serverinit,blobpacked: wipe blobpacked meta before reindexing

Fixes #639

Change-Id: Ic202e4478e4979a29b71404c08c3188cbb3c292b

pkg/blobserver/blobpacked/blobpacked.go

@@ -270,6 +270,22 @@ func newFromConfig(ld blobserver.Loader, conf jsonconfig.Obj) (blobserver.Storag
 	return sto, nil
 }
 
+func WipeMeta(s blobserver.Storage) error {
+	bps, ok := s.(*storage)
+	if !ok {
+		return fmt.Errorf("argument is not blobpacked storage but a %T", s)
+	}
+	wiper, ok := bps.meta.(sorted.Wiper)
+	if !ok {
+		return fmt.Errorf("blobpacked meta storage type %T doesn't support sorted.Wiper", bps.meta)
+	}
+	log.Printf("Wiping blobpacked meta type %T ...", bps.meta)
+	if err := wiper.Wipe(); err != nil {
+		return fmt.Errorf("error wiping blobpacked meta sorted key/value type %T: %v", bps.meta, err)
+	}
+	return nil
+}
+
 func (s *storage) anyMeta() (v bool) {
 	// TODO: we only care about getting 1 row, but the
 	// sorted.KeyValue interface doesn't let us give it that

pkg/serverinit/serverinit.go

@@ -39,6 +39,7 @@ import (
 
 	"camlistore.org/pkg/auth"
 	"camlistore.org/pkg/blobserver"
+	"camlistore.org/pkg/blobserver/blobpacked"
 	"camlistore.org/pkg/blobserver/handlers"
 	"camlistore.org/pkg/httputil"
 	"camlistore.org/pkg/index"
@@ -324,6 +325,13 @@ func (hl *handlerLoader) setupHandler(prefix string) {
 				exitFailure("Error reindexing %s: %v", h.prefix, err)
 			}
 		}
+		// TODO(mpl): make an interface that is "storage that has an internal index" and switch type on it?
+		if h.htype == "storage-blobpacked" && hl.reindex {
+			log.Printf("Wiping %s, because reindexing ...", h.prefix)
+			if err := blobpacked.WipeMeta(pstorage); err != nil {
+				exitFailure("Error wiping %s's meta: %v", h.prefix, err)
+			}
+		}
 		hl.handler[h.prefix] = pstorage
 		if h.internal {
 			hl.installer.Handle(prefix, unauthorizedHandler{})