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Ludovic Fernandez 2018-01-09 21:46:04 +01:00 • committed by Traefiker
parent d88554fa92
commit 044d87d96d
239 changed files with 42372 additions and 7011 deletions
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490
vendor/github.com/docker/distribution/registry/storage/paths.go generated vendored Normal file
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package storage
import (
"fmt"
"path"
"strings"
"github.com/opencontainers/go-digest"
)
const (
storagePathVersion = "v2" // fixed storage layout version
storagePathRoot = "/docker/registry/" // all driver paths have a prefix
// TODO(stevvooe): Get rid of the "storagePathRoot". Initially, we though
// storage path root would configurable for all drivers through this
// package. In reality, we've found it simpler to do this on a per driver
// basis.
)
// pathFor maps paths based on "object names" and their ids. The "object
// names" mapped by are internal to the storage system.
//
// The path layout in the storage backend is roughly as follows:
//
// <root>/v2
// -> repositories/
// -><name>/
// -> _manifests/
// revisions
// -> <manifest digest path>
// -> link
// tags/<tag>
// -> current/link
// -> index
// -> <algorithm>/<hex digest>/link
// -> _layers/
// <layer links to blob store>
// -> _uploads/<id>
// data
// startedat
// hashstates/<algorithm>/<offset>
// -> blob/<algorithm>
// <split directory content addressable storage>
//
// The storage backend layout is broken up into a content-addressable blob
// store and repositories. The content-addressable blob store holds most data
// throughout the backend, keyed by algorithm and digests of the underlying
// content. Access to the blob store is controlled through links from the
// repository to blobstore.
//
// A repository is made up of layers, manifests and tags. The layers component
// is just a directory of layers which are "linked" into a repository. A layer
// can only be accessed through a qualified repository name if it is linked in
// the repository. Uploads of layers are managed in the uploads directory,
// which is key by upload id. When all data for an upload is received, the
// data is moved into the blob store and the upload directory is deleted.
// Abandoned uploads can be garbage collected by reading the startedat file
// and removing uploads that have been active for longer than a certain time.
//
// The third component of the repository directory is the manifests store,
// which is made up of a revision store and tag store. Manifests are stored in
// the blob store and linked into the revision store.
// While the registry can save all revisions of a manifest, no relationship is
// implied as to the ordering of changes to a manifest. The tag store provides
// support for name, tag lookups of manifests, using "current/link" under a
// named tag directory. An index is maintained to support deletions of all
// revisions of a given manifest tag.
//
// We cover the path formats implemented by this path mapper below.
//
// Manifests:
//
// manifestRevisionsPathSpec: <root>/v2/repositories/<name>/_manifests/revisions/
// manifestRevisionPathSpec: <root>/v2/repositories/<name>/_manifests/revisions/<algorithm>/<hex digest>/
// manifestRevisionLinkPathSpec: <root>/v2/repositories/<name>/_manifests/revisions/<algorithm>/<hex digest>/link
//
// Tags:
//
// manifestTagsPathSpec: <root>/v2/repositories/<name>/_manifests/tags/
// manifestTagPathSpec: <root>/v2/repositories/<name>/_manifests/tags/<tag>/
// manifestTagCurrentPathSpec: <root>/v2/repositories/<name>/_manifests/tags/<tag>/current/link
// manifestTagIndexPathSpec: <root>/v2/repositories/<name>/_manifests/tags/<tag>/index/
// manifestTagIndexEntryPathSpec: <root>/v2/repositories/<name>/_manifests/tags/<tag>/index/<algorithm>/<hex digest>/
// manifestTagIndexEntryLinkPathSpec: <root>/v2/repositories/<name>/_manifests/tags/<tag>/index/<algorithm>/<hex digest>/link
//
// Blobs:
//
// layerLinkPathSpec: <root>/v2/repositories/<name>/_layers/<algorithm>/<hex digest>/link
//
// Uploads:
//
// uploadDataPathSpec: <root>/v2/repositories/<name>/_uploads/<id>/data
// uploadStartedAtPathSpec: <root>/v2/repositories/<name>/_uploads/<id>/startedat
// uploadHashStatePathSpec: <root>/v2/repositories/<name>/_uploads/<id>/hashstates/<algorithm>/<offset>
//
// Blob Store:
//
// blobsPathSpec: <root>/v2/blobs/
// blobPathSpec: <root>/v2/blobs/<algorithm>/<first two hex bytes of digest>/<hex digest>
// blobDataPathSpec: <root>/v2/blobs/<algorithm>/<first two hex bytes of digest>/<hex digest>/data
// blobMediaTypePathSpec: <root>/v2/blobs/<algorithm>/<first two hex bytes of digest>/<hex digest>/data
//
// For more information on the semantic meaning of each path and their
// contents, please see the path spec documentation.
