private def loadNAsync()

in core/src/main/scala/org/apache/pekko/persistence/cassandra/snapshot/CassandraSnapshotStore.scala [124:159]

33 lines of code
9 McCabe index (conditional complexity)


  private def loadNAsync(metadata: immutable.Seq[SnapshotMetadata]): Future[Option[SelectedSnapshot]] = metadata match {
    case Seq() => Future.successful(None) // no snapshots stored
    case md +: mds =>
      load1Async(md)
        .map {
          case DeserializedSnapshot(payload, OptionVal.Some(snapshotMeta)) =>
            Some(SelectedSnapshot(md.withMetadata(snapshotMeta), payload))
          case DeserializedSnapshot(payload, OptionVal.None) =>
            Some(SelectedSnapshot(md, payload))
        }
        .recoverWith {
          case _: NoSuchElementException if metadata.size == 1 =>
            // Thrown load1Async when snapshot couldn't be found, which can happen since metadata and the
            // actual snapshot might not be replicated at exactly same time.
            // Treat this as if there were no snapshots.
            Future.successful(None)
          case e =>
            if (mds.isEmpty) {
              log.warning(
                s"Failed to load snapshot [$md] ({} of {}), last attempt. Caused by: [{}: {}]",
                snapshotSettings.maxLoadAttempts,
                snapshotSettings.maxLoadAttempts,
                e.getClass.getName,
                e.getMessage)
              Future.failed(e) // all attempts failed
            } else {
              log.warning(
                s"Failed to load snapshot [$md] ({} of {}), trying older one. Caused by: [{}: {}]",
                snapshotSettings.maxLoadAttempts - mds.size,
                snapshotSettings.maxLoadAttempts,
                e.getClass.getName,
                e.getMessage)
              loadNAsync(mds) // try older snapshot
            }
        }
  }