// DescribeLogDirsRequest requests directory information for topic partitions.
// This request was added in support of KIP-113.
DescribeLogDirsRequest => key 35, max version 4, flexible v2+
  // Topics is an array of topics to describe the log dirs of. If this is
  // null, the response includes all topics and all of their partitions.
  Topics: nullable[=>]
    // Topic is a topic to describe the log dir of.
    Topic: string
    // Partitions contains topic partitions to describe the log dirs of.
    Partitions: [int32]

// DescribeLogDirsResponse is returned from a DescribeLogDirsRequest.
DescribeLogDirsResponse =>
  ThrottleMillis(1)
  // The error code, or 0 if there was no error.
  ErrorCode: int16 // v3+
  // Dirs pairs log directories with the topics and partitions that are
  // stored in those directores.
  Dirs: [=>]
    // ErrorCode is the error code returned for describing log dirs.
    //
    // KAFKA_STORAGE_ERROR is returned if the log directory is offline.
    ErrorCode: int16
    // Dir is the absolute path of a log directory.
    Dir: string
    // Topics is an array of topics within a log directory.
    Topics: [=>]
      // Topic is the name of a Kafka topic.
      Topic: string
      // Partitions is the set of queried partitions for a topic that are
      // within a log directory.
      Partitions: [=>]
        // Partition is a partition ID.
        Partition: int32
        // Size is the total size of the log sements of this partition, in bytes.
        Size: int64
        // OffsetLag is how far behind the log end offset is compared to
        // the partition's high watermark (if this is the current log for
        // the partition) or compared to the current replica's log end
        // offset (if this is the future log for the patition).
        //
        // The math is,
        //
        // if IsFuture, localLogEndOffset - futurelogEndOffset.
        //
        // otherwise, max(localHighWatermark - logEndOffset, 0).
        OffsetLag: int64
        // IsFuture is true if this replica was created by an
        // AlterReplicaLogDirsRequest and will replace the current log of the
        // replica in the future.
        IsFuture: bool
    // TotalBytes is the total size in bytes of the volume the log directory is
    // in.
    TotalBytes: int64(-1) // v4+
    // UsableBytes is the usable size in bytes of the volume the log directory
    // is in.
    UsableBytes: int64(-1) // v4+