images

Documentation

Index

• Constants
• Variables
• func Check(ctx context.Context, provider content.Provider, image ocispec.Descriptor, ...) (available bool, required, present, missing []ocispec.Descriptor, err error)
• func Children(ctx context.Context, provider content.Provider, desc ocispec.Descriptor, ...) ([]ocispec.Descriptor, error)
• func Config(ctx context.Context, provider content.Provider, image ocispec.Descriptor, ...) (ocispec.Descriptor, error)
• func Dispatch(ctx context.Context, handler Handler, descs ...ocispec.Descriptor) error
• func Manifest(ctx context.Context, provider content.Provider, image ocispec.Descriptor, ...) (ocispec.Manifest, error)
• func Platforms(ctx context.Context, provider content.Provider, image ocispec.Descriptor) ([]ocispec.Platform, error)
• func RootFS(ctx context.Context, provider content.Provider, configDesc ocispec.Descriptor) ([]digest.Digest, error)
• func Walk(ctx context.Context, handler Handler, descs ...ocispec.Descriptor) error
• type Handler
• type HandlerFunc
  • func ChildrenHandler(provider content.Provider, platform string) HandlerFunc
  • func Handlers(handlers ...Handler) HandlerFunc
  • func (fn HandlerFunc) Handle(ctx context.Context, desc ocispec.Descriptor) (subdescs []ocispec.Descriptor, err error)
• type Image
  • func (image *Image) Config(ctx context.Context, provider content.Provider, platform string) (ocispec.Descriptor, error)
  • func (image *Image) RootFS(ctx context.Context, provider content.Provider, platform string) ([]digest.Digest, error)
  • func (image *Image) Size(ctx context.Context, provider content.Provider, platform string) (int64, error)
• type Store

Constants

const (
	MediaTypeDockerSchema2Layer            = "application/vnd.docker.image.rootfs.diff.tar"
	MediaTypeDockerSchema2LayerForeign     = "application/vnd.docker.image.rootfs.foreign.diff.tar"
	MediaTypeDockerSchema2LayerGzip        = "application/vnd.docker.image.rootfs.diff.tar.gzip"
	MediaTypeDockerSchema2LayerForeignGzip = "application/vnd.docker.image.rootfs.foreign.diff.tar.gzip"
	MediaTypeDockerSchema2Config           = "application/vnd.docker.container.image.v1+json"
	MediaTypeDockerSchema2Manifest         = "application/vnd.docker.distribution.manifest.v2+json"
	MediaTypeDockerSchema2ManifestList     = "application/vnd.docker.distribution.manifest.list.v2+json"
	// Checkpoint/Restore Media Types
	MediaTypeContainerd1Checkpoint        = "application/vnd.containerd.container.criu.checkpoint.criu.tar"
	MediaTypeContainerd1CheckpointPreDump = "application/vnd.containerd.container.criu.checkpoint.predump.tar"
	MediaTypeContainerd1Resource          = "application/vnd.containerd.container.resource.tar"
	MediaTypeContainerd1RW                = "application/vnd.containerd.container.rw.tar"
	MediaTypeContainerd1CheckpointConfig  = "application/vnd.containerd.container.checkpoint.config.v1+proto"
	// Legacy Docker schema1 manifest
	MediaTypeDockerSchema1Manifest = "application/vnd.docker.distribution.manifest.v1+prettyjws"
)

mediatype definitions for image components handled in containerd.

oci components are generally referenced directly, although we may centralize here for clarity.

Variables

var (
	// ErrSkipDesc is used to skip processing of a descriptor and
	// its descendants.
	ErrSkipDesc = fmt.Errorf("skip descriptor")

	// ErrStopHandler is used to signify that the descriptor
	// has been handled and should not be handled further.
	// This applies only to a single descriptor in a handler
	// chain and does not apply to descendant descriptors.
	ErrStopHandler = fmt.Errorf("stop handler")
)

Functions

func Check

func Check(ctx context.Context, provider content.Provider, image ocispec.Descriptor, platform string) (available bool, required, present, missing []ocispec.Descriptor, err error)

Check returns nil if the all components of an image are available in the provider for the specified platform.

If available is true, the caller can assume that required represents the complete set of content required for the image.

missing will have the components that are part of required but not avaiiable in the provider.

If there is a problem resolving content, an error will be returned.

func Children

func Children(ctx context.Context, provider content.Provider, desc ocispec.Descriptor, platform string) ([]ocispec.Descriptor, error)

Children returns the immediate children of content described by the descriptor.

func Config

func Config(ctx context.Context, provider content.Provider, image ocispec.Descriptor, platform string) (ocispec.Descriptor, error)

Config resolves the image configuration descriptor using a content provided to resolve child resources on the image.

