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(platform 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.Platform(platform)) if err != nil { return nil, err } if layer.IsEmpty(newLayer.DiffID()) { _, err := rl.layerStore.Release(newLayer) return &releaseableLayer{layerStore: rl.layerStore}, err } 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.Platform].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.Platform].layerStore) return image, layer, err } } image, err := daemon.pullForBuilder(ctx, refOrID, opts.AuthConfig, opts.Output, opts.Platform) if err != nil { return nil, nil, err } layer, err := newReleasableLayerForImage(image, daemon.stores[opts.Platform].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 }