distribution

README

Distribution

The Docker toolset to pack, ship, store, and deliver content.

This repository's main product is the Docker Registry 2.0 implementation for storing and distributing Docker images. It supersedes the docker/docker- registry project with a new API design, focused around security and performance.

This repository contains the following components:

Component	Description
registry	An implementation of the Docker Registry HTTP API V2 for use with docker 1.6+.
libraries	A rich set of libraries for interacting with,distribution components. Please see godoc for details. Note: These libraries are unstable.
dist	An experimental tool to provide distribution, oriented functionality without the docker daemon.
specifications	Distribution related specifications are available in docs/spec
documentation	Docker's full documentation set is available at docs.docker.com. This repository contains the subset related just to the registry.

How does this integrate with Docker engine?

This project should provide an implementation to a V2 API for use in the Docker core project. The API should be embeddable and simplify the process of securely pulling and pushing content from docker daemons.

What are the long term goals of the Distribution project?

The Distribution project has the further long term goal of providing a secure tool chain for distributing content. The specifications, APIs and tools should be as useful with Docker as they are without.

Our goal is to design a professional grade and extensible content distribution system that allow users to:

• Enjoy an efficient, secured and reliable way to store, manage, package and exchange content
• Hack/roll their own on top of healthy open-source components
• Implement their own home made solution through good specs, and solid extensions mechanism.

More about Registry 2.0

The new registry implementation provides the following benefits:

• faster push and pull
• new, more efficient implementation
• simplified deployment
• pluggable storage backend
• webhook notifications

For information on upcoming functionality, please see ROADMAP.md.

Who needs to deploy a registry?

By default, Docker users pull images from Docker's public registry instance. Installing Docker gives users this ability. Users can also push images to a repository on Docker's public registry, if they have a Docker Hub account.

For some users and even companies, this default behavior is sufficient. For others, it is not.

For example, users with their own software products and may want to maintain an registry for private, company images. Also, you may wish to deploy your own image repository for images used to test or in continuous integration. For these use cases and others, deploying your own registry instance may be the better choice.

Contribute

Please see CONTRIBUTING.md for details on how to contribute issues, fixes, and patches to this project. If you are contributing code, see the instructions for building a development environment.

Support

If any issues are encountered while using the Distribution project, several avenues are available for support:

IRC	#docker-distribution on FreeNode
Issue Tracker	github.com/docker/distribution/issues
Google Groups	https://groups.google.com/a/dockerproject.org/forum/#!forum/distribution
Mailing List	docker@dockerproject.org

License

This project is distributed under Apache License, Version 2.0.

Documentation

Overview

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 README.md.

Index

• Variables
• type Descriptor
• type ErrLayerInvalidDigest
  • func (err ErrLayerInvalidDigest) Error() string
• type ErrManifestUnknown
  • func (err ErrManifestUnknown) Error() string
• type ErrManifestUnverified
  • func (ErrManifestUnverified) Error() string
• type ErrManifestVerification
  • func (errs ErrManifestVerification) Error() string
• type ErrRepositoryNameInvalid
  • func (err ErrRepositoryNameInvalid) Error() string
• type ErrRepositoryUnknown
  • func (err ErrRepositoryUnknown) Error() string
• type ErrUnknownLayer
  • func (err ErrUnknownLayer) Error() string
• type ErrUnknownManifestRevision
  • func (err ErrUnknownManifestRevision) Error() string
• type Layer
• type LayerService
• type LayerUpload
• type ManifestService
• type Namespace
• type Repository
• type Scope
• type SignatureService

Variables

var (
	// ErrLayerExists returned when layer already exists
	ErrLayerExists = fmt.Errorf("layer exists")

	// ErrLayerTarSumVersionUnsupported when tarsum is unsupported version.
	ErrLayerTarSumVersionUnsupported = fmt.Errorf("unsupported tarsum version")

	// ErrLayerUploadUnknown returned when upload is not found.
	ErrLayerUploadUnknown = fmt.Errorf("layer upload unknown")

	// ErrLayerClosed returned when an operation is attempted on a closed
	// Layer or LayerUpload.
	ErrLayerClosed = fmt.Errorf("layer closed")
)

var GlobalScope = Scope(fullScope{})

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

Types

type Descriptor

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

	// Length in bytes of content.
	Length int64 `json:"length,omitempty"`

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

type ErrLayerInvalidDigest

type ErrLayerInvalidDigest struct {
	Digest digest.Digest
	Reason error
}

ErrLayerInvalidDigest returned when tarsum check fails.