func pathFor(spec pathSpec) (string, error) {
// Switch on the path object type and return the appropriate path. At
// first glance, one may wonder why we don't use an interface to
// accomplish this. By keep the formatting separate from the pathSpec, we
// keep separate the path generation componentized. These specs could be
// passed to a completely different mapper implementation and generate a
// different set of paths.
//
// For example, imagine migrating from one backend to the other: one could
// build a filesystem walker that converts a string path in one version,
// to an intermediate path object, than can be consumed and mapped by the
// other version.
rootPrefix := []string{storagePathRoot, storagePathVersion}
repoPrefix := append(rootPrefix, "repositories")
switch v := spec.(type) {
case manifestRevisionsPathSpec:
return path.Join(append(repoPrefix, v.name, "_manifests", "revisions")...), nil
case manifestRevisionPathSpec:
components, err := digestPathComponents(v.revision, false)
if err != nil {
return "", err
}
return path.Join(append(append(repoPrefix, v.name, "_manifests", "revisions"), components...)...), nil
case manifestRevisionLinkPathSpec:
root, err := pathFor(manifestRevisionPathSpec{
name: v.name,
revision: v.revision,
})
if err != nil {
return "", err
}
return path.Join(root, "link"), nil
case manifestTagsPathSpec:
return path.Join(append(repoPrefix, v.name, "_manifests", "tags")...), nil
case manifestTagPathSpec:
root, err := pathFor(manifestTagsPathSpec{
name: v.name,
})
if err != nil {
return "", err
}
return path.Join(root, v.tag), nil
case manifestTagCurrentPathSpec:
root, err := pathFor(manifestTagPathSpec{
name: v.name,
tag: v.tag,
})
if err != nil {
return "", err
}
return path.Join(root, "current", "link"), nil
case manifestTagIndexPathSpec:
root, err := pathFor(manifestTagPathSpec{
name: v.name,
tag: v.tag,
})
if err != nil {
return "", err
}
return path.Join(root, "index"), nil
case manifestTagIndexEntryLinkPathSpec:
root, err := pathFor(manifestTagIndexEntryPathSpec{
name: v.name,
tag: v.tag,
revision: v.revision,
})
if err != nil {
return "", err
}
return path.Join(root, "link"), nil
case manifestTagIndexEntryPathSpec:
root, err := pathFor(manifestTagIndexPathSpec{
name: v.name,
tag: v.tag,
})
if err != nil {
return "", err
}
components, err := digestPathComponents(v.revision, false)
if err != nil {
return "", err
}
return path.Join(root, path.Join(components...)), nil
case layerLinkPathSpec:
components, err := digestPathComponents(v.digest, false)
if err != nil {
return "", err
}
// TODO(stevvooe): Right now, all blobs are linked under "_layers". If
// we have future migrations, we may want to rename this to "_blobs".
