68944ea9cf
Previously, discussions were still ongoing about different storage layouts that could support various access models. This changeset removes a layer of indirection that was in place due to earlier designs. Effectively, this both associates a layer with a named repository and ensures that content cannot be accessed across repositories. It also moves to rely on tarsum as a true content-addressable identifier, removing a layer of indirection during blob resolution.
130 lines
3.3 KiB
Go
130 lines
3.3 KiB
Go
package storage
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import (
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"time"
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"github.com/docker/docker-registry/digest"
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"github.com/docker/docker-registry/storagedriver"
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)
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type layerStore struct {
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driver storagedriver.StorageDriver
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pathMapper *pathMapper
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uploadStore layerUploadStore
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}
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func (ls *layerStore) Exists(name string, digest digest.Digest) (bool, error) {
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// Because this implementation just follows blob links, an existence check
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// is pretty cheap by starting and closing a fetch.
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_, err := ls.Fetch(name, digest)
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if err != nil {
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if err == ErrLayerUnknown {
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return false, nil
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}
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return false, err
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}
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return true, nil
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}
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func (ls *layerStore) Fetch(name string, digest digest.Digest) (Layer, error) {
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blobPath, err := ls.resolveBlobPath(name, digest)
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if err != nil {
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switch err := err.(type) {
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case storagedriver.PathNotFoundError, *storagedriver.PathNotFoundError:
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return nil, ErrLayerUnknown
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default:
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return nil, err
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}
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}
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fr, err := newFileReader(ls.driver, blobPath)
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if err != nil {
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switch err := err.(type) {
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case storagedriver.PathNotFoundError, *storagedriver.PathNotFoundError:
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return nil, ErrLayerUnknown
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default:
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return nil, err
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}
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}
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return &layerReader{
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fileReader: *fr,
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name: name,
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digest: digest,
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// TODO(stevvooe): Storage backend does not support modification time
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// queries yet. Layers "never" change, so just return the zero value
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// plus a nano-second.
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createdAt: (time.Time{}).Add(time.Nanosecond),
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}, nil
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}
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// Upload begins a layer upload, returning a handle. If the layer upload
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// is already in progress or the layer has already been uploaded, this
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// will return an error.
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func (ls *layerStore) Upload(name string) (LayerUpload, error) {
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// NOTE(stevvooe): Consider the issues with allowing concurrent upload of
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// the same two layers. Should it be disallowed? For now, we allow both
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// parties to proceed and the the first one uploads the layer.
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lus, err := ls.uploadStore.New(name)
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if err != nil {
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return nil, err
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}
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return ls.newLayerUpload(lus), nil
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}
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// Resume continues an in progress layer upload, returning the current
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// state of the upload.
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func (ls *layerStore) Resume(uuid string) (LayerUpload, error) {
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lus, err := ls.uploadStore.GetState(uuid)
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if err != nil {
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return nil, err
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}
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return ls.newLayerUpload(lus), nil
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}
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// newLayerUpload allocates a new upload controller with the given state.
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func (ls *layerStore) newLayerUpload(lus LayerUploadState) LayerUpload {
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return &layerUploadController{
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LayerUploadState: lus,
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layerStore: ls,
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uploadStore: ls.uploadStore,
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}
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}
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// resolveBlobId looks up the blob location in the repositories from a
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// layer/blob link file, returning blob path or an error on failure.
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func (ls *layerStore) resolveBlobPath(name string, dgst digest.Digest) (string, error) {
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pathSpec := layerLinkPathSpec{name: name, digest: dgst}
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layerLinkPath, err := ls.pathMapper.path(pathSpec)
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if err != nil {
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return "", err
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}
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layerLinkContent, err := ls.driver.GetContent(layerLinkPath)
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if err != nil {
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return "", err
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}
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// NOTE(stevvooe): The content of the layer link should match the digest.
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// This layer of indirection is for name-based content protection.
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linked, err := digest.ParseDigest(string(layerLinkContent))
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if err != nil {
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return "", err
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}
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bp := blobPathSpec{digest: linked}
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return ls.pathMapper.path(bp)
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}
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