public CommitPoint findCommitPoint(String index, int shardId) throws IOException {
   BlobPath path = BlobStoreIndexGateway.shardPath(basePath, index, shardId);
   ImmutableBlobContainer container = blobStore.immutableBlobContainer(path);
   ImmutableMap<String, BlobMetaData> blobs = container.listBlobs();
   List<CommitPoint> commitPointsList = Lists.newArrayList();
   for (BlobMetaData md : blobs.values()) {
     if (md.length() == 0) { // a commit point that was not flushed yet...
       continue;
     }
     if (md.name().startsWith("commit-")) {
       try {
         commitPointsList.add(CommitPoints.fromXContent(container.readBlobFully(md.name())));
       } catch (Exception e) {
         logger.warn("failed to read commit point at path {} with name [{}]", e, path, md.name());
       }
     }
   }
   CommitPoints commitPoints = new CommitPoints(commitPointsList);
   if (commitPoints.commits().isEmpty()) {
     return null;
   }
   return commitPoints.commits().get(0);
 }