil {
logrus.Errorf("Failed to release ROLayer: %s", err)
}
rl.roLayer = nil
return err
}
func newReleasableLayerForImage(img *image.Image, layerStore layer.Store) (builder.ReleaseableLayer, error) {
if img == nil || img.RootFS.ChainID() == "" {
return &releaseableLayer{layerStore: layerStore}, nil
}
// Hold a reference to the image layer so that it can't be removed before
// it is released
roLayer, err := layerStore.Get(img.RootFS.ChainID())
if err != nil {
return nil, errors.Wrapf(err, "failed to get layer for image %s", img.ImageID())
}
return &releaseableLayer{layerStore: layerStore, roLayer: roLayer}, nil
}
// TODO: could this use the regular daemon PullImage ?
func (daemon *Daemon) pullForBuilder(ctx context.Context, name string, authConfigs map[string]types.AuthConfig, output io.Writer, platform string) (*image.Image, error) {
ref, err := reference.ParseNormalizedNamed(name)
if err != nil {
return nil, err
}
ref = reference.TagNameOnly(ref)
pullRegistryAuth := &types.AuthConfig{}
if len(authConfigs) > 0 {
// The request came with a full auth config, use it
repoInfo, err := daemon.RegistryService.ResolveRepository(ref)
if err != nil {
return nil, err
}
resolvedConfig := registry.ResolveAuthConfig(authConfigs, repoInfo.Index)
pullRegistryAuth = &resolvedConfig
}
if err := daemon.pullImageWithReference(ctx, ref, platform, nil, pullRegistryAuth, output); err != nil {
return nil, err
}
return daemon.GetImage(name)
}
// GetImageAndReleasableLayer returns an image and releaseable layer for a reference or ID.
// Every call to GetImageAndReleasableLayer MUST call releasableLayer.Release() to prevent
// leaking of layers.
func (daemon *Daemon) GetImageAndReleasableLayer(ctx context.Context, refOrID string, opts backend.GetImageAndLayerOptions) (builder.Image, builder.ReleaseableLayer, error) {
if refOrID == "" {
layer, err := newReleasableLayerForImage(nil, daemon.stores[opts.OS].layerStore)
return nil, layer, err
}
if opts.PullOption != backend.PullOptionForcePull {
image, err := daemon.GetImage(refOrID)
if err != nil && opts.PullOption == backend.PullOptionNoPull {
return nil, nil, err
}
// TODO: shouldn't we error out if error is different from "not found" ?
if image != nil {
layer, err := newReleasableLayerForImage(image, daemon.stores[opts.OS].layerStore)
return image, layer, err
}
}
image, err := daemon.pullForBuilder(ctx, refOrID, opts.AuthConfig, opts.Output, opts.OS)
if err != nil {
return nil, nil, err
}
layer, err := newReleasableLayerForImage(image, daemon.stores[opts.OS].layerStore)
return image, layer, err
}
// CreateImage creates a new image by adding a config and ID to the image store.
// This is similar to LoadImage() except that it receives JSON encoded bytes of
// an image instead of a tar archive.
func (daemon *Daemon) CreateImage(config []byte, parent string, platform string) (builder.Image, error) {
if platform == "" {
platform = runtime.GOOS
}
id, err := daemon.stores[platform].imageStore.Create(config)
if err != nil {
return nil, errors.Wrapf(err, "failed to create image")
}
if parent != "" {
if err := daemon.stores[platform].imageStore.SetParent(id, image.ID(parent)); err != nil {
return nil, errors.Wrapf(err, "failed to set parent %s", parent)
}
}
return daemon.stores[platform].imageStore.Get(id)
}
// IDMappings returns uid/gid mappings for the builder
func (daemon *Daemon) IDMappings() *idtools.IDMappings {
return daemon.idMappings
}
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