// A migration strategy would simply leave existing items in place and
// write the new paths, commit a file then delete the old files.
blobLinkPathComponents := append(repoPrefix, v.name, "_layers")
return path.Join(path.Join(append(blobLinkPathComponents, components...)...), "link"), nil
case blobsPathSpec:
blobsPathPrefix := append(rootPrefix, "blobs")
return path.Join(blobsPathPrefix...), nil
case blobPathSpec:
components, err := digestPathComponents(v.digest, true)
if err != nil {
return "", err
}
blobPathPrefix := append(rootPrefix, "blobs")
return path.Join(append(blobPathPrefix, components...)...), nil
case blobDataPathSpec:
components, err := digestPathComponents(v.digest, true)
if err != nil {
return "", err
}
components = append(components, "data")
blobPathPrefix := append(rootPrefix, "blobs")
return path.Join(append(blobPathPrefix, components...)...), nil
case uploadDataPathSpec:
return path.Join(append(repoPrefix, v.name, "_uploads", v.id, "data")...), nil
case uploadStartedAtPathSpec:
return path.Join(append(repoPrefix, v.name, "_uploads", v.id, "startedat")...), nil
case uploadHashStatePathSpec:
offset := fmt.Sprintf("%d", v.offset)
if v.list {
offset = "" // Limit to the prefix for listing offsets.
}
return path.Join(append(repoPrefix, v.name, "_uploads", v.id, "hashstates", string(v.alg), offset)...), nil
case repositoriesRootPathSpec:
return path.Join(repoPrefix...), nil
default:
// TODO(sday): This is an internal error. Ensure it doesn't escape (panic?).
return "", fmt.Errorf("unknown path spec: %#v", v)
}
}
// pathSpec is a type to mark structs as path specs. There is no
// implementation because we'd like to keep the specs and the mappers
// decoupled.
type pathSpec interface {
pathSpec()
}
// manifestRevisionsPathSpec describes the directory path for
// a manifest revision.
type manifestRevisionsPathSpec struct {
name string
}
func (manifestRevisionsPathSpec) pathSpec() {}
// manifestRevisionPathSpec describes the components of the directory path for
// a manifest revision.
type manifestRevisionPathSpec struct {
name string
revision digest.Digest
}
func (manifestRevisionPathSpec) pathSpec() {}
// manifestRevisionLinkPathSpec describes the path components required to look
// up the data link for a revision of a manifest. If this file is not present,
// the manifest blob is not available in the given repo. The contents of this
// file should just be the digest.
type manifestRevisionLinkPathSpec struct {
name string
revision digest.Digest
}
func (manifestRevisionLinkPathSpec) pathSpec() {}
// manifestTagsPathSpec describes the path elements required to point to the
// manifest tags directory.
type manifestTagsPathSpec struct {
name string
}
func (manifestTagsPathSpec) pathSpec() {}
// manifestTagPathSpec describes the path elements required to point to the
// manifest tag links files under a repository. These contain a blob id that
// can be used to look up the data and signatures.
type manifestTagPathSpec struct {
name string
tag string
}
func (manifestTagPathSpec) pathSpec() {}
// manifestTagCurrentPathSpec describes the link to the current revision for a
// given tag.
type manifestTagCurrentPathSpec struct {
name string
tag string
}
func (manifestTagCurrentPathSpec) pathSpec() {}
// manifestTagCurrentPathSpec describes the link to the index of revisions
// with the given tag.
type manifestTagIndexPathSpec struct {
name string
tag string
}
func (manifestTagIndexPathSpec) pathSpec() {}
// manifestTagIndexEntryPathSpec contains the entries of the index by revision.
type manifestTagIndexEntryPathSpec struct {
name string
tag string
revision digest.Digest
}
func (manifestTagIndexEntryPathSpec) pathSpec() {}
// manifestTagIndexEntryLinkPathSpec describes the link to a revisions of a
// manifest with given tag within the index.