The caller can then use the descriptor to resolve and process the configuration of the image.

func Dispatch

func Dispatch(ctx context.Context, handler Handler, descs ...ocispec.Descriptor) error

Dispatch runs the provided handler for content specified by the descriptors. If the handler decode subresources, they will be visited, as well.

Handlers for siblings are run in parallel on the provided descriptors. A handler may return `ErrSkipDesc` to signal to the dispatcher to not traverse any children.

Typically, this function will be used with `FetchHandler`, often composed with other handlers.

If any handler returns an error, the dispatch session will be canceled.

func Manifest

func Manifest(ctx context.Context, provider content.Provider, image ocispec.Descriptor, platform string) (ocispec.Manifest, error)

Manifest resolves a manifest from the image for the given platform.

TODO(stevvooe): This violates the current platform agnostic approach to this package by returning a specific manifest type. We'll need to refactor this to return a manifest descriptor or decide that we want to bring the API in this direction because this abstraction is not needed.`

func Platforms

func Platforms(ctx context.Context, provider content.Provider, image ocispec.Descriptor) ([]ocispec.Platform, error)

Platforms returns one or more platforms supported by the image.

func RootFS

func RootFS(ctx context.Context, provider content.Provider, configDesc ocispec.Descriptor) ([]digest.Digest, error)

RootFS returns the unpacked diffids that make up and images rootfs.

These are used to verify that a set of layers unpacked to the expected values.

func Walk

func Walk(ctx context.Context, handler Handler, descs ...ocispec.Descriptor) error

Walk the resources of an image and call the handler for each. If the handler decodes the sub-resources for each image,

This differs from dispatch in that each sibling resource is considered synchronously.

Types

type Handler

type Handler interface {
	Handle(ctx context.Context, desc ocispec.Descriptor) (subdescs []ocispec.Descriptor, err error)
}

Handler handles image manifests

type HandlerFunc

type HandlerFunc func(ctx context.Context, desc ocispec.Descriptor) (subdescs []ocispec.Descriptor, err error)

HandlerFunc function implementing the Handler interface

func ChildrenHandler

func ChildrenHandler(provider content.Provider, platform string) HandlerFunc

ChildrenHandler decodes well-known manifest types and returns their children.

This is useful for supporting recursive fetch and other use cases where you want to do a full walk of resources.

One can also replace this with another implementation to allow descending of arbitrary types.

func Handlers

func Handlers(handlers ...Handler) HandlerFunc

Handlers returns a handler that will run the handlers in sequence.

A handler may return `ErrStopHandler` to stop calling additional handlers

func (HandlerFunc) Handle

func (fn HandlerFunc) Handle(ctx context.Context, desc ocispec.Descriptor) (subdescs []ocispec.Descriptor, err error)

Handle image manifests

type Image

type Image struct {
	// Name of the image.
	//
	// To be pulled, it must be a reference compatible with resolvers.
	//
	// This field is required.
	Name string

	// Labels provide runtime decoration for the image record.
	//
	// There is no default behavior for how these labels are propagated. They
	// only decorate the static metadata object.
	//
	// This field is optional.
	Labels map[string]string

	// Target describes the root content for this image. Typically, this is
	// a manifest, index or manifest list.
	Target ocispec.Descriptor

	CreatedAt, UpdatedAt time.Time
}

Image provides the model for how containerd views container images.

func (*Image) Config

func (image *Image) Config(ctx context.Context, provider content.Provider, platform string) (ocispec.Descriptor, error)

Config resolves the image configuration descriptor.

The caller can then use the descriptor to resolve and process the configuration of the image.

func (*Image) RootFS

func (image *Image) RootFS(ctx context.Context, provider content.Provider, platform string) ([]digest.Digest, error)

RootFS returns the unpacked diffids that make up and images rootfs.

These are used to verify that a set of layers unpacked to the expected values.

func (*Image) Size

func (image *Image) Size(ctx context.Context, provider content.Provider, platform string) (int64, error)

Size returns the total size of an image's packed resources.

type Store

type Store interface {
	Get(ctx context.Context, name string) (Image, error)
	List(ctx context.Context, filters ...string) ([]Image, error)
	Create(ctx context.Context, image Image) (Image, error)

	// Update will replace the data in the store with the provided image. If
	// one or more fieldpaths are provided, only those fields will be updated.
	Update(ctx context.Context, image Image, fieldpaths ...string) (Image, error)

	Delete(ctx context.Context, name string) error
}

Store and interact with images