ea5b999fc0
In support of making the storage API ready for supporting notifications and mirroring, we've begun the process of paring down the storage model. The process started by creating a central Registry interface. From there, the common name argument on the LayerService and ManifestService was factored into a Repository interface. The rest of the changes directly follow from this. An interface wishlist was added, suggesting a direction to take the registry package that should support the distribution project's future goals. As these objects move out of the storage package and we implement a Registry backed by the http client, these design choices will start getting validation. Signed-off-by: Stephen J Day <stephen.day@docker.com>
83 lines
3 KiB
Go
83 lines
3 KiB
Go
package storage
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import (
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"github.com/docker/distribution/digest"
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"github.com/docker/distribution/manifest"
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)
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// TODO(stevvooe): These types need to be moved out of the storage package.
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// Registry represents a collection of repositories, addressable by name.
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type Registry interface {
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// Repository should return a reference to the named repository. The
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// registry may or may not have the repository but should always return a
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// reference.
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Repository(name string) Repository
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}
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// Repository is a named collection of manifests and layers.
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type Repository interface {
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// Name returns the name of the repository.
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Name() string
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// Manifests returns a reference to this repository's manifest service.
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Manifests() ManifestService
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// Layers returns a reference to this repository's layers service.
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Layers() LayerService
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}
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// ManifestService provides operations on image manifests.
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type ManifestService interface {
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// Tags lists the tags under the named repository.
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Tags() ([]string, error)
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// Exists returns true if the manifest exists.
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Exists(tag string) (bool, error)
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// Get retrieves the named manifest, if it exists.
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Get(tag string) (*manifest.SignedManifest, error)
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// Put creates or updates the named manifest.
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// Put(tag string, manifest *manifest.SignedManifest) (digest.Digest, error)
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Put(tag string, manifest *manifest.SignedManifest) error
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// Delete removes the named manifest, if it exists.
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Delete(tag string) error
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// TODO(stevvooe): There are several changes that need to be done to this
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// interface:
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//
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// 1. Get(tag string) should be GetByTag(tag string)
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// 2. Put(tag string, manifest *manifest.SignedManifest) should be
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// Put(manifest *manifest.SignedManifest). The method can read the
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// tag on manifest to automatically tag it in the repository.
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// 3. Need a GetByDigest(dgst digest.Digest) method.
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// 4. Allow explicit tagging with Tag(digest digest.Digest, tag string)
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// 5. Support reading tags with a re-entrant reader to avoid large
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// allocations in the registry.
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// 6. Long-term: Provide All() method that lets one scroll through all of
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// the manifest entries.
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// 7. Long-term: break out concept of signing from manifests. This is
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// really a part of the distribution sprint.
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// 8. Long-term: Manifest should be an interface. This code shouldn't
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// really be concerned with the storage format.
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}
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// LayerService provides operations on layer files in a backend storage.
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type LayerService interface {
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// Exists returns true if the layer exists.
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Exists(digest digest.Digest) (bool, error)
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// Fetch the layer identifed by TarSum.
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Fetch(digest digest.Digest) (Layer, error)
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// Upload begins a layer upload to repository identified by name,
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// returning a handle.
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Upload() (LayerUpload, error)
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// Resume continues an in progress layer upload, returning a handle to the
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// upload. The caller should seek to the latest desired upload location
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// before proceeding.
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Resume(uuid string) (LayerUpload, error)
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}
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