images, services/images: implement image service

Server and Client images of the image store are now provided. We have
created an image metadata interface and converted the bolt functions to
implement that interface over an transaction. A remote client
implementation is provided that implements the same interface.

Signed-off-by: Stephen J Day <stephen.day@docker.com>

services/images/service.go

@@ -1,32 +1,91 @@
 package images
 
 import (
-	imagesapi "github.com/docker/containerd/api/services/images"
-	"github.com/docker/containerd/images"
+	"github.com/boltdb/bolt"
+	imagesapi "github.com/containerd/containerd/api/services/images"
+	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/plugin"
 	"github.com/golang/protobuf/ptypes/empty"
 	"golang.org/x/net/context"
+	"google.golang.org/grpc"
 )
 
+func init() {
+	plugin.Register("images-grpc", &plugin.Registration{
+		Type: plugin.GRPCPlugin,
+		Init: func(ic *plugin.InitContext) (interface{}, error) {
+			return NewService(ic.Meta), nil
+		},
+	})
+}
+
 type Service struct {
-	store images.Store
+	db *bolt.DB
 }
 
-func NewService(store images.Store) imagesapi.ImagesServer {
-	return &Service{store: store}
+func NewService(db *bolt.DB) imagesapi.ImagesServer {
+	return &Service{db: db}
 }
 
-func (s *Service) Get(context.Context, *imagesapi.GetRequest) (*imagesapi.GetResponse, error) {
-	panic("not implemented")
+func (s *Service) Register(server *grpc.Server) error {
+	imagesapi.RegisterImagesServer(server, s)
+	return nil
 }
 
-func (s *Service) Register(context.Context, *imagesapi.RegisterRequest) (*imagesapi.RegisterRequest, error) {
-	panic("not implemented")
+func (s *Service) Get(ctx context.Context, req *imagesapi.GetRequest) (*imagesapi.GetResponse, error) {
+	var resp imagesapi.GetResponse
+
+	return &resp, s.withStoreTx(ctx, req.Name, false, func(ctx context.Context, store images.Store) error {
+		image, err := store.Get(ctx, req.Name)
+		if err != nil {
+			return mapGRPCError(err, req.Name)
+		}
+		imagepb := imageToProto(&image)
+		resp.Image = &imagepb
+		return nil
+	})
 }
 
-func (s *Service) List(context.Context, *imagesapi.ListRequest) (*imagesapi.ListResponse, error) {
-	panic("not implemented")
+func (s *Service) Put(ctx context.Context, req *imagesapi.PutRequest) (*empty.Empty, error) {
+	return &empty.Empty{}, s.withStoreTx(ctx, req.Image.Name, true, func(ctx context.Context, store images.Store) error {
+		return mapGRPCError(store.Put(ctx, req.Image.Name, descFromProto(&req.Image.Target)), req.Image.Name)
+	})
 }
 
-func (s *Service) Delete(context.Context, *imagesapi.DeleteRequest) (*empty.Empty, error) {
-	panic("not implemented")
+func (s *Service) List(ctx context.Context, _ *imagesapi.ListRequest) (*imagesapi.ListResponse, error) {
+	var resp imagesapi.ListResponse
+
+	return &resp, s.withStoreTx(ctx, "", false, func(ctx context.Context, store images.Store) error {
+		images, err := store.List(ctx)
+		if err != nil {
+			return mapGRPCError(err, "")
+		}
+
+		resp.Images = imagesToProto(images)
+		return nil
+	})
+}
+
+func (s *Service) Delete(ctx context.Context, req *imagesapi.DeleteRequest) (*empty.Empty, error) {
+	return &empty.Empty{}, s.withStoreTx(ctx, req.Name, true, func(ctx context.Context, store images.Store) error {
+		return mapGRPCError(store.Delete(ctx, req.Name), req.Name)
+	})
+}
+
+func (s *Service) withStoreTx(ctx context.Context, id string, writable bool, fn func(ctx context.Context, store images.Store) error) error {
+	tx, err := s.db.Begin(writable)
+	if err != nil {
+		return mapGRPCError(err, id)
+	}
+	defer tx.Rollback()
+
+	if err := fn(ctx, images.NewImageStore(tx)); err != nil {
+		return err
+	}
+
+	if writable {
+		return tx.Commit()
+	}
+
+	return nil
 }