server: split images actions

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

server/image_pull.go

@@ -0,0 +1,82 @@
+package server
+
+import (
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/containers/image/directory"
+	"github.com/containers/image/image"
+	"github.com/containers/image/transports"
+	"golang.org/x/net/context"
+	pb "k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
+)
+
+// PullImage pulls a image with authentication config.
+func (s *Server) PullImage(ctx context.Context, req *pb.PullImageRequest) (*pb.PullImageResponse, error) {
+	logrus.Debugf("PullImage: %+v", req)
+	img := req.GetImage().GetImage()
+	if img == "" {
+		return nil, errors.New("got empty imagespec name")
+	}
+
+	// TODO(runcom): deal with AuthConfig in req.GetAuth()
+
+	// TODO(mrunalp,runcom): why do we need the SandboxConfig here?
+	// how do we pull in a specified sandbox?
+	tr, err := transports.ParseImageName(img)
+	if err != nil {
+		return nil, err
+	}
+	// TODO(runcom): figure out the ImageContext story in containers/image instead of passing ("", true)
+	src, err := tr.NewImageSource(nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	i := image.FromSource(src)
+	blobs, err := i.BlobDigests()
+	if err != nil {
+		return nil, err
+	}
+
+	if err = os.Mkdir(filepath.Join(s.config.ImageDir, tr.StringWithinTransport()), 0755); err != nil {
+		return nil, err
+	}
+	dir, err := directory.NewReference(filepath.Join(s.config.ImageDir, tr.StringWithinTransport()))
+	if err != nil {
+		return nil, err
+	}
+	// TODO(runcom): figure out the ImageContext story in containers/image instead of passing ("", true)
+	dest, err := dir.NewImageDestination(nil)
+	if err != nil {
+		return nil, err
+	}
+	// save blobs (layer + config for docker v2s2, layers only for docker v2s1 [the config is in the manifest])
+	for _, b := range blobs {
+		// TODO(runcom,nalin): we need do-then-commit to later purge on error
+		var r io.ReadCloser
+		r, _, err = src.GetBlob(b)
+		if err != nil {
+			return nil, err
+		}
+		if _, _, err = dest.PutBlob(r, b, -1); err != nil {
+			r.Close()
+			return nil, err
+		}
+		r.Close()
+	}
+	// save manifest
+	m, _, err := i.Manifest()
+	if err != nil {
+		return nil, err
+	}
+	if err := dest.PutManifest(m); err != nil {
+		return nil, err
+	}
+
+	// TODO: what else do we need here? (Signatures when the story isn't just pulling from docker://)
+
+	return &pb.PullImageResponse{}, nil
+}