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package distribution

import ""

Package distribution will define the interfaces for the components of docker distribution. The goal is to allow users to reliably package, ship and store content related to docker images.

This is currently a work in progress. More details are available in the


Package Files

blobs.go doc.go errors.go manifests.go registry.go tags.go


var (
    // ErrBlobExists returned when blob already exists
    ErrBlobExists = errors.New("blob exists")

    // ErrBlobDigestUnsupported when blob digest is an unsupported version.
    ErrBlobDigestUnsupported = errors.New("unsupported blob digest")

    // ErrBlobUnknown when blob is not found.
    ErrBlobUnknown = errors.New("unknown blob")

    // ErrBlobUploadUnknown returned when upload is not found.
    ErrBlobUploadUnknown = errors.New("blob upload unknown")

    // ErrBlobInvalidLength returned when the blob has an expected length on
    // commit, meaning mismatched with the descriptor or an invalid value.
    ErrBlobInvalidLength = errors.New("blob invalid length")
var ErrAccessDenied = errors.New("access denied")

ErrAccessDenied is returned when an access to a requested resource is denied.

var ErrManifestNotModified = errors.New("manifest not modified")

ErrManifestNotModified is returned when a conditional manifest GetByTag returns nil due to the client indicating it has the latest version

var ErrSchemaV1Unsupported = errors.New("manifest schema v1 unsupported")

ErrSchemaV1Unsupported is returned when a client tries to upload a schema v1 manifest but the registry is configured to reject it

var ErrUnsupported = errors.New("operation unsupported")

ErrUnsupported is returned when an unimplemented or unsupported action is performed

var GlobalScope = Scope(fullScope{})

GlobalScope represents the full namespace scope which contains all other scopes.

func ManifestMediaTypes Uses

func ManifestMediaTypes() (mediaTypes []string)

ManifestMediaTypes returns the supported media types for manifests.

func RegisterManifestSchema Uses

func RegisterManifestSchema(mediaType string, u UnmarshalFunc) error

RegisterManifestSchema registers an UnmarshalFunc for a given schema type. This should be called from specific

func UnmarshalManifest Uses

func UnmarshalManifest(ctHeader string, p []byte) (Manifest, Descriptor, error)

UnmarshalManifest looks up manifest unmarshal functions based on MediaType

type BlobCreateOption Uses

type BlobCreateOption interface {
    Apply(interface{}) error

BlobCreateOption is a general extensible function argument for blob creation methods. A BlobIngester may choose to honor any or none of the given BlobCreateOptions, which can be specific to the implementation of the BlobIngester receiving them. TODO (brianbland): unify this with ManifestServiceOption in the future

type BlobDeleter Uses

type BlobDeleter interface {
    Delete(ctx context.Context, dgst digest.Digest) error

BlobDeleter enables deleting blobs from storage.

type BlobDescriptorService Uses

type BlobDescriptorService interface {

    // SetDescriptor assigns the descriptor to the digest. The provided digest and
    // the digest in the descriptor must map to identical content but they may
    // differ on their algorithm. The descriptor must have the canonical
    // digest of the content and the digest algorithm must match the
    // annotators canonical algorithm.
    // Such a facility can be used to map blobs between digest domains, with
    // the restriction that the algorithm of the descriptor must match the
    // canonical algorithm (ie sha256) of the annotator.
    SetDescriptor(ctx context.Context, dgst digest.Digest, desc Descriptor) error

    // Clear enables descriptors to be unlinked
    Clear(ctx context.Context, dgst digest.Digest) error

BlobDescriptorService manages metadata about a blob by digest. Most implementations will not expose such an interface explicitly. Such mappings should be maintained by interacting with the BlobIngester. Hence, this is left off of BlobService and BlobStore.

type BlobDescriptorServiceFactory Uses

type BlobDescriptorServiceFactory interface {
    BlobAccessController(svc BlobDescriptorService) BlobDescriptorService

BlobDescriptorServiceFactory creates middleware for BlobDescriptorService.

