dockerbuild pull on Docker 1.9 is broken

We were incorrectly using tags in Repository. Tested in 1.10 and 1.9 and
this code appears to be correct. Also added more error logging.

Author: smarterclayton

pkg/util/docker/dockerfile/builder/client.go

@@ -117,7 +117,7 @@ func (e *ClientExecutor) Build(r io.Reader, args map[string]string) error {
 			}
 			from, err = e.CreateScratchImage()
 			if err != nil {
-				return err
+				return fmt.Errorf("unable to create a scratch image for this build: %v", err)
 			}
 			defer e.CleanupImage(from)
 		}
@@ -157,7 +157,7 @@ func (e *ClientExecutor) Build(r io.Reader, args map[string]string) error {
 				}
 				v, err := e.Client.CreateVolume(docker.CreateVolumeOptions{Name: volumeName})
 				if err != nil {
-					return err
+					return fmt.Errorf("unable to create volume to mount secrets: %v", err)
 				}
 				defer e.cleanupVolume(volumeName)
 				sharedMount = v.Mountpoint
@@ -181,7 +181,7 @@ func (e *ClientExecutor) Build(r io.Reader, args map[string]string) error {
 		}
 		container, err := e.Client.CreateContainer(opts)
 		if err != nil {
-			return err
+			return fmt.Errorf("unable to create build container: %v", err)
 		}
 		e.Container = container
 
@@ -200,7 +200,7 @@ func (e *ClientExecutor) Build(r io.Reader, args map[string]string) error {
 			})
 		}
 		if err := e.Copy(copies...); err != nil {
-			return err
+			return fmt.Errorf("unable to copy build context into container: %v", err)
 		}
 	}
 
@@ -223,7 +223,7 @@ func (e *ClientExecutor) Build(r io.Reader, args map[string]string) error {
 		}
 
 		if err := e.Client.StartContainer(e.Container.ID, &hostConfig); err != nil {
-			return err
+			return fmt.Errorf("unable to start build container: %v", err)
 		}
 		// TODO: is this racy? may have to loop wait in the actual run step
 	}
@@ -245,7 +245,7 @@ func (e *ClientExecutor) Build(r io.Reader, args map[string]string) error {
 	if mustStart {
 		glog.V(4).Infof("Stopping container %s ...", e.Container.ID)
 		if err := e.Client.StopContainer(e.Container.ID, 0); err != nil {
-			return err
+			return fmt.Errorf("unable to stop build container: %v", err)
 		}
 	}
 
@@ -272,7 +272,7 @@ func (e *ClientExecutor) Build(r io.Reader, args map[string]string) error {
 		Tag:        tag,
 	})
 	if err != nil {
-		return err
+		return fmt.Errorf("unable to commit build container: %v", err)
 	}
 	e.Image = image
 	glog.V(4).Infof("Committed %s to %s", e.Container.ID, e.Image.ID)
@@ -293,7 +293,7 @@ func (e *ClientExecutor) Cleanup() error {
 		Force:         true,
 	})
 	if _, ok := err.(*docker.NoSuchContainer); err != nil && !ok {
-		return err
+		return fmt.Errorf("unable to cleanup build container: %v", err)
 	}
 	e.Container = nil
 	return nil
@@ -389,7 +389,7 @@ func (e *ClientExecutor) LoadImage(from string) (*docker.Image, error) {
 	for _, config := range auth {
 		// TODO: handle IDs?
 		pullImageOptions := docker.PullImageOptions{
-			Repository:    from,
+			Repository:    repository,
 			Tag:           tag,
 			OutputStream:  imageprogress.NewPullWriter(outputProgress),
 			RawJSONStream: true,
@@ -406,7 +406,7 @@ func (e *ClientExecutor) LoadImage(from string) (*docker.Image, error) {
 		continue
 	}
 	if lastErr != nil {
-		return nil, lastErr
+		return nil, fmt.Errorf("unable to pull image (from: %s, tag: %s): %v", repository, tag, lastErr)
 	}
 
 	return e.Client.InspectImage(from)