Several requirements for storing registry data have been compiled and the
backend layout has been refactored to comply. Specifically, we now store most
data as blobs that are linked from repositories. All data access is traversed
through repositories. Manifest updates are no longer destructive and support
references by digest or tag. Signatures for manifests are now stored externally
to the manifest payload to allow merging of signatures posted at different
time.
The design is detailed in the documentation for pathMapper.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This change updates the path mapper to be able to specify upload management
locations. This includes a startedat file, which contains the RFC3339 formatted
start time of the upload and the actual data file.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
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.
Mostly, we've made superficial changes to the storage package to start using
the Digest type. Many of the exported interface methods have been changed to
reflect this in addition to changes in the way layer uploads will be initiated.
Further work here is necessary but will come with a separate PR.
We've added a path mapper to support simple mapping between path objects used
in the storage layer and the underlying file system. The target of this is to
ensure that paths are only calculated in a single place and their format is
separated from the data that makes up the path components.
This commit only includes spec implementation to support layer reads. Further
specs will come along with their implementations.