type BlobEnumerator Uses

type BlobEnumerator interface {
    Enumerate(ctx context.Context, ingester func(dgst digest.Digest) error) error

BlobEnumerator enables iterating over blobs from storage

type BlobIngester Uses

type BlobIngester interface {
    // Put inserts the content p into the blob service, returning a descriptor
    // or an error.
    Put(ctx context.Context, mediaType string, p []byte) (Descriptor, error)

    // Create allocates a new blob writer to add a blob to this service. The
    // returned handle can be written to and later resumed using an opaque
    // identifier. With this approach, one can Close and Resume a BlobWriter
    // multiple times until the BlobWriter is committed or cancelled.
    Create(ctx context.Context, options ...BlobCreateOption) (BlobWriter, error)

    // Resume attempts to resume a write to a blob, identified by an id.
    Resume(ctx context.Context, id string) (BlobWriter, error)

BlobIngester ingests blob data.

type BlobProvider Uses

type BlobProvider interface {
    // Get returns the entire blob identified by digest along with the descriptor.
    Get(ctx context.Context, dgst digest.Digest) ([]byte, error)

    // Open provides a ReadSeekCloser to the blob identified by the provided
    // descriptor. If the blob is not known to the service, an error will be
    // returned.
    Open(ctx context.Context, dgst digest.Digest) (ReadSeekCloser, error)

BlobProvider describes operations for getting blob data.

type BlobServer Uses

type BlobServer interface {
    // ServeBlob attempts to serve the blob, identified by dgst, via http. The
    // service may decide to redirect the client elsewhere or serve the data
    // directly.
    // This handler only issues successful responses, such as 2xx or 3xx,
    // meaning it serves data or issues a redirect. If the blob is not
    // available, an error will be returned and the caller may still issue a
    // response.
    // The implementation may serve the same blob from a different digest
    // domain. The appropriate headers will be set for the blob, unless they
    // have already been set by the caller.
    ServeBlob(ctx context.Context, w http.ResponseWriter, r *http.Request, dgst digest.Digest) error

BlobServer can serve blobs via http.

type BlobService Uses

type BlobService interface {

BlobService combines the operations to access, read and write blobs. This can be used to describe remote blob services.

type BlobStatter Uses

type BlobStatter interface {
    // Stat provides metadata about a blob identified by the digest. If the
    // blob is unknown to the describer, ErrBlobUnknown will be returned.
    Stat(ctx context.Context, dgst digest.Digest) (Descriptor, error)

BlobStatter makes blob descriptors available by digest. The service may provide a descriptor of a different digest if the provided digest is not canonical.

type BlobStore Uses

type BlobStore interface {

BlobStore represent the entire suite of blob related operations. Such an implementation can access, read, write, delete and serve blobs.

type BlobWriter Uses

type BlobWriter interface {

    // Size returns the number of bytes written to this blob.
    Size() int64

    // ID returns the identifier for this writer. The ID can be used with the
    // Blob service to later resume the write.
    ID() string

    // StartedAt returns the time this blob write was started.
    StartedAt() time.Time

    // Commit completes the blob writer process. The content is verified
    // against the provided provisional descriptor, which may result in an
    // error. Depending on the implementation, written data may be validated
    // against the provisional descriptor fields. If MediaType is not present,
    // the implementation may reject the commit or assign "application/octet-
    // stream" to the blob. The returned descriptor may have a different
    // digest depending on the blob store, referred to as the canonical
    // descriptor.
    Commit(ctx context.Context, provisional Descriptor) (canonical Descriptor, err error)

    // Cancel ends the blob write without storing any data and frees any
    // associated resources. Any data written thus far will be lost. Cancel
    // implementations should allow multiple calls even after a commit that
    // result in a no-op. This allows use of Cancel in a defer statement,
    // increasing the assurance that it is correctly called.
    Cancel(ctx context.Context) error

BlobWriter provides a handle for inserting data into a blob store. Instances should be obtained from BlobWriteService.Writer and BlobWriteService.Resume. If supported by the store, a writer can be recovered with the id.