func (ErrLayerInvalidDigest) Error

func (err ErrLayerInvalidDigest) Error() string

type ErrManifestUnknown

type ErrManifestUnknown struct {
	Name string
	Tag  string
}

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

func (ErrManifestUnknown) Error

func (err ErrManifestUnknown) Error() string

type ErrManifestUnverified

type ErrManifestUnverified struct{}

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

func (ErrManifestUnverified) Error

func (ErrManifestUnverified) Error() string

type ErrManifestVerification

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

func (errs ErrManifestVerification) Error() string

type ErrRepositoryNameInvalid

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

func (err ErrRepositoryNameInvalid) Error() string

type ErrRepositoryUnknown

type ErrRepositoryUnknown struct {
	Name string
}

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

func (ErrRepositoryUnknown) Error

func (err ErrRepositoryUnknown) Error() string

type ErrUnknownLayer

type ErrUnknownLayer struct {
	FSLayer manifest.FSLayer
}

ErrUnknownLayer returned when layer cannot be found.

func (ErrUnknownLayer) Error

func (err ErrUnknownLayer) Error() string

type ErrUnknownManifestRevision

type ErrUnknownManifestRevision struct {
	Name     string
	Revision digest.Digest
}

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

func (ErrUnknownManifestRevision) Error

func (err ErrUnknownManifestRevision) Error() string

type Layer

type Layer interface {
	// http.ServeContent requires an efficient implementation of
	// ReadSeeker.Seek(0, os.SEEK_END).
	io.ReadSeeker
	io.Closer

	// Digest returns the unique digest of the blob.
	Digest() digest.Digest

	// Length returns the length in bytes of the blob.
	Length() int64

	// CreatedAt returns the time this layer was created.
	CreatedAt() time.Time

	// Handler returns an HTTP handler which serves the layer content, whether
	// by providing a redirect directly to the content, or by serving the
	// content itself.
	Handler(r *http.Request) (http.Handler, error)
}

Layer provides a readable and seekable layer object. Typically, implementations are *not* goroutine safe.

type LayerService

type LayerService interface {
	// Exists returns true if the layer exists.
	Exists(digest digest.Digest) (bool, error)

	// Fetch the layer identifed by TarSum.
	Fetch(digest digest.Digest) (Layer, error)

	// Upload begins a layer upload to repository identified by name,
	// returning a handle.
	Upload() (LayerUpload, error)

	// Resume continues an in progress layer upload, returning a handle to the
	// upload. The caller should seek to the latest desired upload location
	// before proceeding.
	Resume(uuid string) (LayerUpload, error)
}

LayerService provides operations on layer files in a backend storage.

type LayerUpload

type LayerUpload interface {
	io.WriteSeeker
	io.ReaderFrom
	io.Closer

	// UUID returns the identifier for this upload.
	UUID() string

	// StartedAt returns the time this layer upload was started.
	StartedAt() time.Time

	// Finish marks the upload as completed, returning a valid handle to the
	// uploaded layer. The digest is validated against the contents of the
	// uploaded layer.
	Finish(digest digest.Digest) (Layer, error)

	// Cancel the layer upload process.
	Cancel() error
}

LayerUpload provides a handle for working with in-progress uploads. Instances can be obtained from the LayerService.Upload and LayerService.Resume.

type ManifestService

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

	// Get retrieves the identified by the digest, if it exists.
	Get(dgst digest.Digest) (*manifest.SignedManifest, error)

	// Delete removes the manifest, if it exists.
	Delete(dgst digest.Digest) error

	// Put creates or updates the manifest.
	Put(manifest *manifest.SignedManifest) error

	// Tags lists the tags under the named repository.
	Tags() ([]string, error)

	// ExistsByTag returns true if the manifest exists.
	ExistsByTag(tag string) (bool, error)

	// GetByTag retrieves the named manifest, if it exists.
	GetByTag(tag string) (*manifest.SignedManifest, error)
}

ManifestService provides operations on image manifests.

type Namespace

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 string) (Repository, error)
}

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 Repository

type Repository interface {
	// Name returns the name of the repository.
	Name() string

	// Manifests returns a reference to this repository's manifest service.
	Manifests() ManifestService

	// Layers returns a reference to this repository's layers service.
	Layers() LayerService

	// Signatures returns a reference to this repository's signatures service.
	Signatures() SignatureService
}

Repository is a named collection of manifests and layers.

type Scope

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 SignatureService

type SignatureService interface {
	// Get retrieves all of the signature blobs for the specified digest.
	Get(dgst digest.Digest) ([][]byte, error)

	// Put stores the signature for the provided digest.
	Put(dgst digest.Digest, signatures ...[]byte) error
}

SignatureService provides operations on signatures.