forked from TrueCloudLab/distribution
70ab06b864
This change updates the backend storage package that consumes StorageDriver to use the new Stat call, over CurrentSize. It also makes minor updates for using WriteStream and ReadStream.
123 lines
3.2 KiB
Go
123 lines
3.2 KiB
Go
package storage
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import (
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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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switch err.(type) {
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case ErrUnknownLayer:
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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, ErrUnknownLayer{FSLayer{BlobSum: digest}}
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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, ErrUnknownLayer{FSLayer{BlobSum: digest}}
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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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}, 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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