type CreateOptions Uses

type CreateOptions struct {
    Mount struct {
        ShouldMount bool
        From        reference.Canonical
        // Stat allows to pass precalculated descriptor to link and return.
        // Blob access check will be skipped if set.
        Stat *Descriptor

CreateOptions is a collection of blob creation modifiers relevant to general blob storage intended to be configured by the BlobCreateOption.Apply method.

type Describable Uses

type Describable interface {
    Descriptor() Descriptor

Describable is an interface for descriptors

type Descriptor Uses

type Descriptor struct {
    // MediaType describe the type of the content. All text based formats are
    // encoded as utf-8.
    MediaType string `json:"mediaType,omitempty"`

    // Size in bytes of content.
    Size int64 `json:"size,omitempty"`

    // Digest uniquely identifies the content. A byte stream can be verified
    // against this digest.
    Digest digest.Digest `json:"digest,omitempty"`

    // URLs contains the source URLs of this content.
    URLs []string `json:"urls,omitempty"`

    // Annotations contains arbitrary metadata relating to the targeted content.
    Annotations map[string]string `json:"annotations,omitempty"`

    // Platform describes the platform which the image in the manifest runs on.
    // This should only be used when referring to a manifest.
    Platform *v1.Platform `json:"platform,omitempty"`

Descriptor describes targeted content. Used in conjunction with a blob store, a descriptor can be used to fetch, store and target any kind of blob. The struct also describes the wire protocol format. Fields should only be added but never changed.

func (Descriptor) Descriptor Uses

func (d Descriptor) Descriptor() Descriptor

Descriptor returns the descriptor, to make it satisfy the Describable interface. Note that implementations of Describable are generally objects which can be described, not simply descriptors; this exception is in place to make it more convenient to pass actual descriptors to functions that expect Describable objects.

type ErrBlobInvalidDigest Uses

type ErrBlobInvalidDigest struct {
    Digest digest.Digest
    Reason error

ErrBlobInvalidDigest returned when digest check fails.

func (ErrBlobInvalidDigest) Error Uses

func (err ErrBlobInvalidDigest) Error() string

type ErrBlobMounted Uses

type ErrBlobMounted struct {
    From       reference.Canonical
    Descriptor Descriptor

ErrBlobMounted returned when a blob is mounted from another repository instead of initiating an upload session.

func (ErrBlobMounted) Error Uses

func (err ErrBlobMounted) Error() string

type ErrManifestBlobUnknown Uses

type ErrManifestBlobUnknown struct {
    Digest digest.Digest

ErrManifestBlobUnknown returned when a referenced blob cannot be found.

func (ErrManifestBlobUnknown) Error Uses

func (err ErrManifestBlobUnknown) Error() string

type ErrManifestNameInvalid Uses

type ErrManifestNameInvalid struct {
    Name   string
    Reason error

ErrManifestNameInvalid should be used to denote an invalid manifest name. Reason may set, indicating the cause of invalidity.

func (ErrManifestNameInvalid) Error Uses

func (err ErrManifestNameInvalid) Error() string

type ErrManifestUnknown Uses

type ErrManifestUnknown struct {
    Name string
    Tag  string

ErrManifestUnknown is returned if the manifest is not known by the registry.

func (ErrManifestUnknown) Error Uses

func (err ErrManifestUnknown) Error() string

type ErrManifestUnknownRevision Uses

type ErrManifestUnknownRevision struct {
    Name     string
    Revision digest.Digest

ErrManifestUnknownRevision is returned when a manifest cannot be found by revision within a repository.

func (ErrManifestUnknownRevision) Error Uses

func (err ErrManifestUnknownRevision) Error() string

type ErrManifestUnverified Uses

type ErrManifestUnverified struct{}

ErrManifestUnverified is returned when the registry is unable to verify the manifest.

