Reduce logging when official v2 registry is unavailable

On pull treat an unavailable v2 registry as a non-error fallback.
On push only show v2 error message in debug mode.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

graph/pull.go

@@ -84,7 +84,7 @@ func (s *TagStore) CmdPull(job *engine.Job) engine.Status {
 				log.Errorf("Error logging event 'pull' for %s: %s", logName, err)
 			}
 			return engine.StatusOK
-		} else if err != registry.ErrDoesNotExist {
+		} else if err != registry.ErrDoesNotExist && err != ErrV2RegistryUnavailable {
 			log.Errorf("Error from V2 registry: %s", err)
 		}
 
@@ -374,6 +374,10 @@ type downloadInfo struct {
 func (s *TagStore) pullV2Repository(eng *engine.Engine, r *registry.Session, out io.Writer, repoInfo *registry.RepositoryInfo, tag string, sf *utils.StreamFormatter, parallel bool) error {
 	endpoint, err := r.V2RegistryEndpoint(repoInfo.Index)
 	if err != nil {
+		if repoInfo.Index.Official {
+			log.Debugf("Unable to pull from V2 registry, falling back to v1: %s", err)
+			return ErrV2RegistryUnavailable
+		}
 		return fmt.Errorf("error getting registry endpoint: %s", err)
 	}
 	auth, err := r.GetV2Authorization(endpoint, repoInfo.RemoteName, true)

graph/push.go

@@ -284,7 +284,7 @@ func (s *TagStore) pushV2Repository(r *registry.Session, eng *engine.Engine, out
 	endpoint, err := r.V2RegistryEndpoint(repoInfo.Index)
 	if err != nil {
 		if repoInfo.Index.Official {
-			log.Infof("Unable to push to V2 registry, falling back to v1: %s", err)
+			log.Debugf("Unable to push to V2 registry, falling back to v1: %s", err)
 			return ErrV2RegistryUnavailable
 		}
 		return fmt.Errorf("error getting registry endpoint: %s", err)