Do not merge: additional support routines for CRI use cases

cri/doc.go

@@ -0,0 +1,5 @@
+// Package cri provides helper functions for creating and managing CRI pod
+// sandboxes and containers and metadata associated with them in the format
+// that ocid understands.  The API it provides should be considered to be
+// unstable.
+package cri

cri/image.go

@@ -0,0 +1,195 @@
+package cri
+
+import (
+	"github.com/containers/image/copy"
+	"github.com/containers/image/signature"
+	istorage "github.com/containers/image/storage"
+	"github.com/containers/image/transports"
+	"github.com/containers/image/types"
+	"github.com/containers/storage/storage"
+)
+
+// ImageResult wraps a subset of information about an image: its ID, its names,
+// and the size, if known, or nil if it isn't.
+type ImageResult struct {
+	ID    string
+	Names []string
+	Size  *uint64
+}
+
+type imageService struct {
+	store            storage.Store
+	defaultTransport string
+}
+
+// ImageServer wraps up various CRI-related activities into a reusable
+// implementation.
+type ImageServer interface {
+	// ListImages returns list of all images which match the filter.
+	ListImages(filter string) ([]ImageResult, error)
+	// ImageStatus returns status of an image which matches the filter.
+	ImageStatus(systemContext *types.SystemContext, filter string) (*ImageResult, error)
+	// PullImage imports an image from the specified location.
+	PullImage(systemContext *types.SystemContext, imageName string, options *copy.Options) (types.ImageReference, error)
+	// RemoveImage deletes the specified image.
+	RemoveImage(systemContext *types.SystemContext, imageName string) error
+	// GetStore returns the reference to the storage library Store which
+	// the image server uses to hold images, and is the destination used
+	// when it's asked to pull an image.
+	GetStore() storage.Store
+}
+
+func (svc *imageService) ListImages(filter string) ([]ImageResult, error) {
+	results := []ImageResult{}
+	if filter != "" {
+		if image, err := svc.store.GetImage(filter); err == nil {
+			results = append(results, ImageResult{
+				ID:    image.ID,
+				Names: image.Names,
+			})
+		}
+	} else {
+		images, err := svc.store.Images()
+		if err != nil {
+			return nil, err
+		}
+		for _, image := range images {
+			results = append(results, ImageResult{
+				ID:    image.ID,
+				Names: image.Names,
+			})
+		}
+	}
+	return results, nil
+}
+
+func (svc *imageService) ImageStatus(systemContext *types.SystemContext, nameOrID string) (*ImageResult, error) {
+	ref, err := transports.ParseImageName(nameOrID)
+	if err != nil {
+		ref2, err2 := istorage.Transport.ParseStoreReference(svc.store, "@"+nameOrID)
+		if err2 != nil {
+			ref3, err3 := istorage.Transport.ParseStoreReference(svc.store, nameOrID)
+			if err3 != nil {
+				return nil, err
+			}
+			ref2 = ref3
+		}
+		ref = ref2
+	}
+	image, err := istorage.Transport.GetStoreImage(svc.store, ref)
+	if err != nil {
+		return nil, err
+	}
+
+	img, err := ref.NewImage(systemContext)
+	if err != nil {
+		return nil, err
+	}
+	size := imageSize(img)
+	img.Close()
+
+	return &ImageResult{
+		ID:    image.ID,
+		Names: image.Names,
+		Size:  size,
+	}, nil
+}
+
+func imageSize(img types.Image) *uint64 {
+	if sum, err := img.Size(); err == nil {
+		usum := uint64(sum)
+		return &usum
+	}
+	return nil
+}
+
+func (svc *imageService) PullImage(systemContext *types.SystemContext, imageName string, options *copy.Options) (types.ImageReference, error) {
+	policy, err := signature.DefaultPolicy(systemContext)
+	if err != nil {
+		return nil, err
+	}
+	policyContext, err := signature.NewPolicyContext(policy)
+	if err != nil {
+		return nil, err
+	}
+	if imageName == "" {
+		return nil, storage.ErrNotAnImage
+	}
+	if options == nil {
+		options = &copy.Options{}
+	}
+	srcRef, err := transports.ParseImageName(imageName)
+	if err != nil {
+		if svc.defaultTransport == "" {
+			return nil, err
+		}
+		srcRef2, err2 := transports.ParseImageName(svc.defaultTransport + imageName)
+		if err2 != nil {
+			return nil, err
+		}
+		srcRef = srcRef2
+	}
+	dest := imageName
+	if srcRef.DockerReference() != nil {
+		dest = srcRef.DockerReference().FullName()
+	}
+	destRef, err := istorage.Transport.ParseStoreReference(svc.store, dest)
+	if err != nil {
+		return nil, err
+	}
+	err = copy.Image(policyContext, destRef, srcRef, options)
+	if err != nil {
+		return nil, err
+	}
+	// Go find the image, and attach the requested name to it, so that we
+	// can more easily find it later, even if the destination reference
+	// looks different.
+	destImage, err := istorage.Transport.GetStoreImage(svc.store, destRef)
+	if err != nil {
+		return nil, err
+	}
+	names := append(destImage.Names, imageName, dest)
+	err = svc.store.SetNames(destImage.ID, names)
+	if err != nil {
+		return nil, err
+	}
+	return destRef, nil
+}
+
+func (svc *imageService) RemoveImage(systemContext *types.SystemContext, nameOrID string) error {
+	ref, err := transports.ParseImageName(nameOrID)
+	if err != nil {
+		ref2, err2 := istorage.Transport.ParseStoreReference(svc.store, "@"+nameOrID)
+		if err2 != nil {
+			ref3, err3 := istorage.Transport.ParseStoreReference(svc.store, nameOrID)
+			if err3 != nil {
+				return err
+			}
+			ref2 = ref3
+		}
+		ref = ref2
+	}
+	return ref.DeleteImage(systemContext)
+}
+
+func (svc *imageService) GetStore() storage.Store {
+	return svc.store
+}
+
+// GetImageService returns an ImageServer that uses the passed-in store, and
+// which will prepend the passed-in defaultTransport value to an image name if
+// a name that's passed to its PullImage() method can't be resolved to an image
+// in the store and can't be resolved to a source on its own.
+func GetImageService(store storage.Store, defaultTransport string) (ImageServer, error) {
+	if store == nil {
+		var err error
+		store, err = storage.GetStore(storage.DefaultStoreOptions)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return &imageService{
+		store:            store,
+		defaultTransport: defaultTransport,
+	}, nil
+}