func (ErrManifestUnverified) Error Uses

func (ErrManifestUnverified) Error() string

type ErrManifestVerification Uses

type ErrManifestVerification []error

ErrManifestVerification provides a type to collect errors encountered during manifest verification. Currently, it accepts errors of all types, but it may be narrowed to those involving manifest verification.

func (ErrManifestVerification) Error Uses

func (errs ErrManifestVerification) Error() string

type ErrRepositoryNameInvalid Uses

type ErrRepositoryNameInvalid struct {
    Name   string
    Reason error

ErrRepositoryNameInvalid should be used to denote an invalid repository name. Reason may set, indicating the cause of invalidity.

func (ErrRepositoryNameInvalid) Error Uses

func (err ErrRepositoryNameInvalid) Error() string

type ErrRepositoryUnknown Uses

type ErrRepositoryUnknown struct {
    Name string

ErrRepositoryUnknown is returned if the named repository is not known by the registry.

func (ErrRepositoryUnknown) Error Uses

func (err ErrRepositoryUnknown) Error() string

type ErrTagUnknown Uses

type ErrTagUnknown struct {
    Tag string

ErrTagUnknown is returned if the given tag is not known by the tag service

func (ErrTagUnknown) Error Uses

func (err ErrTagUnknown) Error() string

type Manifest Uses

type Manifest interface {
    // References returns a list of objects which make up this manifest.
    // A reference is anything which can be represented by a
    // distribution.Descriptor. These can consist of layers, resources or other
    // manifests.
    // While no particular order is required, implementations should return
    // them from highest to lowest priority. For example, one might want to
    // return the base layer before the top layer.
    References() []Descriptor

    // Payload provides the serialized format of the manifest, in addition to
    // the media type.
    Payload() (mediaType string, payload []byte, err error)

Manifest represents a registry object specifying a set of references and an optional target

type ManifestBuilder Uses

type ManifestBuilder interface {
    // Build creates the manifest from his builder.
    Build(ctx context.Context) (Manifest, error)

    // References returns a list of objects which have been added to this
    // builder. The dependencies are returned in the order they were added,
    // which should be from base to head.
    References() []Descriptor

    // AppendReference includes the given object in the manifest after any
    // existing dependencies. If the add fails, such as when adding an
    // unsupported dependency, an error may be returned.
    // The destination of the reference is dependent on the manifest type and
    // the dependency type.
    AppendReference(dependency Describable) error

ManifestBuilder creates a manifest allowing one to include dependencies. Instances can be obtained from a version-specific manifest package. Manifest specific data is passed into the function which creates the builder.

type ManifestEnumerator Uses

type ManifestEnumerator interface {
    // Enumerate calls ingester for each manifest.
    Enumerate(ctx context.Context, ingester func(digest.Digest) error) error

ManifestEnumerator enables iterating over manifests

type ManifestService Uses

type ManifestService interface {
    // Exists returns true if the manifest exists.
    Exists(ctx context.Context, dgst digest.Digest) (bool, error)

    // Get retrieves the manifest specified by the given digest
    Get(ctx context.Context, dgst digest.Digest, options ...ManifestServiceOption) (Manifest, error)

    // Put creates or updates the given manifest returning the manifest digest
    Put(ctx context.Context, manifest Manifest, options ...ManifestServiceOption) (digest.Digest, error)

    // Delete removes the manifest specified by the given digest. Deleting
    // a manifest that doesn't exist will return ErrManifestNotFound
    Delete(ctx context.Context, dgst digest.Digest) error

ManifestService describes operations on image manifests.

type ManifestServiceOption Uses

type ManifestServiceOption interface {
    Apply(ManifestService) error

ManifestServiceOption is a function argument for Manifest Service methods

func WithManifestMediaTypes Uses

func WithManifestMediaTypes(mediaTypes []string) ManifestServiceOption

WithManifestMediaTypes lists the media types the client wishes the server to provide.

func WithTag Uses

func WithTag(tag string) ManifestServiceOption

WithTag allows a tag to be passed into Put

type Namespace Uses

type Namespace interface {
    // Scope describes the names that can be used with this Namespace. The
    // global namespace will have a scope that matches all names. The scope
    // effectively provides an identity for the namespace.
    Scope() Scope

