'docker run' can reference an image by REPOSITORY:TAG

graph.go

@@ -35,6 +35,7 @@ func (graph *Graph) Exists(id string) bool {
 }
 
 func (graph *Graph) Get(id string) (*Image, error) {
+	// FIXME: return nil when the image doesn't exist, instead of an error
 	img, err := LoadImage(graph.imageRoot(id))
 	if err != nil {
 		return nil, err

runtime.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path"
 	"sort"
+	"strings"
 	"sync"
 	"time"
 )
@@ -62,15 +63,41 @@ func (runtime *Runtime) containerRoot(id string) string {
 	return path.Join(runtime.repository, id)
 }
 
+func (runtime *Runtime) LookupImage(name string) (*Image, error) {
+	img, err := runtime.graph.Get(name)
+	if err != nil {
+		// FIXME: standardize on returning nil when the image doesn't exist, and err for everything else
+		// (so we can pass all errors here)
+		repoAndTag := strings.SplitN(name, ":", 2)
+		if len(repoAndTag) == 1 {
+			repoAndTag = append(repoAndTag, "")
+		}
+		if i, err := runtime.repositories.GetImage(repoAndTag[0], repoAndTag[1]); err != nil {
+			return nil, err
+		} else if i == nil {
+			return nil, fmt.Errorf("No such image: %s", name)
+		} else {
+			img = i
+		}
+	}
+	return img, nil
+}
+
 func (runtime *Runtime) Create(command string, args []string, image string, config *Config) (*Container, error) {
+	// Lookup image
+	img, err := runtime.LookupImage(image)
+	if err != nil {
+		return nil, err
+	}
 	container := &Container{
 		// FIXME: we should generate the ID here instead of receiving it as an argument
-		Id:              GenerateId(),
-		Created:         time.Now(),
-		Path:            command,
-		Args:            args,
-		Config:          config,
-		Image:           image,
+		Id:      GenerateId(),
+		Created: time.Now(),
+		Path:    command,
+		Args:    args,
+		Config:  config,
+		Image:   img.Id, // Always use the resolved image id
+		//FIXME: store the name under which the image was given, for reference
 		NetworkSettings: &NetworkSettings{},
 		// FIXME: do we need to store this in the container?
 		SysInitPath: sysInitPath,