Merge pull request #992 from estesp/errrbody-likes-errrrors

Use error interfaces for content/metadata

remotes/docker/pusher.go

@@ -31,7 +31,7 @@ func (p dockerPusher) Push(ctx context.Context, desc ocispec.Descriptor) (conten
 	status, err := p.tracker.GetStatus(ref)
 	if err == nil {
 		if status.Offset == status.Total {
-			return nil, content.ErrExists
+			return nil, content.ErrExists("")
 		}
 		// TODO: Handle incomplete status
 	} else if !content.IsNotFound(err) {
@@ -72,7 +72,7 @@ func (p dockerPusher) Push(ctx context.Context, desc ocispec.Descriptor) (conten
 					// TODO: Set updated time?
 				},
 			})
-			return nil, content.ErrExists
+			return nil, content.ErrExists("")
 		}
 		if resp.StatusCode != http.StatusNotFound {
 			// TODO: log error

remotes/docker/status.go

@@ -34,7 +34,7 @@ func (t *memoryStatusTracker) GetStatus(ref string) (Status, error) {
 	defer t.m.Unlock()
 	status, ok := t.statuses[ref]
 	if !ok {
-		return Status{}, content.ErrNotFound
+		return Status{}, content.ErrNotFound("")
 	}
 	return status, nil
 }