    // Repository should return a reference to the named repository. The
    // registry may or may not have the repository but should always return a
    // reference.
    Repository(ctx context.Context, name reference.Named) (Repository, error)

    // Repositories fills 'repos' with a lexicographically sorted catalog of repositories
    // up to the size of 'repos' and returns the value 'n' for the number of entries
    // which were filled.  'last' contains an offset in the catalog, and 'err' will be
    // set to io.EOF if there are no more entries to obtain.
    Repositories(ctx context.Context, repos []string, last string) (n int, err error)

    // Blobs returns a blob enumerator to access all blobs
    Blobs() BlobEnumerator

    // BlobStatter returns a BlobStatter to control
    BlobStatter() BlobStatter

Namespace represents a collection of repositories, addressable by name. Generally, a namespace is backed by a set of one or more services, providing facilities such as registry access, trust, and indexing.

type ReadSeekCloser Uses

type ReadSeekCloser interface {

ReadSeekCloser is the primary reader type for blob data, combining io.ReadSeeker with io.Closer.

type Repository Uses

type Repository interface {
    // Named returns the name of the repository.
    Named() reference.Named

    // Manifests returns a reference to this repository's manifest service.
    // with the supplied options applied.
    Manifests(ctx context.Context, options ...ManifestServiceOption) (ManifestService, error)

    // Blobs returns a reference to this repository's blob service.
    Blobs(ctx context.Context) BlobStore

    // Tags returns a reference to this repositories tag service
    Tags(ctx context.Context) TagService

Repository is a named collection of manifests and layers.

type RepositoryEnumerator Uses

type RepositoryEnumerator interface {
    Enumerate(ctx context.Context, ingester func(string) error) error

RepositoryEnumerator describes an operation to enumerate repositories

type RepositoryRemover Uses

type RepositoryRemover interface {
    Remove(ctx context.Context, name reference.Named) error

RepositoryRemover removes given repository

type Scope Uses

type Scope interface {
    // Contains returns true if the name belongs to the namespace.
    Contains(name string) bool

Scope defines the set of items that match a namespace.

type TagService Uses

type TagService interface {
    // Get retrieves the descriptor identified by the tag. Some
    // implementations may differentiate between "trusted" tags and
    // "untrusted" tags. If a tag is "untrusted", the mapping will be returned
    // as an ErrTagUntrusted error, with the target descriptor.
    Get(ctx context.Context, tag string) (Descriptor, error)

    // Tag associates the tag with the provided descriptor, updating the
    // current association, if needed.
    Tag(ctx context.Context, tag string, desc Descriptor) error

    // Untag removes the given tag association
    Untag(ctx context.Context, tag string) error

    // All returns the set of tags managed by this tag service
    All(ctx context.Context) ([]string, error)

    // Lookup returns the set of tags referencing the given digest.
    Lookup(ctx context.Context, digest Descriptor) ([]string, error)

TagService provides access to information about tagged objects.

type UnmarshalFunc Uses

type UnmarshalFunc func([]byte) (Manifest, Descriptor, error)

UnmarshalFunc implements manifest unmarshalling a given MediaType

type WithManifestMediaTypesOption Uses

type WithManifestMediaTypesOption struct{ MediaTypes []string }

WithManifestMediaTypesOption holds a list of accepted media types

func (WithManifestMediaTypesOption) Apply Uses

func (o WithManifestMediaTypesOption) Apply(m ManifestService) error

Apply conforms to the ManifestServiceOption interface

type WithTagOption Uses

type WithTagOption struct{ Tag string }

WithTagOption holds a tag

func (WithTagOption) Apply Uses

func (o WithTagOption) Apply(m ManifestService) error

Apply conforms to the ManifestServiceOption interface


referencePackage reference provides a general type to represent any way of referencing images within the registry.

Package distribution imports 11 packages (graph). Updated 2020-04-30. Refresh now. Tools for package owners.