type manifestTagIndexEntryLinkPathSpec struct {
name string
tag string
revision digest.Digest
}
func (manifestTagIndexEntryLinkPathSpec) pathSpec() {}
// blobLinkPathSpec specifies a path for a blob link, which is a file with a
// blob id. The blob link will contain a content addressable blob id reference
// into the blob store. The format of the contents is as follows:
//
// <algorithm>:<hex digest of layer data>
//
// The following example of the file contents is more illustrative:
//
// sha256:96443a84ce518ac22acb2e985eda402b58ac19ce6f91980bde63726a79d80b36
//
// This indicates that there is a blob with the id/digest, calculated via
// sha256 that can be fetched from the blob store.
type layerLinkPathSpec struct {
name string
digest digest.Digest
}
func (layerLinkPathSpec) pathSpec() {}
// blobAlgorithmReplacer does some very simple path sanitization for user
// input. Paths should be "safe" before getting this far due to strict digest
// requirements but we can add further path conversion here, if needed.
var blobAlgorithmReplacer = strings.NewReplacer(
"+", "/",
".", "/",
";", "/",
)
// blobsPathSpec contains the path for the blobs directory
type blobsPathSpec struct{}
func (blobsPathSpec) pathSpec() {}
// blobPathSpec contains the path for the registry global blob store.
type blobPathSpec struct {
digest digest.Digest
}
func (blobPathSpec) pathSpec() {}
// blobDataPathSpec contains the path for the registry global blob store. For
// now, this contains layer data, exclusively.
type blobDataPathSpec struct {
digest digest.Digest
}
func (blobDataPathSpec) pathSpec() {}
// uploadDataPathSpec defines the path parameters of the data file for
// uploads.
type uploadDataPathSpec struct {
name string
id string
}
func (uploadDataPathSpec) pathSpec() {}
// uploadDataPathSpec defines the path parameters for the file that stores the
// start time of an uploads. If it is missing, the upload is considered
// unknown. Admittedly, the presence of this file is an ugly hack to make sure
// we have a way to cleanup old or stalled uploads that doesn't rely on driver
// FileInfo behavior. If we come up with a more clever way to do this, we
// should remove this file immediately and rely on the startetAt field from
// the client to enforce time out policies.
type uploadStartedAtPathSpec struct {
name string
id string
}
func (uploadStartedAtPathSpec) pathSpec() {}
// uploadHashStatePathSpec defines the path parameters for the file that stores
// the hash function state of an upload at a specific byte offset. If `list` is
// set, then the path mapper will generate a list prefix for all hash state
// offsets for the upload identified by the name, id, and alg.
type uploadHashStatePathSpec struct {
name string
id string
alg digest.Algorithm
offset int64
list bool
}
func (uploadHashStatePathSpec) pathSpec() {}
// repositoriesRootPathSpec returns the root of repositories
type repositoriesRootPathSpec struct {
}
func (repositoriesRootPathSpec) pathSpec() {}
// digestPathComponents provides a consistent path breakdown for a given
// digest. For a generic digest, it will be as follows:
//
// <algorithm>/<hex digest>
//
// If multilevel is true, the first two bytes of the digest will separate
// groups of digest folder. It will be as follows:
//
// <algorithm>/<first two bytes of digest>/<full digest>
//
func digestPathComponents(dgst digest.Digest, multilevel bool) ([]string, error) {
if err := dgst.Validate(); err != nil {
return nil, err
}
algorithm := blobAlgorithmReplacer.Replace(string(dgst.Algorithm()))
hex := dgst.Hex()
prefix := []string{algorithm}
var suffix []string
if multilevel {
suffix = append(suffix, hex[:2])
}
suffix = append(suffix, hex)
return append(prefix, suffix...), nil
}
// Reconstructs a digest from a path
func digestFromPath(digestPath string) (digest.Digest, error) {
digestPath = strings.TrimSuffix(digestPath, "/data")
dir, hex := path.Split(digestPath)
dir = path.Dir(dir)
dir, next := path.Split(dir)
// next is either the algorithm OR the first two characters in the hex string
var algo string
if next == hex[:2] {
algo = path.Base(dir)
} else {
algo = next
}
dgst := digest.NewDigestFromHex(algo, hex)
return dgst, dgst.Validate()
}